Expression of microRNA-21 and TIMP-3 in paradoxical psoriasiform reactions during treatment with antitumor necrosis factor agents.

Background Expression of microRNA-21 (miR-21) is increased in psoriasis, leading to reduced levels of epidermal tissue inhibitor of matrix metalloproteinase 3 (TIMP-3), a highly potent inhibitor of the tumor necrosis factor alpha (TNFα) sheddase TACE (TNFα-converting enzyme)/ADAM17. We described the profile of miR-21 and TIMP-3 in paradoxical psoriasiform reactions induced by anti-TNFα drugs and in a control group to elucidate the pathogenesis of this reactions. Methods We performed an analytic, cross-sectional, prospective, experimental case-control study. We compared our findings with those of non-induced psoriasis. Results We included 15 patients with a change of morphology (plaque to guttate psoriasis) and 10 patients with induced psoriasis (6 palmoplantar pustulosis, 4 plaque psoriasis). Consecutive patients with different subtypes of non-induced, non-systemically treated psoriasis were included as a control group. We found that most cases with guttate psoriasis and with induced plaque psoriasis cases showed high expression of TIMP-3 expression and decreased or poorly increased levels of miR-21. The expression pattern was not homogeneous in the cases of induced palmoplantar pustulosis. These profiles differ from those of non-induced psoriasis. Discussion We conclude that various pro-inflammatory cytokines profiles are involved in the pathogenesis of paradoxical psoriasiform reactions and non-induced psoriasis. This article is protected by copyright. All rights reserved.