Clinical and Immunologic Assessment of Patients With Psoriasis in a Randomized, Double-blind, Placebo-Controlled Trial Using Recombinant Human Interleukin 10

Abstract

AN IMPORTANT role for T cells in the pathogenesis of psoriasis is supported by both the clinical benefits of treatments that specifically target T cells and the documentation of clonal T-cell proliferation within lesions.^1-3 The T-cell–driven inflammatory response in psoriasis is dominated by type 1 cytokines, with high levels of interleukin 2 (IL-2), interferon γ (IFN-γ), and other proinflammatory cytokines detected within lesions.^4-6 By contrast, IL-10, a type 2 cytokine with a broad spectrum of immunosuppressive and anti-inflammatory effects in vitro and in vivo,^7-9 is absent or markedly diminished in psoriatic skin when compared with normal skin.^10-12 Because of these findings, recombinant human IL-10 (rhIL-10) has been tested as a possible treatment for psoriasis. In several small studies, patients with psoriasis were treated with varying doses of rhIL-10 for relatively short periods (≤6 weeks) with reported efficacy.^13-17 Given this background, we designed a randomized, double-blind, placebo-controlled trial to evaluate safety, efficacy, and immunologic parameters of rhIL-10 treatment in patients with moderate-to-severe psoriasis.