The inducible nitric oxide synthase promoter polymorphism does not confer susceptibility to systemic lupus erythematosus

Abstract

Objective. There is increasing evidence that nitric oxide (NO) may be important in the pathogenesis of systemic lupus erythematosus (SLE). One possible explanation for the differences observed in NO production between SLE patients and controls is variation in the 5′ promoter region of the NOS2 gene, which controls NOS2 transcription. We studied the possible contribution of (CCTTT)n microsatellite polymorphism in the NOS2 promoter region to susceptibility to SLE and the clinical outcome of the disease. Methods. We analysed the distribution of the multiallelic (CCTTT)n repeat within the 5′ upstream promoter region of the NOS2 gene, by a polymerase chain reaction-based method, in 117 SLE patients and 199 healthy subjects from southern Spain. Results. No statistically significant differences between SLE patients and healthy controls were observed with regard to the frequency of (CCTTT)n microsatellite repeats of any given length. Similarly, no associations were found with any of the clinical characteristics tested. Conclusion. We conclude that polymorphism in the NOS2 gene promoter does not play a relevant role in the pathogenesis of SLE in our population.