Cytomegalovirus glomerulopathy in a kidney allograft with response to oral valganciclovir

Cytomegalovirus in urinary sediment in patients with acute kidney injury

Background

Immunosuppression in solid organ transplantation is associated with frequent infections. Renal allograft recipients are susceptible to opportunistic infections and can acquire human cytomegalovirus (HCMV) infections even within the allograft. There, HCMV can be found in both the glomerulus and tubular cells, but is mostly restricted to specific and circumscribed sites. Therefore, not all organ infections are identifiable by immunohistology for HCMV proteins in fine needle core biopsies. Thus, we performed a urinalysis study to search for HCMV-specific RNA transcripts in the urine sediment of patients with acute kidney injury.

Methods

Urinary sediment of 90 patients with acute kidney injury (AKI), including 48 renal transplant recipients (RTX) and 42 non-transplant recipients (nRTX), was collected from morning urine for RNA extraction and reverse transcription. The copy number of HCMV transcripts was evaluated using a UL132 HCMV-specific probe set and by real-time quantitative polymerase chain reaction (RT-qPCR).

Results

Of the 48 RTX patients, ten showed HCMV copies in their urine sediment cells. Within this group, three recipients had negative HCMV serology and received an allograft from an HCMV-seropositive donor. In addition, all three RTX patients on a belatacept-based immunosuppressive regimen had HCMV transcripts in their urine. Of the 42 nRTX patients, only two had detectable HCMV transcripts in urine sediment cells and both were under immunosuppression.

Conclusions

Ten immunosuppressed renal allograft recipients and two immunosuppressed non-transplant patients with AKI showed HCMV copies in urine sediment. Thus, HCMV positivity in urinary sediment appears to be associated with immunosuppression. This study describes a novel noninvasive method for detection of HCMV in urinary sediment. Whether all HCMV infections can be detected or only those with viral replication warrants further investigation.

Cytomegalovirus infection in kidney allografts: a review of literature

Cytomegalovirus (CMV) is an important cause of renal transplantation complications. It can cause different syndromes or end-organ diseases that can lead to unfavourable clinical outcomes and kidney allograft dysfunction. Although well documented as a systemic disease on renal transplant patients, affecting non-renal tissue, as gastrointestinal and respiratory tract, few cases have been reported in English-language indexed journals involving renal allograft lesions secondary to CMV. As an important differential diagnosis and etiological agent to acute and chronic rejection, the possibility of CMV kidney direct infection needs prompt recognition for effective treatment. In this paper, we will review the current literature about CMV nephritis and discuss the findings from each case report.