Acute systemic sarcoidosis complicating ustekinumab therapy for chronic plaque psoriasis

Funding sources: none. Conflicts of interest: none declared. Dear Editor, Ustekinumab is a human monoclonal antibody, which binds to and inhibits interleukin (IL)‐12p40, and is used to treat moderate‐to‐severe psoriasis and psoriatic arthritis. Sarcoidosis is a systemic granulomatous disease in which IL‐12 levels are elevated in tissues, serum and bronchoalveolar lavage samples of affected patients.1 Therefore, there is a rationale for the use of ustekinumab in treating sarcoidosis. The paradoxical induction of a wide range of autoimmune processes such as lupus erythematosus, vasculitis, sarcoidosis and psoriasis, developing after the initiation of antitumour necrosis factor (anti‐TNF) biological therapies, is increasingly being reported.2 We present the first reported case, to our knowledge, of sarcoidosis developing in a patient receiving ustekinumab for chronic plaque psoriasis (or indeed any indication). A 42‐year‐old white female patient with psoriatic arthritis and severe, difficult‐to‐control, chronic plaque psoriasis [Psoriasis Area and Severity Index (PASI) 19·3 and Dermatology Life Quality Index (DLQI) 26 at initiation of therapy] had been treated with ustekinumab 45 mg subcutaneously for 14 months when she presented with lethargy, weight loss, night sweats, a dry cough, dyspnoea and painful lesions on the lower legs. Previous treatments included phototherapy, ciclosporin, acitretin, adalimumab and infliximab (both biologics in combination with methotrexate). Methotrexate 20 mg weekly was continued while ustekinumab was initiated.