Clinical analysis of staphylococcal superantigen hyper-reactive patients with psoriasis vulgaris

It has been recently hypothesized that superantigens, which stimulate T cells expressing particular T cell receptor Vbeta chain gene segments, play a precipitating or aggravating role in psoriasis. In this study, we investigated the peripheral blood mononuclear cell (PBMC) response of patients with psoriasis vulgaris to staphylococcal superantigens (staphylococcal enterotoxin A (SEA), SEB, and SEC1) and its relationship to clinical and laboratory findings. Cytokine secretion was assessed by ELISA in the supernatants of the cultured PBMCs stimulated with SEB. Results of 3H-TdR uptake showed that the PBMCs' response against SEB in patients with psoriasis vulgaris (34,468 +/- 6,455) (mean DPM SD) was significantly higher than that of normal subjects (22,756 +/- 5,780) (p < 0.005). The stimulation index (SI) of patients with psoriasis vulgaris (n = 37) (63.9 +/- 55) was significantly higher than that of normal subjects (n = 24) (26.0 +/- 23) (p < 0.005) and patients with atopic dermatitis (n = 10) (40.7 +/- 30) (p < 0.05). Similar results were obtained in response to SEA and SEC1. SI weakly correlated with the psoriasis area and severity index (PASI) score (r = 0.62) and the serum interleukin-6 (IL-6) concentration (r = 0.45). IL-2 and tumor necrosis factor (TNF-alpha) were secreted at a significantly increased level by PBMCs from psoriatic patients on incubation with SEB, after a 3 day culture period. A higher level of IL-6 was released by PBMCs stimulated with SEB in psoriatic patients than normal controls, however, the difference was not significant. These results raise the possibility that monocytes, as well as T cells, are markedly activated by staphylococcal superantigen in patients with psoriasis vulgaris, which may play a role in the triggering or aggravating of psoriasis mediated by secreted cytokines.