Interleukin 12 production by monocytes from patients with psoriasis and its inhibition by ciclosporin A

Abstract

Background Psoriasis is a T‐helper (Th)1 cytokine‐mediated chronic skin disease and interleukin (IL)‐12 has been shown to play a major role in the development of Th1 responses. Objectives To elucidate the role of IL‐12 in the pathogenesis of psoriasis and to study the effect of ciclosporin A (CsA) on Th1 deviation of this disease. Patients/Methods We investigated IL‐12 production by stimulated monocytes from patients with psoriasis who were treated with or without CsA. Monocytes were stimulated with interferon‐γ plus lipopolysaccharide (LPS) or Staphylococcus aureus Cowan strain I (SAC). The amount of IL‐12 p70 produced by stimulated monocytes was evaluated by enzyme‐linked immunosorbent assay. Results Compared with those from normal controls, LPS‐ but not SAC‐stimulated monocytes from patients with psoriasis produced significantly higher amounts of IL‐12. Interestingly, LPS‐stimulated monocytes from patients with psoriasis treated with CsA produced significantly decreased amounts of IL‐12 compared with those patients not treated with CsA. Conclusions Our results suggest that IL‐12 production by monocytes may have a critical role in the pathogenesis of psoriasis, and that the therapeutic effect of CsA on psoriasis may be achieved by correcting the deviation of the Th1/Th2 balance.