Serum Interleukin-17 and its Correlation with Anti-CCP antibodies, Vitamin D3, and Obesity in Rheumatoid Arthritis women Patients

Background: Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease. Members of the IL-17 cytokine family have various biological functions, including enhancing defense against multiple pathogens while promoting inflammatory pathology during autoimmune disease. Additionally, it has been suggested that vitamin D may be connected to the etiology of RA. Therefore, this study aimed to assess serum IL-17 and vitamin D3 concentrations in RA women and determine how these levels relate to anti-CCP, obesity, and age.Methods: This work included eighty women aged between (22-60) years. Sixty were afflicted with RA and attended the department of rheumatology and medical rehabilitation centre for rheumatic diseases at Rzgary teaching hospital-Erbil, Iraq, compared to twenty healthy women. The concentrations of Anti-CCP antibodies as a diagnostic test, Vitamin D3 and IL-17, were assessed by ELISA. The Mann-Whitney U test and normality were applied for the statistical analysis of the results. Also, the relationship between the study parameters was examined using Pearson's correlation.  The ideal cutoff value for IL-17 with the highest sensitivity and specificity was detected using a Receiver Operating Characteristic (ROC) Curve.   Results: This study revealed that serum IL-17 levels were significantly higher in RA women than in the control group (p < 0.001) and that serum VD3 levels were significantly lower in RA women than in healthy controls. Seropositive anti-CCP Ab was found in about 42% of RA patients.  The pro-inflammatory IL-17 serum level was positively correlated with vitamin D, age, and obesity in RA women. The best IL-17 cutoff for predicting the presence of RA was 69.5 pg/ML, with a sensitivity of 96% and a specificity of 75%. Conclusion: In patients with RA, vitamin D deficiency was common and correlated with age. Consequently, a high level of suspicion is needed when assessing at-risk patients, particularly women who complain of vitamin D deficiency