Pharmacogenetic Predictors of Response to Interferon Beta Therapy in Multiple Sclerosis

First-line therapy with interferon beta (IFN-beta), involved in gene expression modulation in immune response, is widely used for multiple sclerosis. However, 30-50% of patients do not respond optimally. Variants in CBLB, CTSS, GRIA3, OAS1 and TNFRSF10A genes have been proposed to contribute to the variation in the individual response. The purpose of this study was to evaluate the influence of gene polymorphisms on the IFN-beta response in relapsing-remitting multiple sclerosis (RRMS) patients. CBLB (rs12487066), GRIA3 (rs12557782), CTSS (rs1136774), OAS1 (rs10774671) and TNFRSF10A (rs20576) polymorphisms were analysed by Taqman in 137 RRMS patients. Response to IFN-beta and change in the Expanded Disability Status Scale (EDSS) after 24 months were evaluated using multivariable logistic regression analysis. Carriers of at least one copy of the C allele of CTSS-rs1136774 had a better response to IFN-beta (p = 0.0423; OR = 2.94; CI95% = 1.03, 8.40). Carriers of TT genotype of TNFRSF10A-rs20576 had a higher probability of maintaining their EDSS stable after 24 months of IFN-beta treatment (p = 0.0251; OR = 5.71; CI95% = 1.39, 31.75). No influence of CBLB (rs12487066), OAS1 (rs10774671) and GRIA3 (rs12557782) gene polymorphisms in the variation of the individual response to IFN-beta was shown. Our results suggest that the TNFRSF10A-rs20576 and CTSS-rs1136774 gene polymorphisms influence the response to IFN-beta after 24 months, while the CBLB (rs12487066), OAS1 (rs10774671) or GRIA3 (rs12557782) gene polymorphisms had no effect on the variation of the individual response to IFN-beta.