Interleukin-18, interleukin-12B and interferon-\u3b3 gene polymorphisms in Brazilian patients with rheumatoid arthritis: A pilot study

Polymorphisms in interleukin (IL)-18, IL-12 and interferon (IFN)-\u3b3 genes are associated with different levels of cytokines expression and have been associated with rheumatoid arthritis (RA). IL-18 +105 A/C, IL-12B +1188 A/C and IFN-\u3b3 +874 T/A polymorphisms were analyzed by restriction fragment length polymorphism-polymerase chain reaction (PCR) and amplification refractory mutation system PCR from 90 RA patients and 186 healthy individuals. There were significant differences to IL-18 +105 A/C polymorphism between the RA and control groups (odds ratio\u2009=\u20093.77; P\u2009<\u20090.0001). Individual carriers of the variant allele C had a 3.77-fold increased risk of for RA (P\u2009=\u20090.0032). No association was observed for IL-12B and IFN-\u3b3 polymorphisms. Our finds suggest a possible role for IL-18 polymorphism in the RA susceptibility in studied population