Egyptian Rheumatology and Rehabilitation (Jan 2019)
Relation of interleukin-15 with the severity of primary knee osteoarthritis
Abstract
Background Interleukin-15 (IL-15) is a proinflammatory cytokine. IL-15 could be considered a potential biomarker for primary knee osteoarthritis (OA). Aim This study aimed to assess the serum level of IL-15 in primary knee OA patients and assess its relation to clinical severity, functional disabilities, and radiological grading of knee OA. Patients and methods This study included 40 patients with primary knee OA and 40 apparently healthy individuals. Assessment of knee OA was performed using clinical examination, the Western Ontario and McMaster Universities Osteoarthritis Index score, and Health Assessment Questionnaire-Disability Index. Radiological assessment was performed using the Kellgren–Laurence grading scale. Serum level of IL-15 was measured in both patients and control participants. Results There were no statistically significant differences between patients and the control group in sex (P=1.000) and age (P=0.247). The patient group had a statistically significantly higher serum IL-15 level than its level in the control group (P≤0.0001). Serum IL-15 level was significantly higher among patients with knee joint line tenderness and effusion (P≤0.0001). There were statistically significant positive correlations between serum IL-15 level with the Western Ontario and McMaster Universities Osteoarthritis Index total score (P≤0.0001), the Health Assessment Questionnaire-Disability Index score (P≤0.0001), and the Kellgren–Laurence grading scale (P≤0.0001). Conclusion Serum IL-15 is elevated and correlated positively with pain, stiffness, functional disabilities, as well as radiological damage in primary knee OA. This suggests that IL-15 plays an important critical role in the pathogenesis of primary knee OA-related pain, stiffness, and joint damage. IL-15 might be a potential biomarker for assessing the severity of primary knee OA.
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