Lack of detection of lymphotropic polyomavirus DNA in different clinical specimens

Seroprevalence and cross-reactivity of human polyomavirus 9

Many humans have antibodies against simian lymphotropic polyomavirus (LPyV), but its DNA has not been found in humans. Identification of human polyomavirus 9 (HPyV9) led us to compare the seroprevalence and cross-reactivity of LPyV and HpyV9. Results could indicate that humans who have antibodies against LPyV are infected by HPyV9.

Genome analysis of the new human polyomaviruses

Polyomaviridae is a growing family of naked, double-stranded DNA viruses that infect birds and mammals. The last few years, several new members infecting birds or primates have been discovered, including seven human polyomaviruses: KI, WU, Merkel cell polyomavirus, HPyV6, HPyV7, trichodysplasia spinulosa-associated polyomavirus, and HPyV9. In addition, DNA and antibodies against the monkey lymphotropic polyomavirus have been detected in humans, indicating that this virus can also infect man. However, little is known about the route of infection, transmission, cell tropism, and, with the exception of Merkel cell polyomavirus and trichodysplasia spinulosa-associated polyomavirus, the pathogenicity of these viruses. This review compares the genomes of these emerging human polyomaviruses with previously known polyomaviruses detected in man, reports mutations in different isolates, and predicts structural and functional properties of their viral proteins.

Seroprevalence of human polyomavirus 9 and cross-reactivity to African green monkey-derived lymphotropic polyomavirus

Human polyomavirus 9 (HPyV9) was discovered recently in immunocompromised patients and shown to be genetically closely related to B-lymphotropic polyomavirus (LPyV). No serological data are available for HPyV9, but human antibodies against LPyV have been reported previously. To investigate the seroepidemiology of HPyV9 and the sero-cross-reactivity between HPyV9 and LPyV, a capsomer-based IgG ELISA was established using the major capsid protein VP1 of HPyV9 and LPyV. VP1 of an avian polyomavirus was used as control. For HPyV9, a seroprevalence of 47 % was determined in healthy adults and adolescents (n = 328) and 20 % in a group of children (n =101). In both groups, the seroreactivities for LPyV were less frequent and the ELISA titres of LPyV were lower. Of the HPyV9-reactive sera, 47 % reacted also with LPyV, and the titres for both PyVs correlated. Sera from African green monkeys, the natural hosts of LPyV, reacted also with both HPyV9 and LPyV, but here the HPyV9 titres were lower. This potential sero-cross-reactivity between HPyV9 and LPyV was confirmed by competition assays, and it was hypothesized that the reactivity of human sera against LPyV may generally be due to cross-reactivity between HPyV9 and LPyV. The HPyV9 seroprevalence of liver transplant recipients and patients with neurological dysfunctions did not differ from that of age-matched controls, but a significantly higher seroprevalence was determined in renal and haematopoietic stem-cell transplant recipients, indicating that certain immunocompromised patient groups may be at a higher risk for primary infection with or for reactivation of HPyV9.