Polymorphonuclear cells are not sites of persistence of human cytomegalovirus in healthy individuals.

Polymorphonuclear leukocytes (PMNL) have been shown to harbour human cytomegalovirus (HCMV) in viraemic patients, but to date PMNL of asymptomatic healthy subjects have not been examined directly to determine whether this is a normal site of HCMV persistence. Using the polymerase chain reaction (PCR), paired DNA samples prepared from adherent peripheral blood mononuclear cells (PBMC), which are known to be a site of persistence of HCMV, and PMNL of 10 healthy adults were analysed. All of seven individuals who were HCMV seropositive, and one of three who were seronegative gave a reproducible signal for HCMV DNA in their adherent PBMC, whereas none of the paired PMNL DNA samples gave a positive result. The remaining two seronegative subjects showed no HCMV DNA in either the PBMC or PMNL samples. In every case where PCR for HCMV was negative, PCR amplification of a control human gene was used to show there was no inability to amplify the DNA. We conclude that within the leukocyte population of normal asymptomatic HCMV carriers, PMNL do not appear to harbour persistent HCMV whereas adherent PBMC in the same subjects are a site of persistence.