Fetal & Neonatal: Hematology, Oncology and Immunology MR Lokeshwar, Nitin K Shah, Anupam Sachdeva, Bharat R Agarwal, Mamta Vijay Manglani, Asha Pillai
INDEX
Page numbers followed by f refer to figure, fc refer to flow chart and t refer to table
A
ABO
antibodies 81
blood group system 78
hemolytic disease 78, 81
Absolute neutrophil count 183, 188, 210, 302, 303, 347
Acid-base derangements 297
Acidosis 177
Acne 429, 430, 432
Acquired immune deficiency syndrome 290
Acquired platelet dysfunction, causes of 167
Activated partial thromboplastin time 9, 120, 121, 121fc, 137, 174, 176, 177, 283
Adaptive immune system 318, 321, 330
Addison's disease 409
Adenitis 430
Adenoma 230
Adenosine deaminase 342, 356358
deficiency 358, 358fc, 361, 431
enzyme replacement therapy 363
Adenosine diphosphate 20, 165, 169
receptor defects 166
Adenosine monophosphate, cyclic 16
Adenosine triphosphate 67, 167
Adhesion molecule deficiency 185
Afibrinogenemia 175, 285
Agammaglobulinemia 208, 367, 437
X-linked 345, 366, 367, 369f, 370f, 372f
Aicardi-Goutières syndrome 409
Albinism-neutropenia syndrome 191
Alkaline phosphate 185
Allergic reactions 296
Alloimmune neonatal neutropenia 189, 349
Alpha-1 acid glycoprotein 268
Alpha-1 anti-trypsin deficiency 128
Alpha-2 antiplasmin deficiency 175, 177
Alpha-fetoprotein 379
value references 233t
serum 257
Alpha-gamma storage pool deficiency 175
Alpha-granule disorders 161, 165
Alpha-thalassemia 25, 35, 97, 226
Alport syndrome 163
Altman classification 256f
Alveolar rhabdomyosarcoma 252
congenital 272
Ambiguous lineage, acute leukemia of 226, 227
Amegakaryocytic thrombocytopenia, congenital 108, 157, 159, 160
American Academy of Pediatrics 128
American Joint Committee on Cancer 263
Amniocentesis 445
Amniotic fluid 84
analysis 77
spectrophotometric analysis of 84
Anaplastic large-cell lymphoma 390
Anaplastic lymphoma kinase 239
Anemia 63, 70, 71, 95, 211, 278, 304
aplastic 104
chronic 278
congenital dyserythropoietic 25, 226
dimorphic 67
hemolytic 63, 91
megaloblastic 67
microangiopathic 90, 90f
nonimmune hemolytic 87
nutritional 63, 66fc, 68
pernicious 409
prevention of 68
Angioedema, hereditary 423
Angiosarcoma 230, 234
Angiotensin-converting enzyme inhibitors 288
Aniridia syndrome 245
Antibody
antinuclear 372, 405
deficient disorders 366, 367t
Anticoagulation systems 142f
Antiglobin test 78
Anti-neutrophil antibody-mediated disorders 211
Antiphospholipid syndrome 143, 149
Antithrombin 138, 143
deficiency 142
Antithrombotic therapy 149
Aorta-gonad-mesonephros region 13
APGAR score 65
Apoptosis, X-linked inhibitor of 398
Apoptotic pathways 405f
Arachidonic acid 169
Artemis deficiency 358
Arterial blood gases 113
Artery, umbilical 30
Arthralgia 434
Arthritis 432
pyogenic 429, 430
Arthrogryposis 161
renal dysfunction 165, 166
Ataxia telangiectasia 360, 376, 377, 379, 436
Atresia, esophageal 255
Atypical hemolytic uremic syndrome 418, 421, 425f
Autoimmune
lymphoproliferative syndrome 191, 209, 388, 404, 406
polyendocrinopathy syndrome 409, 409t
Autoimmunity 372, 378, 388
Autoinflammatory
diseases 390, 429f
activity index 434, 434t
disorders 341, 436
syndrome 428431, 433t, 435t
Autosomal dominant 185
inheritance 444
thrombocytopenia 175
Autosomal recessive 389
hypogammaglobulinemia 371
inheritance 444
B
Bacillus calmette-guérin 250, 361, 440
Bacterial sepsis, severe 226
Bacteroides 89
Barium sulphate adsorbed plasma 121
Bart's disease 45
Barth syndrome 208, 211
B-cell 331
activation 323
evaluation 362
Beckwith-Wiedemann syndrome 245
Behçet disease 361
Bernard-Soulier syndrome 20f, 157, 159, 160, 163175, 177
Bicytopenia 209
Bile duct atresia 129
Biliary hypoplasia 128
Bland spindle cells 245
Blau syndrome 429, 430
Bleeding 176, 200, 377
disorders 122
neonate 178fc
tendency 200
time 167, 176
types of 163
Blindness, congenital 45
Blood
components, gamma irradiation of 288
counts, normal 4
group incompatibilities 226
irradiator, dosimetry of 290
loss 277, 278
products 363
sugar 113
transfusion 72
therapy 277
warming of 287
Bloom syndrome 360, 377, 379
Blueberry muffin appearance 226f
Bone marrow 3, 14, 331, 354f
examination 395
failure 157, 348
syndromes 211
hematopoiesis 4
juvenile 5
hypoplasia 177
infiltration 194
Brain
abscess 343f
gamma-aminobutyric acid 65
tumor 217, 220
Bronchial-associated lymphoid tissue 331
Bronchiectasis, management of 438
Bruch's membrane 264
Bruton tyrosine kinase 208, 370f
Buckley disease 438
Burkholderia cepacia 201, 342, 439
Byler disease 129
C
Calcium channels deficiency 360, 361, 383
Campylobacter jejuni 369
Cancer 217
fetal origins of 217
Candida albicans 338
Candida parapsilosis 338
Carboxyhemoglobin 88
Carcinoma 272
hepatocellular 230
Cartilage hair hypoplasia 208, 211, 348, 360, 377, 380, 442
Cell lines, maturation of 50f
Cellular blood components, leukocyte depletion of 288
Central nervous system 71, 103, 113, 157, 218, 225, 244, 270, 393, 402
Central venous catheter 143
occlusion, prophylaxis of 148
Cephalhematoma 119
Cerebellum 65
Cerebral
artery, middle 26, 27, 29, 30, 294
cortex 65
Cernunnos deficiency 359, 361
Charge syndrome 377, 380, 442
Chédiak-Higashi syndrome 161, 164, 165, 191, 199, 200, 200f, 204, 208, 342, 350, 351, 394f, 395f
Chemotaxis, disorders of 199
Chemotherapy 259
Chickenpox 363
Cholestasis syndrome 161
Chorioamnionitis 295
Chorioangioma, placental 25, 294
Choriocarcinoma 230, 257
Chorionic villus sampling 34, 34f, 444, 445
Circle of Willis 26
Citrate phosphate dextrose 295
Classic autoinflammatory syndromes 429
Clear cell sarcoma 244, 246, 252
Clostridium perfringens 89
Clostridium welchii 89
Coagulation tests 137
Cold autoinflammatory, familial 433
Collagen adenosine diphosphate 168
Collagen receptor
defects 166
deficiency 175
Colostrum 332
Combined T-cell and B-cell
defects 354
immunodeficiencies 341, 342, 440
Comèl-Netherton syndrome 377, 383
Complement system 328, 415t
Complete blood cell count 70, 210
Complex regional multifocal osteomyelitis 433
Congenital high airway obstruction syndrome 258
Connective tissue disorders 175
Coombs test 29fc, 77, 78
Cordocentesis 30, 445
Corpus striatum 65
Corticosteroid therapy 185
Corticotropin-releasing hormone 64
C-reactive protein 210
Creutzfeldt-Jakob disease 296
Crigler-Najjar syndrome 45
Cryopyrin-associated periodic syndromes 430, 433, 435
Cryptosporidium 361
Cytokine 14
Cytomegalovirus 70, 77, 155, 211, 226, 295, 296, 339, 361, 384, 390
infection 348
D
Dandy-Walker malformation 255
Dendritic cells 49, 50, 318, 322
Dense granule disorders 161, 165
Dense tubular system 20
Denys-Drash syndrome 245
Deoxyadenosine triphosphate 358
Deoxyribonucleic acid 369, 443
Dermatofibrosarcoma 252
Desmopressin 122, 172
Diabetes mellitus 167, 176
Diamond-Blackfan anemia 102, 108, 226
Dianzani autoimmune lymphoproliferative disease 406
Diaphragmatic hernia, congenital 258
Diarrhea 434
Diencephalic syndrome 221f
Diethylaminoethyl column chromatography 82
Diffuse infantile hepatic hemangioma 231
DiGeorge anomaly 377, 436
DiGeorge syndrome 281, 380, 442
Dihydrorhodamine 202, 204
dye oxidation 351
Disseminated intravascular coagulation 119, 135, 144, 154156, 167, 174, 176178, 284
Dithiothreitol method 82
Double volume exchange transfusion 139
Down syndrome 161, 185, 217, 219, 225227
Duodenal atresia 103
Dysfibrinogenemia 142, 175, 285
Dyskeratosis congenita 106, 383
Dysplasia, immune-osseous 360, 377, 380
Dysproteinemia 167
Dysprothrombinemia 123, 175
E
Ectodermal dystrophy 409
Eczema 378
Edward syndrome 161
Ehlers-Danlos syndrome 163, 175
Elevated liver transaminases 396
Elliptocytosis, hereditary 93
Ellis-Van Creveld syndromes 225
Embryonic arterial cell clusters 3, 4
regulation of 5
Endocrine pancreas 409
Endomitosis 22
Enterobacter aerogenes 419
Enzymatic pathways, disorders of 91
Enzyme-linked immunosorbent assay 296, 382
Ependymoma 222
Epinephrine 185
Epithelial membrane antigen 252
Epsilon aminocaproic acid 172
Epstein's syndromes 159
Epstein-Barr virus 360, 390, 393, 399
Erysipeloid eruption 432
Erythroblast transformation 23
Erythrocyte
sedimentation rate 202, 337
transfusion 185
Erythroid cell maturation 52
Erythropoiesis 6, 6fc, 49, 304f
antenatal 58
developmental 49
embryonic development of 49
primitive 5
transcriptional regulation of 51
Erythropoietin 23, 49, 59, 66, 70, 91, 153, 298, 303, 304, 307, 307t
stimulating agents 303
Escherichia coli 89, 190, 210, 328, 333, 336, 347, 349, 419
Ethylenediaminetetraacetic acid 28, 30
Ewing's protocol 248
Ewing's sarcoma 250
Extracorporeal membrane oxygenation 167, 277
Extraembryonic yolk sac 3
F
Facial anomalies 377, 379
Fanconi anemia 102, 103f, 103t, 104f, 104t, 105f, 158, 159, 161, 175
Febrile nonhemolytic transfusion reactions 288
Fechtner's syndromes 159
Ferrous fumarate 67
Ferrous gluconate 67
Ferrous glycine sulfate 67
Ferrous succinate 67
Fetal
albumin 268
anemia 25, 26, 27, 30fc, 31, 294
causes of 25, 294
management of 294
blood
sampling 77, 84, 445
typing 76
bone marrow hematopoiesis, regulation of 5
bradycardia, transient 295
effects 64
erythropoiesis 303
gene therapy 45
germ cell tumors 254
hematological disorders 43
hematopoiesis 3, 4t, 6
hemoglobin 4, 6, 25, 26, 49, 58, 109
hereditary persistence of 39
hydrops 259
immunity 325
kell blood group 44
liver 3
myeloid series 299
stem cell therapy 44
therapy 44, 77
umbilical cord 29
Fetomaternal transfusion 59
Fever 394, 403, 431, 434
Fibrin degradation products 8, 135, 180
Fibrinogen 137, 142, 176
Fibrinolytic pathway 125
Fibronectins 333
Fibrosarcoma 252, 253
infantile 252
Fibrosis, cystic 128
Fils syndrome 377
Fistula, arteriovenous 25
Flavonoids 225
Flow cytometry 168, 397, 445
Fluorescent in situ hybridization 226
Focal infantile hepatic hemangioma 230, 231f
Focal nodular hyperplasia 230, 232
Folate
deficiencies 68
metabolism 377, 383
Folic acid deficiency 67
Free fatty acids 268
Fresh frozen plasma 137, 138, 210, 283, 284, 296
use of 284
Fungal
infections 338
sepsis 211
Furazolidone 95
G
Gamma granule deficiency 175
Gamma-glutamyl carboxylase 124
Gamma-thalassemia 97
Ganglioneuroblastoma 239, 241
Ganglioneuroma 239, 241
Ganulocytes, development of 7fc
Gaslini diagnostic score 432
Gastric
acidity 328
mucosa 409
secretions 328
Gastrointestinal
syndromes, acquired 217
tract 327, 409
Gaucher-type histiocytes 185
Gene
competition 54
therapy 363
Genetics 201
disorders 112
testing 38, 265
Germ cell tumor 254, 258
abdominal 256, 259
fetal 258
intracranial 256
mediastinal 256
neonatal 258
Germinoma 257
Giant
cytoplasmic granules 200f
platelets 156
Giardia lamblia 369
Glanzmann's thrombasthenia 163, 164, 169, 175
Gliomas, low-grade 222
Globin loci 49
Glomerulonephritis, membranoproliferative 418
Glucose 6-phosphate dehydrogenase
classes of 94t
deficiency 25, 91, 94, 203
Glucose phosphate isomerase deficiency 96
Glutathione
metabolism, disorders of 96
synthetase deficiency 350
Glycogen storage disease 45, 208, 211, 302
Glycolipids 333
Glycoprotein 169, 298, 333
Gonadal germ cell tumor 256
Graft-versus-host disease 288, 325, 361
transfusion associated 281, 296
Granule deficiency 201f
Granulocyte 13, 6fc
colony stimulating factor 14, 106, 185, 189, 211, 298, 303, 334, 347
role of 350
macrophage colony stimulating factor 14, 298, 319, 334
monocyte colony stimulating factor 185, 347
myeloid progenitor 50
transfusion 203, 279
Granulomatous disease, chronic 16, 201, 204, 338, 350, 439, 440, 444
Granulopoiesis 13, 13fc
Graves’ disease 334
Gray platelet syndrome 157, 159, 163, 165
Griscelli disease 208
Griscelli syndrome 343f, 394, 395f
H
Haemophilus influenzae 333, 336, 366, 369, 373, 374, 381, 420
Hamartoma, mesenchymal 230, 232, 232f
Head and neck
germ cell tumors 255
squamous cell carcinoma 104
Headache 434
Heart 103
disease, congenital 144
Heat instability test 99f
Heinz bodies 91, 99f
Hemangioblasts 21
Hemangioendothelioma, infantile hepatic 230
Hemangioma 25, 159
infantile 230
Hematological disorders, inherited 38
Hematopoiesis 3, 50
embryonic 50
physiology of 3
primitive 50
regulation of 4
Hematopoietic stem cell 3, 4, 6, 21, 44, 49, 50f, 326
transplantation 173, 190, 362, 363, 441
Hemoglobin 4, 7, 36, 59, 59t, 88, 106
electrophoresis, role of 35
Hemolysis 87
causes of 87, 88
intrinsic causes of 87, 91
Hemolytic
anemia, autoimmune 361
disease 27, 79, 81, 177, 294, 348
uremic syndrome, complement-mediated 424
Hemophagocytes 396f
Hemophagocytic lymphohistiocytosis
familial 342, 344, 345, 389, 398, 398fc, 439
genetics of 392
primary 391f
revised 399t
secondary 390t
treatment of 400
Hemophagocytosis 404
Hemophilia 122
A 45, 119
B 45
C 124, 175
Hemorrhage
antenatal 176
fetomaternal 25, 31, 294
gastrointestinal 176
intracranial 120, 130, 176
intrathoracic 25
intraventricular 176, 305
periventricular 284
pulmonary 176, 177
transplacental 83
Hemorrhagic disease 120, 127
Hemostasis 8
developmental 8
physiology of 8
primary 9, 175
secondary 9
Henoch-Schönlein purpura 418
Heparin 138, 146
unfractionated 146, 147t, 148
Hepatic hemangioma, asymptomatic focal 231
Hepatic veno-occlusive disease 377, 384
Hepatitis 128
autoimmune 409
B 296
C 296
viruses 296
Hepatoblastoma 230, 232, 233f, 272
Hereditary angioedema 420, 422
Hermansky-Pudlak syndrome 161, 164, 165
Herpes 226
simplex virus 339, 382, 390
Hexokinase deficiency 96
High performance liquid chromatography 33, 41, 97
Hip, congenital dislocation of 255
Histiocytic disorders 226
Hodgkin's disease 272
Hodgkin's lymphoma 404
Homovanillic acid 242
Human
chorionic gonadotropin 258
immunodeficiency virus 63, 226, 290, 296, 332, 390
leukocyte antigen 43, 106, 164, 281, 325, 359, 438
megakaryocyte growth 24
papillomavirus 106, 382
platelet antigen 179
protein C 139
T-cell lymphotropic virus 359
Hyperbilirubinemia 88, 113, 392
Hyperimmunoglobulin
D syndrome 429, 433, 435
E syndromes 381, 438
M syndrome 438
Hyperkalemia 296, 297
Hyperleukocytosis 226
Hyperlipidemia 396
Hypertension 176
pregnancy-induced 208, 348
Hypertriglyceridemia 403
Hyperviscosity syndrome 111, 113
Hypofibrinogenemia 177, 403
Hypogammaglobulinemia 209
transient 367, 373
Hypoglycemia 296, 297
Hypoparathyroidism 409
Hypoprothrombinemia 123
Hypospadias reflux 255
Hypothalamus 65
Hypothryoidism 409
Hypoxia 96, 155, 177
Hypoxic ischemic encephalopathy 309
I
Ichthyosiform 432
Idiopathic dense-granule
deficiency 164
disorder 165
Idiopathic thrombocytopenic purpura 23, 155
Immune
cells 327
deficiency syndromes 390
dysregulation 388
diseases of 341, 344
syndromes 387, 387t
hemolytic disease 74, 76
neutropenia 193
system 317, 318
aberrations of 317
development of 326, 326t
function of 317
organs of 318, 331
thrombocytopenia 371
Immunity
cell-mediated 326
cellular 344
In vitro fertilization 35, 177
Infantile cancers, management of 218
Infections 14, 89, 144, 176, 177, 192, 377
congenital 155
prevention of 363
Innate immune system 318, 319, 327
role of 428
Innate lymphoid cells 319f
development of 319fc
International Fanconi Anemia Registry 102, 104
International Neuroblastoma 240
Staging System 220, 240, 240t
International Society of Pediatric Oncology Liver Tumor Study Group 233
International Union of Immunological Societies 341, 377, 389
Interstitial lung disease 431
Intestinal atresia, multiple 377
Intrauterine
fetal blood transfusion 26, 2830
growth restriction 154, 176
infection 32, 89
platelet transfusion 295
transfusion 83, 294, 295
Intravenous immunoglobulin 77, 179, 160, 211, 212, 367, 437
replacement therapy 363
Iron
deficiency anemia, treatment of 66
inhibitors 67
requirement 64
therapy 72
Ischemia, hypoxic 135
Isovaleric acidemia 159
Itch deficiency 408
J
Jacobsen syndrome 159, 165, 442
Janus-associated kinase 356, 357
Jaundice 95
Job's syndrome 377, 438
Joints, swelling of 434
K
Kaposi's sarcoma 272, 361
Kasabach-Merritt syndrome 90, 156, 159, 161, 176, 177
Ketotic glycinemia 159
Klebsiella pneumoniae 336
Klippel-Feil syndromes 225
Kostmann syndrome 208, 209, 348
Kupffer cells 328
L
Lactate dehydrogenase 241, 258
Lactation 64
Langerhans cell histiocytosis 226
Lectin-binding pathway deficiency 420
Leiomyosarcoma 252
Leishmania 400
Leucine-rich repeat containing receptors 320
Leukemia 5, 104, 194, 217, 218, 225, 226, 230, 270, 272
acute 226f
lymphoblastic 218
myeloid 228
neonatal 226
Leukemoid reaction 186
Leukocyte
adhesion defect 198, 199, 199t, 204, 338, 350, 351
management of 198
adhesion deficiency 185, 439, 440
depletion 288
Leukoplakia 107f
Liley's chart 27
Liley's curve 84
modified 84f, 85f
Lipoblastoma 253
Lipodystrophy 432
Lipopolysaccharide 14, 16, 328
Lipoprotein 143
Liposarcoma 253
myxoid 252
Listeria monocytogenes 332, 336
Liver 4, 409
disease 167, 176, 177
extrarenal rhabdoid tumor of 235f
failure 177
hematopoiesis 4
regulation of 5
infantile choriocarcinoma of 234
tumors, benign 235
Low-molecular-weight heparin 146, 147t, 148
Lung
disease, chronic 305
injury, acute 285, 296
Lymph nodes 331
draining 250
Lymphoblastic leukemia, acute 104, 143, 217, 218, 225, 227
Lymphocyte 6fc, 354
Lymphohistiocytosis, hemophagocytic 157, 191, 194, 209, 211, 226, 344, 389, 390, 393, 394, 397399, 399t, 400, 401f, 402f, 403fc
Lymphoid organs
primary 318
secondary 318
Lymphoid tissue 331
gut-associated 331
nasopharynx-associated 331
skin associated 331
Lymphoma 194, 272, 408
Lymphopenia 344
Lymphopoiesis, primary 354f
Lymphoproliferative syndrome, X-linked 393, 406
M
Macroglobulinemia 112
Macrophage 318, 333
activation syndrome 390, 398
colony-stimulating factors 299
Macrothrombocytopenia 175
X-linked 159
Malaria 63, 89, 296
Marfan syndrome 163, 175
Marrow failure syndrome 209
Mast cells 330
Maternal
alloimmunization 25, 75
management of 77
antibody testing 76
antithyroid-stimulating hormone receptor 334
autoantibodies 175
blood grouping 76
hemorrhage 176
hypertension 348
hypoferremia 65
immune thrombocytopenic purpura 175
rash 176
systemic lupus erythematosus 175
May-Hegglin anomaly 157, 159, 160, 175
May-Hegglin syndrome 163
Mean corpuscular
hemoglobin 33, 60, 60t, 67, 92
concentration 60t
volume 33, 60, 60t, 67, 87, 88
Measles 363
Mediterranean fever, familial 199, 428, 429, 433, 435
Medulloblastoma 222
Megakaryoblastic leukemia, acute 219
Megakaryocyte 19, 19f, 21
cell biology 24
maturation 21, 22
Membrane attack complex 415, 416
Mental
development index 279, 309
retardation 103
Metabolic disorders 159
Metamyelocytes 89f
Methylene tetrahydrofolate reductase polymorphism 143
Microbicidal metabolism, disorders of 201
Microphthalmia 103
Migratory erythema 432
Mixed lineage leukemia 217, 225
Molluscum contagiosum 377
Monocytes 6fc
development of 7fc
Mononuclear cells 14
Montreal platelet syndrome 159
Moraxella catarrhalis 366, 373, 374
Morbilliform rash 432
Muckle-Wells syndrome 430, 430f
Mucocutaneous candidiasis, chronic 342, 409, 409t, 436
Multifocal infantile hepatic hemangioma 231, 231f
Multiple coagulation factors, hereditary deficiency of 124
Mumps 363
Myalgia 434
Mycobacteria 361
Mycobacterial diseases 342, 342f, 345
Mycobacterium avium 342
Mycobacterium bovis 339
Mycophenolate mofetil 407, 424
Myelocytes 89f
Myelodysplastic syndrome 167, 190
Myelofibrosis 5
Myelogenous leukemia, acute 159
Myeloid leukemia
acute 23, 104, 219, 225, 227
chronic 52
Myeloma, multiple 112
Myelomonocytic leukemia, juvenile 227, 228, 396
Myeloperoxidase deficiency 202, 350, 351
Myelopoiesis 299f
Myeloproliferative disorder 167, 228
N
Nalidixic acid 95
Naphthalene 95
National Neonatal Perinatal Database 135, 336
Natural killer cells 53, 75, 327, 330, 341, 389, 391, 398
Nausea 434
Necrosis 245
Necrotizing enterocolitis 78, 89, 154, 178, 179, 189, 278, 284, 303, 305, 309, 348
Neisseria meningitides 33, 373, 419
Neonatal
acute lymphoblastic leukemia 227f
alloimmune
neutropenia 207
thrombocytopenia 154, 158, 175, 177, 179
bone marrow 15
cell-mediated responses 331
erythropoiesis 303
gastrointestinal tract 327
germ cell tumor 254, 257, 259
granulocytes 16t
hemolysis 88
hemophagocytic lymphohistiocytosis 399
hemostasis 10
immune
neutropenia 193
system 337
immunity 325, 327
infections 155
intensive care unit 113, 125, 135, 153, 183, 188, 272, 303, 338
jaundice 91
leukemia 225, 226
development of 225
liver tumor 230, 230t
malignant 232
malignancies 270
megakaryopoiesis 153
myeloid series 299
necrotizing enterocolitis 328
neutropenia 195
causes of 189t
immune mediated 349
neutrophils 15
quantitative insufficiency of 15
onset multisystem inflammatory disease 432
polycythemia 111
polymorphonuclear leukocyte 300
sepsis 17, 89, 89f, 300, 327, 336
soft tissue sarcomas 250
thrombocytopenia 153, 154, 159
causes of 154
tumors 271, 272t
distribution of 270t
Wilms’ tumor 246
Nephroblastomatosis 244, 247
Nephroma
cystic 244, 247
mesoblastic 244, 245, 245t
Neuroblastoma 217, 219, 226, 230, 234, 238, 239, 239f, 270, 272
familial 239
infantile 220f
intrarenal 247
Neutropenia 188, 189, 191, 192, 194, 206, 207, 210, 347, 348, 369
antibody-mediated 349
autoimmune 189, 193, 207, 211, 348, 349, 361
causes of 207, 211t, 348
chronic benign 193
congenital 211
cyclic 190, 208, 211, 348, 349
drug-induced 189, 192, 211, 350
familial benign 191
idiopathic 189, 211
severe congenital 109, 190, 303fc, 342
symptoms of 188
Neutrophil 208, 318, 329
antibodies 194
chemotaxis 350
development of 14
dysfunction 350, 351
extracellular traps 16
function defects 198, 203fc, 204
disorders 204t
immunodeficiency syndrome 186
morphology 207
number, disorders of 348
progenitors, infection of 211
reference range of 183f
Neutrophilia 183, 185
causes of 185
hereditary 185, 186
mechanism of 183
Next generation sequencing technique 44, 446
Nicotinamide adenine dinucleotide phosphate 94, 329
Nijmegen breakage syndrome 360, 377, 379
Nitroblue tetrazolium 345
dye reduction test 351
Nodular regenerative hyperplasia 371
Non-Hodgkin's lymphoma 404
Nonrhabdomyosarcoma soft tissue tumors 253
Nonsteroidal anti-inflammatory drugs 164, 218
Noonan syndrome 226228
North American Survey 104
Northern Neonatal Nursing Initiative Trial Group 283
Novel erythropoiesis stimulating protein 310
Nucleotide oligomerization domain 320, 321
O
Omenn syndrome 338, 342, 358, 361, 436, 442
Omphalitis 343f
Opportunistic infections, management of 363
Oral
cavity 369f
polio 363
vaccine 440
ulcer 419f
Organic acidemias 211, 348
Osmotic fragility test 93
Ossifying renal tumor 244, 247
Osteogenesis imperfecta 163, 175
P
Packed red blood cells 210, 295
transfusion 277, 278
Pain
abdominal 434
chest 434
Paralytic poliomyelitis, vaccine-associated 342
Parathyroid glands 409
Paris-Trousseau syndrome 159, 165, 169
Paroxysmal nocturnal hemoglobinuria 418, 421
management of 424
Partial volume exchange transfusion 114
Parvovirus 70
B19 infection 294
Patau syndrome 161
Peak systolic velocity 26, 29, 30
Pegademase bovine 363
Pelger-Huët anomaly 186
Pentraxins 319
Peptides, antimicrobial 319, 327, 329
Perinatal sepsis 155
Periodic fevers 430
Periodontitis, juvenile 350
Peyer's patches 190
Phagocytic defects 343, 345
Pharyngitis 430
Phenazopyridine 95
Phosphatidylserine 166
Phosphofructokinase deficiency 96
Phosphoglycerate kinase deficiency 96
Phosphorus, deficiency of 67
Placenta previa 176
Placental red cell transfusion 112
Plasma 283284
albumin 268
globulin 268
transfusion 284, 285
Plasminogen activator inhibitor deficiency 175
Plasmodium falciparum 90
Plasmodium vivax 90
Platelet 19, 50, 137
antibody-induced platelet dysfunction 167
count 176, 280
developmental
aspects of 19
pathway of 21fc
disorders, severe 172
dysfunction 164, 172
formation 22
function 20
analyzer 168, 168t, 281
defects 163, 169
disorders 172, 177, 179
test 170t
granule disorders 164
hemostatic function 167, 168
neutralization procedure 121
nucleotide assays 168
number 167
production, exogenous stimulation of 24
receptors, disorders of 166
structure 20
transfusion 172, 179t, 280
Pleomorphic spindle cell neoplasm 251t
Pneumatocele 381
Pneumocystis carinii 377, 438
Pneumocystis jirovecii 338, 339, 342, 361, 384, 408, 438
pneumonia 362, 384
Polycythemia 111, 144
hyperviscosity, pathophysiology of 112fc
medical management of 113
Polymerase chain reaction 30, 217, 339, 390
Pompe disease 45
Portal hypertension, idiopathic noncirrhotic 371
Portal vein thrombosis 144
Primary immunodeficiency 336, 354, 436, 440t
diseases 366
disorders 341, 342, 376, 387, 417, 441, 444
Properdin deficiency 419
Prostaglandins 334
Prosthetic cardiac valves 144
Protease inhibitors 333
Proteins 327
antimicrobial 329
C deficiency 142, 143
S deficiency 142
zeta chain-associated 357
Prothrombin 142
complex concentrate 122, 131, 284
deficiency 123
time 9, 120, 131, 174, 176, 178, 283
Pseudomonas aeruginosa 89, 366
Pseudoxanthoma elasticum 163
Psoriasis 361
Purine nucleoside phosphorylase 342, 357, 359
deficiency 359, 361
Purpura fulminans 139f
Pyknocytosis, infantile 90
Pyoderma gangrenosum 429, 430, 432
Pyridoxine, deficiency of 67
Pyruvate kinase deficiency 25, 91, 95
Q
Qualitative platelet defects, treatment of 172
Quebec platelet syndrome 166
Queenan curve 85f
R
Raccoon eyes 239
Radius syndrome 160
Ranitidine 211
Rash 432
erythematous 419f
Red blood cell 4, 25, 59t, 61t, 63, 81, 87, 207, 409
alloimmunization 25
normal 60f
Red cell
adenosine deaminase 108
components 291f
count 60
indices 60
Refractory disease 403
Renal tumors 230, 244, 244t
Renal vein thrombosis 177
Respiratory distress syndrome 179
Respiratory syncytial virus 339
Reticular dysgenesis 189, 209, 211, 348, 349, 358, 361
Reticulocyte 61f
count 60, 113
hemoglobin 68
Retinoblastoma 217, 222, 263265
heritable 264
Retinocytoma 264
Retinoma 264
Rh blood group system 74
Rh hemolytic disease 82
Rh isoimmunization 74
Rhabdoid tumor 222, 230
malignant 234, 244, 246
Rhabdomyosarcoma 230, 251, 252
congenital 226
Rhesus disease, severe 176
Rheumatoid arthritis, juvenile 390
Rotavirus 363
Rubella 226
infection 348
S
Sacrococcygeal teratoma 254, 255, 255f, 256f, 259
Sarcoma
embryonal 230, 234
epithelioid 252
hepatic 230
high grade 251f
Scalp 409
Schimke immunoosseous dysplasia 381
Schimke syndrome 377
Sclerosing cholangitis 129
Scott syndrome 166
Sebastian's syndromes 159
Selective immunoglobulin A deficiency 372
Seminoma 257
Sepsis 135, 176, 177, 185, 189
Septicemia 348
Serositis 361
Serratia marcescens 439
Serum alfa-fetoprotein values, normal range of 258t
Serum glutamic pyruvic transaminase 396
Severe Chronic Neutropenia International Registry 102, 190
Shwachman-Diamond syndrome 102, 108, 191, 348, 349
Sickle cell 98f
anemia 5, 98
disease 40, 98
Simpson-Golabi-Behmel syndrome 245
Sjögren syndrome 361
Skin 409
hypopigmentation 200
immune system 327
pigmentation 103
abnormal 107f
rash 434
Soft tissue
neoplasms 251
sarcomas 250, 252, 252t
swelling 250, 250f
Solid tumors 104, 219
Specific granule deficiency 200, 204, 350
Spherocytosis, hereditary 25, 91, 92f
Spina bifida 255
Spindle cell sarcoma, nonpleomorphic 252t
Spleen 331
Splenectomy 173, 408
Splenic follicles 190
Staphylococcus aureus 188, 210, 300, 336, 338, 342, 347, 349, 366, 374, 381, 439
Staphylococcus epidermidis 210
Stem cell
factor 51, 299
transplant 105, 401f, 402f
Stomach 409
Stomatitis, aphthous 430
Stomatocytosis, hereditary 94
Storage pool diseases 169
Streptococcus pneumoniae 89, 333, 366, 369, 373, 374, 381, 420, 423
infections 419
Streptococcus pyogenes 369, 373
Stress erythropoiesis 5
Sulfacetamide 95
Sulfamethoxazole 95
Sulfanilamide 95
Sulfapyridine 95
Syndromic thrombocytopenia, causes of 159
Synovial sarcoma 250f, 251f, 252
Syphilis 70, 226
Systemic lupus erythematosus 155, 361, 390, 417, 419f
T
T-cell 330, 354
activation 322
defects 443
evaluation 362
function 362
lineage development 357f
lymphopenia, Secondary 442
receptor excision circles 362, 370, 442f
Teratoma 230
hepatic 232
Tertiary lymphoid organs 318
Tetralogy of Fallot 185
Thalassemia 5
homozygous 294
Thiazides 211
Thiazolesulfone 95
Thrombocytopenia 90f, 155, 159, 160, 176178
absent radii 109, 175
amegakaryocytic 185
autoimmune 177, 361
congenital 384, 376, 377
heparin induced 144, 175
inherited 156, 157
X-linked 159, 376, 378
Thromboembolism, prophylaxis of 149
Thrombophilia 141
heritable 141, 142t
Thrombopoietin 22, 298
Thrombosis 143
management of 148
Thrombotic thrombocytopenic purpura 154, 361
Thymic defects 377, 380
Thymus 331
cells 354
Thyroid gland 409
Tissue plasminogen activator 8
Toll-like receptor 15, 320, 327, 328, 329t, 338
Tonsillar fossa 369f
TORCH infections 177, 185
Total iron binding capacity 68
Total parenteral nutrition 218, 307
Toxoplasmosis 226
Transfusion transmitted infections 296
Trauma 144, 167
Triose phosphate isomerase deficiency 96
Tumor
cells 251
hypothalamic 221f
malignant 272
markers 257
mediastinal 259
necrosis factor 319, 356, 429
Turner syndromes 225
Twin-twin transfusion
donors of 348
syndrome 25, 31, 112, 226, 348
Typical radial ray deformity 104f
U
Umbilical
cord, hematoma of 295
stump, infection of 343f
vessels, treatment of 59
United Kingdom Dyskeratosis Congenita Registry 10
Uridine diphosphoglucuronosyl transferase gene 95
Urinary plasminogen activator 8
Urticarial rash 430f, 432
V
Varicella zoster virus 382
Vascular endothelial growth factor 5
Vasculitis 361
Vein, umbilical 30
Velocardiofacial syndrome 159, 160, 384
Vesicoureteric reflux 255
Vibrio cholera 333
Video-assisted thoracic surgery 259
Viral infections 176, 211, 296, 338, 390
postnatal 89
Vitamin
A, deficiency of 67
B12 68
defects of 377, B12 383
C, deficiency of 67
E deficiency 90, 91
K 124
antagonists 147, 148
K deficiency 119, 127, 133, 175, 177
bleeding 127, 133, 174, 175, 177
K dependent
clotting factors deficiency 120, 124
coagulation factors 174
proteins, carboxylation of 129
K, role of 129
Vitiligo 409
Vomiting 434
von Willebrand disease 119, 159, 163, 168, 169, 175, 177, 285
von Willebrand factor 21, 120, 122, 142, 160, 163, 174
W
WAGR syndrome 245
Warts 209
Wasp interacting protein deficiency 378
Whim syndrome 191, 209
White blood cells 6, 198
Whole blood transfusion 277
Wilms’ tumor 217, 244247
syndrome 245
Winged-Helix-Nude deficiency 359, 362
Wiskott-Aldrich syndrome 109, 157, 159, 169, 175, 177, 208, 211, 281, 338, 342, 343, 350, 360, 376378, 423, 436, 438, 444
Witebsky's partial neutralization test 82
Wright-Giemsa stain 161
X
Xanthogranuloma, juvenile 226
Y
Yolk sac
hematopoiesis 35
tumors 230, 254
Z
Zinc
deficiency of 67
protoporphyrin 68
×
Chapter Notes

Save Clear


1Fetal Hematology and Antenatal Diagnosis of Hematological Disorders
Section Editors
Anupam Sachdeva, Shubha R Phadke
  • Physiology of Hematopoiesis
    Vinod Gunasekaran, Anupam Sachdeva
  • Developmental Hemostasis and Physiology of Hemostasis in the Fetus and the Newborn
    Shrimati Shetty
  • Granulocytes: Development and Physiology
    Tulika Seth
  • Developmental Aspects of Platelets
    Sangeeta Mudaliar
  • Fetal Anemia
    Meenal Agarwal
  • Thalassemia in the Fetus: Prenatal Diagnosis
    Prajnya Ranganath
  • Genetic Counseling for Hematological Disorders
    Roshan Colah, Khushnooma Italia
  • Fetal Hematological Disorders: Future Ahead
    Shubha R Phadke

Physiology of HematopoiesisChapter 1

Vinod Gunasekaran,
Anupam Sachdeva
 
INTRODUCTION
Hematopoiesis is an integral part in the growth process of embryo into fetus and later into an adult. It is essential for survival of fetus and to produce hematopoietic stem cells, which later contributes to hematopoiesis throughout the life. In the fetus, the blood cells are the first among the different cell types to become functionally mature. Erythroid cells are the first among the blood cells to be seen in the conceptus. Throughout the fetal development, hematopoiesis occurs in multiple sites before getting shifted to the final sites (bone marrow and thymus).1 The synthesis occurs in waves beginning in the extraembryonic yolk sac early in the fetal life, later involving arterial cell clusters before migrating to fetal liver and finally seeding the bone marrow. The initial blood cells synthesized have limited progenitor activity, while the definitive adult-type hematopoietic stem cells (HSCs) have multi-lineage differentiation. The hemoglobin produced in early fetal development also differs from that of adult hemoglobin. This chapter discusses these physiological processes in detail.
 
STEPS IN FETAL HEMATOPOIESIS
The fetal hematopoiesis occurs sequentially in four structures as follows and is illustrated in Flow chart 1.1:
  1. Extraembryonic yolk sac
  2. Embryonic arterial cell clusters
  3. Fetal liver
  4. Bone marrow.
 
Yolk Sac Hematopoiesis (Mesoblastic Phase)
Fetal hematopoiesis first starts in the mesoderm of extra embryonic yolk sac (seen as blood islands attached to vascular endothelium).2 These are seen as early as 16 days of embryonic development. The cells initially produced here are primitive erythroid cells, macrophages and megakaryocytes.1 At 4.5 weeks of development, various clonogenic progenitors of these series of cells have been documented. Fetal cardiac activity and blood circulation starts at day 21 of development. Yolk sac hematopoiesis totally disappears after 6–8 weeks of gestation. Thus, this phase is short lived (16 days–8 weeks of gestation) as compared to birds and rodents.2
 
Embryonic Arterial Cell Clusters
Previously, it was thought that the yolk sac generated stem cells seed fetal liver and bone marrow and is the sole source of hematopoiesis throughout the adult life. But, it has been observed that as the embryo matures, the major arteries in embryo, yolk sac and placenta produce HSCs.
At 27th day, these are first detected attached to aorta, and are seen in increased numbers by 35th day to finally disappear by 40th day.2 Precursors of aorta (splanchnopleura) are intrinsically found to be capable of generating HSCs on 19th day (i.e. prior to onset of blood circulation), thereby confirming the embryonic origin rather than the migratory HSCs from yolk sac.
zoom view
Flow chart 1.1: Ontogeny of hematopoiesis in humans from embryo to adult life
Abbreviation: HSCs: hematopoietic stem cells
4Also these cells are exclusively capable of generating B- and T-lymphocytes unlike the yolk sac derived cells. The HSCs do not differentiate further in these sites rather they migrate to fetal liver, bone marrow and thymus for further differentiation.2
In both yolk sac and embryonic origin of HSCs, these arise in proximity to vascular endothelium, thereby leading to a postulation that a common precursor angiohematopoietic cell (hemangioblast) differentiates into hematopoietic as well as vascular endothelial cells. Recently, human placenta in first trimester has been found to be niche which supports the terminal differentiation of primitive erythroid cells along with interactions from macrophages.
 
Liver Hematopoiesis (Hepatic Phase)
As the blood circulation is established, these HSCs from yolk sac reaches the embryo and seed the fetal liver first from where hematopoiesis occur till the seeding of bone marrow occurs later. Liver is embryologically derived from the endodermal diverticulum of foregut and the mesodermal structure septum transversum (starting from 22nd day of gestation). At 23rd day, first hepatic colonization is said to occur by CD34 negative erythromyeloid cells. A 2nd colonization occurs at 30th day by CD34+ late stage progenitors (derived from embryonic arterial cell clusters), after which liver is able to sustain hematopoiesis (by 32nd day). Embryo–to–fetal hemoglobin switch including the shift in synthesis of ε chains to α and γ chains occur in the liver. However, recent studies have shown that definitive erythropoiesis occurs as a second wave in yolk sac as well.1
 
Bone Marrow Hematopoiesis (Myeloid Phase)
In bone marrow, hematopoiesis starts from 11th week (10.5 weeks) of gestation. Primary logettes are specialized mesenchymal structures in marrow from where it occurs. The niche supporting these cells comprises of fibrillar material and osteoblasts. Myeloid series are the earliest to differentiate followed by erythroid cells. CD34+ HSCs are however initially absent in the bone marrow and are acquired later which are capable of sustaining hematopoiesis all through the life. At birth, the hematopoiesis is predominant in marrow.3 The fetus contains HbFα2 γ2 (90%) and HbAα2β2 (5–10%).4 Fetal hemoglobin (HbF) has a left-shifted oxygen dissociation curve (high affinity to oxygen), facilitating oxygen delivery to fetus from the placenta.3 Adult hemoglobin (HbA) is first detected in fetal circulation at 13th week.3 But the fetal-to-adult switch in hemoglobin production (HbF → HbA) starts at around 32 weeks of gestation and is completed shortly after birth.1 In circulation, this process is largely complete by 6 months of postnatal life.4 HbA at birth is around 20–30% of the total Hb.3 A normal adult has HbA (97%), HbA2α2δ2 (2.5%) and HbF (0.5%).4
 
NORMAL BLOOD COUNTS IN FETUS
Over a period of time (from 18th week to 30th week of gestation), parameters including white cell count (4.68 × 109/L–7.71 × 109/L), hemoglobin (11.69–13.64 g%), hematocrit (HCT) and red blood cell (RBC) count progressively increases whereas mean corpuscular volume decreases from 131 fL to 114 fL. Platelet count remains comparable to adult values throughout this time. The platelet counts are also found to increase from 32 weeks of gestation till birth and continues to rise during the first 9 weeks after birth to a level of around 7,50,000/µL. These platelets in neonates are however found to be hyporesponsive to agonists with decreased granule secretion and expression of fibrinogen binding sites for the initial 2–4 weeks of life.5 Differential count shows lymphocyte predominance (80%) throughout this time.6 The time points of significant events in fetal hematopoiesis are summarized in Table 1.1.
Table 1.1   Important time points in fetal hematopoiesis
Gestational age
Event
16 days
Yolk sac hematopoiesis starts
19 days
Splanchnopleura capable of initiating hematopoiesis
21 days
Fetal cardiac activity starts
22 days
Liver development starts
23 days
First hepatic colonization occurs (CD34–cells)
27 days
Embryonic arterial cell clusters first detected around aorta
30 days
Second hepatic colonization occurs (CD34+ late stage progenitors)
32 days
Liver can sustain hematopoiesis
4–5 weeks
Peak yolk sac hematopoiesis seen
35 days
Embryonic arterial cell clusters seen in maximum
40 days
Embryonic arterial cell clusters totally disappears
6–8 weeks
Yolk sac hematopoiesis disappears
8–9 weeks
Platelets first seen in circulation
10.5 weeks
Bone marrow hematopoiesis starts (from primary logettes)
13 weeks
HbA first detected in circulation
32 weeks
Fetal-to-adult Hb switch (HbF HbA) starts
 
REGULATION OF HEMATOPOIESIS
Unlike most other organs, bone marrow has to continuously regenerate hematopoietic elements throughout the life, even when introduced into another host. This capacity of the bone marrow forms the basis for blood donations and administration of myelosuppressive chemotherapy in malignancies. It is also this phenomenon which has formed the basis of hematopoietic stem cell transplantation in the recent years. This continuous renewal occurs in sequential steps of maturation and differentiation from a multipotent stem cell. During progressive steps, this cell gets committed to definite cell lineages. This process occurs in stroma and is regulated by a variety of growth factors and hormones. Hematopoietic stem cells (HSCs) are also regulated by 5signals from neighboring cells during the continuous self-renewal process. This microenvironment is called the niche. HSCs differentiate to wide variety of hematopoietic elements including erythrocytes, platelets, granulocytes (eosinophil, basophils and neutrophils), lymphocytes (T, B and NK cells), monocyte-macrophage system, dendritic cells and mast cells. Any derangements in the niche of hematopoiesis lead to wide range of pathological conditions including anemia, neutropenia, thrombocytopenia, pancytopenia and leukemia.
 
Regulation of Yolk Sac Hematopoiesis
The visceral endoderm layer of yolk sac regulates mesoblastic phase of hematopoiesis by secreting certain factors including Indian Hedgehog and vascular endothelial growth factor (VEGF). GATA4, a transcription factor is essential for differentiation of visceral endoderm.7 Absence of this factor leads to inability to form blood cell islands in this phase. The primitive erythroid progenitors express receptors for stem cell factor (named c-Kit), transforming growth factor-β, erythropoietin, angiopoietin and VEGF, thereby making these factors regulate hematopoiesis.
 
Regulation of Embryonic Arterial Cell Clusters
The tissues located ventrally to dorsal aorta are found to support HSCs. This niche supports hematopoiesis through cytokines, soluble factors and physical anchorage. Some of these factors include Flt3 ligand, stem cell factor and interleukin-3 (IL-3).7 Catecholamines also exert influence via sympathetic nerves around arteries located here.
 
Regulation of Liver Hematopoiesis
The HSCs in fetal liver is supported by a niche consisting of sinusoidal endothelial cells, stromal fibroblasts, macrophages and hepatoblasts. Secretory factors including stem cell factor, IL-6, IL-7, erythropoietin and thrombopoietin secreted by hepatoblasts regulate this phase.7 HSCs adhere to sinusoidal endothelial cells which help in orientation of HSCs and in mitosis. Liver macrophages form a microenvironment called erythroblastic island and help in engulfing the nuclei expelled by the erythroid precursors. A central macrophage is surrounded by a mixed type of cells along with erythroid precursors to form this erythroblastic island, providing a niche for erythropoiesis.
 
Regulation of Fetal Bone Marrow Hematopoiesis
The long bones develop from mesodermal progenitors initially as cartilaginous bone templates that later get vascularized and form epiphyseal plates. Along with vascular endothelial cells (that form blood vessels), osteoblasts also occupy the bone marrow cavity and play a key role in the establishment of fetal bone marrow niche for HSCs. The process of HSCs homing the marrow and starting hematopoiesis is regulated by chemotactic factors (CXCL12 and its receptor CXCR4 along with other associated molecules).7 Animal studies have shown that mutation of these factors leads to clinical condition with normal liver hematopoiesis but defective homing of bone marrow with HSCs.
 
Regulation of Neonatal and Juvenile Bone Marrow Hematopoiesis
Like any other organ, bone marrow also needs to adapt to the profound physiological changes that occur after birth. Onset of breathing leading to changes in oxygen content of blood and exposure to external environment leading to immune system activation are the major changes to tackle by the neonatal bone marrow. The exact changes in bone marrow niche are not exactly delineated yet.7 Recognition of increased calcium ions released by the bone matrix is a crucial step. As the ossification process ensues with age, preserving a niche for lifelong hematopoiesis is essential which is regulated by transcription factors.
 
Regulation of Adult Bone Marrow Hematopoiesis
In an adult bone, HSCs are seen predominantly in metaphyseal regions, but also in diaphyseal and epiphyseal regions. They are localized in two distinct niches in endosteal region (close to bone) and in perivascular region (close to arterioles). HSCs are adherent to osteoblasts which supports hematopoiesis. The role of osteoclasts in hematopoiesis is controversial. The endosteal niche is regulated by various cytokine signaling and cell adhesion molecules. The HSCs in perivascular niche is supported by the surrounded mesenchymal type cells. These mesenchymal cells secrete stem cell factor, CXCL12 thereby regulating hematopoiesis. Megakaryocytes and thrombopoietin are also found to be essential for normal hematopoiesis.7 As aging occurs, hematopoietic cells in the bone marrow are gradually replaced by yellow adipose tissue in selected areas. This adipose tissue has been found to have an inhibitory effect on the HSCs.
 
STRESS ERYTHROPOIESIS
In the postnatal life, erythropoiesis is usually restricted to bone marrow. But under anemic stress including blood loss, hemolysis (sickle cell anemia, thalassemia), infiltrative conditions (leukemia, myelofibrosis), the erythroid precursors home the extramedullary organs (spleen and liver) and begins erythropoiesis. Erythroblastic islands are formed here. This clinically manifests with splenomegaly and hepatomegaly.
 
ERYTHROID LINEAGE DIFFERENTIATION
 
Primitive Erythropoiesis
For a short duration of around 48 hours, the hematopoiesis in yolk sac is predominated by primitive erythroid cells.1 These are large nucleated cells. The differentiated elements of these cells are detected in the circulation even after birth though in a minority. Gastrulation is a developmental step in 6embryo in which a single-layered blastula is reorganized into a three-layered gastrula (having ectoderm, mesoderm and endoderm). The mesoderm gives rise to primitive erythroid cells. Various transcriptional factors (GATA1, EKLF/KLF1, etc.), signaling from the endoderm, TGF-β and Wnt/β catenin signaling pathways regulate initiation and further differentiation.1 Macrophages are the first blood cells to appear in fetal circulation, whereas neutrophils are the last to appear.6 Platelets are first seen at 8–9 weeks of gestation.6 The primitive erythroid cells differ from the definitive erythroid cells (produced later in fetal liver and bone marrow). They possess different globin genes with different O2 carrying capacity and also differ in response to hypoxia, cytokines and various regulatory pathways. These cells synthesize embryonic hemoglobins (having ζ and ε chains). These include Hb Portland (ζ 2γ2), Hb Gower I (ζ 2 ε2) and Hb Gower II(α2ε2).4 These primitive cells are also found to retain the nucleus within circulation till around mid-gestation after which the mature enucleated cells circulate till shortly after birth.1 This is in contrast to the definitive eythroid cells which get enucleated before being released in the circulation. The nucleated primitive cells in circulation undergo maturation after reaching fetal liver. The proerythroblast develops to orthochromatic erythroblast and later into reticulocyte (after enucleation). Macrophages nurse these cells and phagocytose the expelled nuclei. Their lifespans are similar to that of definitive erythroid cells and are destroyed later by spleen.1
 
Definitive Erythropoiesis
The first definitive erythrocytes are released from the fetal liver. Simultaneously, the hemogloblin synthesis is switched to HbF/HbA containing α, β and γ globin chains. The maturation of HSCs to erythrocytes occurs in serial steps with commitment into specific lineages and maturation occurring at various stages.8 The stages of development erythropoiesis and thrombopoiesis are depicted in Flow chart 1.2.
 
DIFFERENTIATION OF WHITE BLOOD CELLS
The differentiation of white blood cells from HSCs is depicted in Flow chart 1.3. The various precursors of granulocytes and monocytes formed in the bone marrow during the development process are illustrated in Flow chart 1.4.
 
CLINICAL SIGNIFICANCE OF FETAL HEMATOPOIESIS
  • In β-thalassemia, as a result of decreased or absent β-chain synthesis, HbF levels are persistently increased beyond 6 months of age. These are not due to compensatory rise in HbF, but because of survival advantage of RBCs with HbFα2γ2
  • In case of deletion of whole genes encoding β- or δ-globin chains, variable increase in γ chain production occur leading to two different clinical conditions (hereditary persistence of fetal hemoglobin (HPFH) (with no anemia due to sufficient γ chain production) and δβ thalassemia (with moderately severe anemia due to insufficient γ chain production)4
zoom view
Flow chart 1.2: Steps in erythropoiesis and thrombopoiesis
Abbreviation: HSCs, hematopoietic stem cells
zoom view
Flow chart 1.3: Differentiation process of granulocytes, lymphocytes and monocytes
Abbreviations: CFU, colony-forming unit; HSCs, hematopoietic stem cells
  • Fetal hemoglobin is elevated in adults in conditions like chemotherapy induced marrow aplasia, recovery from iron deficiency anemia, aplastic anemia (congenital or acquired), sickle cell anemia, thalassemia intermedia, HPFH, δβ thalassemia, etc.7
zoom view
Flow chart 1.4: Stages in development of granulocytes and monocytes
 
KEY POINTS
  • Hematopoiesis occurs in different waves during fetal life (mesoblastic, embryonic arterial cell clusters, hepatic and myeloid phases)
  • In yolk sac, primitive hematopoiesis starts at 16 days and disappears by 6–8 weeks of gestation
  • Primitive erythropoiesis produces RBCs with embryonal hemoglobin [Hb Portland (ζ2γ2), Hb Gower I (ζ2ε2) and Hb Gower II (α2ε2)].
  • Fetal liver starts definitive hematopoiesis by 32nd day of gestation.
  • Bone marrow starts hematopoiesis by 10.5 weeks of gestation and continues throughout the life
  • Fetal-to-adult switch in hemoglobin synthesis starts by 32 weeks of gestation and is largely complete by birth
  • The fetus contains HbFα2γ2 (90%) and HbAα2β2 (5–10%)
  • In circulation, adult hemoglobin (HbA) accounts for 20–30% of total hemoglobin at birth and reaches the adult value of around 97% by 6 months of age.
  • Differentiation of HSCs is regulated by various mechanisms including stem cell factor, Indian hedgehog signaling, chemokines (CXCL12 and CXCR4), erythropoietin and thrombopoietin along with the surrounding cellular niche.
REFERENCES
  1. Baron MH, Isern J, Fraser ST. The embryonic origins of erythropoiesis in mammals. Blood. 2012;119(21):4828–37.
  1. Tavian M, Peault B. Embryonic development of the human hematopoietic system. Int J Dev Biol. 2005;49:243–50.
  1. Finne PH, Halvorsen S. Regulation of Erythropoiesis in the Fetus and Newborn. Arch Dis Childhood. 1972;47:683–7.
  1. Wood WG, Weatherall DJ. Developmental genetics of the human haemoglobins. Biochem J. 1983;215:1–10.
  1. Revel-Vilk S. The conundrum of neonatal coagulopathy. Hematology Am Soc Hematol Educ Program. 2012;2012:450–4.
  1. Forestier F, Daffos F, Catherine N, Renard M, Andreux JP. Developmental Hematopoiesis in Normal Human Fetal Blood. Blood. 1991;77(11):2360–3.
  1. Al-Drees MA, Yeo JH, Boumelhem BB, Antas VI, Brigden KW, Colonne CK, et al. Making Blood: The Haematopoietic Niche throughout Ontogeny. Stem Cells Int. 2015;2015:571893.
  1. Dzierzak L, Philipsen S. Erythropoiesis: development and differentiation. Cold Spring Harb Perspect Med. 2013:1;3(4): a011601.