Clinical Significance of Isolated Cytomegalovirus-Infected Gastrointestinal Cells

Abstract

Background. Cytomegalovirus (CMV) infection of the gastrointestinal (GI) tract is associated with high mortality in immunosuppressed patients. However, few studies have correlated blood CMV load with GI histopathological findings. Furthermore, there have been few studies determining the clinical significance of isolated CMV infection. Design. Cases were selected for the diagnosis of GI CMV infection by searching the information system of a tertiary hospital. The electronic medical record was reviewed for each case to determine blood viral load, clinicopathological features at the time of diagnosis and clinical outcomes after discharge. Results. In all, 30 patients with CMV-positive intestinal biopsies confirmed by immunohistochemistry (IHC) were identified. All were immunosuppressed. CMV inclusions were also recognized by hematoxylin and eosin stain in 27% of the cases, and the remaining cases were identified by IHC alone. CMV blood load was only positive in 17% of the cases; 8 cases had only isolated CMV-infected cells (0.1-0.5 IHC count/high-power field), with the following outcomes: worsening symptoms that responded to antiviral therapy (n = 5); clinical improvement without treatment (n = 1); death without treatment (n = 2). Conclusions. CMV infection of the intestines is clinically significant but will not always present with classic viral cytopathic changes. IHC should be considered in any case where there is a clinical suspicion for CMV infection. Identification of isolated CMV infection by IHC should be considered clinically significant. Current blood viral load tests have poor sensitivity in detecting CMV intestinal infection. Future studies will investigate the predictive value of positive peripheral blood viral load in patients with intestinal symptoms.