Val/Leu247 polymorphism of β 2 -glycoprotein I and thrombosis in Chinese patients with SLE.

Introduction To determine the polymorphism at position 247 of the β ₂ -glycoprotein I (β ₂ GPI) gene in patients with systemic lupus erythematosus ( SLE) and healthy controls in the Chinese Han Population and elucidate the relationship between β ₂ GPI polymorphisms and anti-β₂ GPI levels, and furthermore investigate the correlation between β ₂ GPI polymorphisms and thrombosis in patients with SLE. Methods The β ₂ GPI polymorphisms of 300 patients with SLE and 300 healthy controls were examined by single-specific-primer polymerase chain reaction ( SSP- PCR), the efficacy of which was confirmed by sequencing technology. Anti-β₂ GPI antibodies were tested by enzyme-linked immunosorbent assay. β ₂ GPI polymorphisms associated with thrombosis and the presence of anti-β₂ GPI antibodies were also statistically evaluated with SPSS software. Results The genotype expressions and the allele frequencies were obtained in both patients with SLE and healthy controls. The SLE patients with thrombosis had significantly higher frequencies of the VV genotype and V allele than those without thrombosis and the controls, and there were no differences in VV genotype and V allele expression between the SLE patients without thrombosis and the controls. In contrast, the presence of anti-β₂ GPI antibody was related to the VV genotype of β ₂ GPI, and the anti-β₂ GPI-positive patients had obviously higher frequencies of the VV genotype than the negative ones and the controls. Conclusion The study results suggested that the V/V genotype and the V-encoding allele at position 247 of the β ₂ GPI gene had strong correlation with the occurrence of thrombosis and the production of the anti-β₂ GPI antibodies, showing that the Val²⁴⁷ β ₂ GPI allele may be one of the genetic risk factors for the development of thrombosis in patients with SLE. [ABSTRACT FROM AUTHOR]