Thesis (Ph.D.) - Cairo University - Faculty of Medicine - Department of Microbiology and Immunology

Background:Rheumatoid arthritis (RA) is a chronic progressive systemic inflammatory autoimmune disease of the joints, which can lead to long term joint damage, resulting in chronic pain, loss of function, and disability. Interleukin-6 (IL-6) encodes a cytokine protein, which causesinflammation, maintains immune homeostasis and plays an essentialrole in RA pathogenesis and IL-6 -174 G/C promoter polymorphism may play a role in susceptibility of RA. Aim of the work: To evaluate the clinical significance of serum levels of interleukin-6 (IL-6) and its-174 G/C promoter polymorphism in Rheumatoid arthritis (RA) patients and to compare with the controls. Patients and methods:This study enrolled 25 RA patients and 25 age and gender matched healthy controls. Demographic, clinical and serological data were prospectively evaluated. Disease activity score (DAS28) and radiological data were assessed. Serum IL-6 level was measured and promoter (-174G/C) genotyped. Results: Serum IL-6 levels were significantly higher in RA patients compared to the controls(pvalue = 0.001), especially those with CC promoter polymorphism. There was a significant correlation between IL-6 and duration of morning stiffness,disease activity,hemoglobin and ESR level. Fifteen patients had GG IL-6 (-174 G/G) gene promoter polymorphism, 8 were GC and 2 CC. ALL controls were GG. There wassignificant association between gene polymorphism and age at disease onset.The age at disease onset(p= 0.0172) was older in those with GG genotype (38.5± 10.25 years), 33.5 ±.71 years in those with CC genotype and was younger in with GC genotype (27.9± 7.9 years). None of the other studied parameters would predict the IL-6 promoter polymorphism. Conclusion:Serum IL-6 levels and -174 G/C promoter polymorphism were higher in RA patients than in healthy controls. The positive correlation of IL-6 with the DAS28 andduration of morning stiffness may confirm its{u2019} increased involvement in the pathogenesis of RA and may point to the need for considering of anti-IL-6 agents in their management plan

Issued also as CD