More recently, the LMD technique was applied to endomyocardial biopsy specimens in order to precisely separate and collect the cardiomyocytes and the infiltrating lymphocytes in the cardiac tissue infected by Epstein-Barr virus (EBV).17 Paraffin-embedded sections from nine patients with chronic heart failure and a histologic diagnosis of inflammatory cardiomyopathy, with PCR positivity for EBV on whole frozen tissue, were studied. LMD was applied in this series to assess whether the viral genome was localized in the myocytes, the inflammatory cells, or both. The selection of cells was immunohistochemically guided by α-sarcomeric actin antibody staining for cardiomyocytes and CD45RO staining for lymphocytes (Fig 2
). EBV genome was detected by PCR analysis in cardiomyocytes of all patients and was absent in infiltrating lymphocytes, thus suggesting a cytopathic role of this virus and the opportunity for an antiviral/immunomodulatory therapy. Importantly, this study showed that PCR analysis of nucleic acids extracted from a small number of microdissected cells does not cause a loss of sensitivity compared with PCR performed on the whole frozen tissue, with the advantage to allow the cellular localization of the viral agent. The combination of highly sensitive PCR analysis with the microscopical selection of the targeted cells might be useful in the investigation of the different cellular tropism (ie, cardiomyocytes, endothelial cells, fibroblasts, smooth muscle cells) of the viruses infecting the heart, thus improving our knowledge of viral myocarditis in terms of pathogenesis, clinical manifestations, and possible therapeutic options. Similarly, this method can be applied to human atherosclerotic lesions to investigate the presence of microbial agents in the different cellular components of the plaque (ie, foam cells, smooth-muscle cells, lymphocytes, endothelial cells, fibroblasts).