JHEP Reports (Jan 2024)

Fine mapping identifies independent HLA associations in autoimmune hepatitis type 1

  • You Li,
  • Lu Zhou,
  • Zuxiong Huang,
  • Yue Yang,
  • Jiming Zhang,
  • Ling Yang,
  • Yun Xu,
  • Junping Shi,
  • Shanhong Tang,
  • Xiaoling Yuan,
  • Jie Xu,
  • Yiling Li,
  • Xu Han,
  • Jia Li,
  • Yanmin Liu,
  • Ying Sun,
  • Xiaozhi Jin,
  • Xiao Xiao,
  • Bangmao Wang,
  • Qiuxiang Lin,
  • Yang Zhou,
  • Xuejiao Song,
  • Yong Cui,
  • Lilin Hu,
  • Yuhu Song,
  • Jie Bao,
  • Ling Gong,
  • M. Eric Gershwin,
  • Xianbo Zuo,
  • Huiping Yan,
  • Zhengsheng Zou,
  • Ruqi Tang,
  • Xiong Ma

Journal volume & issue
Vol. 6, no. 1
p. 100926

Abstract

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Background & Aims: Association studies have greatly refined the important role of the major histocompatibility complex (MHC) region in autoimmune hepatitis (AIH). However, the effects of human leucocyte antigen (HLA) polymorphisms on AIH are not well established. The aim of this study is to systematically characterise the association of MHC variants with AIH in our well-defined cohort of patients. Methods: We performed an imputation-based analysis on the extensive association observed within the MHC region using the Han-MHC reference panel, and tested the comprehensive associations of HLA polymorphisms with AIH in 1622 Chinese AIH type 1 patients and 10,466 population controls. Results: A total of 588 HLA variants were significantly associated with AIH, with HLA-B∗35:01 (p = 8.17 × 10−304; odds ratio [OR] = 7.32) contributing the strongest signal. Stepwise conditional analysis revealed additional independent signals at HLA-B∗08:01 (p = 1.35 × 10−33; OR = 4.26) and rs7765379 (p = 5.08 × 10−18; OR = 1.66). A strong link between the lead HLA variant and clinical phenotypes of AIH was observed: patients with HLA-B∗35:01 were less frequently positive for ANA and tended to have higher serum AST and ALT levels at diagnosis, but lower serum IgG levels. Conclusions: Our study reveals three novel and independent variants at HLA-B∗35:01, HLA-B∗08:01, and rs7765379 associated with AIH across the whole MHC region in the Han Chinese population. The findings illustrate the value of the MHC region in AIH and provide a new perspective for the immunogenetics of AIH. Impact and implications: This study revealed three novel and independent variants associated with autoimmune hepatitis across the whole major histocompatibility complex region in the Han Chinese population. These findings are significant in identifying autoantigens, providing insights into the activation of the autoimmune processes, and further advancing our understanding of the immunogenetic basis underlying autoimmune hepatitis.

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