The IL-6 promoter polymorphism is associated with disease activity and disability in systemic sclerosis.
Systemic sclerosis (SSc) is a rare, autoimmune disease characterized by cutaneous and visceral fibrosis. Interleukin- 6 (IL-6) is involved in the pathogenesis of many immune-mediated diseases. IL-6 plays an important role in the initiation and promotion of fibrosis. The polymorphism in the position -174 (G/C) of the promoter region of the IL-6 gene (IL-6pr) may alter the expression of the gene. Complete linkage disequilibrium was observed between the -174 and -597 alleles. The aim of this study is to investigate the possible influence of -597 (-174) IL-6pr polymorphism on the susceptibility and/or the clinical course of SSc in Romanian population. Genotyping of -597 variant was performed by an RFLP method on 20 SSc patients and 26 healthy subjects. Patients having the homozygous GG (-597) genotype had higher disease activity and disability scores than heterozygous GA patients: the European Scleroderma Study Group (EScSG) disease activity score was 5.0 +/- 3.3 in homozygous GG subjects vs. 2.4 +/- 3.6 in heterozygous GA patients (p < 0.05), and the Disability Index of the Health Assessment Questionnaire (HAQ-DI) was 1.42 +/- 1.04 in homozygous GG subjects vs. 0.53 +/- 0.55 in heterozygous GA patients (p < 0.05). No difference was observed in the distribution of allele frequencies between SSc patients and healthy controls.


CONCLUSIONS
The GG homozygosis was found to be associated with a higher degree of illness activity and disability in SSc patients. No statistically significant differences were found between SSc patients and healthy controls with respect to the -597 allele distribution.
Sfrent-Cornateanu
Roxana
R
Department of Physiopathology and Immunology, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania. roxanasfrent@yahoo.com
Mihai
Carina
C
Balan
Simona
S
Ionescu
R
R
Moldoveanu
E
E
D000328:Adult; D000483:Alleles; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics*; D015810:Linkage Disequilibrium; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D012595:Scleroderma, Systemic / Q000235:genetics* / Q000503:physiopathology
D015850:Interleukin-6