Background In previous study, we found in Polymyalgia rheumatica (PMR) patients a significant correlation between the number of relapses and serum soluble interleukin-6 receptors (sIL-6R) concentrations at baseline and after 1, 3, and 12 months of therapy (1). The Asp358Ala (T/G) polymorphism of the interleukin 6 receptor (IL6R) was related with high levels of ser1um sIL-6R.
Objectives The Aim of our study was to evaluate the relationship between Asp358Ala (T/G) polymorphism of IL6R gene and susceptibility and severity of the PMR
Methods We studied 104 patients with pure PMR and 94 healthy controls. Serum levels of s-IL6R were evaluated using highly sensitive, commercial sandwich enzyme-linked immunosorbent assay kits (R&D Systems, Minneapolis, MN) according to the manufacturer's instructions. The IL6R Asp358Ala polymorphism (rs8192284) were molecularly genotyped
Results The distribution of allele and genotype frequencies did not differ significantly between PMR patients and healthy controls. Carriers of the Asp358Ala T allele (TT+GT) in PMR patients was 58.7% and in Healthy controls was 60.6% (p=0.78).
Homozygosity for the T allele in PMR patients was 16.3% and in healthy control was 12.8% (p=0.48). However the patients and controls with this polymorphism presented higher level of serum s-IL6R. Finally, PMR patients with relapses/recurrences showed more frequently homozygosity for the T allele, but the difference with patients without relapses/recurrences was not statistically significant (p=0.07).
Conclusions Asp358Ala (T/G) polymorphism of the IL6R was related with high serum levels of s-IL6R; however, no correlation existed between this polymorphism and PMR susceptibily. Moreover, a bordeline correlation existed between TT homozygosity and relapses/recurrences in these patients.
Pulsatelli L, Boiardi L, Pignotti E et al. Serum interleukin-6 receptor in polymyalgia rheumatica: a potential marker of relapse/recurrence risk. Arthritis Rheum. 2008;59:1147–54.
Disclosure of Interest None declared