Cytologic and genetic study of polyomavirus-infected or polyomavirus-activated cells in human urine

To carry out a morphologic and genetic study of human polyomavirus infection or activation in child and adult urine specimens.

The study was carried out on 16 urine samples from children with human polyomavirus infection and 104 samples from adults with virus activation identified among 18800 consecutive urine samples (0.64%).

All specimens from children showed numerous typical intranuclear inclusion-bearing (INIB) cells. All adult specimens with cytological features similar to childhood specimens were defined as type 1 adult cases. We identified 14 adult cases with marked immunologic suppression as type 1 cases. The inclusions were large, homogeneous, and basophilic, and they were mainly attributable to the BK virus, as demonstrated by a polymerase chain reaction. These infected or activated cells revealed features demonstrating their origin in the superficial transitional epithelium of the urinary tract. Adult cases with different cytologic features were designated as type 2 adult cases. In type 2 adult cases, the number of virus-activated cells was lower, and degenerated intranuclear inclusion-bearing cells with a coarse chromatin pattern were observed in most cases. These characteristics were identified in 90 adults without immunologic suppression. A polymerase chain reaction with BamHI digestion demonstrated JC virus DNA in nearly all of these specimens.

The JC virus-activated cells found in type 2 adult cases and the BK virus-infected cells found in childhood cases were not of clinical importance. However, the BK virus-activated cells associated with immunologic suppression may have prognostic significance.