[Molecular biological screening of viruses important to transfusion medicine]

The usefulness of the direct virus detection by polymerase chain reaction (PCR) and reverse transcription/polymerase chain reaction (RT PCR) for blood donor screening was investigated, including the following viruses: cytomegalovirus (CMV), hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency type 1 virus (HIV1). Hepatitis C viraemia was detected by RT PCR in 97% of anti-HCV-positive haemophiliacs, in 48% of anti-HCV-positive hepatitis patients, in only 21% of anti-HCV-positive blood donors from North-West Germany, and not at all in 945 blood donors with elevated serum ALT. In order to compare HIV1 detection by PCR and by p24 antigen determination, we tested 34 anti-HIV1-positive AIDS patients for p24 antigen, HIV1 RNA and HIV1 provirus DNA. 97% had HIV1 provirus DNA, 35% had HIV RNA, but only 30% had p24 antigen. A multiplex PCR specific for HBV, HCV and HIV1 (RNA and DNA) was developed for the investigation of a blood donor population from Namibia, where HBV and HIV1 infections occur more frequently than in German blood donors. The prevalence of anti-HIV1 antibodies in this population was 0.6%. HIV1 RNA was never detected in the plasma of 2,569 anti-HIV1-negative donors. HIV1 provirus DNA was present in 75% of the 16 anti-HIV1-positive individuals. None of these anti-HIV1-positive blood donors was also positive for p24 antigen. CMV infections and reactivations in 130 immunocompromised heart transplant patients and in 420 healthy anti-CMV-positive blood donors were monitored using cytochemical detection of CMV early antigen, and PCR. CMV DNA was neither detected in the plasma nor in the leucocytes of any anti-CMV-positive blood donor. During the course of CMV reactivation in immunocompromised heart transplant patients, CMV DNA was always detectable first in granulocytes and afterwards in the plasma. The cytochemical demonstration of CMV early antigen was typically delayed by several days and was observed in only 11% of those blood samples which contained CMV DNA in leucocytes. The determination of CMV DNA in leucocytes proved to be the most sensitive method to detect viraemia. Thus, CMV detection in leucocytes is the method of choice for the monitoring of transplant patients. This method is also promising for blood donor screening. The sensitive routine monitoring of blood donations for virus infections by multiplex PCR is practicable. However, nucleic acid must be extracted both from the plasma and from the cellular compartments of blood in order to detect HIV and CMV provirus DNA. Lysate from EDTA blood is a suitable material for this purpose. The determination of the surrogate marker serum ALT activity is of no use in hepatitis C screening, and determination of p24 antigen is not required in HIV1 screening.