Background: Recent data suggest a direct impact of ghrelin and leptin on the immune system. Ghrelin appears to antagonize these effects. The role of ghrelin and leptin in the context of ANCA-associated vasculitis (AV) has not been reported.
Methods: Fasting serum ghrelin, free and bound leptin levels were measured in 44 patients with active AV and 25 in matched healthy controls. Follow-up under immunosuppressive therapy was available in 25 patients (1, 3, 6, 12 and 24 months). The Birmingham vasculitis activity score (BVAS), circulating endothelial cells (CECs) were used as markers of disease activity.
Results: All patients with active AV had markedly elevated ghrelin levels (390 pmol/l±24.5 pmol/l (S.E.M.), compared to healthy controls (Co) 294 pmol/l±13.2; P=0.003). 24 months treatment decreased levels to 278 pmol/l±10.9. Leptin levels not significantly altered in active disease (14.6 ng/ml ±3.8 vs. 10.8 ng/ml ±1.9 Co) increased during initial treatment (24.5 ng/ml ±4.2; P=0.025). Circulating ghrelin concentrations correlated positively and leptin negatively with systemic markers of inflammation (BVAS, leukocyte-count, CRP (all P<0.005), CECs (P>0.05) each with an optimal prediction by the ghrelin/leptin ratio (CECs, P=0.004; BVAS and CRP, both P<0.001).
Conclusion: The ghrelin/leptin ratio closely mirrors inflammation and endothelial damage in patients with AV. The data suggest that a disturbed in-vivo balance of the ghrelin/leptin-axis may contribute to the pathogenesis of AV and to the susceptibility to infections seen in these patients.