Benign B-cell precursors (hematogones) are the predominant lymphoid population in the bone marrow of preterm infants.
Bone marrow (BM) findings in 3rd-trimester stillborns and full-term living neonates have been previously described. However, there is no information regarding BM composition in living preterm infants. Specifically, it is unknown whether the BM lymphocytosis seen in full-term infants at 1-4 weeks of age also occurs in preterm infants. Furthermore, the lineage of these cells has never been investigated. We used a panel of immunohistochemical stains to characterize the BM composition in 11 neonates (8 living and 3 deceased). Unlike in the other age groups, immature B cells (hematogones) were the most common lymphoid population, accounting for 10-60% (mean 34%) of all cells. In two additional cases (both living patients), flow cytometry revealed a level of 3.8% of immature B cells in a <1-week-old neonate and 25.7% in a 19-week-old infant. Immature B cells were not identified in 6 peripheral blood samples from preterm neonates. These findings are pertinent for the interpretation of BM and peripheral blood samples in this age group as survival improves and diagnostic samples become more common.
Department of Pathology, College of Medicine, University of Arizona, Tucson, AZ 85724, USA. rimsza@ahsc.arizona.edu
Lisa M
LM
Rimsza
Vonda K
VK
Douglas
Patrick
P
Tighe
Matthew A
MA
Saxonhouse
Darlene A
DA
Calhoun
Robert D
RD
Christensen
Martha C
MC
Sola
D015703:Antigens, CD / Q000032:analysis; D018941:Antigens, CD19 / Q000032:analysis; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology; D001854:Bone Marrow Cells / Q000166:cytology*; D017252:CD3 Complex / Q000032:analysis; D051925:CD79 Antigens; D005434:Flow Cytometry; D005865:Gestational Age; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D007231:Infant, Newborn; D007234:Infant, Premature; D017493:Leukocyte Common Antigens / Q000032:analysis; D018655:Lymphocyte Count; D015260:Neprilysin / Q000032:analysis; D011947:Receptors, Antigen, B-Cell / Q000032:analysis
D015703:Antigens, CD; D018941:Antigens, CD19; D017252:CD3 Complex; D051925:CD79 Antigens; C497881:CD79A protein, human; D011947:Receptors, Antigen, B-Cell; D017493:Leukocyte Common Antigens; D015260:Neprilysin