Intercellular Adhesion Molecule-1 Gene Polymorphisms in Isolated Polymyalgia Rheumatica

Objective: In untreated polymyalgia rheumatica (PMR), high levels of circulating soluble intercellular adhesion molecule-1 (ICAM-1) have been observed. To investigate the clinical implication of ICAM-1 polymorphisms in isolated PMR, we examined their potential influence in an unselected series of patients.

Methods: We studied 72 patients with isolated PMR and 129 ethnically matched controls from Lugo, Spain. Patients and controls were genotyped for HLA-DRB1 and ICAM-1 polymorphism at codons 241 and 469 by molecular methods.

Results: The distribution of alleles and genotypes for each ICAM-1 polymorphism did not show significant differences between patients with isolated PMR and controls. There were also no associations between ICAM-1 polymorphisms and relapses of the disease. The latter was primarily associated with carriage of an HLA-DRB1*0401 allele (OR 7.2, p = 0.01), although all relapsed patients with HLA-DRB1*0401 also carried the GG genotype of the ICAM-1 polymorphism at codon 241. The presence of both HLA-DRB1*0401 and the GG241 ICAM-1 genotype gave an OR of 15.2 (p = 0.005) after correction for age and sex.

Conclusion: Although ICAM-1 polymorphisms alone do not appear to be associated with disease severity in isolated PMR, the presence of both HLA-DRB1*0401 and the ICAM-1 codon 241 GG homozygosity was significantly associated with increased risk of relapses in these patients.