Association of interleukin-6 and its-174GC promoter polymorphism with clinical and laboratory characteristics of non hepatitis C virus rheumatoid arthritis patients

Abstract EN

Background: Interleukin-6 is a cytokine protein, which causes inflammation, maintains immune homeostasis and shows a role in rheumatoid arthritis pathogenesis.

IL-6-174G/C promoter polymorphism may have a role in susceptibility to RA.

Aim of the work: To evaluate the clinical significance of serum levels of IL-6 and its -174G/C promoter polymorphism in RA patients in comparison with the controls.

Patients and methods: This study enrolled 25 non hepatitis C virus RA patients versus 25 age and gender matched controls.

Demographic, clinical and laboratory data were prospectively evaluated.

Serum IL-6 level and promoter (-174G/C) genotype were determined.

Results: Serum IL-6 levels was significantly higher in RA patients compared to control subjects (p = .001), especially those with CC promoter polymorphism.

There was a significant correlation between IL and 6 level and duration of morning stiffness, disease activity, hemoglobin concentration and ESR level.

15/25 patients had (-174G/G) gene promoter polymorphism, 8/25 were GC and 2/25 were CC.

All controls were GG.

There was significant association between gene polymorphism and age at disease onset (p =.0172), which was older in those with GG genotype (38.5 ± 10.25 years) than those with CC (33.5 ± 0.71 years) and younger in GC genotypes (27.9 ± 7.9 years).

None of the other clinical, laboratory or radiological parameters would predict the IL-6 promoter polymorphism.

Conclusion: Serum IL-6 levels and -174G/C promoter polymorphism were higher in RA patients than in healthy controls.

The positive correlation of IL-6 level with the DAS28 and duration of morning stiffness may confirm its’ increased involvement in the pathogenesis of RA and may point to the need for considering of anti-IL-6 agents in their management plan.

The negative correlation of IL-6 level with the hemoglobin level may confirm IL-6 play a significant role in anemia of RA.