Role of virus-induced myocardial affections in sudden infant death syndrome: a prospective postmortem study.

The cause of sudden infant death syndrome (SIDS) is an unresolved problem of high relevance. Previous studies indicate a role of infections. In our prospective study, we investigated the frequency of virus-induced myocardial affections in SIDS. Postmortem samples from SIDS victims and control subjects were investigated prospectively. Pediatric cases of unnatural death served as controls. Samples were studied for enteroviruses, adenoviruses, parvovirus B19, and Epstein-Barr virus applying PCR. Immunohistochemical investigations for inflammatory cells, the necrosis marker C5b-9((m)) complement complex, and the enteroviral capsid protein VP1 were performed. Overall, 62 SIDS victims were studied. As controls, 11 infants were enrolled. Enteroviruses were detected in 14 (22.5%), adenoviruses in 2 (3.2%), Epstein-Barr viruses in 3 (4.8%), and parvovirus B19 in 7 (11.2%) cases of SIDS. Control group samples were completely virus negative. Compared with controls, immunohistochemical investigations partially revealed a significant increase in the number of T lymphocytes in SIDS myocardial samples (p < 0.05). Furthermore, cases with elevated numbers of leukocytes and macrophages, microfocal C5b-9((m))(+) necroses, and enteroviral VP1 capsid protein within the myocardium were detected. Applying a comprehensive combination of molecular and immunohistochemical techniques, our results demonstrate a clearly higher prevalence of viral myocardial affections in SIDS. Our results emphasize the importance of PCR-based diagnosis of viral myocardial affections. We suggest preliminary criteria for cellular immunohistochemical diagnosis of viral myocardial affections derived from our findings. For future investigations in SIDS, we suggest a comprehensive approach that includes PCR and immunohistochemistry. Our results offer novel strategies for diagnosis of pediatric myocardial viral affections.