Effect of etretinate on peripheral T lymphocytes in psoriatic patients before, during and after 6 months of therapy.

Total peripheral T lymphocytes, OKT4 helper/inducer cells and OKT8 suppressor/cytotoxic cells, as well as T lymphocyte function determined by the local xenogeneic graft-versus-host reaction (GVHR), were investigated in 14 psoriatic patients prior to institution of treatment with etretinate, during the course of treatment and 6 months after its initiation. After approximately 2 months of treatment, there was a significant increase in the number of E-rosette-forming lymphocytes and OKT4 subpopulations with a return to normal levels after 6 months of treatment. The GVHR was positive in only 5/11 patients prior to therapy but in 9/11 patients after 2 and 6 months. Our results indicate that etretinate has a stimulatory effect on T lymphocytes and their subset counts.