IL17A and rheumatoid arthritis: The levels also did not evolve under treatment, whether the patients responded or not, which possibly reflects a lack of implication of this cell population in RA at late stages of the disease continuum (i.e. DMARD-resistant, biologic-drug-naive), which appears to contribute to the explanation of the disappointing results with treatments targeting IL-17 in clinical trials among patients with established RA [41].