Revista de diagnóstico y biomarcadores moleculares

Expression of Complement Receptor Type 1 on Erythrocytes in Autoimmune Diseases

Abstract

Deng-Ho Yang, Chen-Hung Chen, Cheng-Chung Wei and Ya-Wen Cheng

Objective: The expression of complement receptor type 1 on different cells is associated with autoimmunity. Erythrocyte-Complement Receptor Type 1 (E-CR1) is a candidate for early diagnosis of Systemic Lupus Erythematosus (SLE) and assessed the roles of disease activity. We evaluated the expression of E-CR1 in the patients with SLE and other autoimmune diseases.

Methods: We conducted a cross-sectional investigation of 3 groups: (1) 36 patients with SLE; (2) 51 patients with other diseases including Rheumatoid Arthritis (RA), Sjögren’s syndrome, anti-phospholipid syndrome, Mixed Connective Tissue Disease (MCTD), Raynaud’s disease, ankylosing spondylitis, pulmonary Tuberculosis (TB); and (3) 26 healthy controls. Erythrocytes were analyzed by flow cytometry to determine levels of E-CR1.

Results: We found a significant reduction in the mean levels of E-CR1 in SLE patients compared to patients with healthy controls (1.79 ± 0.16 versus 3.82 ± 0.32, P<0.05). However, in patients with RA, MCTD, and TB, decreased E-CR1 levels were also observed. There was a statistically significant correlation between reduced levels of E-CR1 and SLE disease activity index (r=-0.326, P<0.05). The E-CR1 levels were inversely correlated with urine daily protein loss (r=-0.364, P<0.05).

Conclusions: Although E-CR1 levels may be a useful diagnostic marker for SLE, a possible limitation is that no significant differences in E-CR1 levels were observed among patients with SLE, those with MCTD and TB. Overall, E-CR1 levels in SLE patients are related to disease activity index and reflect renal clearance through urine daily protein loss.