The −844C/T polymorphism in the Fas ligand promoter associates with Taiwanese SLE

Abstract
FasL expression is critical in T-cell activation-induced apoptosis, which is involved in lupus pathogenesis. This study identified two SNPs in the FasL promoter regions from –1145 to –45 by genomic DNA sequencing. The –844C/T polymorphism was previously described by its location in and affect on the CCAAT/enhancer-binding protein β (C/EBPB β)-binding site and the other (–1094A/C, a novel polymorphism) was located at the NF-κB transcription-binding site. FasL gene promoter polymorphisms were genotyped in 260 systemic lupus erythematosus (SLE) patients and 280 healthy controls using MassArray matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry. The distribution of FasL promoter –844C/C genotype, predominant in Taiwanese, was skewed in Taiwanese SLE patients (odds ratio: 1.53; P-value=0.014). FasL promoter −844C/T polymorphism genotype distributions of Taiwanese, African Americans, and Caucasians differed. Moreover, no particular clinical association of −844C/T and −1094A/C polymorphisms with SLE was found in patients in Taiwan. This study confirmed that −844C/C genotype is associated with lupus susceptibility. The –1094A/C polymorphism is not significantly associated with lupus disease susceptibility, albeit the role of NF-κB pathway in FasL promoter activation remains unclear. Fas/FasL pathway may contribute to SLE polygenic disease entity.