Background SNV are a group of rare conditions characterized by inflammation and necrosis of blood vessel walls. Despite current immunosuppressive treatment of SNV their clinical course and outcome are highly variable. That's why searching new biomarkers that may be useful for determining vasculitis activity, responding to treatment and risk of relapse are needed.
Objectives To identify serum levels of the biomarkers of vascular wall damage before and after induction treatment of SNV.
Methods Three serum proteins (alpha actin 2 (α-SMA), endothelin-1 (ET-1) and elastin) representing damage of blood vessel walls and anti-neutrophil cytoplasmic antibodies (ANCA) titres were measured in 22 pts with SNV (granulomatosis with polyangiitis – 12, eosinophilic granulomatosis with polyangiitis – 2, microscopic polyangiitis – 3, polyarteritis nodosa – 5) before induction treatment and at 6.75±3.33 (M ± SD) months after the beginning of induction therapy, and also in 26 healthy controls. The 22 pts included 6 male and 16 female with median age 48.8±10.5 years. Pts received induction therapy based on EULAR Recommendations for the Management of Primary Small and Medium Vessel Vasculitis (2009). Clinical activities of pts were calculated according to the Birmingham Vasculitis Activity Score (BVAS). All pts with SNV after induction treatment were divided into group of responding to treatment (decrease BVAS in 5 and more points, group1, n=17) and group of non-adequate response to treatment (without decrease BVAS in 5 and more points, group 2, n=5). The outcomes of this study were the differences in markers levels in pts with SNV before and after induction treatment, and also the differences in markers levels between pts with responding to treatment and pts with non-adequate response to treatment estimated by analysis of the absolute changes in markers levels.
Results The mean BVAS in pts before treatment was 20.7±6.09 and 7.47±8.01 - after treatment (4.29±3.60 in group 1 and 22.3±5.03 in group 2). The titers of ANCA were elevated in 72.7% of pts before treatment and remained elevated in 54.5% of pts during treatment. There were no differences in levels of ET-1 and elastin in pts with SNV before treatment and controls, and also after induction treatment. The levels of α-SMA were significantly higher (by 52%) in pts with active SNV (94.1±87.8 ng/ml) compared with controls (44.7±25.7 ng/ml, p<0.05) and showed twofold decreasing due to treatment (45.8±31.3 ng/ml, p<0.05). The analysis revealed that the levels of α-SMA in group 1 during treatment decreased from 94.6±81.3 ng/ml to 39.9±22.3 ng/ml (p<0.05). There were no significant differences in levels of α-SMA before and after treatment in group 2 (108.7±124.9 ng/ml vs 102.6±36.0 ng/m).
Conclusions The levels of serum α-SMA are elevated in severe active SNV. There are significant differences in levels of this marker before and approximately at 7 months after beginning of induction therapy in pts with SNV, especially in pts with responding to treatment. α-SMA hasn't shown differences before and approximately at 7 months after beginning of induction therapy in pts with non-adequate clinical response to treatment. This biomarker may be useful for estimating response to treatment in pts with SNV, but the future researches are needed.
Disclosure of Interest None declared