AUTOANTIBODIES AGAINST CD-74 – A NEW DIAGNOSTIC MARKER FOR SPONDYLOARTHRITIS (SpA)

Abstrakt

Background: Spondyloarthritis(SpA) is a common debilitating inflammatory disorder. Establishing the diagnosis is often difficult since abnormalities on conventional X-ray develop with a latency of several years and only HLA-B27 is used as a laboratory marker. The goal of our study was to identify new autoantibodies as diagnostic markers of SpA.

Objective: To study the frequency of anti-CD-74 in patients with axial spondyloarthropathy, compare the frequency of anti-CD-74 and HLA B-27 positivity, study the sensitivity and specificity of anti-CD-74 and to correlate the disease characteristics with anti-CD-74 antibodies.

Study-Design: Case-Control study

Material & Methods: All the patients with axial spondyloarthritis fulfilling modified New York criteria for Ankylosing Spondylitis (AS) were taken as cases. There were two groups of controls, 50 were disease-controls with back pain other than SpA and 50 were normal healthy controls. Anti CD74 antibody levels were analysed using a commercially available ELISA kit.

Results: A total of 160 patients were included- 60 cases, 50 normal controls and 50 disease controls. The mean anti CD74 antibody levels in cases was 4.03± 2.78(P value<.001), in disease controls was 1.95 ± 1.76(P value=1.08) and in normal controls was 1.29 ± 0.89 (P value< 0.01). The overall sensitivity and specificity were 73% and 70% respectively with an NPV of 81.4%.

Conclusions: Study concludes that autoantibody assay against CD74 provides an additional tool for diagnosing spondyloarthropathies.