Detection of herpes simplex virus type 1 in rheumatic valvular tissue.

BACKGROUND: Rheumatic heart disease (RHD) is the most important sequela of rheumatic fever (RF): evidence that streptococcal infection is aetiological is prominent, but sometimes contradictory. Acute HSV-1 infection in mouse leads to carditis and valvulitis whereas recurrent infection results in inflammatory granulomatous lesions that resemble Aschoff bodies. Cells containing HSV-1 inclusions or virus infected giant cells appear similar to Anitschkow cells or Aschoff cells respectively. We hypothesized that HSV-1 infection also may be involved in RHD. METHODS: Formalin-fixed, paraffin-embedded valvular tissue samples from 32 patients with RHD were investigated for evidence of HSV-1 infection. HSV-1 antigen was detected by immunohistochemistry, using HSV-1-specific monoclonal and polyclonal antibodies. HSV-1 glycoprotein D gene sequences were amplified by nPCR, using beta-globin gene amplification in the same samples as internal control. Valvular tissue from 5 cases of sudden death and 3 cases died of neisseria meningitis without a history of valvular disease was used for comparison. HSV-1-infected lung tissue was used as positive control. RESULTS: HSV-1 antigens were detected in valvular tissues from 21 of 32 (65.6%) patients. Fifteen of these 21 (46.9% of cases), but no antigen-negative sample, were positive also for HSV DNA. Nucleotide sequence of PCR products was homologous to the targeted region of the HSV-1 glycoprotein D gene. HSV-1 antigen was present also in one case of sudden death but viral DNA was not found in any tissue sample from the comparison group. Results from reagent and positive controls were as anticipated. CONCLUSIONS: This is the first study to show the presence of HSV-1 antigen and genomic DNA in valvular tissues from patients with RHD and provides evidence for an association of HSV-1 infection with some cases of rheumatic valvular disease.

Detection of enterovirus capsid protein VP1 in myocardium from cases of myocarditis or dilated cardiomyopathy by immunohistochemistry: further evidence of enterovirus persistence in myocytes.

The association of enteroviruses with myocardial disease has been investigated extensively by molecular biological techniques to detect viral RNA, but remains controversial. This retrospective study investigated the involvement of enterovirus in myocarditis or dilated cardiomyopathy (DCM) by detection of viral antigens in myocardial samples from a new patient series using an optimized immunohistochemical technique. Formalin-fixed, paraffin-embedded biopsy, autopsy or explanted myocardial tissue samples were obtained from 136 subjects. These comprised histologically proven cases of acute fatal myocarditis (n=10), DCM (n=89, including 10 patients with healing/borderline myocarditis) and a comparison group of samples from 37 unused donor hearts and cases with other conditions. A monoclonal antibody 5-D8/1 directed against a conserved, non-conformational epitope in capsid protein VP1 was employed for broad detection of different enterovirus serotypes. Investigations were performed blindly. Histological sections from 7 of 10 fatal myocarditis cases, 47 of 89 patients (52.8%) with DCM were positive for the viral capsid protein VP1 by immunohistochemical staining. Consecutive sections of positive samples were negative when the antibody was omitted or replaced with subclass- and concentration-matched normal mouse IgG. In contrast, only 3 of 37 samples (8.1%) in the comparison group were positive (Yates corrected chi(2)=19.99, P<0.001: odds ratio =12.68). VP1 staining was distributed in individual or grouped myofibers and localized in the cytoplasm of myocytes. In some cases, VP1 was detected in only a few myofibers within an entire section. These results provide further evidence of enterovirus involvement in a high proportion of DCM cases and demonstrate that VP1 is present in disease stages from acute myocarditis, healing myocarditis to end-stage DCM requiring cardiac transplantation, indicating translation of viral protein during persistent enterovirus infection.

Herpes simplex virus type 1 infection associated with atrial myxoma.

Some findings suggest an infectious factor in cardiac myxoma and certain histopathological features indicate herpes simplex virus type 1 (HSV-1) infection. We hypothesized that HSV-1 may be involved in the pathogenesis of cardiac myxoma. Paraffin-embedded tissue samples from 17 patients with atrial myxoma were investigated for HSV-1 antigen by immunohistochemistry and viral genomic DNA by nested polymerase chain reaction. The histogenesis and oncogenesis of atrial myxoma were assessed by the expression of calretinin, Ki67, and p53 protein, respectively. Autopsy myocardial samples, including endocardium from 12 patients who died by accident or other conditions, were used for comparison. HSV-1 antigen was detected in atrial myxoma from 12 of 17 patients: 8 of these 12 samples were positive also for HSV-1 DNA. No HSV-1 antigen or DNA was found in tissue from the comparison group. Antigens of HSV-2, varicella-zoster virus, Epstein-Barr virus, and cytomegalovirus were not found in atrial myxoma. Calretinin was found in myxoma cells of all 17 cases but Ki67 was present only in smooth muscle cells or infiltrating cells in some cases. p53 was not detectable in any myxoma. Most infiltrating cells were cytotoxic T lymphocytes. These data suggest that HSV-1 infection is associated with some cases of sporadic atrial myxoma and that these may result from a chronic inflammatory lesion of endocardium.