QUANTITATION OF CYTOMEGALOVIRUS DNA AND CHARACTERIZATION OF VIRAL GENE-EXPRESSION IN BRONCHOALVEOLAR CELLS OF INFECTED PATIENTS WITH AND WITHOUT PNEUMONITIS

Cytomegalovirus (CMV) is often present in bronchoalveolar lavage (BAL) fluid of immunosuppressed patients without CMV pneumonitis. The amoun t of viral DNA within BAL cells of patients with definite CMV pneumoni tis and of viral shedders was quantitated by polymerase chain reaction (PCR) and the extent of CMV gene expression within BAL cells was defi ned by reverse transcription-PCR. No viral DNA was detected in 6 viral shedders, and 12 had low copy numbers (mean, 72 copies/10(5) BAL cell s; median, 20) compared with numbers in pneumonitis patients (267,580 and 57,000, respectively). When CMV intranuclear inclusions were absen t within BAL cells of patients with pneumonitis, copy numbers (mean, 9 362; median, 7110) were still significantly higher than among shedders . Expression of viral glycoprotein H mRNA was detected in BAL cells of all 11 pneumonitis patients tested but in 0 of 18 viral shedders. Thu s, high-grade infection and viral replication within BAL cells are int egral features of CMV pneumonitis but not viral shedding.