Systemic lupus erythematosus (SLE) is a systemic autoimmune disorder that affects many organs and is characterized by cytokine imbalance and hereditary factors that give a predisposition to the diseases development. The present study aimed to determine whether single nucleotide polymorphism (SNP) in the promoter region of IL-6 gene (-174G/ C) plays an important role in the SLE in Iraqi population. Blood samples of 103 SLE patients and 100 healthy individuals were collected. Serological test of serum anti-dsDNA was assayed, and it was very efficient in diagnosis of the disease. The sensitivity and specificity of anti-dsDNA was 96.2% and 100%, respectively, with high predictive value. The Genotyping of IL-6 gene SNP was carried out by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. The genotype distribution showed significant difference (P<0.05) between controls (GG: n= 69, 69%; GC: n=22, 22%; CC: n=9,9 %) and SLE patients (GG : n= 38, 36.89 %; GC : n=41, 39.80 %; CC : n=24, 23.3%). C allele frequency was significantly increased in SLE patients than in controls (X2=25.204; P<0.05; OR=3.043, 95% CI=1.954-4.738). In conclusion, the frequency of C allele (heterozygous and /or homozygous) in Iraqi SLE patients may indicated that it may be play a big role in pathogenesis of SLE and it can be considered as a major cause of local tissue inflammation that involved in all certain complication of SLE disease.

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