Val/Leu247 polymorphism of β2-glycoprotein I and thrombosis in Chinese patients with SLE

To determine the polymorphism at position 247 of the β2-glycoprotein I (β2GPI) gene in patients with systemic lupus erythematosus (SLE) and healthy controls in the Chinese Han Population and elucidate the relationship between β2GPI polymorphisms and anti-β2GPI levels, and furthermore investigate the correlation between β2GPI polymorphisms and thrombosis in patients with SLE.

The β2GPI 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-β2GPI antibodies were tested by enzyme-linked immunosorbent assay. β2GPI polymorphisms associated with thrombosis and the presence of anti-β2GPI antibodies were also statistically evaluated with SPSS software.

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-β2GPI antibody was related to the VV genotype of β2GPI, and the anti-β2GPI-positive patients had obviously higher frequencies of the VV genotype than the negative ones and the controls.

The study results suggested that the V/V genotype and the V-encoding allele at position 247 of the β2GPI gene had strong correlation with the occurrence of thrombosis and the production of the anti-β2GPI antibodies, showing that the Val(247) β2GPI allele may be one of the genetic risk factors for the development of thrombosis in patients with SLE.