In contrast to increased FoxP3 expression in JIA in isolated Treg after 5 days of incubation in cell culture media enriched with Th17-inducing stimuli, specific in vitro blockade of IL-17A resulted in adjustment of FoxP3-expression to normal proportions as found in controls which might underline one mechanism of clinical effectiveness of IL-17 blockade in rheumatic diseases. This evidence concerns the gene IL17A and rheumatic disorder.