Is mannose binding lectin (MBL) gene polymorphism predictive of damage in systemic lupus erythematosus (SLE)?

Abstract

BACKGROUND: MBL gene polymorphism leads to low serum levels of MBL. We and others have previously shown MBL insufficiency predisposes to the development of rheumatoid arthritis (RA) and SLE in different ethnic populations. In RA, MBL insufficiency is associated with severe and erosive disease. It is not known whether low MBL level causes more severe organ damage in SLE. METHODOLOGY: Patients who satisfied the ACR criteria for the classification of SLE were recruited. The clinical presentation and disease damage index as determined according to the SLICC/ACR criteria were reviewed. Serum levels of MBL were measured by ELISA. Promoter polymorphisms and codon 54 mutations of the MBL gene were determined by PCR. RESULTS: 129 SLE patients with mean6sd duration of disease of 9.266.7 (median, range57.0, 1-31 years) years were recruited. The average cumulative SLICC score was 1.261.0 (1.0, 0-8). MBL codon 54 gene mutation was detected in 40.1% (51/127) of patients and correlated with low serum MBL level (p,0.05). There were no significant differences in damage scores between patients with (group 1, n551) and without (group 2, n576) codon 54 mutation, and those with lower (,243 ng/dl) (group 3, n532) and upper (.1439 ng/dl) (group 4, n532) inter-quartile ranges of serum MBL levels. There was no correlation between MBL gene polymorphism and serum levels of MBL level and damage to specific organ system (neurological p50.5, ocular p50.34, renal p50.5). CONCLUSIONS: Although MBL gene polymorphism and MBL insufficiency predispose to the development of SLE, they are not associated with lupus disease severity.