HLA-DRB1 and multiple sclerosis: Ramagopalan et al [26] showed that the VDRE corresponding to the Multiple Sclerosis (MS) associated DRB1*1501 haplotype bound to recombinant VDR/RXR with high specificity in vitro in contrast to relatively lower affinity for the VDRE variants observed in the non-MS associated HLA-DRB1 haplotypes which were not responsive to vitamin D3 [26].