Dept. of Internal Medicine, Virology, Pediatrics, Hematology, PGIMER, Chandigarh, India.
Abstracts of the papers presented at the XVIII National Conference of Indian Virological Society at Post Graduate Institute of Medical Education and Research, Chandigarh, India, December 11–13, 2008.
Myocarditis is defined as an inflammatory disorder of the myocardium with or without necrosis of the myocytes associated with inflammatory infiltrate. Many viruses have been attributed as the causative agents of myocarditis and the subsequent development of dilated cardiomyopathy (DCM). The role of antiviral drugs in DCM is gaining importance recently. We aimed to detect the viral genome and expression of coxsackie-adenovirus receptor (CAR) in autopsied myocardial tissue of patients with dilated cardiomyopathy. Formalin-fixed myocardial tissues collected during autopsy from 20 cases of DCM were included in the study group. Tissues of 16 cases each of rheumatic heart disease (RHD) and non-cardiac disease were taken as controls. The formalin-fixed tissues were evaluated for Adenovirus and Parvovirus B-19 DNA by polymerase chain reaction. The expression of CAR was detected by immunohistochemistry by using specific primary antibody. The grade of positivity was expressed as weak (1+), moderate (2+) and marked (3+) in the myocytes, interstitial cells and endothelial cells. Parvovirus B-19 DNA was detected in 3 cases of DCM, 3 cases of RHD and 1 case of non-cardiac disease whereas adenovirus DNA was detected in none of the DCM cases and control groups. Of the 19 DCM cases, 12 showed 2+ to 3+ positivity for CAR in myocytes and endothelial cells and 4 cases showed 1+ positivity in myocytes and endothelial cells. There was no increased expression of CAR in the remaining cases. Among the control cases, 1 RHD case and 1 non-cardiac case showed 1+ positivity in myocytes. Rest of the controls were negative for CAR expression. Increased myocardial CAR expression in DCM cases implies the role of either coxsackievirus or adenovirus in the pathogenesis of DCM. Although Coxsackievirus B has been considered as the major cause of viral myocarditis, Adenoviruses have established a significant association with this disease entity in recent years. Parvovirus B-19 may be an important cause of viral myocarditis ultimately leading to dilated cardiomyopathy; however, being a ubiquitous virus, the possibility of an incidental finding cannot be ruled out.
