Blood transfusions and immunophenotypic alterations of lymphocyte subsets in sickle cell anemia. The Transfusion Safety Study Group.

Transfusions purportedly induce dysfunction of cell-mediated immunity in sickle cell anemia (SCA). We studied hematologic and lymphocytic indices in 173 human immunodeficiency virus (HIV)-negative subjects with SCA and 131 black controls. Children aged 1 to 7 years with SCA had leukocyte counts and percentages of granulocytes, monocytes, natural killer cells, and T-cell markers (CD2+CD11b+, CD4+CD26+, CD4+CD29+) that were significantly higher than those for control children. Percent total lymphocytes was decreased for this age group, but the total number of lymphocytes and T and B cell counts were similar to controls. Platelets were not increased. Adolescents (aged 8 to 17 years) and adults (aged > or = 18 years) with SCA had increased total leukocytes and monocytes and lymphocytes counts that remained level instead of decreasing, as did comparably aged controls. Lymphocyte subsets typically increased in count, but their percentage remained similar to children. The exception was CD56+ cell counts, which were increased in adolescents and adults. No lymphocytic subset change suggested impaired cellular immunity, and none could be related to transfusion. Prophylactically transfused patients had higher granulocyte counts, but these may arise from the complications of SCA itself.