Serum and synovial fluid levels of interleukin-17 in correlation with disease activity in patients with RA

Abstract

The aim of this study was to evaluate serum and synovial levels of IL-17A by ELISA in rheumatoid arthritis (RA) and find out the correlations between IL-17A levels and various clinical, laboratory parameters and RA disease activity and severity indices. Group I consists of 30 adult active RA patients fulfilling the ARA 1987 revised criteria, with knee effusion and receiving basic therapy, and with a mean age of 41.47±11.49 years and mean disease duration of 9.5±4.16 years. Group II consisted of 13 healthy volunteers, age- and sex-matched, with a mean age of 39.08±14.19 years. RA patients showed significantly higher mean serum IL-17A levels than controls (11.25±9.67 vs. 0.6±1.4 pg/mL, respectively, p=0.0002). Synovial IL-17A levels showed a significant positive correlation with serum IL-17A levels (r=0.5 and p=0.005). RA patients with negative rheumatoid factor (RF) had non-significantly higher mean serum IL-17A levels (12±9.86 pg/mL) compared to those with positive RF (10.82±9.81 pg/mL); however, the mean synovial IL-17A levels were nearly the same. Significant positive correlations were found between both serum and synovial IL-17A levels and DAS-28 scores (r=0.556, 0.392 and p=0.001, 0.032, respectively). RA patients with class III functional status showed significantly higher mean serum IL-17A levels (17.53±13.43 pg/mL) than classes I and II (8.97±6.97 pg/mL, p=0.009). These led us to conclude that the elevated serum and synovial IL-17A levels in RA patients parallel the degree of disease activity and severity. This may highlight the usefulness of IL-17 (especially serum level) as a possible marker for more aggressive joint involvement and damage.

Interleukin-17A Levels Increase in Serum of Children With Juvenile Idiopathic Arthritis

“…However, analysis of the relationship of IL-17A and hemoglobin levels showed no significant correlation in patients with rheumatoid arthritis. 42 No significant difference was found in our study in the mean thrombocyte count in children with detectable and undetectable IL-17A levels. Taking in consideration that the emergence of thrombocytosis in inflammation, including JIA, is primarily the consequence of IL-1, tumor necrosis factor alpha and IL-6, 44,45 while IL-17A stimulates the production and displays the synergetic effects with these cytokines, 39 the correlation of IL-17A levels and thrombocyte count could be expected, although it has not been proved in our study.…”

“…However, in the patients with rheumatic arthritis, a significant correlation Interleukin-17A in Juvenile Idiopathic Arthritis was found between IL-17A levels in the synovial fluid and the number of leukocytes. 42 In addition, the number of Th17 cells significantly correlated with the number of leukocytes in the synovial fluid. 43 In our study, no significant difference was found in the mean values of hemoglobin between children with detectable and undetectable IL-17A levels.…”

Enhanced and persistent levels of interleukin (IL)-17+CD4+ T cells and serum IL-17 in patients with early inflammatory arthritis

“…This study shows that the levels of peripheral IL-17 peripheral blood compared with healthy controls [3,14,[18][19][20][21]. However, conflicting data exist [22,23], including a recent study which showed that patients with early RA within a cohort of EIA had lower levels of Th17 cells [24].…”

Polyfunctional, Pathogenic CD161+ Th17 Lineage Cells Are Resistant to Regulatory T Cell–Mediated Suppression in the Context of Autoimmunity

“…T cells are thought to play a key role in RA pathogenesis (10)(11)(12) with both experimental models and clinical research focusing on the role of Th17 cells, which produce IL-17 as their signature cytokine (13)(14)(15)(16)(17). Indeed, Th17 cells have recently been targeted by the use of anti-IL-17 in RA, although with somewhat disappointing results (18).…”