Peripheral blood monocytes in psoriatic patients overproduce cytokines.

Interleukin-1 alpha (IL-1 alpha), interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha) and interleukin-8 (IL-8) production by peripheral monocytes in 15 patients with psoriasis vulgaris and 13 healthy controls were investigated using an enzyme-linked immunosorbent assay. Polymorphonuclear leukocytes, mononuclear leukocytes, monocytes, lymphocytes and serum were isolated and cultured for 1, 12, 24 and 48 h in RPMI 1640 medium without fetal calf serum to release the cytokines. All cytokine levels in serum were very low in both psoriatic patients and the controls. However, a significant increase in the IL-1 alpha levels in the monocyte culture supernatants was observed in the psoriatic patients compared with that of the controls. IL-1 beta and IL-8 levels in the monocyte supernatants were also significantly increased in the psoriatic patients compared with the controls. TNF-alpha levels in the 12-h supernatants of the monocytes increased in some samples from psoriatic patients but not in the 48-h supernatants. Our study confirmed the overproduction of cytokines in the peripheral monocytes of the psoriatic patients and suggest the activation of monocytes in the patients with psoriasis.