Background It is now recognized that some pro-inflammatory cytokines, such as IL-17, contribute to synovial neoangiogenesis and osteocartilaginous destruction in rheumatoid arthritis (RA). The serum concentration of this cytokine has also been associated with the disease activity.
Objectives The present study sought to determine the relationship between IL-17 plasma concentration and clinical, biological and ultrasound activity parameters in patients with RA.
Methods This is a prospective study including patients with RA (1987 ACR criteria). Disease activity was evaluated by global pain intensity visual analog scale (VASP), visual analog scale for patient’s overall assessment of disease activity (VASOA), duration of morning stiffness, tender joint counts (TJCs), swollen joint counts (SJCs), erythrocyte sedimentation rate (ESR), C-Reactive Protein (CRP) and Disease Activity Score (DAS28). The patients underwent blinded power Doppler ultrasonography (PDUS) and grey-scale ultrasonography (GSUS) examination of 22 joints (10 metacarpophalangeal, 10 proximal interphalangeal and wrists), within the 2 hours of clinical assessment, using a handheld 13-18 MHz transducer. In GSUS, the grade ranged from 0 (no synovial thickening, no articular effusion) to 3 (marked synovial thickening). Similarly, in PDUS, the grade ranged from 0 (absence of signal) to 3 (confluent vessel signals in more than 50% of the synovial area). PDUS and GSUS semi-quantitative scores were established, ranging from 0 to 66 and corresponding to the sum of the different grades for each joint. The plasma concentration of IL-17 was determined by enzyme-linked immunosorbent assay (ELISA) kits. The significance level for Pearson correlation was set at p <0.05.
Results A total of 38 patients with RA were evaluated, 5 were male. Their ages ranged from 30 to 70 years (mean: 52.4 ± 10.3 years). Their histories of RA ranged from 7 to 456 months (mean: 124 ± 98 months). The mean VASP arose to 57 mm [0-100], the mean VASOA to 58 mm [0-100] and the mean duration of morning stiffness to 37.76 minutes [0-240]. The mean TJCs, SJCs, ESR, CRP and DAS28 were 7, 6, 46, 16.8 and 5.2, respectively. The score average value in GSUS was 17 ± 14 [0-51] and that in the PDUS 14 ± 14 [0-53]. The mean plasma concentration of IL-17 was 7.8 IU [5.81-22.49]. The CRP value was significantly and positively correlated with the plasma concentration of IL-17 (p=0.025, r=0.374). The GSUS and PDUS score was significantly and strongly correlated with the concentration of IL 17 (p=0.007 and p=0.000).
Conclusions Our study shows that the plasma concentration of IL-17 may serve as a quantitative index of the disease activity in RA.
References Leipe J, Grunke M, Dechant C, Reindl C, Kerzendorf U, Schulze-Koops H, Skapenko A. Role of Th17 Cells in Human Autoimmune Arthritis. Arthritis Rheum 2010;62:2876–85.
Disclosure of Interest None Declared