Proinflammatory Soluble Interleukin-15 Receptor Alpha Is Increased in Rheumatoid Arthritis

• Published in: Arthritis Vol. 2012; no. 2012; pp. 270 - 276
• Main Authors: Machado Diaz, Ana Cecilia, Chico Capote, Araceli, Arrieta Aguero, Celia Aurora, Rodríguez Alvarez, Yunier, García del Barco Herrera, Diana, Estévez del Toro, Miguel, Guillen Nieto, Gerardo E., Santos Savio, Alicia
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Limiteds 01.01.2012; Hindawi Puplishing Corporation; Hindawi Publishing Corporation
• ISSN: 2090-1984; 2090-1992
• DOI: 10.1155/2012/943156

Rheumatoid arthritis (RA) is an autoimmune and inflammatory disease in which many cytokines have been implicated. In particular, IL-15 is a cytokine involved in the inflammatory processes and bone loss. The aim of this study was to investigate the existence in synovial fluid of soluble IL-15Rα, a private receptor subunit for IL-15 which may act as an enhancer of IL-15-induced proinflammatory cytokines. Soluble IL-15Rα was quantified by a newly developed enzyme-linked immunosorbent assay (ELISA) in samples of synovial fluid from patients with RA and osteoarthritis (OA). The levels of IL-15Rα were significantly increased in RA patients compared to OA patients. Also, we studied the presence of membrane-bound IL-15 in cells from synovial fluids, another element necessary to induce pro-inflammatory cytokines through reverse signaling. Interestingly, we found high levels of IL-6 related to high levels of IL-15Rα in RA but not in OA. Thus, our results evidenced presence of IL-15Rα in synovial fluids and suggested that its pro-inflammatory effect could be related to induction of IL-6.