Incidence and Characteristics of Myocarditis and Parvovirus B19 Viral DNA at Autopsy A Single Institution Study of 21 Cases
SA Koepsell, SJ Radio. University of Nebraska Medical Center, Omaha, NE
Background: Multiple reports have described Parvovirus B19 (PVB) DNA in association with myocarditis. Despite this association, limited information exists to establish whether PVB is a contributor or bystander in the pathogenesis of myocarditis. We evaluated the prevalence of PVB DNA in cases of myocarditis at autopsy in order to investigate and correlate the clinicopathologic findings associated with PVB positive cases of myocarditis.
Design: All postmortem cases of non-fungal myocarditis at UNMC from 2002 through October 2008 (n = 21, females = 12, age range=22-78 years; mean = 46) were tested for PVB DNA using PCR on paraffin-embedded cardiac tissue with appropriate positive and negative controls. The gross and histologic pathologic characteristics and clinical data were assessed.
Results: The incidence of non-fungal myocarditis at autopsy was 2%. Of the 21 patients with myocarditis, PVB DNA was present in 13 cases, absent in 1 case, and indeterminate in the remaining 7 cases due to inadequate genomic DNA. Clinically, five of the PVB-positive patients had compromised immune function from either advanced malignancy or transplantation. Cardiomyopathic features were present in all 13 patients and included hypertrophy in 12 patients (5 males, 7 females), biventricular dilatation in 8 patients (4 moderate, 4 severe) and interstitial fibrosis in 10 patients (5 mild, 5 moderate). Histologically, the PVB DNA positive-myocarditis tended to be characterized by a mild lymphohistiocytic, patchy infiltration with minimal myocyte damage. The maximum CD45-positive cell count per high-power field averaged 37.4 in immunocompetent patients and 10.6 in immunocompromised patients (p=0.03). Two cases showed significant myocardial eosinophils and/or giant cells in addition to the patchy, mild lymphocytic infiltration.
Conclusions: Our findings indicate that PVB DNA is present in at least 62% of the cases of postmortem myocarditis at our institution. The typical histologic pattern of PVB-associated myocarditis consisted of a mild, patchy lymphocytic infiltrate with minimal myocyte damage. All PVB-positive cases also had associated features of a cardiomyopathy. These results indicate that PVB infection in the myocardium may contribute to a mild, insidious myocarditis. Further studies to localize the virus in cardiac tissue and to assess for viral activity should further elucidate the role of PVB in myocarditis and dilated cardiomyopathy.
Monday, March 9, 2009 9:30 AM
Poster Session I Stowell-Orbison/Autopsy Award # 7, Monday Morning