Prevalence of infection by JC and BK polyomaviruses in kidney transplant recipients and patients with chronic renal disease.

The present study investigated the prevalence of infection by JC and BK polyomaviruses (JCV and BKV) in patients with chronic renal disease (CRD), kidney transplant recipients, and a control group of asymptomatic subjects. We tested a total of 295 urine samples. After DNA extraction, polymerase chain reaction assay was used to amplify a fragment of 173 bp of the polyomavirus T antigen, followed by analysis using the BamHI restriction endonuclease. Infection by polyomavirus was detected in 17.6% (52/295 subjects) of the subjects. Whereas 30.5% (18/59) of transplant recipients were infected, the frequency was only 22.4% (30/134) in the control subjects, and 3.9% (4/102) in the CRD group (all JCV). The vast majority of infections (88.9%; 16/18) in transplant recipients were of the BKV type, whereas this type was absent in CRD patients, and made up only 10.0% (3/30) of infections in the control group. The risk of BKV infection was 72 times greater in renal transplant patients than in asymptomatic subjects. The low frequency of infection found in CRD patients may have been related to elevated levels of urea excreted in the urine, together with reduced urine volume and cell content. These factors may combine to reduce viral load or inhibit amplification. The results of the study indicate a need for the routine screening for polyomavirus in pre- and post-transplant patients, as well as organ donors, considering that BKV infection has been associated with graft rejection in kidney transplants.

D1S80 polymorphism in Amerindians from the Amazon region of Brazil.

The allele frequency distribution at the D1S80 locus (pMCT118) was analyzed in five Amerindian tribes from the Brazilian Amazon (Zoé, Awá-Guajá, Urubú-Kaapór, Katuena, and Xikrin of Bacajá) and was compared with distributions described for other worldwide populations. Nine different segregating alleles were identified in a sample of 139 individuals; alleles *18, *25, and *30 predominated in all tribes. Although the tribes are usually characterized by a low within-population diversity, they have a high interpopulational diversity, probably because of genetic drift acting on small isolated populations. Our data are similar to data for other Brazilian Amerindian tribes; these were combined for comparison with other human populations. Brazilian Amerindians are similar to the Pehuenche from Chile and to North American natives. However, the closest similarity was observed between Brazilian Amerindians and Polynesian populations (Samoans), probably reflecting common ancestry. Brazilian Amerindians and Asian populations have some similarities in terms of allele distribution (high frequencies of alleles *18 and *30), but the values of heterozygosity and the number of alleles are higher in Asians. Brazilian Amerindians are also clearly different from Europeans.