RETROVIRAL TRANSMISSION BY THE TRANSPLANTATION OF CONNECTIVE-TISSUE ALLOGRAFTS - AN EXPERIMENTAL-STUDY

The transmission of a retrovirus by the transplantation of allografts of connective tissues was studied in a feline model with use of the fe line leukemia virus, a retrovirus with a replication cycle and patholo gical characteristics similar to those of the human immunodeficiency v irus. The retrovirus was used to infect four specific-pathogen-free ca ts that were subsequently used as tissue donors. Fresh allografts of m enisci, patellar ligaments, and patellar ligament and bone composites were harvested from infected donors and were transplanted into the kne e joints of twelve specific-pathogen-free cats. A fresh cancellous-bon e allograft was transplanted into the proximal part of the tibia of fo ur additional specific-pathogen-free cats, which served as positive co ntrol animals. Additional grafts from infected donors were harvested a nd were stored at -80 degrees Celsius for ten weeks. A fresh-frozen gr aft was then transplanted into the knee of twelve other specific-patho gen-free cats. Samples of plasma were obtained weekly from all twenty- eight cats and were tested with both an enzyme-linked immunosorbent as say to detect the presence of viral antigen and an immunofluorescent a ntibody assay to determine exposure to the virus. All types of fresh a nd fresh-frozen connective-tissue allografts from the infected donors resulted in transmission of the retrovirus to the recipient cats. The recipients had evidence of viral antigen or rising antibody titers as early as two weeks after the transplantation. Histological examination of specimens of the allografts revealed normal incorporation of the t ransplanted tissues, with no sign of rejection of the graft. CLINICAL RELEVANCE: The ability of fresh-frozen connective-tissue allografts to transmit the feline leukemia retrovirus suggests that types of tissue s other than bone could also act as a vector for the transmission of o ther retroviruses, such as the human immunodeficiency virus. If the hu man immunodeficiency virus can be thus transmitted, viricidal steriliz ation of connective-tissue grafts may be warranted, especially since s ome carriers of the human immunodeficiency virus have been shown to be seronegative at the time of harvest of grafts.