Autoantibodies in psoriasis as predictors for loss of response and anti-infliximab antibody induction

Background Infliximab is successfully used to treat psoriasis and psoriatic arthritis. However, some patients lose therapeutic response after several cycles. Antibodies to infliximab (infliximab‐Abs) are induced during treatment in a subgroup of patients and are thought to be associated with loss of response (LOR). Routine screening for infliximab‐Abs is expensive and not regularly performed. A reliable and affordable method for identifying patients who are at risk for LOR to infliximab is desirable. Objectives To analyse the development of antinuclear antibodies (ANA)/antidouble‐stranded DNA antibodies (anti‐dsDNA) over time in patients with psoriasis receiving infliximab. To analyse if there is an association between ANA titres/anti‐dsDNA concentrations, infliximab‐Ab status and LOR. Methods A retrospective data analysis of 29 patients with psoriasis receiving infliximab was carried out. ANA titres and anti‐dsDNA concentrations were regularly monitored in these patients and sera were tested for infliximab‐Abs by enzyme‐linked immunosorbent assay. Results Median ANA titres increased from 1 : 80 interquartile range (IQR) 0 to 1 : 320, n = 29] pretreatment, to 1 : 1280 (IQR 1 : 640 to 1 : 1920, n = 15) after infusion 10, and 1 : 1920 (IQR 1 : 1280 to 1 : 2560, n = 10) after infusion 20. Infliximab‐Abs were found in 21% of patients. Infliximab‐Ab‐positive patients and patients with LOR had significantly higher pretreatment anti‐dsDNA concentrations and higher pretreatment ANA titres than infliximab‐Ab‐negative and responsive patients, respectively. Conclusions The results of this study suggest a role for autoantibodies in the identification of patients with psoriasis at higher risk of developing infliximab‐Abs and of LOR under treatment with infliximab.