MedWire News: Variation in the interferon regulatory factor 5 (IRF5) gene significantly alters individual susceptibility to rheumatoid arthritis (RA), confirm findings from a large study.
Antonio Gonzalez (University of Santiago, Spain) and colleagues note that "results from exploration of IRF5 polymorphisms in RA susceptibility have been unclear."
They explain: "Two studies have shown a lack of association, whereas another study indicated a positive association, but only preferentially in a minor subset of RA patients in whom anti-citrullinated protein antibodies (ACPA) were absent."
To investigate further, Gonzalez et al looked for links between five IRF5 polymorphisms and RA incidence in 1338 patients with RA and 1342 generally healthy control volunteers. They also retrospectively reviewed data from a further 3282 RA patients and 2399 control individuals involved in previous studies.
Overall, the researchers found a significant association between the rs2004640 polymorphism of the IRF5 gene and RA susceptibility, with an odds ratio of 0.88 versus control volunteers.
This relationship was most significant in patients negative for ACPA antibodies and positive for the shared RA epitope.
The only patients in whom IRF5 polymorphisms were unrelated to RA risk were those who tested positive for ACPA and negative for the shared epitope.
When these patients were excluded from the general analysis, the relationship between the susceptibility haplotype of IRF5 and RA increased in significance, giving odds ratios of up to 1.8 versus control individuals.
This contrasted with an odds ratio for RA of 0.76 in individuals with the protective haplotype of IRF5, compared to controls.
The authors conclude that their work "may help us to better understand the different mechanisms involved in RA expression."
The results are reported in the journal Arthritis and Rheumatism.
http://www.medwire-news.md/437/75434/Bone_Health/IRF5_gene_influence_on_RA_risk_confirmed.html
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