Polyomavirus persistence in lymphocytes: prevalence in lymphocytes from blood donors and healthy personnel of a blood transfusion centre.

BK and JC polyomaviruses (BKV and JCV) are widespread in humans and are thought to persist and reactivate under immune alterations. In addition to the kidney, lymphoid cells have been proposed as a site of latency. However, while this was shown to occur in immunocompromised patients, discordant data were published for healthy humans. To help to solve this issue, an extensive study (231 healthy subjects) was carried out on peripheral blood mononuclear cells (PBMC) from blood donors of two towns and from operators of a blood transfusion centre. To discriminate between past and recent infection, nested PCRs for BKV and JCV non-coding control region (NCCR) and VP1 DNA sequences were carried out. Twenty-two per cent of subjects had BKV NCCR, but only 7% also had BKV VP1, as detected by PCR assays of similar sensitivities; the latter positivity was found to decrease with age. In both towns, the BKV WW archetypal DDP strain, subtype I, was found. Only 0.9% of subjects contained JCV DNA, for both NCCR and VP1. Blood operators presented a statistically significant increased prevalence of BKV NCCR (3. 0-fold) and BKV VP1 (9.4-fold) sequences with respect to blood donors of comparable ages, suggesting the possibility of occupational risk of BKV (re)infection or reactivation. Since the possibility of amplifying BKV VP1 sequences from PBMC of healthy humans is lost with age, this suggests that PBMC are not a site of polyomavirus persistence in healthy individuals and that detection of BKV VP1 DNA in PBMC is probably indicative of recent infection or reactivation.