ESR1 and rheumatoid arthritis: In this study, there were significant correlations between serum levels of IL-17 and disease activity parameters (CDAS and VAS) in the RA group, and our results are consistent with reports of previous studies performed on Egyptian RA patients; one study found a correlation between the serum level of IL-17 and DAS-28, ESR, CRP, and TNF-α [19,34].