The association of levels of interleukin 17 and subgroups and interleukin 23 with clinical and radiological parameters in rheumatoid arthritis patients

Objective: In this study, our aim was to determine serum levels of IL-17A, IL-17B, IL-17C, IL-17F and IL-23 in rheumatoid arthritis (RA) patients and to investigate the association of these cytokines with clinical, laboratory and radiological parameters in RA. Materials and methods: Seventy RA patients fulfilling 1987 ACR criteria and control group of 41 volunteers (20 OA patients and 20 healthy subjects) were enrolled in the study. Patients and control group serum IL-17A, IL-17B, IL-17C, IL-17F and IL-23 levels were measured with ELISA method. RA patients? plain radiographic images of bilateral hands were scored (modified Sharp Van der Heijde method) also edema and erosion scores (RA MRI scoring (RAMRIS) system) of hand and wrist MRI scans of the most affected side were calculated. The association between serum levels of IL-17 and IL-23 with clinical, laboratory and radiological findings in RA were evaluated. Results: In our study serum IL-23 levels of RA patients were significantly higher than control group. There was no statistically significant difference for serum IL-17A, IL-17B, IL-17C, IL-17F levels between RA patients and control group. When analyzed according to DAS-28 scoring system, there was not any statistically significant difference for IL-17A, IL-17B, IL-17C, IL-17F levels between RA patients (remission, low, moderate and high disease activity) and control group. On the other hand serum levels of IL-23 were significantly higher in all RA groups compared with controls. No correlations were found between IL-17A, IL-17B, IL-17C, IL-17F and IL-23 levels and disease duration, quality of life and functional status scores, Sharp Van der Heijde score and laboratory parameters. Only a weak negative correlation was found between RF and anti-CCP with IL-17A, IL-17B and IL-17A, IL-17F respectively. There was a moderate positive correlation between IL-17A, IL-17C levels and both wrist and total edema MRI scores. When RA patients were divided into two groups according to MRI edema scores, it was found that levels of IL-17A, IL-17C and IL-17F levels were significantly higher in the group with higher edema scores. Conclusion: Our results showed that, inspite of being a useful marker to support the diagnosis of RA, IL-23 does not give additional information about disease activity in RA patients. It is known that IL-17 is higher at early phases and acute attacks rather than late phases in RA patients. We also found that serum levels of IL-17A, IL-17B, IL-17C, IL-17F were similar between patients most of whom had established RA and control group. On the other hand, our data showing that patients with higher IL-17A, IL-17C and IL-17F levels had higher MRI edema scores, allowed us to think that these cytokines could be used as a marker of acute attacks and a parameter for prediction of preerosive and destructive changes and rapid disease progression. Key words: Rheumatoid arthritis, Interleukin 17, Interleukin 23, MRI.