RESUMO
OBJECTIVE: TNF inhibitors (TNFi) comprise 5 products whose structure and signalling differ. An individual patient with a rheumatic disease may respond to one TNFi but not to another. In addition, 30-40% of the patients respond inadequately to TNFi. The different TNFi downstream signalling may lead to their clinical efficacy. Several reports showed that TNFi exhibited differential effects on Th17 cells. We analyzed the different TNFi effects on IL-17A expression in the peripheral blood mononuclear cells (PBMCs) of patients with rheumatic diseases in order to evaluate the predictive capability of responses in an ex-vivo setting. METHODS: PBMCs were co-cultured with the different TNFi or medium (control), and IL-17A mRNA levels were analyzed by qPCR. IL-17A expression levels in response to 4 TNFi (except certolizumab pegol) were compared with control. IL-17A expression in the assay was correlated to the clinical responses. Assay sensitivity and specificity for distinguishing responders from non-responders was calculated by receiver-operating characteristic (ROC) analysis. RESULTS: The results of a retrospective cohort of patients with rheumatic diseases (n = 82) correlated with their therapeutic responses to the different TNFi with 89.5% accuracy. The assay predicted the responses of a prospective cohort (n = 54) to specific TNFi with 79% accuracy. CONCLUSION: This functional assay could assist in predicting the odds for response to TNFi therapy, indicating whether a given patient is likely to respond to a specific TNFi.