Poor diagnostic value of in situ hybridization and immunohistochemistry in endomyocardial biopsies to detect cytomegalovirus after heart transplantation.

Cytomegalovirus (CMV) infection is a major cause of morbidity and death in heart transplant recipients. Cardiac graft involvement in CMV infection is a matter of controversy, considering its frequency and its relationship with acute or chronic rejection. Four heart transplant patients were selected because of a severe CMV infection (systemic, gastrointestinal, ophthalmic, and neurologic involvement). Immunoglobulin M and increased immunoglobulin G CMV antibodies developed. Twenty-two routine endomyocardial biopsies (EMB; mean: 5.5 EMB per patient; range, 3 to 9) from these patients were selected covering the period of CMV infection. Grading of rejection showed 12 biopsies with "no evidence of rejection (grade 0)," nine biopsies with "mild acute rejection (grade 1B)," and one biopsy with "moderate acute rejection (grade 3A)." One EMB exhibited a single CMV inclusion in an endothelial cell detectable by light microscopy. The EMB were assessed for CMV infection using in situ hybridization (ISH) for the detection of CMV genome with a biotinylated CMV probe and immunohistochemistry (IHC) for the detection of CMV immediate-early antigen with the monoclonal antibody E13. ISH and IHC detected a single CMV-infected cell, respectively, in one and two EMB from two patients. The patient with a CMV inclusion determined by light microscopy was also positive with both techniques. Positive ISH and IHC were always in enlarged inclusion-bearing cells, which were easily observable with routine staining. One EMB had mild acute rejection, and the other one had no rejection.(ABSTRACT TRUNCATED AT 250 WORDS)