Adenovirus (ADV) is a DNA virus causing community-acquired respiratory infections in immunocompetent individuals. In immunocompromised patients, ADV can infect a wide variety of tissues, including the lungs, liver, GI, and urinary tract, including the kidney. Patients with severe immunodeficiency often develop multisystemic infections.
Intranuclear replication of adenoviruses produces inclusion bodies that can often be seen by light microscopy. Early stages of viral replication produce small inclusion bodies, which may be eosinophilic or amphophilic on H&E stained sections. As the inclusion bodies enlarge, they become more basophilic, have degeneration of the nuclear membrane, and the resulting “smudge cells” with indistinct nuclear-cytoplasmic borders can be seen in histologic and cytologic preparations. Cytoplasmic inclusions are NOT seen and multinucleation is uncommon. In the lung, ADV infects epithelial cells lining the respiratory passages. ADV in the liver demonstrates as random foci of infection and are often scattered throughout the parenchyma. Foci of tissue necrosis are frequently seen in severe ADV infections with easily identified inclusions at the borders of such necrotic foci. ADV serotypes 40 and 41 have been described as causes of gastroenteritis.
ADV clone 20/11 is an IgG1, kappa isotype monoclonal antibody that comes in an ascites fluid format and is specific to all 41 serotypes of ADV.
Pretreatment of FFPE tissue sections can be accomplished with EIER or HIER. The author's preferred proteolytic enzyme to digest tissue sections is 0.25% trypsin (Ref2), pH 7.6-7.8 for 15 minutes at 37° C. Citrate HIER solution can also be used with very good results.
In the images, an ADV infected liver is demonstrated with a mouse IgG1 monoclonal antibody cocktail of clones 2/6 and 20/11, using DAB chromogen.
