Muscle pathology in polymyalgia rheumatica: histochemical and immunohistochemical study.
Immunohistochemical studies were performed on muscle biopsy specimens of polymyalgia rheumatica (PMR) to evaluate the extent of muscle and peripheral nerve involvement. The routine histochemistry revealed a mild variation of fiber size, type 2 fiber atrophy and type 2A or 2B fiber deficiency. In 63% of the PMR cases small angular fibers, pyknotic nuclear clumps or target-targetoid fibers were observed, suggesting neurogenic changes, although abnormalities were mild in degree. In immunocytochemical studies, neither major histocompatibility complex (MHC) class 1 nor class 2 products were expressed on the muscle surface membrane of PMR. But regarding intramuscular vessels, MHC class 2 products were distinctly visualized. On serial sections, combined deposits of IgG and Clq in perimysial arteries were seen in 38% of PMR. These results suggest that arteries of small caliber might be involved in immunopathological processes, causing muscle and peripheral nerve damage.
Kojima
S
S
Department of Neurology, Toranomon Hospital, Tokyo, Japan.
Takagi
A
A
Ida
M
M
Shiozawa
R
R
D000368:Aged; D003165:Complement System Proteins / Q000378:metabolism; D005260:Female; D006680:HLA Antigens; D006651:Histocytochemistry; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D011111:Polymyalgia Rheumatica / Q000276:immunology / Q000378:metabolism / Q000473:pathology*
D006680:HLA Antigens; D007136:Immunoglobulins; D003165:Complement System Proteins