Ethnic heterogeneity in the distribution of the OKT4 antigen on lymphocytes: studies in three black families.

Human T lymphocytes bear characteristic membrane antigens which allow for identification on these cells and their subpopulations with monoclonal antibody reagents directed against the specific cell-surface antigens. During a study of T lymphocyte subpopulations in a group of 41 infants from a high risk nursery, three of the seven black infants studied were found to be missing cells reactive with the monoclonal antibody OKT4 which identifies the helper-inducer subset of T cells. Immunological evaluation of these infants and study of their family members revealed that the OKT4 non-reactive lymphocytes reacted normally with another antibody, OKT4A, which also identifies the helper-inducer subset of T cells. The deficiency of the antigen recognized by the OKT4 antibody appeared not to reflect T cell immaturity and was not associated with obvious immunodeficiency. The OKT4 negative phenotype appeared to be transmitted in an autosomal recessive mode. Our studies suggest that heterozygosity for this phenotype is relatively common among the black population and that heterozygotes are not easily distinguishable from the random population on the basis of lymphocyte reactivity with the OKT4 monoclonal antibody.