Detection of human cytomegalovirus, Epstein-Barr virus, and herpes simplex virus in diffuse interstitial pneumonia by polymerase chain reaction and immunohistochemistry

Using formalin-fixed and paraffin-embedded tissues from autopsy, the authors examined infection by human cytomegalovirus, Epstein-Barr virus, and herpes simplex virus in 54 patients with primary or secondary diffuse interstitial pneumonia (DIP) by polymerase chain reaction and immunohistochemistry and compared it with that in 32 persons without lung complications. Polymerase chain reaction and immunohistochemistry demonstrated that approximately 40% and 30% of DIP were positive for human cytomegalovirus and Epstein-Barr virus, respectively, but none of 32 controls had evidence of infection by human cytomegalovirus and Epstein-Barr virus. The polymerase chain reaction was more sensitive than the immunohistochemical technique for detection of herpes simplex virus. The former technique revealed herpes simplex virus infection in approximately 90% of DIP and controls and the latter in approximately 50% of each group. However, immunohistochemistry had the advantage of demonstrating the morphologic location of infected cells and of allowing their semiquantitative evaluation. Herpes simplex virus was more extensively distributed in the lungs of several DIP cases than in those of controls, suggesting the reactivation of herpes simplex virus. Only DIP patients (31 cases [57.4%]) were infected by two or three kinds of herpesviruses. The combination of polymerase chain reaction and immunohistochemistry revealed that these herpesviruses proliferated in many cases of DIP.