Familial OKT4 epitope deficiency: Studies on antigen density and lymphocyte function

Abstract

The family of a case of hereditary deficiency of OKT4 epitope on helper T cells was investigated. A 30-year-old woman was found to have hardly any OKT4 + T cells (0.7%, normal 24–51%), but normal OKT3, OKT8, OKT11, OKIa 1, Leu1, Leu2a, Leu3a, Leu7, and B 1 positive cells. The response to mitogens (PHA, PWM, and Con A) and helperor suppressor-T-cell functions of her peripheral lymphocytes were normal. She had normal helper-T-cell populations detected with OKT4A (39.1%) and Leu3a (39.5%) monoclonal antibodies. One of her sisters had the same defect, but other members of the family had normal lymphocyte subsets. Lymphocyte functions were also found to be normal in all family members examined. The peak position of the fluorescence intensity of OKT4 + cells was about half that of normal controls in five members of this family. Considering that these were carriers of OKT4 epitope deficiency, the OKT4 epitope abnormality was inherited as an autosomal codominant trait in this family. Similar OKT4 epitope deficiency with normal Leu3a + and OKT4A + cells was found in 38 of 8866 (0.43%) other subjects in Japan by the examination of routine blood samples.