The histopathologic identification of CMV infected cells in biopsies of human renal allografts. An evaluation of 100 transplant biopsies by in situ hybridization.

In order to determine the incidence and significance of CMV infected cells within human renal allograft biopsies 100 transplant biopsies were examined for the presence of CMV DNA within the renal tissue specimens using the in situ hybridization technique. In 41 cases CMV infected cells were predominantly found within proximal tubular epithelial cells, although typical nuclear inclusion ("owl eyes") were absent. In only one case was CMV detected within a few glomerular cells. The presence of CMV infected cells within allograft biopsies does not correlate with active CMV infection of the patients at the time of biopsy. There are no significant differences in the distribution of primary and secondary CMV infections between patients with positive and negative biopsy findings. No significant differences as to the histological alterations between CMV infected and non-infected biopsies could be found. The data give evidence that the renal allograft is more often affected by CMV than is generally appreciated. The in situ hybridization technique may be useful for the fast detection of latently CMV infected cells in renal transplants and thus may influence the choice of therapeutic steps early after transplantation. Furthermore, it may facilitate the diagnosis of interstitial nephritis due to virus infection if typical nuclear inclusions in routinely stained tissue sections are absent.