Correlation between serum cysteine-rich protein 61 and disease activity of antineutrophil cytoplasmic antibody-associated vasculitis.

Abstract

Cysteine-rich protein 61 (CYR61) stimulates protein kinase B (Akt)-mediated nuclear factor-kappa B (NF-κB) signalling leading to an increase in pro-inflammatory cytokines, which play important roles in the pathogenesis of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). Hence, we investigated whether serum CYR61 was correlated with disease activity of AAV in a single-centre prospective cohort. Seventy-two patients with AAV were randomly selected and included. Serum CYR61, interleukin (IL)-6 and IL-8 levels were quantified with the patients' stored sera, and clinical and laboratory data at the time of blood sampling were collected. Spearman's correlation and linear regression analysis was conducted to analyse the correlation between continuous variables. The optimal cut-off of serum CYR61 for predicting high disease activity was identified using the receiver operator characteristic curve. Birmingham vasculitis activity score (BVAS) was used as a measure to assess disease activity, and high disease activity was defined as BVAS ≥ 12. Serum CYR61 significantly correlated with BVAS (r = 0.249), erythrocyte sedimentation rate (r = 0.283), C-reactive protein (r = 0.298) and serum IL-6 (r = 0.319). However, a linear association was not found between CYR61 and BVAS (β = 0.102, P = 0.304). The relative risk (RR) for high disease activity in AAV patients with serum CYR61 ≥ 236.2 pg/mL was higher than those with serum CYR61 < 236.2 pg/mL (RR 3.316, P = 0.018). Even though serum CYR61 was not directly proportional to the increase of BVAS, it could be predictive of high disease activity in AAV. Key Points • Serum CYR61 was significantly correlated with BVAS along with ESR, CRP and serum IL-6. • The cut-off of serum CYR61 for high disease activity of AAV was obtained as 236.2 pg/mL. • AAV patients with serum CYR61 ≥ 236.2 pg/mL had increased risk of having higher disease activity than those with serum CYR61 < 236.2 pg/mL (RR 3.316, P = 0.018).