New-onset autoantibody-mediated nephritis during ustekinumab therapy for psoriasis in patients with and without prior systemic lupus erythematosus

Abstract

Psoriasis and lupus erythematosus (LE) are autoimmune diseases that affect the skin. Patients with these diseases may share a similar genetic predisposition, as genome-wide association studies have identified common genetic polymorphisms. Yet, the coexistence of these diseases is uncommon, an observation previously thought to be owing to the T helper (Th)2 immune predominance in systemic lupus erythematosus (SLE) in contra-distinction to the Th1 immune predominance in psoriasis. A review of more than 1800 SLE patients at the Toronto Lupus Clinic found that the incidence of psoriasis is increased in this population compared with the general population (estimated at 3.89% in their cohort compared with 1.6% in the Canadian population).1 Patients with concurrent SLE and psoriasis may have unusual photosensitive psoriasis with the initial presentation of psoriasis lesions on the sun-exposed extremities.2, 3 The treatment of psoriasis in patients with SLE can be problematic. Phototherapy is generally avoided. Antimalarial medications such as hydroxychloroquine and chloroquine may induce photosensitivity and psoriasis, although this notion has been mostly based on case reports and small series. Ustekinumab, a monoclonal antibody to the p40 subunits of the interleukin (IL)-12 and IL-23 receptors, is a safe and efficacious treatment for psoriasis and has been used anecdotally to treat subacute cutaneous LE4 and hypertrophic LE.5 Ustekinumab has shown possible efficacy in cutaneous LE when used to treat 5 patients with coexisting psoriasis and LE.6 Ustekinumab has recently been studied as a treatment for SLE in a phase 2 study of 102 adults showing improvement in musculoskeletal and cutaneous disease activity at 24 weeks.7 Here we report on 3 patients treated with ustekinumab for psoriasis. Two patients with prior SLE had new-onset lupus nephritis while on ustekinumab. A third individual had probable SLE with vasculitis and nephritis while on ustekinumab. This case series highlights similarities in clinical presentation suggesting a common mechanism.