Objective: This study investigated the influence of HLA class-I and -II genes in the response to IFN-β in relapsing-remitting multiple sclerosis (MS) patients.

Methods: In this cohort, 231 relapsing-remitting MS patients who are classified into IFN-β responders (n = 146) and nonresponders (n = 85) and 180 ethnic-matched healthy controls were analyzed. Clinical outcome of IFN-β therapy particularly Expanded Disability Status Scale scores were evaluated in relation to HLA-A, -B and -DRB1 alleles and haplotypes.

Results: Increased frequencies of HLA-DRB1*04 allele and HLA-A*03-B*44-DRB1*04 haplotype, and decreased frequency of HLA-B*15 were associated with better response to IFN-β treatment.

Conclusions: The possibility of genetic screening particularly HLA typing prior to starting IFN-β therapy for MS may permit the identification of likely responders or nonresponders.