Cellular basis of defective cell-mediated lympholysis in atopic dermatitis.

Peripheral blood lymphocytes (PBL) from patients with atopic dermatitis (A.D.) were examined for their capacity to generate cytotoxic T lymphocytes (CTL) during mixed lymphocyte cultures (MLC). Cell-mediated lympholysis (CML) activity, but not proliferative response during MLC, was significantly decreased (p less than 0.01) in patients with A.D. (n = 19) compared with normal controls (n = 19) or patients with other skin diseases (n = 14). Regression analysis revealed a significant correlation (p less than 0.001) between CML activity and the percentage of circulating T8+ suppressor/cytotoxic T cells. Deficient CML activity in A.D. patients, however, was not corrected when isolated autologous T4+ and T8+ cells were recombined at a normal ratio (2:1) of T4+ to T8+ cells. Examination of CML activity in co-cultures of isolated T4+ and T8+ cells obtained from two A.D. patients and their respective HLA-identical healthy siblings indicated that the defect in CML resided in both the helper/inducer T4+ cells and the effector T8+ cells. The defective cytotoxic T cell function reported in the present study may account for the increased susceptibility of patients with A.D. to develop severe viral infections.