Serum soluble interleukin-7 receptor alpha levels are negatively correlated with the simultaneous activity of antineutrophil cytoplasmic antibody-associated vasculitis

Abstract

OBJECTIVES: This study investigated whether serum soluble interleukin-7 receptor alpha (sIL-7Rα) levels could reflect the simultaneous activity of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). METHODS: Sixty patients with AAV were included in this study. AAV-related variables and clinical and laboratory data were collected at the two-time points (at early high and late low BVAS) for each patient along with blood sampling. Serum sIL-7Rα levels and the populations of CD3+CD4+ and CD3+CD8+ T cells expressing membranous IL-7Rα (mIL-7Rα) were compared between patients at different time points and between patients and healthy controls. RESULTS: Serum sIL-7Rα levels were significantly lower in AAV patients at early high BVAS than in those at late low BVAS, and the direction of change in serum sIL-7Rα levels increased as BVAS decreased. Serum sIL-7Rα levels were inversely correlated with BVAS, erythrocyte sedimentation rate and C-reactive protein levels. In addition, serum sIL-7Rα levels in AAV patients at early high BVAS exhibited significantly lower levels than those in healthy controls. Particularly, AAV patients at early high BVAS showed significantly increased populations of CD3+ T cells and CD3+CD8+ T cells expressing mIL-7Rα compared to those at late low BVAS. CONCLUSIONS: This study demonstrated that not only serum sIL-7Rα levels but also the populations of CD3+ and CD3+CD8+ T cells expressing m IL-7Rα were negatively correlated with simultaneous BVAS in patients with AAV. Therefore, we suggest that serum sIL-7Rα levels can be an additional and useful biomarker for assessing the simultaneous activity of AAV.