Serum leptin and ghrelin correlate with disease activity in ANCA-associated vasculitis.

OBJECTIVES: To study serum levels of leptin and ghrelin in ANCA-associated vasculitis (AAV). METHODS: Thirty-seven patients with AAV (21 patients with active AAV at initial presentation and during follow-up, 16 patients with AAV in long-term remission) and 21 matched healthy controls were included. Serum levels of leptin and ghrelin were measured at 0, 6 and 12 months by radioimmunoassay. Disease activity was gauged by Birmingham Vasculitis Activity Score (BVAS), CRP and circulating endothelial cells (CECs). RESULTS: Leptin levels were significantly lower in patients than in healthy controls (9.1 +/- 6.1 vs 22.3 +/- 22.4 ng/ml; P < 0.05). The difference persisted when corrected for BMI. Leptin levels increased significantly after 6 (27.8 +/- 21.9 ng/ml; P < 0.001) and 12 months (24.6 +/- 21.0 ng/ml; P < 0.001). Ghrelin levels were significantly elevated in patients compared with controls (402.6 +/- 112.9 vs 294.8 +/- 70.9 pmol/l; P < 0.005) and declined to normal values at 12 months (306.4 +/- 36.2 pmol/l). There was a significant positive correlation between ghrelin levels and disease activity, whereas leptin levels were negatively correlated with disease activity (CRP, BVAS and CECs). Accordingly, correlations between the ghrelin/leptin ratio and markers of disease activity reached the highest level of significance (all P < 0.001). CONCLUSIONS: Active AAV is characterized by decreased serum leptin and increased serum ghrelin, both of which return to normal with successful therapy. The role of leptin and ghrelin during the pathogenesis of AAV and the effects of these peptides on endothelial cells warrant further study.