Mixed infection with human cytomegalovirus and human polyomavirus (BKV).

Mixed infection, the infection of a single cell by two distinguishable viruses, has been demonstrated electron microscopically in human embryo lung (HEL) and human embryo kidney (HEK) cells infected with human cytomegalovirus (HCMV) and human polyomavirus (BKV). There was no evidence of enhancement of HCMV by BKV in either cell system; however, in HEL cells under certain conditions, HCMV enhanced the growth rate of BKV. Since both BKV and HCMV are often found in the urine of immunosuppressed patients, the enhancement of BKV by HCMV may be of clinical significance.