Expression of Bcl-2 in inclusion body myositis.
OBJECTIVE
On the background of the possible role of the anti-apoptotic protein Bcl-2 to inhibit apoptosis induced by the Fas/Fas ligand system in inflammatory myopathies we investigated the expression of Bcl-2 in inclusion body myositis (IBM).


METHODS
We examined muscle tissue from seven IBM patients and controls by immunocytochemistry using antibodies against Bcl-2, Fas (a member of the tumor necrosis factor receptor family) and the regeneration marker, neural cell adhesion molecule (N-CAM). We also investigated the occurrence of DNA fragmentation by the terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL)-method.


RESULTS
Both Bcl-2 and Fas were up-regulated in muscle fibers in IBM and disease controls. Bcl-2 was expressed by regenerating muscle fibers while Fas was expressed by non-regenerating muscle fibers associated with inflammatory cell infiltrates. Bcl-2 and Fas were also expressed by inflammatory cells. There were scattered TUNEL positive nuclei and most of these appeared to be inflammatory cells.


CONCLUSIONS
The low occurrence of apoptotic myonuclei is not related to Bcl-2 expression, which is confined to regenerating muscle cells in IBM and other myopathies.
Fyhr
Ing-Marie
IM
Department of Pathology, Sahlgrenska University Hospital, Göteborg University, S-413 45 Göteborg, Sweden. ingmarie.fyhr@path.gu.se
Lindberg
C
C
Oldfors
A
A
D048868:Adaptor Proteins, Signal Transducing; D000906:Antibodies / Q000032:analysis; D017209:Apoptosis / Q000235:genetics / Q000276:immunology; D001706:Biopsy; D002352:Carrier Proteins / Q000235:genetics; D053938:DNA Fragmentation / Q000235:genetics / Q000276:immunology; D053200:Fas-Associated Death Domain Protein; D015870:Gene Expression / Q000235:genetics; D019254:Genes, bcl-2 / Q000235:genetics* / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D018485:Muscle Fibers, Skeletal / Q000473:pathology; D018482:Muscle, Skeletal / Q000473:pathology; D018979:Myositis, Inclusion Body / Q000175:diagnosis / Q000235:genetics*; D019006:Neural Cell Adhesion Molecules / Q000032:analysis / Q000235:genetics / Q000276:immunology
D048868:Adaptor Proteins, Signal Transducing; D000906:Antibodies; D002352:Carrier Proteins; C505533:FADD protein, human; D053200:Fas-Associated Death Domain Protein; D019006:Neural Cell Adhesion Molecules