Mannose-binding protein genetic polymorphisms in black patients with systemic lupus erythematosus

Objective. To determine whether dysfunctional or deficient mannose-binding protein (MBP) variants are found with increased frequency in black patients with systemic lupus erythematosus (SLE) compared with controls. Methods. Allele-specific polymerase chain reaction amplification of 4 different polymorphic sites was performed on samples from 92 black SLE patients and 86 geographically matched black controls. Results. Two structural polymorphisms of MBP, associated with low serum levels of MBP, were found with significantly increased frequency in the SLE patient population compared with controls. In contrast, a promoter haplotype associated with particularly high serum levels of MBP was negatively associated with SLE. Conclusion. Deficiencies of MBP predispose individuals to SLE.