Autoantibodies in Serum of Systemic Scleroderma Patients: Peptide-Based Epitope Mapping Indicates Increased Binding to Cytoplasmic Domains of CXCR3.

Systemic sclerosis (SSc) is a severe chronic autoimmune disease with high morbidity and mortality. Sera of patients with SSc contain a large variety of autoantibody (aab) reactivities. Among these are functionally active aab that bind to G protein-coupled receptors (GPCR) such as C-X-C motif chemokine receptor 3 (CXCR3) and 4 (CXCR4).

Antibodies against chemokine receptors CXCR3 and CXCR4 predict progressive deterioration of lung function in patients with systemic sclerosis.

Background: The chemokine receptors CXCR3 and CXCR4 are involved in the pathogenesis of fibrosis, a key feature of systemic sclerosis (SSc). It is hypothesized that immunoglobulin (Ig)G antibodies (abs) against these two receptors are present in patients with SSc and are associated with clinical findings.

Methods: Anti-CXCR3 and anti-CXCR4 ab levels were measured in 449 sera from 327 SSc patients and in 234 sera from healthy donors (HD) by enzyme-linked immunosorbent assay (ELISA).