Detection of parasite DNA in Chagas heart disease.

BRANDARIZ S.; SCHIJMAN A; VIGLIANO C; ARTEMAN P; VIOTTI R; BELDJORD C; LEVIN MJ

LANCET

ELSEVIER SCIENCE INC

Lugar: Londres; Año: 1995 vol. 346 p. 1370 - 1371

0140-6736

Chronic Chagas heart disease (cChHD) resulting from infection with Trypanosoma cruzi is a slowly evolving inflammatory cardiomyopathy. Histopathology reveals mononuclear cell infiltration, myocyte damage, and fibrosis. Since parasite cells are rarely found at sites of myocarditis, autoimmunity has been postulated as the cause of cChHD. We have searched for anti-T cruzi antibodies that differentiate the serological profile of chronically infected individuals with or without cChHD. We have used the serum from a cChHD reference patient with high concentrations of anti-T cruzi antibodies as an immunological probe for isolating parasite recombinant antigens from a T cruzi expression library. The reference serum came from JL, a deceased 27-year-old male, NYHA FC IV. Three T cruzi recombinant (JL derived) antigens JL5, C-P0 (two ribosomal proteins), and JL9 (a microtubule-associated protein)- were homologous to their human counterparts, and were predominantly recognized by sera from patients with cChHD. This led us to propose a molecular mimicry mechanism for generation of autoantibodies in cChHD, further substantiated by the detection of crossreactive epitopes between C-P0 and the human ß1-adrenergic receptor. This hypothesis needed to be tested by identification of the parasite and/or parasite vestiges in pathologic specimens of heart tissue with diffuse myocarditis, but without intracytoplasmic amastigote nests. Amplification of a T cruzi 330 base pairs-minicircle DNA fragment was done with S35 and S36 primers using as a template DNA prepared from one 5 µm-thick section of a 10% formaldehyde-fixed and paraffin-embedded block of JL's left ventricular free wall. Detection  of T cruzi DNA in the heart tissue of patient JL by PCR points to parasite persistence in this organ, and suggest that, in this case, heart parasitation was a prevalent stimulus for the perpetuation of myocardial inflammation, and for generation of a strong anti-T cruzi humoral response, with high serum concentrations of crossreacting antibodies.