title: Microscopic method for assaying F cell production: illustrative changes during infancy and in aplastic anemia.
abstract: Fetal hemoglobin (HbF)-bearing reticulocytes (F reticulocytes) can be detected in peripheral blood by a modification of the microscopic single-cell radial immunodiffusion method. Thereby otherwise inappreciable changes in HbF production can readily be recognized. F reticulocyte frequencies are reporducibly measurable whenever the product of whole blood HbF-bearing red cell (F cell) frequency and reticulocyte frequency is approximately 5 X 10(-4) or greater. Serial analyses of F reticulocytes and nonreticulocyte F cells (F erythrocytes) illustrate that (1) levels of F reticulocytes and F erythrocytes are persistently similar in normal adults with more than 6% F cells and thus cell survival times of F and non-F cells must be essentially the same, (2) changing levels of F reticulocytes can be sensitive predictors of later changes in mature F cell frequencies during infancy and in adults recovering from aplastic anemia, and (3) alterations in F reticulocyte frequency and the amount of HbF per F reticulocyte are discordant in some settings but concordant in others.
mesh_terms: D000328:Adult; D000741:Anemia, Aplastic / Q000097:blood*; D001772:Blood Cell Count / Q000379:methods; D005782:Gels; D006801:Humans; D005779:Immunodiffusion; D007223:Infant; D012156:Reticulocytes; D012685:Sepharose
chemical_list: D005782:Gels; D012685:Sepharose