Differential detection of colinear genes and RNA transcripts by modified reverse transcription and PCR

Detection of cytomegalovirus mRNA and DNA encoding the immediate early gene in peripheral blood leukocytes from immunocompromised patients

Detection of cytomegalovirus (CMV) DNA in peripheral blood leukocytes has been shown to be a sensitive marker of CMV infection. However, the specificity with regard to its clinical significance is less clear, since infections considered to be latent may be detected. In this report, the presence of CMV immediate early antigen (IEA) DNA and mRNA in peripheral blood leukocytes detected by PCR was investigated and related to the appearance of CMV pp65 antigen, CMV serology, and clinical status. Thirty-seven consecutive samples were submitted to the laboratory from 36 immunocompromised patients, on a routine basis for analysis because of a potential risk of CMV infection. To facilitate differentiation between DNA and mRNA, primers were chosen in exons 2 and 3 of the immediate early gene of CMV. Keratin type I mRNA and the ssu rRNA gene served as internal controls. Thirty specimens were CMV antibody positive, of which 11 were also CMV IEA DNA positive. Two of seven seronegative samples were CMV IEA DNA positive. No relation was found between serology and the presence of CMV IEA DNA as determined in 37 samples. Five of 32 samples that could be analyzed were positive for CMV IEA mRNA, of which four were also positive in the pp65 antigen detection technique. A clear relation was found between the presence of CMV IEA mRNA and CMV pp65 antigen in leukocytes and with the clinical findings as well (P < 0.01). It is concluded that detection of CMV mRNA may have a role in diagnosis of an active clinically relevant CMV infection.