title: IgG subclass reactivity to Trypanosoma cruzi in chronic chagasic patients.
abstract: BACKGROUND
  The anti-Trypanosoma cruzi antibodies isotype profile in Chagas' disease has been studied in relation to different clinical manifestations. A high titer of IgG anti-T. cruzi antibodies is found in patients with cardiac involvement, while a high titer of IgA anti-T. cruzi antibodies is associated with digestive forms.
  
  
  OBJECTIVE
  The aim of this work was to analyze the IgG subclass reactivity of anti-T. cruzi antibodies in patients with chronic Chagasic cardiomyopathy.
  
  
  METHODS
  Twelve consecutive chagasic patients were analyzed for IgG subclass reactivity to a T. cruzi antigenic extract. They had a complete clinical evaluation, peripheral EKG, echocardiography, left ventriculogram, and coronariography.
  
  
  RESULTS
  All patients came from rural areas of Mexico and had lived in endemic zones for over seven years. They presented left ventricular endsystolic dimension above 42 mm in 58% (7/12) and ejection fraction below 50% in 58% (7/12). We found that IgG1 and IgG2 anti-T. cruzi antibodies showed higher titer than IgG3 antibodies, with consistently low titer of IgG4 antibodies. Expression of the four IgG subclasses of anti-T. cruzi antibodies suggest a mixed Th1/Th2-like immune response under a probably continuous chronic antigenic stimulation. On the other hand, high levels of IgG2 anti-T. cruzi antibodies showed a tendency to be associated with severe cardiomegaly.
  
  
  CONCLUSIONS
  Our results suggest that a mixed Th1/Th2-like immune response may take place in chronic chagasic patients under a chronic antigenic stimulation.
authors.affiliation: Laboratorio de Inmunoparasitología, Instituto Nacional de Cardiología I. Chávez, INCICH, Juan Badiano No. 1, 14080 México D.F.
authors.forename: N
authors.initials: N
authors.lastname: Hernández-Becerril
authors.forename: A
authors.initials: A
authors.lastname: Nava
authors.forename: P A
authors.initials: PA
authors.lastname: Reyes
authors.forename: V M
authors.initials: VM
authors.lastname: Monteón
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood / Q000276:immunology*; D000937:Antigen-Antibody Reactions; D002598:Chagas Cardiomyopathy / Q000097:blood / Q000276:immunology*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D014349:Trypanosoma cruzi / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan; D007074:Immunoglobulin G