Background: Parvovirus B19 (B19V) has been identified as the most common virus in dilated cardiomyopathy (DCM) patients by PCR techniques. We investigated the detectability and the expression pattern of B19V proteins by immunohistology (IH) in endomyocardial biopsies (EMBs) from DCM patients, and its association with the standard proof of B19V genomes by nested PCR (nPCR.
Material and Method: EMBs from 30 DCM patients were analyzed by nPCR for B19V genomes, and IH of B19V VP1/VP2 expression was carried out using the antibody clone R92F6. The specificity of this antibody was investigated on 293T cells transfected with pB19-M20. Positive anti-B19V IH staining (positive in n=14/46.6%) and nPCR proof of B19V genomes (positive in n=15/50%) were significantly associated (p=0.0003).
Results: Based on the B19V nPCR results, the sensitivity of anti-B19V-VP1/VP2 IH was 80.0%, and the specificity was 86.0%. B19V immunostaining was observed on interstitial cells in all IH positive cases, and was noted additionally on endothelial cells in 1, and on cardiomyocytes in 4 cases.
Conclusions: IH detection of B19V VP1/VP2 expression provides a high association with the nPCR proof of B19V genomes in DCM patients. IH detection of B19V proteins enables a differentiation of B19V VP1/VP2 expressing cells within the myocardium.

Keywords: Parvovirus B19, Human - immunology, Genome, Viral - genetics, Fluorescent Antibody Technique, Endocardium - virology, Cell Line, Cardiomyopathy, Dilated - virology, Viral Load, Transfection, Polymerase Chain Reaction, Capsid Proteins - immunology, Biopsy, Antibodies, Viral - immunology, Adult