Role of several cytokines and vitamin D deficiency in the progression of rheumatoid arthritis in Iraqi patients

Background: Rheumatoid arthritis (RA) is an inflammatory, systemic autoimmune disease that affects the synovial joints and connective tissues. It is thought that the etiopathogenesis of RA may be associated with the levels of pro- and anti-inflammatory cytokines as well as a vitamin D deficiency. Aim: This study sought to investigate the effects of vitamin D and of the serum levels of interleukin (IL)-17, IL-37, IL-8, and IL-10 on the progression of RA in Iraqi patients. Methodology: Blood was taken from 120 participants: 62 newly-diagnosed cases of RA and 58 healthy individuals. In order to compare the serum levels of cytokines in RA patients and in healthy individuals, an enzyme-linked immunosorbent test was used. We also assessed the serum levels of vitamin D by using the Cobas e 411 analyzer (Roche). Results: Our findings demonstrated that RA patients had greater serum levels of IL-8, IL-17, and IL-37 and lower levels of IL-10 compared to those of the control group. On the other hand, the serum vitamin D levels in RA patients were considerably lower than those of the healthy individuals. Conclusion: This study reveals a low level of vitamin D in the serum of Iraqi RA patients, which may be directly related to the enhancement of the stimulation of many inflammatory cytokines, thereby increasing the severity of the disease.