Lyophilization does not inactivate infectious retrovirus in systemically infected bone and tendon allografts.

Background: A review of multiple transplantations of human immunodeficiency virus-infected musculoskeletal allografts found that recipients of lyophilized (freeze-dried) bone or tendon from an infected donor all tested negative for human immunodeficiency virus. The finding that 75% of the recipients of fresh-frozen bone from the same donor contracted human immunodeficiency virus has led to speculation that freeze-drying may render retroviral-infected musculoskeletal allografts noninfectious.

Hypothesis: Lyophilization does not inactivate retrovirus in systemically infected bone and tendon.

Study Design: Controlled laboratory study.

Methods: Tendons and cortical bone segments from cats systemically infected with feline leukemia virus were used in this study. Feline embryonic fibroblast cells were cultured in the presence of fresh-frozen or freeze-dried cortical bone or tendon segments. At each passage, feline leukemia virus p27 antigen was measured in media by enzyme-linked immunosorbent assay, and feline leukemia virus (pro)viral nucleic acids were quantified by real-time quantitative polymerase chain reaction in the DNA extracted from cells.

Results: Enzyme-linked immunosorbent assay results and quantitative polymerase chain reaction results demonstrated retroviral antigen and proviral DNA in all cultured cell replicates after exposure to fresh-frozen or freeze-dried bones or tendons.

Conclusion: Freeze-drying (lyophilization) of retroviral-infected cortical bone and tendon does not inactivate retrovirus.

Clinical Relevance: These results conclusively demonstrate that freeze-drying should not be relied on to inactivate infectious retrovirus in systemically infected musculoskeletal allografts.