Objective: To investigate potential associations between the -174 G/C interleukin-6 (IL-6) promoter polymorphism and susceptibility to and clinical features of giant cell arteritis (GCA), particularly in patients with or without polymyalgia rheumatica (PMR) and with or without ischemic complications.
Methods: One hundred and twenty-six patients with biopsy-proven GCA who were residents in Reggio Emilia, Italy, and 112 population-based controls from the same geographic area were genotyped for IL-6 polymorphism at position -174 by molecular methods. Patients were divided in subgroups according to presence or absence of PMR and ischemic complications (visual loss, jaw claudication, cerebrovascular accidents, aortic arch syndrome).
Results: Distribution of the G/C 174 genotype was similar in patients with GCA and controls. No significant associations with the IL-6 promoter polymorphism at position -174 were found when GCA patients with or without PMR or with or without ischemic complications were compared. Further, IL-6 genotypes did not significantly affect levels of C-reactive protein or other inflammatory markers at diagnosis.
Conclusion: Our findings show that the 174 G/C promoter IL-6 polymorphism does not seem to be implicated in susceptibility to and clinical expression of GCA.