Serum cytokines and activation ex vivo of CD4+ and CD8+ T cells in chagasic chronic Mexican patients

The clinical manifestations of human Chagas disease are associated with several factors, including immunological alterations, in this regard, many studies propose that tissue damage might be more severe in the absence of immune regulatory mechanisms, other factors are the genetic background of host and parasite. Trypanosoma cruzi population is genetically, biochemistry and pathogenic diverse along the Latin-America continent and phylogenetic ally are divided into six intra-species lineages TcI-VI. The TcI lineage has a wide distribution with heterogeneous virulence and pathogenesis within strains. In Mexico, the main circulating lineage is TcI in human infections. We analyzed intracytoplasmic cytokines of unstimulated peripheral T lymphocytes, and the level of cytokines (IL-2, IL-4, IL-12, IL-10, IFN-γ and sIL-2R) in the serum of Mexican chagasic subjects. The population studied consisted of 15 asymptomatic individuals, 17 patients with chronic chagasic cardiopathy (CCC), 20 patients with cardiopathy but negative serology for T. cruzi, and 10 healthy subjects. The analysis of CD4+ cells revealed that CCC and asymptomatic patients have higher CD25+ and CD69 activation markers than controls. The Th1 subset (CD4+/IFN- γ +) was higher in CCC than in asymptomatic and control subjects, whereas Th2 subset was markedly high in asymptomatic subjects. Circulating cytokines were below level detection with the exception of IL-2 and sIL-2R. Infection with Mexican Trypanosoma cruzi strains in asymptomatic chagasic subjects have a tendency for a Th2 response with higher CD8+/IFN-γ T cells. In contrast, CCC patients have low levels of intracellular IFN- γ and IL-2 cytokines. In both groups circulating serum cytokines are below the detectable level.

ITS1 PCR-RFLP Diagnosis and Characterization of Leishmania in Clinical Samples and Strains from Cases of Human Cutaneous Leishmaniasis in States of the Mexican Southeast.

American cutaneous leishmaniasis includes a spectrum of clinical forms localized cutaneous, diffuse cutaneous, and mucocutaneous leishmaniasis which can be caused by different strains of Leishmania belonging to the L. mexicana or L. braziliensis complexes which may coexist in the same endemic area. We evaluated the PCR-RFLP assay of the ITS1 genes for direct identification of Leishmania species in 163 clinical samples and 21 Mexican isolates of Leishmania. In relation to the Mexican isolates of Leishmania 52% displayed a pattern similar to the L. (L.) mexicana, 5% showed a mixed pattern compatible with L. (L.) mexicana and L. (V.) braziliensis, eight with L. (L.) amazonensis and L. (L.) mexicana, and one to L. (V.) braziliensis. Most of the clinical samples, 109/116 (94%), gave a pattern similar to that of the L. mexicana, two clinical samples gave similar patterns to that of Leishmania braziliensis, and 5 samples gave patterns that suggest a coinfection of L. (L.) mexicana and L. (V.) braziliensis or L. (L.) mexicana and L. (L.) amazonensis. The ITS1 PCR-RFLP assay is a multipurpose tool for diagnosis of Leishmania from clinical samples and enables determination of the infecting species of New World Leishmania in the field in relatively short time and low cost.

Enzyme-linked immunosorbent assay and polymerase chain reaction performance using Mexican and Guatemalan discrete typing unit I strains of Trypanosoma cruzi.

Thirteen Trypanosoma cruzi isolates from different geographic regions of Mexico and Guatemala belonging to discrete typing unit (DTU) I and a reference CL-Brener (DTU VI) strain were used to perform enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). A panel of 57 Mexican serum samples of patients with chronic chagasic cardiopathy and asymptomatic infected subjects (blood bank donors) were used in this study. DNA from the above 14 T. cruzi strains were extracted and analyzed by PCR using different sets of primers designed from minicircle and satellite T. cruzi DNA. The chronic chagasic cardiopathy serum samples were easily recognized with ELISA regardless of the source of antigenic extract used, even with the CL-Brener TcVI, but positive serum samples from blood bank donors in some cases were not recognized by some Mexican antigenic extracts. On the other hand, PCR showed an excellent performance despite the set of primers used, since all Mexican and Guatemalan T. cruzi strains were correctly amplified. In general terms, Mexican, Guatemalan, and CL-Brener T. cruzi strains are equally good sources of antigen when using the ELISA test to detect Mexican serum samples. However, there are some strains with poor performance. The DTU I strains are easily detected using either kinetoplast or satellite DNA target designed from DTU VI strains.

Immunological identification of Trypanosoma cruzi lineages in human infection along the endemic area.

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.

Serological and parasitological screening of Trypanosoma cruzi infection in mothers and newborns living in two Chagasic areas of Mexico.

BACKGROUND: Maternal-fetal transmission of Trypanosoma cruzi generally occurs in 2-12% of pregnant infected mothers. This transmission form has been poorly studied in Mexico where only one case of congenital infection published in 1998 has been reported. METHODS: We screened 145 mothers and their delivered babies in two hospitals of endemic regions in Mexico (states of Chiapas and Veracruz) searching for anti-T. cruzi antibodies and circulating parasites by hemoculture and PCR. RESULTS: In Poza Rica, Veracruz, 3/85 (3.5%) mothers were seropositive for T. cruzi infection and in Palenque, Chiapas, 3/60 (5%) cases. In total 6/145 (4.1%) were seropositive subjects. Although cord blood samples of delivered babies from seropositive mothers have IgG anti-T. cruzi antibodies, none presented PCR and positive hemoculture. CONCLUSIONS: Although a high relative seroprevalence of T. cruzi infection in pregnant women was detected, no case of vertical transmission was recognized. Undoubtedly, further studies of large samples are necessary to evaluate maternal transmission risk in Mexico.

Autoantibodies to human heart conduction system in Chagas' disease.

Destruction of heart tissue in chronic chagasic cardiopathy may be caused by autoimmune recognition of heart tissue. Indirect evidence suggests that there is antigenic cross-reactivity between Trypanosoma cruzi and heart tissue. The objective of this study was to determine whether seric autoantibodies against atrio-ventricular (AV) node and sinus auricular node tissues are markers of chronic cardiopathy condition. We searched for the presence of seric autoantibodies against AV node and sinus auricular node tissues in 25 sera from chronic chagasic cardiopathy patients, 20 sera from non-chagasic cardiopathy patients, 20 sera from indeterminate chagasic subjects, and 20 sera from healthy blood donors as controls. Diagnosis of dilated cardiopathy was established based on the left-ventricular end systolic dimension and cardiothoracic ratio on chest x-radiography and impaired contracting ventricle, and chagasic etiology by demonstration of circulating antibodies using ELISA and IIF. Autoantibody detection against conduction heart tissue was carried out by immunohistochemical test. The tissues were obtained from non-cardiopathy necropsy case. Human sera were diluted at 1:10 in PBS-FSB. Goat antihuman laminin was used as positive control. Autoantibodies were more frequently found in chronic chagasic cardiopathy (20%) compared to non-chagasic cardiopathy (5%) and indeterminate chagasic subjects (5%), pattern staining define interstitial and membrane targets on rich conduction system tissue. In conclusion seric autoantibodies against heart conduction system are not a good markers for chagasic cardiopathy group. Their presence showed no clear association with complex rhythm/conduction aberrations.

Trypanosoma cruzi isolates from Mexican and Guatemalan acute and chronic chagasic cardiopathy patients belong to Trypanosoma cruzi I.

Trypanosoma cruzi is classified into two major groups named T. cruzi I and T. cruzi II. In the present work we analyzed 16 stocks isolated from human cases and four isolated from triatomines from diverse geographical origins (Mexico and Guatemala). From human cases four were acute cases, six indeterminates, and six from chronic chagasic cardiophatic patients with diagnosis of dilated cardiomyopathy established based on the left-ventricular end systolic dimension and cardiothoracic ratio on chest X-radiography and impaired contracting ventricle and different degree conduction/rhythm aberrations. DNA samples were analyzed based on mini-exon (ME) polymorphism, using a pool of three oligonucleotide for the amplification of specific intergenic region of T. cruzi ME gene. All the Mexican and Guatemalan isolates regardless their host or vector origin generated a 350 bp amplification product. In conclusion T. cruzi I is dominant in Mexico and Guatemala even in acute and chronic chagasic cardiopathy patients. To our knowledge, this is the first study describing predominance of T. cruzi I in human infection for North and Central America.

[Heterogeneous distribution of the prevalence of anti-Trypanosoma cruzi antibodies among blood donors in the State of Puebla, Mexico]. / Distribución heterogénea de la prevalencia de anticuerpos contra Trypanosoma cruzi en donadores de sangre en Puebla, México.

OBJECTIVE: To determine the seroprevalence and associated factors, of antibodies against Trypanosoma cruzi (T. cruzi Ab) among blood donors living in rural and suburban areas and risk regions. MATERIAL AND METHODS: A cross-sectional study was conducted from January to December 2003, in 2489 blood donors of seven regions of Puebla, who were evaluated for mandatory viral and T. cruzi serological tests using validated procedures. RESULTS: The seroprevalence for T. cruzi Ab was 1.24% (31/2489), similar to hepatitis C (HVC) (1.5%) and higher than human immunodeficiency virus (HIV) (0.4%) and hepatitis B (HVB) (0.3%). The highest seroprevalences were observed in the regions of Tehuacan-Sierra Negra and Mixteca, up to 2.6%, while in Sierra nororiental and Angelopolis no positive blood donors were identified. A positive association was observed between seropositivity and being older than forty years and being born and raised in Tehuacan-Sierra Negra and Mixteca. CONCLUSIONS: T. cruzi seroprevalence distribution is heterogeneous, from 0% to 2.6%, with higher seroprevalences in the regions of Tehuacan-Sierra Negra and Mixteca.

Trypanosoma cruzi isolates from Mexican and Guatemalan acute and chronic chagasic cardiopathy patients belong to Trypanosoma cruzi I

Trypanosoma cruzi is classified into two major groups named T. cruzi I and T. cruzi II. In the present work we analyzed 16 stocks isolated from human cases and four isolated from triatomines from diverse geographical origins (Mexico and Guatemala). From human cases four were acute cases, six indeterminates, and six from chronic chagasic cardiophatic patients with diagnosis of dilated cardiomyopathy established based on the left-ventricular end systolic dimension and cardiothoracic ratio on chest X-radiography and impaired contracting ventricle and different degree conduction/rhythm aberrations. DNA samples were analyzed based on mini-exon (ME) polymorphism, using a pool of three oligonucleotide for the amplification of specific intergenic region of T. cruzi ME gene. All the Mexican and Guatemalan isolates regardless their host or vector origin generated a 350 bp amplification product. In conclusion T. cruzi I is dominant in Mexico and Guatemala even in acute and chronic chagasic cardiopathy patients. To our knowledge, this is the first study describing predominance of T. cruzi I in human infection for North and Central America.

Distribución heterogénea de la prevalencia de anticuerpos contra Trypanosoma cruzi en donadores de sangre en Puebla, México / Heterogeneous distribution of the prevalence of anti-Trypanosoma cruzi antibodies among blood donors in the State of Puebla, Mexico

OBJETIVO: Identificar la seroprevalencia de anticuerpos anti Trypanosoma cruzi (Ac anti-T. cruzi) en donadores de sangre que habitan en ámbito rural y suburbano, así como las regiones del estado de mayor riesgo y factores asociados. MATERIAL Y MÉTODOS: Estudio transversal realizado de enero a diciembre de 2003. Se analizaron 2 489 donadores de sangre reclutados en 10 puestos de sangrado del Instituto Mexicano del Seguro Social (IMSS) distribuidos en las siete regiones económicas del estado de Puebla, México. Se determinó la seroprevalencia mediante las pruebas serológicas obligatorias del panel viral y, además, para T. cruzi, región de reclutamiento y de origen de los donadores. RESULTADOS: La seroprevalencia de Ac anti-T. cruzi fue de 1.24 por ciento (31/2 489) comparable con la obtenida para el virus de la hepatitis C (1.5 por ciento) y por arriba de la del virus de la inmunodeficiencia humana (0.4 por ciento) y del antígeno de superficie del virus de la hepatitis B (0.3 por ciento). Las regiones de Tehuacán-Sierra Negra y Mixteca fueron las de mayor riesgo con seroprevalencias, por el origen del donador, de 2.6 por ciento para T. cruzi, mientras que en los originarios de las regiones Sierra nororiental y Angelópolis no se detectaron casos positivos. Se observó asociación entre ser seropositivo y mayor de 40 años y ser originario de las regiones de Tehuacán-Sierra Negra y Mixteca. CONCLUSIONES: La distribución de seroprevalencia a T. cruzi es heterogénea, oscila desde 0 por ciento hasta 2.6 por ciento, y se reconoce a Tehuacán-Sierra Negra y Mixteca como las regiones de mayor riesgo.

[Biotic and abiotic determinants of seroprevalence of antibodies against Trypanosoma cruzi in Palmar de Bravo, Puebla, Mexico]. / Factores bióticos y abióticos que determinan la seroprevalencia de anticuerpos contra Trypanosoma cruzi en el municipio de Palmar de Bravo, Puebla, México.

OBJECTIVE: To establish the relationship between seroprevalence for antibodies against Trypanosoma cruzi and its relationship with biotic and abiotic factors. MATERIAL AND METHODS: A cross-sectional study was conducted between August 2000 and September 2001. The study population consisted of a simple random sample of 390 volunteers residing in Palmar de Bravo, Puebla, Mexico. Sample and data collection procedures included assaying antibodies against T. cruzi with validated assays, and searching for domestic reservoirs and triatomine bugs. The relationship between biotic and abiotic factors with seropositivity was assessed. Statistical analysis was conducted using Kappa values for diagnostic tests; statistical significance was assessed with 2 x 2 tables, chi-squared test with Yates' correction, Fisher exact test, and odds ratios. RESULTS: The seroprevalence of T. cruzi infection in humans was 4%; in domestic reservoirs (horses, pigs, and dogs) only 10% of canine reservoirs were positive. Vector species recognized were T. borberi and T. pallidipennis, with a Dispersion Area Index and a Colonization Index of 55% and 40%, respectively. The most important risk factors associated with positive serology were altitude (>2,150 and <2,180 meters above sea level), presence of triatomines, age, time of residence, and participation in a social assistance program. CONCLUSIONS: T. cruzi infection was identified in human beings, vectors, and possibly in domestic reservoirs, in communities located over 2,000 meters above sea level.

Factores bióticos y abióticos que determinan la seroprevalencia de anticuerpos contra Trypanosoma Cruzi en el municipio de Palmar de Bravo, Puebla, México / Biotic and abiotic determinants of seroprevalence of antibodies against Trypanosoma cruzi in Palmar de Bravo, Puebla, Mexico

OBJETIVO: Determinar la prevalencia de anticuerpos contra Trypanosoma cruzi y su relación con los factores bióticos y abióticos en Palmar de Bravo, Puebla, México. MATERIAL Y MÉTODOS: Estudio transversal efectuado en agosto de 2000 a septiembre de 2001, con una muestra aleatoria simple de 390 voluntarios residentes en Palmar de Bravo, Puebla, México. Se hizo determinación de anticuerpos contra T cruzi con técnicas serológicas validadas, búsqueda del vector y de reservorios domésticos, así como determinación de asociación entre caso positivo y factores de riesgo bióticos y abióticos. El análisis estadístico consistió en índice Kappa para las pruebas diagnósticas, empleando tabla de contingencia de 2 x 2; ji cuadrada corregida de Yates, exacta de Fisher y la razón de posibilidad para estimar la significancia de la asociación de factores bióticos y abióticos. RESULTADOS: La seroprevalencia fue de 4 por ciento en la población humana estudiada y de los reservorios (equinos, porcinos y caninos), sólo 10 por ciento de los caninos resultaron reactivos. Los vectores identificados fueron T barberi y T pallidipennis, con índice de dispersión e índice de colonización de 55 y 40 por ciento, respectivamente. Los factores de riesgo más importantes fueron la altitud (>2 150 y <2 180 metros sobre el nivel del mar), los años de residencia, el pertenecer a un programa de asistencia social, la presencia de triatóminos y la edad. CONCLUSIONES: En localidades ubicadas a una altitud mayor a los 2 000 metros sobre el nivel del mar se reconocieron vectores infectados con T cruzi, casos humanos y probablemente reservorios domésticos.

Electrocardiographic findings in Mexican chagasic subjects living in high and low endemic regions of Trypanosoma cruzi infection.

In México the first human chronic chagasic case was recognized in 1940. In spite of an increasing number of cases detected since that time, Chagas disease in México has been poorly documented. In the present work we studied 617 volunteers subjects living in high and low endemic regions of Trypanosoma cruzi infection with seroprevalence of 22% and 4% respectively. Hemoculture performed in those seropositive subjects failed to demonstrate circulating parasites, however polymerase chain reaction identified up to 60% of them as positives. A higher level of anti-T. cruzi antibodies was observed in seropositive residents in high endemic region, in spite of similar parasite persistence (p < 0.05). On standard 12 leads electrocardiogram (ECG) 20% to 22% seropositive individuals from either region showed right bundle branch block or ventricular extrasystoles which were more prevalent in seropositive than in seronegative individuals (p < 0.05). In conclusion, the frequency or type of ECG abnormality was influenced by serologic status but not by endemicity or parasite persistence. Furthermore, Mexican indeterminate patients have a similar ECG pattern to those reported in South America.

Electrocardiographic findings in Mexican chagasic subjects living in high and low endemic regions of Trypanosoma cruzi infection

In México the first human chronic chagasic case was recognized in 1940. In spite of an increasing number of cases detected since that time, Chagas disease in México has been poorly documented. In the present work we studied 617 volunteers subjects living in high and low endemic regions of Trypanosoma cruzi infection with seroprevalence of 22 percent and 4 percent respectively. Hemoculture performed in those seropositive subjects failed to demonstrate circulating parasites, however polymerase chain reaction identified up to 60 percent of them as positives. A higher level of anti-T. cruzi antibodies was observed in seropositive residents in high endemic region, in spite of similar parasite persistence (p < 0.05). On standard 12 leads electrocardiogram (ECG) 20 percent to 22 percent seropositive individuals from either region showed right bundle branch block or ventricular extrasystoles which were more prevalent in seropositive than in seronegative individuals (p < 0.05). In conclusion, the frequency or type of ECG abnormality was influenced by serologic status but not by endemicity or parasite persistence. Furthermore, Mexican indeterminate patients have a similar ECG pattern to those reported in South America

Seroprevalence of human Trypanosoma cruzi infection in diferent geografic zones of Chiapas, Mexico

Foi feito um estudo sorológico em quatro zonas geográficas do estado de Chiapas México. Foram colhidas 1333 amostras dos habitantes das 13 comunidades situadas na costa, na região central montanhosa, na floresta lacandona e na região chamada mesochiapas. Cento cinqüenta e uma pessoas (11,3 por cento) foram identificadas como soropositivas. A infecção pelo Trypanosoma cruzi teve a influência da geografia local. Na floresta lacandona nas montanhas centrais, foi encontrada uma prevalência de 32,1 e 13,8 por cento respectivamente, mais que na costa 1,2 por cento. Na zona de mesochiapas não foi encontrada nenhuma pessoa com sorologia positiva entre 137 estudadas. Como encontramos sorologia positiva em crianças menores de 10 anos, pensamos que exista uma transmissão ativa contínua. Na costa foi reconhecido o vetor Triatoma dimidiata e na floresta Lacandona o Rhodnius prolixus

IgG subclass reactivity to Trypanosoma cruzi in chronic chagasic patients / Reactividad de subclases de IgG a trypanosoma cruzi en pacientes crónicos chagásicos

La respuesta humoral anti-Trypanosoma cruzi y el isotipo de inmunoglobulina presente en individuos con enfermedad de Chagas se ha estudiado en relación con las distintas manifestaciones clínicas. Se ha encontrado que títulos altos de IgG anti-T. cruzi específicos estan preferentemente presentes en pacientes con daño cardiaco, mientras que en la forma digestiva es la IgA anti- T. cruzi. En el presente trabajo se estudiaron 12 pacientes consecutivos con diagnóstico de enfermedad de Chagas Todos ellos tenían una evaluación clínica completa y estudios electrocardiográfico, ecocardiográfico, ventriculografía y coronariografía, además del estudio serológico de detección de anticuerpos IgG anti-T. cruzi. En ellos se analizó el perfil de subclases de IgG anti-T. cruzi.Todos los pacientes provenían de áreas rurales de México y algunos habían vivido allí siete o hasta 65 años. En 7/12 (58 por ciento) de ellos presentaron dilatación ventricular izquierda con una dimensión final sistólica por arriba de 42 mm y con una fracción de expulsión por abajo del 50 por ciento en 7/12 (58 por ciento). Los títulos de anticuerpos de IgG1 e IgG2 anti-T. cruzi fueron más altos que los de IgG3, mientras que los niveles de IgG4 anti-T. cruzi, si bien fueron positivos, resultaron ser consistetemente los más bajos. La expresión de las cuatro subclases de IgG anti-T. cruzi sugiere que se induce una respuesta mixta tipo Th1/Th2 en estos pacientes chagásicos crónicos. Aunque el tamaño de muestra estudiado es pequeño, encontramos que los niveles altos de IgG2 anti-T. cruzi presentaban una tendencia a asociarse con el grado de cardiomegalia.

Cardiopatía chagásica en Tehuantepec. Informe preliminar / Chagasic cardiopathy in Tehuantepec

La tripanosomosis americana (TA) fue descrita en México en el estado de Oaxaca, probablemente es endémica en zonas rurales. Antes de este informe no se conocían casos de cardiopatía chagásica crónica en el Istmo de Tehuantepec. Objetivo: Identificar pacientes con TA entre los que acuden a consulta de cardiología y establecer diagnóstico de miocardiopatía dilatada (MD). Material y métodos: Pacientes consecutivos que en el período de enero de 1995 a septiembre de 1997 fueron clasificados como MD. Se realizó historia clínica con anamnesis epidemiológica, serie cardíaca, ECG y ecocardiograma, además se estudió el suero en busca de anticuerpos IgG anti T. cruzi (inmunofluorescencia, ELISA y elec-troinmunotransferencia). Resultados: En 540 consultas se encontraron 16 (2.4 por ciento) casos de MD, 13 de éstos (81 por ciento) tienen anticuerpos anti T. cruzi. Todos vienen de medio rural pobre, tienen insuficiencia cardíaca global y/o trastornos del ritmo o conducción e hipocinesia. El diagnóstico de cardiopatía chagásica crónica (CCC) se estableció sin dificultad. Conclusiones: La TA y su consecuencia de la CCC se encontraron con frecuencia en una población seleccionada en la consulta de cardiología de 2 Hospitales Generales en Salina Cruz, Oaxaca. Es necesario estudiar adecuadamente la situación epidemiológica en el Istmo de Tehuantepec en relación a TA.

Cardiopatía reumática y enfermedades de chagas / Rheumatic cardiopathy and chagas disease

La cardiopatía reumática es frecuente en países no desarrollados; la enfermedad de Chagas típica de zonas rurales, comienza a afectar las áreas urbanas. Las dos entidades tienen una relativa alta incidencia y prevalancia en América Latina. Sin embargo, no encontramos en la literatura reportes de pacientes con diagnóstico simultáneo de ambas. Nuestro objetivo es presentar el primer caso en el que se logró demostrar la coincidencia de cardiopatía reumática y enfermedad de Chagas

Diagnóstico serológico de la enfermedad de Chagas: autosuficiencia y concordancia interlaboratorios / Serologic diagnosis of Chagas disease: Self sufficiency and interlaboratory concordance

El dato fundamental en el diagnóstico de la tripanosomiasis americana (enfermedad de Chagas), en su fase crónica, es el estudio serológico, ya que es difícil la demostración del parásito en circulación o en los tejidos. Una seria limitación en el diagnóstico serológico se relaciona con la estandarización de las diferentes técnicas accesibles, y esto depende considerablemente de la calidad de los antígenos usados para el inmunodiagnóstico. En México no se ha abordado este problema. Los laboratorios del Instituto Nacional de Cardiología y del Instituto Nacional de Diagnóstico y Referencia Epidemiológicos, compararon sus técnicas de inmunodiagnóstico: inmunofluorescencia indirecta, hemaglutinación y ensayo inmunoenzimático en fase sólida (ELISA), con cepas de T. cruzi aisladas en México. La concordancia interlaboratorios fue de 0.8 (Indice Kappa) y la sensibilidad, especificidad y valor predictivo positivo y negativo de las pruebas, aseguran resultados confiables en el inmunodiagnóstico de la enfermedad de Chagas

American trypanosomiasis (Chagas'disease) is becoming a relatively common condition in North America. Diagnosis at the chronic stage depends on demonstration of specific antibodies in body fluids, since parasitologic or pathologic diagnosis is uncertain at this stage. Therefore, standardization of immunodiagnostic techniques is mandatory, and it depends on antigen quality. Locally prepared antigens and crude extracts obtained from Mexican isolates, -both from infected vector and human cases- were compared using three different immunodiagnostic assays -indirect immunofluorescence, hemagglutination and enzyme linked immunosorbant assay (ELISA)- at two different laboratories from the Instituto Nacional de Cardiología and the Instituto Nacional de Diagnóstico y Referencia Epidemiológicos. Concordance between laboratories reached a significant Kappa value (0.8) and sensitivity, specificity and predictive values of individual diagnostic assays were adequate to use these tests in clinical diagnoses. This is the first attempt to standardize immunodiagnostic techniques in Mexico.