HLA allele distribution distinguishes sporadic inclusion body myositis from hereditary inclusion body myopathies

Abstract

We studied the HLA class II associations in patients with sporadic inclusion body myositis (s-IBM) and hereditary inclusion body myopathies (h-IBM) and attempted to distinguish these myopathies on the basis of HLA allele assignments. Forty-five patients, 30 with s-IBM and 15 with h-IBM, underwent HLA class II allele-specific typing using polymerase chain reaction sequence-specific primers for 71 alleles contained in the DRβ1, DRβ3-5, and DQβ1 loci. In s-IBM, we found a high (up to 77%) frequency of DRβ1 * 0301, DRβ3 * 0101 (or DRβ3 * 0202) and DQβ1 * 0201 alleles. No significant association with alleles in the DR and DQ haplotypes was found among the 15 h-IBM patients. The strong association of prominent alleles with s-IBM, but not h-IBM, suggests that s-IBM is a distinct disorder with an immunogenetic background that differs from h-IBM.