Safety of Transplant Tissue Unaided by Lyophilization

Researchers have found that a method called lyophilization, used to inactivate retroviruses such as HIV from bones and connective tissues used in transplant procedures, is not effective.

In an experiment, investigators at the Laboratory for Comparative Orthopedic Research (LCOR) at Michigan State University (MSU, East Lansing, USA) put five samples each of bone and tissue infected with feline leukemia virus, similar to HIV, through the lyophilization process. In every case, the virus survived the process.

"Contrary to currently held clinical beliefs, lyophilization should not be relied upon as an extra measure of security for processing connective tissue allografts,” said Steven P. Arnoczky, a professor of surgery in MSU's College of Veterinary Medicine and one of the lead researchers.

A study conducted in 1985 suggested that lyophilization, also known as freeze drying, might inactivate HIV. As a result, many surgeons seeking to protect their patients would specifically request tissues that had gone through the lyophilization process. In one case, distribution of tissues from an HIV-infected donor resulted in spreading the virus in 52 contaminated allografts. Still, the chance of contracting a bacterial or viral infection from a connective tissue implant is rare.




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