Single human cytomegalovirus gB genotype shed in multiple sites at the time of diagnosis in renal transplant recipients

Human cytomegalovirus (HCMV) is a major cause of morbidity and mortality in immunocompromised patients, such as renal transplant recipients. Analysis of the gene encoding the envelope glycoprotein B (gB) showed that clinical isolates adopted one of the sequence configurations, permitting the isolates to be assigned a gB genotype of 1-4. It has been suggested that HCMV gB genotypes could be correlated with tropism and pathogenesis. A number of reports in the literature refer to shedding of different gB strains, permitting follow-up of renal transplant recipients. Considering that a single strain might be responsible for the clinical expression of the disease in multiply exposed individuals, the frequency distribution of gB genotypes was examined by nested polymerase chain reaction and restriction fragment length polymorphism in 20 renal transplant recipients at the time of diagnosis. The association between gB genotypes and cellular tropism was determined using blood, saliva, and urine for each patient. HCMV gB genotype 2 was found more frequently than other genotypes (gB2, 40%; gB1, 30%; gB3, 25%; and gB4, 5%) in renal transplant recipients. The gB type did not correlate with tropism for different body sites. All the patients with HCMV infections presumably harbored a single HCMV strain at the time of diagnosis. In multiply exposed patients, the immunomodulation provided by acute HCMV infection could favor later shedding of different strains.