Human polyomaviruses DNA detection in peripheral blood leukocytes from immunocompetent and immunocompromised individuals.

Peripheral blood leukocytes from immunocompetent and immunocompromised individuals were analyzed for human polyomarivus BK and JC DNA presence. A nested polymerase chain reaction which amplify the transcriptional control region of the genome of both viruses was employed. The immunocompromised patients included bone marrow transplantation recipients and AIDS patients. BKV sequences were detectable in 52.8-62.5% of the individuals included in this study, whereas the percentage of individuals with JCV sequences in peripheral blood lymphocytes varied from 38.8% to 50%. The frequency of reactivations of BKV and JCV were also determined by detection of shedding in urine of viral DNA. The highest frequency of reactivations of either BKV or JCV was demonstrable in the group of bone marrow transplantation recipients, but reactivations occurred also in immunocompetent individuals. JCV sequences amplified from urine samples showed a restriction pattern similar to the archetype one, whereas sequences obtained from lymphocytes showed rearranged pattern as well as archetype pattern. Finally all JCV sequences from cerebrospinal fluid seemed to be rearranged. These observations suggest that peripheral blood lymphocytes have a fundamental role in the persistence of polyomaviruses infection and in the dissemination at least of JCV within the organism allowing that rearranged variants, better adapted to grow in brain tissue, emerge.