CD46 in a Spanish cohort of multiple sclerosis patients: genetics, mRNA expression and response to interferon-beta treatment

Background: In a prior study of our group we found an up-regulation of CD46 expression in a cohort of Spanish multiple sclerosis (MS) patients. Objective: To evaluate the potential role of CD46 in the response to interferon-beta treatment in MS patients through the analysis of five tagging single nucleotide polymorphisms (SNPs) and measurement of mRNA. Methods: A total of 406 MS patients and 513 control patients were analysed for five SNPs at the CD46 locus. Furthermore, 163 MS patients and 163 matched control patients were analysed by RT-PCR for the CD46 mRNA expression in three blood samples (basal, and at 6 and 12 months of interferon-beta treatment) collected in the course of a I-year follow-up. Results: Two genotypes of rs2724385 polymorphism (AT and TT) could be markers of response to interferon-beta therapy in MS patients (p=0.007 and p = 0.006, respectively). Furthermore, the frequency of interferon-beta responders was 44.4% (32/72) in MS patients with an increased CD46 mRNA expression, vs. 65.9% (60/91) in patients with a decreased CD46 mRNA expression (p=0.006). Conclusion: The present study shows that CD46 could be associated with the response to interferon-beta therapy; however, the genetic results should be replicated in an independent cohort and further studies are needed to confirm the role of CD46.