Immunological features of psoriasis. Effects of Ro-109359, concanavalin A, pokeweed mitogen, and methotrexate on cultivated lymphocytes.

Isolated peripheral mononuclear cells of psoriasis patients with different disease characteristics, e. g. head-localised, quiescent guttata, confluent active widespread and erythrodermic, were cultured in a modified Mishell-Dutton system. Using the plaque-forming cell (PFC) assay, single cell antibody formation was studied, and class distribution monitored, adding pokeweed mitogen (PWM), concanavalin A (ConA), methotrexate (MTX) or Ro-109359/31, as well as autologous sera to the culture. PFC-estimation vs. sheep red blood cells (SRBC) and burro red blood cells (BRBC) revealed a distinct suppression of primarily IgG-PFC in some of the PWM-treated patients' cultures; ConA maximally reduced PFC by only 50%, compared to 100% for normal immune cells. Ro-109359/31 reduced mainly IgG-PFC in the co-cultures with PWM or autologous sera. MTX resulted in a reduction of IgG-PFC and IgM-PFC equally. The results were compared with cultured immune cells from normal individuals. The two antigenically different indicators, the partial abolition of ConA induced suppression, broad-based immunoglobulin elevation in the sera, and the mainly IgG-formation hint at the role of polyclonal B-cell activation in the perpetuation of psoriasis, which can be specifically reduced by Ro-109359/31. Suppressor cell dysfunctions remain to be discussed.