HLA-DRB1 does not have a role in clinical response to interferon-beta among Iranian multiple sclerosis patients

Introduction Despite recent improvements in our knowledge about genetic role in multiple sclerosis (MS) etiology, the role of human leukocyte antigen (HLA) in clinical response to immunotherapy is not completely known. In this study we evaluated the relationship between HLA-DRB1 genotype, which has been proved to be more common in Iranian MS patients, and clinical response to interferon-beta (IFNβ), which is the most common immunotherapy for relapsing-remitting MS. Methods Sixty eight Iranian patients were followed for two years and finally classified as responder or non-responder based on clinical criteria; more than one relapse in follow-up period or a 1-point progression in Expanded Disability Status Scale (EDSS) confirmed in 6 months of follow-up was considered as non-response. HLA-DRB1 typing was performed by Polymerase Chain Reaction (PCR) for all patients and data was analyzed by STATA 12th edition. Results There were 47 (69%) responders and 21 (31%) non-responders. These two groups were demographically and clinically comparable. Fisher's exact test did not show any difference between HLA-DRB1 allele frequencies in responders and non-responders. Conclusions Our findings confirmed the lack of association between HLA-DRB1 and clinical response to IFNβ among MS patients as previous studies had done. We concluded that currently available data do not support a role for HLA class II genes as modifiers of response to immunotherapy. More investigations are needed to extend this finding to all types of HLA alleles and to interactions of specific ones