CHARACTERIZATION OF VIREMIA AT DIFFERENT STAGES OF VARICELLA-ZOSTER VIRUS-INFECTION

Varicella-zoster virus (VZV) viremia at different stages of infection was characterized. Different approaches were used, polymerase chain re action (PCR), isothermal transcription based nucleic acid amplificatio n (NASBA), and immunofluorescence to describe and quantitate viral inf ection of peripheral blood mononuclear cells (PBMC). In patients with acute varicella 200 to 5,000 copies of the viral genome in every 150,0 00 PBMC were found with quantitative competitive PCR (OCPCR). With NAS BA, viral transcriptional activity was detected in these cells. RNA tr anscribed from the immediate early gene IE 63 as well as from the late gene 68 were found, indicating a productive infection. Glycoprotein g E specific immunofluorescence visualized by confocal laser scanning mi croscopy revealed that only 1 in 10,000 to 100,000 PBMC was infected. T and B lymphocytes as well as monocytes expressed viral protein on th eir surface. Similar results were obtained with PBMC from immunocompet ent tester patients. In some cases a transient viremia was found short ly after the onset of rash, although the viral load seemed to be lower than in patients with varicella. Examination of blood samples from 16 persons with postherpetic neuralgia (PHN) signs of viral replication in PBMC were not detected. In conclusion, the data suggest that VZV vi remia is a frequent event in patients with varicella and tester, but n ot in those with postherpetic neuralgia. Moreover, the results indicat ed that subclinical reactivations occur both in immunocompromised and immunocompetent individuals. J. Med. Virol. 56:97-98, 1998. (C) 1998 W iley-Liss, Inc.