Side effects of anti-TNFa therapy in juvenile idiopathic arthritis

Aim of the study: To report adverse events registered in our population affected by JIA and treated with anti-TNFαblockers.

Methods: Ninety-five patients were enrolled to be treated with Etanercept, median age 14 years (range 4-34); median duration of therapy 12 months (range 1-40). 19 patients were als treated with MTX (median dose 12.5 mg/week).Fifty-six patients were enrolled to be treated with Infliximab associated with MTX (median dose of MTX 8.8mg/week),median age 23.2 years (range 7.8-34.9); median duration of therapy 20.1 months (range 1.4-60.4). All adverse events were divided in definitely, probably and possibly related to the biologic agent.

Results: Side effects definitely related to Infliximab were the reactions to infusions and the Anti-dsDNA positivity. Side effects definitely related to Etanercept were severe headache and thrombocytopenia. Side effects probably correlated to both the biological agents were behavioural modifications and pain amplification syndrome. Probably correlated to the treatment with Etanercept was the onset of Crohn’s disease in 3 patients. Possibly correlated to the biological agents were the new onset or flare-up of Chronic Iridocyclitis and single cases of thyroideal cancer, hypoglossal nerve paralysis and a severe Cytomegalovirus pulmonary infection. No case of tuberculosis infection was registered during this study.

Conclusions: Treatment with a TNFαantagonist seems to be associated with various adverse events. Some of them,like onset of Crohn’s disease, behavioural modifications are unusual and others, like pain amplification syndrome were never described before.

Children and young adults affected by JIA should be monitored very carefully so as to limit as much as possible the risk of serious side effects on anti-TNFα therapy.