Aberrations in T-cell subpopulations in patients with psoriasis and psoriatic arthritis.

Peripheral blood T-cell subpopulations and B-cell numbers from 25 patients with uncomplicated psoriasis and 22 patients with psoriatic arthritis were compared with those of 24 age- and sex-matched healthy volunteers and 11 patients with radiologically defined erosive osteoarthritis. The numbers of early and late rosettes were found to be reduced in patients with psoriasis, with and without arthritis, while the total T-cell population (measured by aminoethylthiouronium bromide-rosettes) was found to be normal. There was no difference in the number of B cells between psoriatic patients and controls. Dose-response studies of mitogen stimulation with phytohemagglutinin and concanavalin A revealed generally higher proliferative responses in the psoriatic patients only at supraoptimal concentrations. The pokeweed mitogen response, however, was reduced in patients with cutaneous psoriasis and increased in patients with psoriatic arthritis. These studies further support the concept of an immunologic imbalance in lymphocyte populations from patients with psoriasis and psoriatic arthritis.