Patients with abnormal proportions of T-lymphocyte subsets have reduced in vitro cellular immunity

Abstract

Monoclonal antibodies which identify helper/inducer (OKT4) and cytotoxic/suppressor (OKT8) subsets of human T lymphocytes have recently been used to investigate immunoregulation in isolated cell populations, as well as in human disease states. However, the relationship between relative proportions of OKT4- and OKT8-positive blood lymphocytes and in vitro cellular immune function in patients with immunodeficiencies has not been studied extensively. We enumerated T-lymphocyte subsets with OKT4 and OKT8 antibodies, and measured proliferative responses to allogeneic cells in mixed lymphocyte culture (MLC) and to phytohemagglutinin (PHA), in peripheral blood mononuclear cells (PBMCs) from 60 patients with varying degrees of immunodeficiency and 20 healthy controls. Controls had 56.0 ± 5.3% (mean ± 1SD) OKT4-positive lymphocytes, 28.6 ± 5.9% OKT8-positive lymphocytes, and an OKT4/8 ratio of 2.05 ± 0.55. We defined as abnormal values of less than 40% OKT4-positive or greater than 45% OKT8-positive lymphocytes (3 SD below and above mean values, respectively), or an OKT4/8 ratio of less than 1.2. Patients with these abnormal percentages of T-lymphocyte subsets had significantly lower mean MLC and PHA responses ( P < 0.001), and higher incidences of abnormal MLC and PHA responses ( P < 0.01). Abnormal proportions of T-lymphocyte subsets correlated with low MLC and PHA responses in most immunodeficient patients, although some patients with low MLC and PHA responses had normal subset distributions. T-Cell subset proportions were heterogeneous among patients with the same diagnosis.