Genotyping studies show a polarized geographic distribution of Trypanosoma cruzi lineages in humans. Here, we assessed their distribution along Latin America through an immunological approach we designated Western blot (WB) assay with Trypomastigote small-surface antigen (TSSA) I and TSSA II (TSSA-WB). These antigens are expressed by T. cruzi I (TCI; now TcI) and T. cruzi II (TCII; reclassified as TcII to TcVI) parasites. TSSA-WB showed good concordance with genotyping tests. An unexpected frequency of TSSA II recognition was observed in Colombia, Venezuela, and Mexico (northern region of Latin America). In Argentina and Paraguay (southern region), immunophenotyping confirmed the already reported TCII (TcII to TcVI) dominance. The lineage distribution between these regions showed significant difference but not among countries within them (except for Colombia and Venezuela). TSSA-WB shows TCII emergence in the northern region where TCI was reported as dominant or even as the unique T. cruzi lineage infecting humans.

Eight patients were studied to determine the possible use of clofazimine for treating erythema dyschromicum perstans (EDP). The T-helper/T-suppressor cytotoxic ratio (CD-4/CD-8) and the in vitro lymphoproliferative response on stimulation with phytohemaglutin (PHA) and concanavalin A (Con A) were determined in peripheral blood before and after treatment. Of the eight patients studied, seven had excellent to good responses, whereas only one had a marginal response. The immunologic evaluation before and after treatment showed a significant change in the CD-4/CD-8 ratio, a decrease of the response to PHA, and no change in the response to Con A. The results obtained show that clofazimine is useful for treating this nosologic entity because of its cosmetic effect, and also because it induces changes in cell-mediated response, which could be very important therapeutically.

Neuroendocrine/inflammatory and endothelial functions have been indicated as crucial for heart failure (HF) patients. We evaluated relation in HF patients among cytokines and asymmetric dimethylarginine (ADMA) and left ventricular ejection fraction (LVEF) at baseline and after long-term administration of carvedilol. Interleukin 10 (IL-10), interleukin 18 (IL-18), and ADMA were measured in 22 NYHA class II to IV HF patients at baseline and after 40 +/- 14 months of carvedilol treatment. Patients were divided into 2 groups according to whether, after treatment with carvedilol, LVEF had increased at least 5% (responders) or less than 5% (non-responders). In responders (11 of 22 patients), LVEF increased from 38 +/- 6% to 50 +/- 7%, (P < 0.001); in non-responders, it decreased from 36 +/- 9% to 31 +/- 6%, (P = 0.02); NYHA class significantly decreased in both groups. IL-18 decreased in responders (from 586.4 +/- 128 to 183.13 +/- 64.4 pg/mL; P < 0.001) and in non-responders (from 529.3 +/- 116.25 to 142.4 +/- 58.9 pg/mL; P < 0.001). IL-10 increased in responders (from 0.49 +/- 0.25 to 2.01 +/- 1.01 pg/mL; P < 0.001) and in non-responders (from 0.64 +/- 0.31 to 1.33 +/- 0.59 pg/mL; P < 0.001). Conversely, ADMA levels decreased only in responders (from 0.67 +/- 0.16 to 0.44 +/- 0.15 micromol/L; P < 0.001), and an inverse correlation was observed between basal ADMA levels and changes in LVEF after treatment. In HF patients, carvedilol appears to reduce symptoms and the expression of inflammation, regardless of the LV functional response. In those patients showing improvement of LVEF, the reduction of inflammation is paralleled by a reduction of ADMA. We surmise that carvedilol could be effective at various independent levels as a result of possible pleiotropic effects of this agent.

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The partial suppression of the cell-mediated immune response by Trypanosoma cruzi antigens in patients with Chagas' disease is demonstrated in a costimulation assay with T. cruzi antigens and Mycobacterium tuberculosis purified protein derivative (PPD) or Tetanus toxoid (TT). Mononuclear cells from 13 patients with chagasic infection without evidence of heart disease, 10 patients with chagasic cardiomyopathy and 7 healthy blood bank donors were stimulated with antigen A (autoclaved epimastigotes), PPD, TT, PPD + A, PPD + TT and TT + A. The average percentage of suppression induced by costimulation of mononuclear cells with PPD and antigen A was 47.1% in patients with chagasic infection without heart disease (INF), 38.8% in patients with chagasic cardiomyopathy (CDM) and 23.3% in healthy controls. Similar values were observed when living trypomastigotes were used. A costimulatory study with PPD and TT, PPD and A and TT and A was carried out in 8 patients with chagasic infection, in order to evaluate the possibility that this difference could be due to a nonspecific inhibitory effect. The mean suppression induced by TT + PPD was -8.9, with TT + A was 52.7 and with PPD + A was 50.1. The data reported show that T. cruzi antigens induce a specific suppression of the proliferative response of mononuclear cells, that might be relevant to the persistence of the parasite in the host.