Recovery and inactivation of infectious retroviruses from factor VIII concentration.

The ability of infectious retroviruses to withstand the procedures used for factor VIII concentration was investigated. Mouse retroviruses added to human plasma survived these procedures and remained infectious in lyophilised samples of factor VIII. Lyophilised material had to be heated at 68 degrees C for several hours before substantial quantities of infectious virus became inactivated. These findings support the possible role of retroviruses in AIDS, and indicate that factor VIII concentrates must be heated to inactivate these infectious viruses.