A review of allograft processing and sterilization techniques and their role in transmission of the human immunodeficiency virus.

Human immunodeficiency virus (HIV) infection via vascular organ and tissue transplantation is well documented. The majority of these transmissions occurred before the development of HIV antibody testing, which is now a routine screening tool used before organ and tissue procurement and transplantation. There exists what is commonly referred to as a "window" of seronegativity after HIV infection. Potential donors may be infectious with the HIV virus but not yet detected with available HIV antibody tests. Bone and soft tissue retrieval may be done in either a sterile or clean, nonsterile manner. Deep freezing and freeze-drying (lyophilization) are two commonly used modes of preserving bone and soft tissue allografts. In 1985, a screened donor who was in the window of seronegativity underwent vascular organ and musculoskeletal tissue harvest. The bone and soft tissue procured underwent a variety of processing and preservation techniques. There have been no known cases of HIV transmission from the processed freeze-dried tissues. Evidence now exists that early HIV infection, before HIV antibody production, may be the most infectious period. The HIV antigen testing may allow earlier detection of an infectious donor, thus closing the window of seronegativity. It is unknown whether this nontransmission of HIV to the recipients of the processed and freeze-dried tissue was due to the processing or the nature of the tissue itself.