Figure 2).

On the basis of Masson trichrome stains (A) and immunohistochemical detection of CD68+ macrophages (B), healing myocarditis was diagnosed in the patient. Interestingly, no CD3+ T lymphocytes were present at this stage of disease. A significant part of the myocardium revealed fibrosis (light gray-stained tissue). Visualization of the human herpesvirus 6 (HHV-6) DNA in interstitial mononuclear cells of the myocardium as detected by radioactive RNA/DNA in situ hybridization (C). Inset shows the detection of HHV-6 DNA by nested polymerase chain reaction (PCR) in endomyocardial biopsies (lane 1), peripheral blood leukocyte preparation (lane 2) and plasma (lane 3) of the patient. Control PCRs are shown in lanes 4 to 6 (HHV-6-negative patient [lane 4], PCR without DNA [lane 5] and HHV-6-positive control [lane 6]). M Marker (φX174 Hae III)