Interleukin-10 Gene Promoter and NFKB1 Promoter Insertion/Deletion Polymorphisms in Systemic Sclerosis

Authors


Correspondence to: R. M. Xavier, MD, Hospital de Clínicas de Porto Alegre, Serviço de Reumatologia, 6 andar, sala 630, Rua Ramiro Barcelos 2350, Bairro Bom Fim, CEP 90035-903, Porto Alegre-RS, Brazil. E-mail: rmaxavier@hcpa.ufrgs.br

Abstract

Systemic sclerosis (SSc) is a connective tissue disease characterized by fibrotic, immunological and vascular abnormalities. Nuclear factor-kB (NFKB), as a key transcription factor involved in the regulation of immune responses, appears to be a good candidate for studies on the pathogenesis of autoimmune diseases, as well as the interleukin-10 (IL-10) polymorphism, which other studies have suggested an association with SSc. Our objective was to study the association of NFKB and IL-10 gene polymorphisms with SSc. One hundred and fifty-one SSc patients and 147 healthy bone marrow donors were enrolled in a case–control study. Blood was collected for DNA extraction; typing of IL-10 genes was made by polymerase chain reaction with sequence-specific primers (PCR–SSP), and NFKB gene typing was made by restriction fragment length polymorphism (RFLP). Patients underwent clinical evaluation, serology, Doppler echocardiography and chest high-resolution computed tomography. The frequency of IL-10 (−1082) GG genotype was found to be significantly higher in SSc patients (36.4%) as compared to healthy controls (22.4%) (P = 0.012). The frequency of heterozygous genotype GA was significantly lower (P = 0.004) in patients (38.4%) in comparison with control subjects (55.8%). A predominance of the high-producing IL-10 phenotype (GCC+/GCC+) was observed in SSc patients compared with healthy controls (37.7% versus 24.5%, respectively; OR: 1.87, 95% CI: 1.10–3.19, P = 0.019). No significant difference was found in the allelic and genotype distribution of the NFKB promoter polymorphism between patients and controls. No statistically significant associations were found between IL-10 or NFKB polymorphisms clinical and laboratory features of SSc. Our results confirmed the association of the high-producing phenotype (GCC+/GCC+) with increased risk for SSc, but found no correlation with NFKB polymorphisms.

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