Feline immunodeficiency virus associated myopathy in the adult cat.
Human immunodeficiency virus (HIV-1) associated myopathy can be a debilitating disease in humans, leading to weakness, myalgia, and muscle wasting. Subclinical neuromuscular involvement is also common. A range of histologic lesions have been described in both forms that include both inflammatory and degenerative changes. The purpose of this study was to determine whether a myopathy was present in adult cats experimentally infected with feline immunodeficiency virus (FIV). Six specific pathogen-free, laboratory-housed cats were challenged intravenously with 1000 TCID50 of the Maryland isolate of FIV (FIV-MD) at 8 months of age. The highest serum creatine kinase values were seen at 18 months postinfection (mean 9838, SD 4805 U/L) compared to preinfection (mean 950, SD 374 U/L). Needle EMG studies revealed abnormal spontaneous activity in 2 cats. All FIV-MD infected cats exhibited at least one abnormality in muscle pathology. Of the 24 muscle samples, 15 (63%) had histopathologic lesions. The predominant histologic abnormalities consisted of perivascular and pericapillary lymphocytic infiltration, and myofiber necrosis, phagocytosis, and regeneration. Lymphocytic infiltration was graded 2+ or higher in 12 of 24 muscle samples (0 = negligible; 4+ = extensive). Immunohistochemical phenotypic lymphocyte labeling in all cats demonstrated only CD8+ lymphocyte staining. This report demonstrates the presence of a FIV associated inflammatory myopathy in the adult cat. Several similarities are apparent in comparison to HIV-1 associated polymyositis reported in humans. Future studies in the cat may thus prove useful in elucidating the pathogenesis of retrovirus related myopathy in humans.
Podell
M
M
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Comprehensive Cancer Center, The Ohio State University, Columbus 43210, USA.
Chen
E
E
Shelton
G D
GD
D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000473:pathology; D002415:Cats; D003402:Creatine Kinase / Q000097:blood; D004576:Electromyography; D016089:Immunodeficiency Virus, Feline; D007150:Immunohistochemistry; D016180:Lentivirus Infections; D018482:Muscle, Skeletal / Q000473:pathology; D009220:Myositis / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology / Q000821:virology*
D003402:Creatine Kinase