Inactivation and partition of human immunodeficiency virus during Kistler and Nitschmann fractionation of human blood plasma.

We studied the inactivation of the etiologic agent of the acquired immunodeficiency syndrome, human immunodeficiency virus, in the course of the Kistler and Nitschmann cold ethanol fractionation of human blood plasma. By measuring reverse transcriptase activity and viral infectivity, we have shown that the virus load is reduced by a factor of 10(4) during the initial and at least a factor of 10(6) during the subsequent steps of the fractionation procedure. This loss of virus may be observed in the absence or in the presence of antibodies against human immunodeficiency virus and is due to a combination of chemical inactivation, physical partition, and injury caused by repeated freezing and thawing. The laboratory data therefore further confirm epidemiological studies which indicate that immunoglobulin preparations obtained by ethanol fractionation do not transmit human immunodeficiency virus.