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Expression of HLA‐DR and its enhancing molecules in muscle fibers in polymyositis
Author(s) -
Inukai Akira,
Kuru Satosi,
Liang Yideng,
Takano Akemi,
Kobayashi Yasushi,
Sakai Motoko,
Doyu Manabu,
Sobue Gen
Publication year - 2000
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/(sici)1097-4598(200003)23:3<385::aid-mus10>3.0.co;2-t
Subject(s) - ciita , polymyositis , major histocompatibility complex , antigen presentation , antigen processing , immunology , mhc class ii , human leukocyte antigen , antigen , biology , mhc class i , microbiology and biotechnology , immune system , t cell
Polymyositis (PM) is an autoimmune inflammatory muscle disease of unknown cause in which cellular immunity is thought to play an important pathogenic role. Class II major histocompatibility complex (class II MHC: human leukocyte antigen (HLA)‐DR operates as a cofactor of antigen presentation in immunological responses. There has been a major debate over whether muscle fibers themselves synthesize and express HLA‐DR molecules and play a role in antigen presentation in PM pathogenesis. In this study, we demonstrated that most muscle fibers from patients with PM synthesized and expressed HLA‐DR molecules on their surface. Human leukocyte antigen‐DR expression was highly specific to PM. In addition, class II transactivator (CIITA), human leukocyte antigen DM (HLA‐DM), and invariant chain (Ii), which are indispensable for expression of mature HLA‐DR molecules and for antigen processing and presentation, were co‐expressed. One of the cytokines that could induce this expression is interferon‐gamma (IFN‐γ), released by activated lymphocytes. Our results indicate that in PM muscle fibers synthesize and express HLA‐DR molecules and may contribute to the inflammatory responses together with lymphocytes. © 2000 John Wiley & Sons, Inc. Muscle Nerve 23: 385–392, 2000