Cytomegalovirus infection of gastrointestinal endothelium demonstrated by simultaneous nucleic acid hybridization and immunohistochemistry.

To demonstrate the degree of involvement of endothelial cells in cytomegalovirus (CMV) infection of the gastrointestinal tract we have stained sections from gastrointestinal specimens that showed inclusion bodies on hematoxylin-eosin staining. Factor VIII was first detected using a rabbit anti-factor VIII primary antibody and an alkaline phosphatase-labeled sheep anti-rabbit secondary antibody. The CMV was then visualized with a biotin-labeled CMV probe detected by a streptavidin peroxidase technique with aminoethyl carbazole as the chromogen. Factor VIII staining was a bright blue and CMV a brick red. The specimens included one small-bowel resection and four colonic resections, as well as an esophageal biopsy. The patients' diagnoses included bone marrow transplant recipient, acquired immunodeficiency syndrome, ulcerative colitis, and renal transplant recipient. Cells positive for both CMV and factor VIII ranged from 35% to 60% of positive cells in a representative section, and the relative percentages (mean +/- SE) for cell type for infected cells were: endothelial, 48.9 +/- 4.5; vascular luminal (factor VIII negative), 6.1 +/- 1.7; perivascular (factor VIII negative in vascular wall), 16.2 +/- 3.2; and other cell (non-vascular factor VIII negative), 28.9 +/- 5.1. These findings and clustering of infected cells around the vessels provide evidence that CMV infection of the gastrointestinal tract is primarily vasculitic and related to infection of endothelial cells.