Flow cytometric analysis of fetal hemoglobin in erythroid precursors of beta-thalassemia.
Fetal hemoglobin (HbF), the major hemoglobin species in fetal life, drops to <1% in normal adults, where it is restricted to a few 'F-cells', which may increase in various acquired and genetic conditions, including thalassemia. Using flow cytometry, we studied the percentage of HbF-containing cells and their HbF content in RBC, reticulocytes (retics) and normoblasts (NRBC) present in the peripheral blood of patients with beta-thalassemia. Thiazol orange, a nucleic acid-specific dye, and anti-CD45 antibodies identified the various blood cells and antihuman HbF antibodies quantitated HbF. The results indicated that F-RBC were more numerous in beta-thalassemic (both transfused and nontransfused) patients than in normal donors, but, in most cases, their HbF content was comparable, suggesting that increased HbF in thalassemia is mainly due to higher %F-cells rather than an increased HbF per cell. Among the retics, the %F-cells and their HbF content were highest in immature retics and decreased with maturation to levels of RBC. This may reflect preferential maturation of F-retics into RBC in the circulation. The NRBC population contained the lowest %F-cells. This could be due to preferential maturation of F-NRBC, having more normal phenotype than non-F-NRBC, in the bone marrow into F-retics, while non-F-NRBC enter the circulation.
Amoyal
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I
Department of Hematology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
Fibach
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E
D016022:Case-Control Studies; D004906:Erythrocyte Count; D004912:Erythrocytes / Q000737:chemistry / Q000473:pathology; D015672:Erythroid Precursor Cells / Q000737:chemistry* / Q000473:pathology*; D005319:Fetal Hemoglobin / Q000032:analysis*; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D010641:Phenotype; D012156:Reticulocytes / Q000737:chemistry / Q000473:pathology; D013156:Splenectomy; D017086:beta-Thalassemia / Q000097:blood*
D005319:Fetal Hemoglobin