Absence of tumor necrosis factor-alpha in suction blister fluids and stratum corneum from patients with psoriasis.

Tumor necrosis factor (TNF)-alpha is a cytokine with multiple biological properties, particularly proinflammatory, apart from the induction of tumor necrosis. In order to elucidate the role of TNF-alpha in the pathogenesis of psoriasis, we have carried out bioassay and enzyme-linked immunosorbent assay for TNF-alpha in suction blister fluids and horny tissue extracts from psoriatic skin. Although bioassay showed some activities in the suction blister fluids and horny tissue extracts, there were no significant differences between the levels of activities from normal and psoriatic skin. They were at the background level and pretreatment of the samples with anti-TNF-alpha antiserum failed to abrogate the activities. ELISA confirmed the absence of TNF-alpha. Therefore, the present study could not verify that TNF-alpha plays a major role in the pathogenesis of psoriasis.