title: Immunostaining Detection of Cytomegalovirus in Gastrointestinal Biopsies: Clinicopathological Correlation at a Large Academic Health System.
abstract: BACKGROUND
  Cytomegalovirus (CMV) infection can be asymptomatic in healthy individuals but may cause serious complications in immunocompromised patients. We investigated the clinicopathological correlation of CMV in gastrointestinal (GI) biopsies at our institute between January 1, 2013 and December 31, 2015.
  
  
  METHODS
  A total of 105 non-neoplastic GI biopsies tested positive for CMV by immunohistochemistry (IHC). The IHC results were stratified as "true positive" if > 2 cells stained, or "rare positive" if only 1 - 2 cells stained. Clinical information including comorbidities, serum CMV viral loads, and treatment was reviewed and correlated.
  
  
  RESULTS
  Overall 1% of all GI biopsies were positive for CMV by immunostaining. The most frequently involved organ was colon, followed by esophagus, stomach, ileum and duodenum. When > 2 cells were stained positive, serum CMV viral loads were positive in 52.2%, negative in 17.2%, and not tested in 27.6% of cases. When only 1 - 2 cells stained positive, CMV viral loads were positive in 23.4%, negative in 25.5%, and not tested in 51.1% of cases. We further showed that clinical management of CMV differs based on both pathological findings and underlying diseases.
  
  
  CONCLUSIONS
  The role of CMV in GI biopsies remains controversial. We propose an algorithm of performing CMV immunostaining based on clinicopathological correlation.
authors.affiliation: Department of Pathology, University of California, San Diego, CA, USA.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Liao
authors.affiliation: Department of Pathology, University of California, San Diego, CA, USA; Department of Medicine, University of California, San Diego, CA, USA.
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Reed
authors.affiliation: Department of Pathology, University of California, San Diego, CA, USA.
authors.forename: Grace Y
authors.initials: GY
authors.lastname: Lin
keywords: Cytomegalovirus; Gastrointestinal biopsy; Immunostaining