AB0811 Increased levels of serum wisteria floribunda agglutinin-positive mac-2 binding protein in systemic sclerosis

Abstract

Background Mac-2 binding protein is a cell-adhesive glycoprotein of the extracellular matrix secreted as a ligand of galectin-3 (Mac-2). Recently, a Wisteria floribunda agglutinin positive-M2BP (M2BP) assay developed using a lectin-antibody sandwich immunoassay has shown promise as a new fibrotic marker in liver fibrosis and interstitial lung disease (ILD) to detect unique fibrosis-related glycoalteration. Systemic sclerosis (SSc) is an intractable connective tissue disease that causes skin and organ fibrosis. Progressive fibrosis is now recognised to be one of the major causes of morbidity and mortality in SSc. Objectives The aim of this study is to evaluate the utility of serum M2BP levels in patients with SSc. Methods We retrospectively measured serum M2BP levels in 76 patients with SSc and 16 healthy controls (HC). We excluded patients of viral hepatitis and cirrhosis. Serum levels of M2BP were measured using HISCL® M2BP glycosylation isomer Assay Kit. IHC was performed on 5 samples of normal skin, 7 stored samples of SSc skin and 2 samples of SSc-ILD lung tissue. We examined the relationship between serum M2BP levels and clinical parameters in patients with SSc. Results The mean age was 62.7 years in SSc patients and 54.6 years in HC. There were 57 limited cutaneous SSc patients and 19 diffuse cutaneous SSc patients. The mean duration of SSc patients was 9.8 years. Serum M2BP levels were significantly higher in patients with SSc than in HC (0.853±0.701 cutoff index [COI], 0.325±0.111 COI, respectively; p<0.00001). Receiver operating characteristic (ROC) curve analysis indicated that serum M2BP correctly differentiated between SSc patients and HC with a sensitivity of 81.6% and specificity of 87.5%. In patients with SSc, a significant correlation was not found between serum M2BP levels and age, sex, mRSS, ILD, pulmonary artery hypertension (PAH), SSc-types, dermatoscopy findings. In multivariant analysis, disease duration was a only independent factor for higher serum M2BP levels more than 0.64 COI, serum M2BP median (odds ratio 0.935, 95% CI 0.878–0.996, p=0.0385). We detected the protein level of M2BP in SSc patient\`s fibroblast of skin and SSc Patient\`s proliferating type II alveolar cells adjacent to fibrotic lesions of lung tissue. Conclusions In this study, for the first we demonstrated that M2BP is expressed in skin and lung tissue in SSc patients in IHC and more over the serum M2BP level tends to be higher in patients with short disease duration. It is reveal that M2BP play an important role of fibrosis in early stage of SSc. The serum level of M2BP may be a novel biomarker of SSc. Disclosure of Interest None declared