To assess whether the polymorphism of the macrophage migration inhibitory factor (MIF) gene at the position -173 is implicated in the disease susceptibility, risk of cardiovascular (CV) events and presence of subclinical atherosclerosis in patients with rheumatoid arthritis (RA).
A series of 293 unselected patients fulfilling the 1987 American College of Rheumatology classification criteria for RA seen at the rheumatology outpatient clinic of Hospital Xeral-Calde, Lugo, Spain and 526 matched controls were studied for differences in the MIF-173 G/C gene biallelic polymorphism. A total of 182 consecutive patients that had been periodically followed between March 1996 and September 1996 until patient's death or January 1, 2008 were assessed for the presence of CV events. Moreover, between March and December 2007, a subgroup of unselected RA patients with no history of CV events was studied for the presence of subclinical atherosclerosis by the assessment of the endothelial function (n=107) and the carotid artery intima-media thickness (IMT) (n=91) by ultrasonography studies. Patients and controls were genotyped for the MIF-173 G/C gene polymorphism using a PCR system with pre-developed TaqMan allelic discrimination assay.
No significant differences in allele or genotype frequencies for the MIF-173 gene polymorphism between RA patients and controls were found. Forty-four of the 182 patients followed between 1996 and January 2008 experienced CV events. Although the frequency of MIF-173 GG homozygous was increased in those who had CV events (88.6%) compared to those who did not suffer these complication (73.2%), the difference was not statistically significant. It was also the case when we analyzed the potential influence of MIF-173 genotypes in the presence of endothelial dysfunction or increased carotid IMT of patients with RA.
Our results do not show that MIF-173 gene polymorphism may infer a direct risk for disease susceptibility or CV disease in patients with RA.