[The proliferative response of T cells against cruzipain in chronic chagasic cardiopathy]

Oxidative stress in chronic cardiopathy associated with Chagas disease

BACKGROUND

Chagas disease is characterized by chronic inflammation similar to autoimmune diseases. The imbalance between prooxidant and antioxidant defenses is known as oxidative stress, and is often associated with inflammatory processes of many diseases.

METHODS

The present work measured some components of the antioxidant system present in the blood of four groups of patients in different stages of chronic Chagas heart disease (n=10 each group), according to the modified Los Andes clinical-hemodynamic classification. Each group of chagasic patients was compared with four groups of healthy subjects, and chagasic group IV was compared to group V, characterized by rheumatic cardiac disease, giving a total of 90 subjects. Antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), and the contents of reduced (GSH), oxidized (GSSG) and total glutathione (TG) were assayed.

RESULTS

SOD, CAT and GR activities showed essentially no differences among the four groups, however, intraerythrocytic GSH concentrations showed decreased values parallel to the progression of the disease. In addition, the glutathione peroxidase (GPx) activities were higher in groups III and V and lower in groups I, II and IV, also suggesting an antioxidant depletion with progression of the disease. In contrast, except for SOD and CAT activities, patients from group V showed a generally higher antioxidant capacity compared to the chagasic group IV.

CONCLUSION

The results indicate a general increase of oxidative stress parallel to the progression of Chagas disease.

Humoral immune response to cruzipain and cardiac dysfunction in chronic Chagas disease

The humoral immune response to epitopes expressed on cruzipain was evaluated in 31 Chagas disease patients (CDP) with different degrees of cardiac dysfunction. We took advantage of the availability of anti-Trypanosoma cruzi microsomal fraction monoclonal antibodies (MoAbs) reactive with epitopes that are recognized (5A9B11) or not recognized (1A10C11) by CDP sera. The 5A9B11- and 1A10C11-like epitopes are expressed on cruzipain. The reactivity of 5A9B11 against cruzipain was completely inhibited by sera of severe cardiopathy patients while a partial inhibition was found with sera from chagasic patients with mild disease. CDP sera did not block cruzipain recognition by 1A10C11. The antigenic determinants recognized by CDP sera appeared to be linear and carbohydrate free. When the overall anti-cruzipain immune response was evaluated, 70% of CDP with severe disease showed cruzipain titers higher than 1/800 while none of them displayed titers lower that 1/400. This report shows for the first time that the humoral immune response against epitopes expressed on cruzipain appeared to be related with the severity of chronic Chagas disease.