Human leukocyte antigen class I in polymyositis: Leukocyte infiltrates, regeneration, and impulse block

✍ Scribed by Tormod Fladby; Margitta T. Kampman; Sissel Løseth; Sigurd Lindal; Svein Ivar Mellgren

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 419 KB
• Volume: 20
• Category: Article
• ISSN: 0148-639X
• DOI: 10.1002/(sici)1097-4598(199712)20:12<1534::aid-mus8>3.0.co;2-9

✦ Synopsis

In polymyositis (PM), T-cell mediated myocytotoxicity is directed against strongly human leukocyte antigen class I positive (HLA-I+) muscle fibers. Fiber regeneration probably is partly responsible for this HLA-I up-regulation. We have evaluated regeneration, denervation/impulse blockade, and focal leukocyte infiltrates as possible HLA-I inducing factors in PM. Distinctive patterns of HLA-I, nerve cell adhesion molecule (NCAM), and vimentin expression accompany denervation and regeneration. Regenerating fibers also have centralized nuclei. Using semiquantitative methods, we examined strongly HLA-I+ fibers in PM muscle biopsies for these markers. Sarcoplasmic HLA-I levels were related to the presence of leukocyte infiltrates and invasion of fibers. Strongly HLA-I+ fibers were frequently invaded, and regeneration-associated changes were usually observed at sites of fiber damage. Sarcoplasmic HLA-I levels were stable along intact fibers, also adjacent to leukocyte infiltrates. A majority of the strongly HLA-I+ fibers were nonregenerating (NCAM+ only). Though other mechanisms cannot be excluded, this suggests that impulse blockade or denervation may contribute to extra HLA-I up-regulation in these fibers.