Lack of association between FCRL3 and FcγRII polymorphisms in Japanese type 1 autoimmune hepatitis

Autoimmune hepatitis (AIH) is an organ-specific autoimmune disease characterized by chronic inflammation of the liver. Although the HLA-DRB1⁎0405 allele is associated with type 1 AIH in Japanese, the exact genetic etiology of AIH remains undefined. Recently, polymorphisms of Fcγ receptors (FcγR) and Fc receptor-like gene 3 (FCRL3) were linked to a variety of autoimmune diseases, and may be at least partially responsible for susceptibility to AIH. In this study, we genotyped FcγRIIA, FcγRIIB, and four FCRL3 polymorphisms in 87 Japanese patients with type 1 AIH and 97 ethnically matched controls using the TaqMan assay. Although we were able to detect significantly lower serum IgG concentrations in AIH patients specifically with the FCRL3− 110A/A genotype, we observed no difference in the distribution of the genotypes between patients and controls, implying that susceptibility to type 1 AIH in Japanese patients is not influenced by FcγRIIA, FcγRIIB, or FCRL3 polymorphisms.