Identification of BANK1 polymorphisms by unlabelled probe high resolution melting: association with systemic lupus erythematosus susceptibility and autoantibody production in Han Chinese.

OBJECTIVES: The three functional SNPs of BANK1 (rs10516487, rs17266594 and rs3733197) have been shown to be associated with SLE in Caucasian populations. The aim of this study was to investigate whether the association of BANK1 polymorphisms with SLE could be replicated in a Chinese population and whether the autoantibody production is relevant to BANK1 polymorphisms.
METHODS: Genotyping of three variants in BANK1 was carried out by unlabelled probe high resolution melting (HRM) assay in 264 SLE cases and 268 controls in a Chinese Han population living in Shanghai region. The genotype frequencies of the detected polymorphisms were analysed in relation to the production of autoantibodies (ANA, anti-dsDNA, anti-RNP, anti-SSA, anti-SSB and anti-Smith) in SLE patients.
RESULTS: Samples with the target genotypes were accurately detected and easily distinguishable by unlabelled probe HRM assay. The frequencies of the rs10516487 C allele and the rs17266594 T allele were significantly increased compared with the controls (C allele: 88.6 vs 83.2%, P = 0.011; T allele: 88.3 vs 83.2%, P = 0.019). However, the frequencies of the rs3733197 G allele were not associated with SLE (G allele: 79.9 vs 79.1%, P = 0.741). The rs10516487 and rs17266594 polymorphisms were significantly associated with high-titre ANA (≥1 : 320) and production of anti-SSA antibodies in SLE patients compared with the control subjects.
CONCLUSIONS: Genotyping using unlabelled probes is a rapid, accurate and cost-effective closed-tube method. This study implies that rs10516487 and rs17266594 polymorphisms might contribute to individual susceptibility to SLE and influence the ANA/SSA autoantibody response in SLE patients in Chinese population.