Effectiveness of Nifurtimox in the Treatment of Chagas Disease: a Long-Term Retrospective Cohort Study in Children and Adults.

Chagas disease (ChD), caused by Trypanosoma cruzi, has a global prevalence due to patient migration. However, despite its worldwide distribution, long-term follow-up efficacy studies with nifurtimox (NF) are scarce and have been conducted with only small numbers of patients. A retrospective study of a large cohort of ChD treated children and adults with NF. Treatment response was evaluated by clinical, parasitological, and serological after-treatment evaluation. A total of 289 patients were enrolled, of which 199 were children and 90 adults. At diagnosis, 89.6% of patients were asymptomatic. Overall, all symptomatic patients showed clinical improvement. At baseline, parasitemia was positive in 130 of 260 (50%) patients. All but one adult patient had cleared their parasitemia by the end of treatment. That patient was considered a treatment failure. Median follow-up time for children was 37.7 months, with an interquartile range of (IQR25-75 12.2 to 85.3), and for adults was 14.2 months (IQR25-75, 1.9 to 33.8). After treatment, a decrease of T. cruzi antibodies and seroconversion were observed in 34.6% of patients. The seroconversion profile showed that, the younger the patient, the higher the rate of seroconversion (log rank test; P value, <0.01). At least 20% seroreduction at 1 year follow-up was observed in 33.2% of patients. Nifurtimox was highly effective for ChD treatment. Patients had excellent treatment responses with fully resolved symptoms related to acute T. cruzi infection. Clearance of parasitemia and a decrease in T. cruzi antibodies were observed as markers of treatment response. This study reinforces the importance of treating patients during childhood since the treatment response was more marked in younger subjects. (This protocol was registered at ClinicalTrials.gov under registration number NCT04274101).

Adverse Events Associated with Nifurtimox Treatment for Chagas Disease in Children and Adults.

Nifurtimox (NF) is one of the only two drugs currently available for Chagas disease (ChD) treatment. However, data on NF safety are scarce, and many physicians defer or refuse NF treatment because of concerns about drug tolerance. In a retrospective study of adverse drug reactions (ADRs) associated with NF treatment of ChD, children received NF doses of 10 to 15 mg/kg/day for 60 to 90 days, and adults received 8 to 10 mg/kg/day for 30 days. A total of 215 children (median age, 2.6 years; range, 0 to 17 years) and 105 adults (median age, 34 years; range, 18 to 57 years) were enrolled. Overall, 127/320 (39.7%) patients developed ADRs, with an incidence of 64/105 adults and 63/215 children (odds ratio [OR] = 3.7; 95% confidence interval [CI], 2.2 to 6.3). We observed 215 ADRs, 131 in adults (median, 2 events/patient; interquartile range for the 25th to 75th percentiles [IQR25-75], 1 to 3) and 84 in children (median, 1 event/patient; IQR25-75 = 1 to 1.5) (Padjusted < 0.001). ADRs were mainly mild and moderate. Severe ADRs were infrequent (1.2% in children and 0.9% in adults). Nutritional, central nervous, and digestive systems were the most frequently affected, without differences between groups. Treatment was discontinued in 31/320 (9.7%) patients without differences between groups. However, ADR-related discontinuations occurred more frequently in adults than in children (OR = 5.5, 95% CI = 1.5 to 24). Our study supports the safety of NF for ChD treatment. Delaying NF treatment due to safety concerns does not seem to be supported by the evidence. (This study has been registered in ClinicalTrials.gov under identifier NCT04274101.).

Prevalencia de patología cardíaca en la enfermedad de Chagas: años 2004-2012. Programa y Red de Chagas de CABA / Prevalence of cardiac pathology in Chagas disease: 2004 -2012. Program and Chagas CABA network

El Instituto Universitario de Ciencias de las Salud ha mostrado un particular compromiso con la formación de sus estudiantes en la estrategia de Atención Primaria de la Salud, con las prácticas asistenciales dedicadas al 1er nivel de atención ambulatoria y a las patologías prevalentes en ese ámbito. Del mismo modo se han desenvuelto las actividades de formación en investigación. Como exponente de esa orientación, la revista Ciencias de la Salud publicó en el Vol. 2, N°1, 2011:4-9, el artículo “Prevalencia de la Enfermedad de Chagas” de Érica G. Morais, que había obtenido el premio “Futuros Líderes”, otorgado por el Curso Anual Internacional de Investigación en Ciencias de la Salud (IUCS-AMA, Prof. Carlos Álvarez Bermúdez). Aquella investigación formaba parte de un proyecto más amplio realizado en el Hospital Teodoro Álvarez entre 2004 y 2012, en el que participaron un conjunto de investigadores, que compartieron la autoría de la actual publicación. El Dr. Jorge Mitelman, Prosecretario de Ciencia y Técnica del IUCS e integrante de ese equipo, preparó además una reseña sobre la jornada del INCOSUR, realizada en abril del presente año, describiendo asimismo el proceso de desarrollo de la Ciudad de Buenos Aires, como área no endémica, para encarar las consecuencias de la enfermedad de Chagas

Epstein-Barr virus BZLF1 gene polymorphisms: malignancy related or geographically distributed variants?

The ubiquitous Epstein-Barr virus (EBV) is related to the development of several lymphoid and epithelial malignancies and is also the aetiological agent for infectious mononucleosis (IM). BZLF1, an immediate early gene, plays a key role in modulating the switch from latency to lytic replication, hence enabling viral propagation. Polymorphic variations in the coded protein have been studied in other geographical regions in a search for viral factors that are inherent to malignancies and differ from those present in benign infections. In the present study, in samples of paediatric patients with benign IM and paediatric patients with malignant lymphomas, we detected previously described sequence variations as well as distinctive sequence polymorphisms from our region. By means of phylogenetic reconstruction, we characterized new phylogenetically distinct variants. Moreover, we described an association between specific variants and the studied pathologies in our region, particularly variant BZLF1-A2 with lymphomas and BZLF1-C with IM. Additionally, length polymorphisms within intron 1 were also assessed and compared between pathologies resulting in an association between 29-bp repeated units and lymphomas. In conclusion, this is the first report to characterize BZLF1 gene polymorphisms in paediatric patients from our geographical region and to suggest the association of these polymorphisms with malignant lymphomas.

Respuesta de anticuerpos frente a antígenos recombinantes de T. Cruzi en niños con enfermedad de Chagas congénita / Antibody response against recombinant TCruzi's antigens in children with congenital chagas disease

INTRODUCCIÓN La enfermedad de Chagas es una zoonosis causada por el T. cruzi, para el cual no existe una técnica serológica única que presente la sensibilidad y especificidad para hacer el diagnóstico o seguimiento de los pacientes. Según los cálculos, cada año se presentan 1000-1300 nuevos casos de Chagas congénito en Argentina. OBJETIVOS Valorar la respuesta de anticuerpos frente a diferentes antígenos recombinantes (SAPA, Ag1, Ag2, Ag13, Ag36 y TSSA) para el diagnóstico y seguimiento de la enfermedad de Chagas congénita. MÉTODOS Se realizó un estudio exploratorio abierto, con seguimiento longitudinal de una cohorte de pacientes con enfermedad de Chagas congénito y niños no infectados nacidos de madres con enfermedad de Chagas. Se incluyó en el estudio a hijos de madres chagásicas menores de 18 meses. RESULTADOS Hubo 10 pacientes con parasitemia + y 82 con parasitemia. Un total de 49 pacientes arribaron al control serológico del noveno mes, con 48 negativos y 1 positivo (Chagas congénito). Los anticuerpos contra antígenos recombinantes mostraron resultados similares a los de la serología convencional en pacientes tratados. DISCUSIÓN La serología convencional y los anticuerpos contra antígenos recombinantes no mostraron diferencias en pacientes tratados. Tanto los pacientes tratados a edades tempranas para Chagas congénito como los hijos de madres chagásicas no infectados negativizaron la serología para el noveno mes de seguimiento. La utilización del microhematocrito para la detección del Chagas congénito demostró ser altamente eficaz.

Development of an ionic liquid-based dispersive liquid-liquid microextraction method for the determination of nifurtimox and benznidazole in human plasma.

Dispersive ionic liquid-liquid microextraction combined with liquid chromatography and UV detection was used for the determination of two antichagasic drugs in human plasma: nifurtimox and benznidazole. The effects of experimental parameters on extraction efficiency-the type and volume of ionic liquid and disperser solvent, pH, nature and concentration of salt, and the time for centrifugation and extraction-were investigated and optimized. Matrix effects were detected and thus the standard addition method was used for quantification. This microextraction procedure yielded significant improvements over those previously reported in the literature and has several advantages, including high inter-day reproducibility (relative standard deviation=1.02% and 3.66% for nifurtimox and benznidazole, respectively), extremely low detection limits (15.7 ng mL(-1) and 26.5 ng mL(-1) for nifurtimox and benznidazole, respectively), and minimal amounts of sample and extraction solvent required. Recoveries were high (98.0% and 79.8% for nifurtimox and benznidazole, respectively). The proposed methodology offers the advantage of highly satisfactory performance in addition to being inexpensive, simple, and fast in the extraction and preconcentration of these antichagasic drugs from human-plasma samples, with these characteristics being consistent with the practicability requirements in current clinical research or within the context of therapeutic monitoring.

Efficacy of voriconazole in a murine model of acute Trypanosoma cruzi infection.

OBJECTIVES: Antifungal triazole derivatives have been studied as possible alternatives for the treatment of Chagas' disease. Voriconazole has demonstrated in vitro activity against Trypanosoma cruzi, but its efficacy in vivo has not yet been tested. We aimed to determine the effect of voriconazole in a murine model of acute T. cruzi infection. METHODS: Treatment efficacy was evaluated by comparing parasitaemia, mortality and organ involvement (by histological examination) of infected mice. RESULTS: Treatment with voriconazole significantly lowered parasitaemia and mortality compared with controls, reduced the percentage of mice with amastigote nests in heart and skeletal muscle and moderately decreased myocardial inflammation. CONCLUSIONS: Our findings support the potential of voriconazole for the treatment of acute Chagas' disease and motivate future animal studies using varying doses and treatment schemes. Further evaluation of voriconazole for clinical use in human Chagas' patients is warranted.

Trypanosoma cruzi discrete typing units in Chagas disease patients from endemic and non-endemic regions of Argentina.

Genetic diversity of Trypanosoma cruzi may play a role in pathogenesis of Chagas disease forms. Natural populations are classified into 6 Discrete Typing Units (DTUs) Tc I-VI with taxonomical status. This study aimed to identify T. cruzi DTUs in bloodstream and tissue samples of Argentinean patients with Chagas disease. PCR-based strategies allowed DTU identification in 256 clinical samples from 239 Argentinean patients. Tc V prevailed in blood from both asymptomatic and symptomatic cases and Tc I was more frequent in bloodstream, cardiac tissues and chagoma samples from immunosuppressed patients. Tc II and VI were identified in a minority of cases, while Tc III and Tc IV were not detected in the studied population. Interestingly, Tc I and Tc II/VI sequences were amplified from the same skin biopsy slice from a kidney transplant patient suffering Chagas disease reactivation. Further data also revealed the occurrence of mixed DTU populations in the human chronic infection. In conclusion, our findings provide evidence of the complexity of the dynamics of T. cruzi diversity in the natural history of human Chagas disease and allege the pathogenic role of DTUs I, II, V and VI in the studied population.

Congenital infections with Trypanosoma cruzi or Toxoplasma gondii are associated with decreased serum concentrations of interferon-γ and interleukin-18 but increased concentrations of interleukin-10.

Little is known about the immune responses of newborns with congenital Chagas disease (CCD) or congenital toxoplasmosis (CT) but they probably differ to those seen in adults with Chagas disease or toxoplasmosis, leading to differences in pathology. The concentrations of interleukin-18 (IL-18), interferon-γ (IFN-γ) and interleukin 10 (IL-10) in the sera of infants with CCD or CT were determined and compared with those in the sera of uninfected controls (born to mothers who were seropositive or seronegative for Trypanosoma cruzi). The infants with CCD or CT were found to have lower IL-18 and IFN-γ concentrations but higher IL-10 concentrations than the uninfected controls. The IL-18 and IFN-γ concentrations were also significantly lower in the infants with CCD than in those with CT. Although the infants with symptomatic CT had significantly higher serum concentrations of IL-18 than those with asymptomatic infection with Toxoplasma, the infants with symptomatic CCD had similar serum concentrations of IL-18 to the infants with asymptomatic Tr. cruzi infection. Taken together, these results indicate that IL-10 contributes to the suppression of pro-inflammatory immune responses and therefore, perhaps, to clinically overt CCD and CT.

[Acute toxoplasmosis: clinical and laboratory data in eleven patients]. / Toxoplasmosis aguda: datos clínicos y de laboratorio en 11 pacientes.

INTRODUCTION: The clinical and laboratory data of immunocompetent patients with acute toxoplasmosis (AT) are described. PATIENTS AND METHODS: We performed a retrospective study of patients with AT attended between 1996 and 2004. Diagnostic criteria consisted of compatible clinical findings (generalized and cervical lymphadenopathies) and specific serology against Toxoplasma gondii (high IgG and IgM and/or reactive IgA). IgG and IgM determinations were performed by ELFA and IgA determinations by ELISA. IgM-CMV, heterophil antibodies, hemogram, hepatic chemistry were also determined and funduscopic examination was performed. RESULTS: Eleven immunocompetent patients with AT were evaluated. The mean age was 8.8 years (95 % CI: 3.6-12.9). The patients were evaluated between the first and the third month after symptom onset. Of the 11 patients, hard elastic lymphadenopathies were found in 10, single cervical lymphadenectomy in three and generalized lymphadenectomy in seven. One patient showed no symptoms. In one patient, nodal histology showed the Piringer-Kuchinka triad. None of the patients showed alterations in the hemogram, hepatic chemistry or funduscopic examination. The mean IgG value was 4.143 UI/ml (95 % CI: 2.570 and 5.717). IgM was reactive in nine of the 11 patients (81.8 %) and IgA in seven out of 10 patients (70 %). In all patients, at least one of these two immunoglobulins was reactive. In all patients, clinical outcome was favorable without parasiticide treatment. CONCLUSION: Except for one asymptomatic patient, all the patients had generalized lymphadenopathies and only 27.2 % showed cervical lymphadenopathies. A negative IgM or IgA result does not rule out a diagnosis of AT. Parasiticide treatment is unnecessary in this entity. Acute toxoplasmosis should be considered early in children with lymphadenopathies to avoid invasive procedures.

Toxoplasmosis aguda: datos clínicos y de laboratorio en 11 pacientes / Acute toxoplasmosis: clinical and laboratory data in eleven patients

Introducción Se describen la clínica y el laboratorio de pacientes inmunocompetentes con toxoplasmosis aguda (TA). Pacientes y métodos Se trata de un estudio retrospectivo de pacientes con TA asistidos entre 1996 y 2004. Criterios diagnósticos: clínica compatible (adenopatías generalizadas o cervicales) y serología específica contra Toxoplasma gondii (IgG elevada e IgM y/o IgA reactiva). La determinación de IgG e IgM se realizó por ELFA, las IgA por ELISA. Se realizó IgM-CMV, anticuerpos heterófilos, hemograma, hepatograma y fundoscopia. Resultados Se evaluaron 11 pacientes inmunocompetentes con TA, edad media: 8,8 años (intervalo de confianza del 95 % [IC 95 %]: 3,6-12,9). Concurrieron entre 1 y 3 meses del inicio de los síntomas. En 10/11 se hallaron adenopatías elásticas, cervicales únicas en tres y generalizadas en siete. Un paciente fue asintomático. La histología del ganglio de un paciente presentó la tríada de Piringer-Kuchinka. Ninguno presentó alteraciones del hemograma, hepatograma y del fondo de ojo. La media de la IgG: 4,143 U/ml (IC 95 %: 2,570-5,717). La IgM se detectó en 9/11 (81,8 %), la IgA en 7/10 (70 %). Todos los pacientes presentaron al menos una de estas dos inmunoglobulinas reactivas. La evolución clínica fue favorable sin tratamiento parasiticida. Conclusión Excepto un paciente asintomático, todos presentaron adenopatías generalizadas y sólo el 27,2 % cervicales. Un resultado negativo de IgM o IgA no descarta el diagnóstico. El tratamiento parasiticida es innecesario en esta patología. Es importante pensar tempranamente en esta etiología en niños con adenopatías, esto ahorraría procedimientos invasivos

Introduction The clinical and laboratory data of immunocompetent patients with acute toxoplasmosis (AT) are described. Patients and methods We performed a retrospective study of patients with AT attended between 1996 and 2004. Diagnostic criteria consisted of compatible clinical findings (generalized and cervical lymphadenopathies) and specific serology against Toxoplasma gondii (high IgG and IgM and/or reactive IgA). IgG and IgM determinations were performed by ELFA and IgA determinations by ELISA. IgM-CMV, heterophil antibodies, hemogram, hepatic chemistry were also determined and funduscopic examination was performed. Results Eleven immunocompetent patients with AT were evaluated. The mean age was 8.8 years (95 % CI: 3.6-12.9). The patients were evaluated between the first and the third month after symptom onset. Of the 11 patients, hard elastic lymphadenopathies were found in 10, single cervical lymphadenectomy in three and generalized lymphadenectomy in seven. One patient showed no symptoms. In one patient, nodal histology showed the Piringer-Kuchinka triad. None of the patients showed alterations in the hemogram, hepatic chemistry or funduscopic examination. The mean IgG value was 4.143 UI/ml (95 % CI: 2.570 and 5.717). IgM was reactive in nine of the 11 patients (81.8 %) and IgA in seven out of 10 patients (70 %). In all patients, at least one of these two immunoglobulins was reactive. In all patients, clinical outcome was favorable without parasiticide treatment. Conclusion Except for one asymptomatic patient, all the patients had generalized lymphadenopathies and only 27.2 % showed cervical lymphadenopathies. A negative IgM or IgA result does not rule out a diagnosis of AT. Parasiticide treatment is unnecessary in this entity. Acute toxoplasmosis should be considered early in children with lymphadenopathies to avoid invasive procedures

Enfermedad de Chagas congenita: experiencia del Hospital de Niños Ricardo Gutiérrez, Buenos Aires, Argentina / Congenital Chagas disease: experience in the Hospital de Niños, Ricardo Gutiérrez, Buenos Aires, Argentina

Epidemiological, clinical, diagnostic, and therapeutic data from children who were born to mothers infected with T. cruzi who came to our hospital are presented. In addition, we exhibit the preliminary results of a technique that detects the anti F2/3 antibodies: these would be able to confirm the cure earlier than conventional serology. We also show the results of PCR diagnosis. Most of the mothers (76,1%) resided in Argentina, the rest were from Bolivia and Paraguay The median average age at diagnosis of the patients was 8,5 months (range 15 days-10 years). Out of 168 children, 64,98% were asymptomatic at diagnosis. The diagnosis criteria were: T. cruzi observation by microhematocrit technique in patients less than 7 month old. Two reactive serological tests in patients older than 8 months. A nifurtimox dose used in these patients was 10-13 mg/kg/d during 60 days. Although 31% presented side effects, none of them had to be dropped from the treatment. Cure criteria was conventional serology negativization. Of the patient population, we cured 87,2% of them, 98% of those under 3 years, and 100% of those who received treatment before age 8 months. We compared the time of negativization between conventional serology and anti F2/3 in 21 children. The latter were very useful to demonstrate (p>0,001) the success of the treatment, in those that started treatment after 8 months of age. PCR testing of a group of all patients, showed a diagnostic sensibility of 80,3% and a specificity of 97,8%.

[Toxocariasis: clinical and laboratory features in 54 patients]. / Toxocariasis: aspectos clínicos y de laboratorio en 54 pacientes.

OBJECTIVE: To describe the clinical and laboratory findings in children with toxocariasis. METHODS: Fifty-four children with reactive serology to Toxocara determined by ELISA were prospectively identified between January 1998 and September 2000. The patients were divided into three groups: asymptomatic children (n 24), those with visceral larva migrans (n 16) and those with ocular larva migrans (n 14). Age, serology titers, and eosinophil count at diagnosis were compared among the groups. The patients received treatment with albendazole 10-15 mg/kg/day for 15 days or thiabendazole 25 mg/kg/day in two series of 7 days. RESULTS: The clinical features were as follows: 24 children (44.4 %) were asymptomatic, pneumonitis was found in 9 (16.7 %), hepatomegaly in 6 (11.1 %), acute posterior uveitis in 5 (9.3 %), strabismus in 5 (9.3 %), leukocoria in 4 (7.4 %), fever in 3 (5.6 %). There was 1 case of keratitis, 1 of cataracts, 1 of myocarditis and 1 case of pneumonia with pleural effusion. Some patients showed more than one clinical feature. Four children experienced loss of vision in the affected eye. No differences in age or serology titers were found among the groups. Eosinophil count was lower in the group with ocular larva migrans than in the other groups (p < 0.001). Children with active disease showed clinical improvement and a 70.4 % decrease in eosinophilic count one year after treatment. Serological titers showed an unpredictable pattern during the follow-up. CONCLUSIONS: Most of the infected children were asymptomatic. In the post-treatment follow-up, clinical improvement and a decrease in eosinophilic count were observed. Further studies are needed to evaluate the efficacy of treatment, especially in asymptomatic children.

Toxocariasis: aspectos clínicos y de laboratorio en 54 pacientes / Toxocariasis: clinical and laboratory features in 54 patients

Objetivo: Describir los hallazgos clínicos y de laboratorio en niños con toxocariasis. Métodos: En forma prospectiva se diagnosticaron 54 niños con serología reactiva por técnica de enzimoinmunoanálisis (ELISA) para Toxocara, entre enero de 1998 y septiembre de 2000. Se dividieron en 3 grupos: asintomáticos, 24; larva migrans visceral, 16; larva migrans ocular, 14. Se compararon la edad, los títulos serológicos y la eosinofilia al diagnóstico entre los grupos. Se indicó como tratamiento 10-15 mg/kg/día de albendazol durante 15 días o 25 mg/kg/día de tiabendazol en 2 series de 7 días. Resultados: Los hallazgos clínicos fueron: asintomáticos, 24 casos (44,4 por ciento); neumonitis, 9 (16,7 por ciento); hepatomegalia, 6 (11,1 por ciento); uveítis posterior aguda, 5 (9,3 por ciento); estrabismo, 5 (9,3 por ciento); leucocoria, 4 (7,4 por ciento); fiebre, 3 (5,6 por ciento). Hubo un caso de queratitis, uno de cataratas, uno de miocarditis y uno de neumonía con derrame. Algunos pacientes presentaron más de un signo clínico. Cuatro pacientes perdieron la visión del ojo lesionado. No se encontraron diferencias en la edad y los títulos serológicos entre los grupos. Se halló menor eosinofilia en los niños con compromiso ocular con relación a los otros grupos (p < 0,001). Se observó mejoría clínica en los niños con infección activa y una disminución del 70,4 por ciento en el recuento de eosinófilos en el seguimiento a un año postratamiento. Los títulos serológicos mostraron un comportamiento errático en el seguimiento. Conclusiones: La mayor parte de los infectados fueron asintomáticos. En el seguimiento postratamiento se evidenció una mejoría clínica y caída en el recuento de eosinófilos. Se plantea la necesidad de ampliar el estudio valorando la eficacia del tratamiento especialmente en aquellos niños asintomáticos (AU)

Presence of IgM antibodies to Trypanosoma cruzi urinary antigen in sera from patients with acute Chagas' disease.

An 80-kilodalton Trypanosoma cruzi antigen is eliminated in the urine of infected hosts during the acute stage of Chagas' disease. We show that affinity-purified urinary antigen is recognised by IgM antibodies in the sera from acute chagasic patients. Comparing our urinary antigen assay with that using a whole T. cruzi lysate antigen for IgM antibody detection, we demonstrated that ELISA with urinary antigen increases the diagnostic sensitivity and specificity of IgM serology in recent chagasic infection. Twenty-six of 30 patients with acute T. cruzi infection had serum IgM antibodies that reacted with urinary antigen by ELISA, while lysate antigen IgM was detected in 24 sera. When sera from patients suffering other parasitoses were tested, strong cross-reactions occurred in ELISA with T. cruzi lysate antigen, whereas ELISA with urinary antigen proved to better discriminate acute chagasic patients. Human antibodies to urinary antigen immunoprecipitated this T. cruzi urinary antigen and also inhibited the binding of monoclonal antibody to urinary antigen in an inhibition assay. These findings suggest that urinary antigen may be useful for the development of serodiagnostic procedures for acute T. cruzi infection.

Neurosyphilis in an eight-year-old child: usefulness of the SPECT study.

An 8-year-old boy with symptomatic late-onset congenital syphilis is reported. The child had been undertreated when he was 78 days of age, but his clinical and serologic follow-up did not occur until he was 3 years of age. At that time, he was asymptomatic, and cerebrospinal fluid disclosed not only hypercellularity but also a reactive Venereal Disease Research Laboratories test. Although he was then retreated at 4 years of age, he developed seizures. Cranial computed tomography and magnetic resonance imaging were normal, but two single photon emission computed tomography scans performed when he was 5 years of age and then 7 years of age demonstrated areas of hypoperfusion that closely agreed with the alterations on electroencephalograph. Brain single photon emission computed tomography was able to detect cerebral nervous system abnormalities in this young patient with neurosyphilis, whereas other image studies did not.

Detection and characterization of antigens in urine of patients with acute, congenital, and chronic Chagas' disease.

Monoclonal antibodies raised against purified Trypanosoma cruzi urinary antigens were used in an enzyme-linked immunosorbent assay (ELISA) capture test for parasite antigens present in urine specimens of Argentinean and Brazilian patients with Chagas' disease. At diagnosis, antigenuria was demonstrated by ELISA in all acutely and congenitally infected infants studied. Moreover, T. cruzi urinary antigens were detected in samples from three of five patients with acute infections and four of five patients with congenital infections following chemotherapy. At least one ELISA-positive urine specimen from each individual was recorded in a longitudinal survey of 12 chronic chagasic patients. The same parasitic antigens (90 to 80 kDa, pI 5.7 to 6.0; 70 to 65 kDa, pI 4.9 to 4.5; 50 to 45 kDa, pI 5.3 to 5.1; and 40 to 35 kDa, pI 4.8 to 4.5) were identified by immunoprecipitation and two-dimensional polyacrylamide gel electrophoresis analysis of urine samples from patients with different forms of chagasic infection. The 90- to 80-kDa urinary protein resembles a trypomastigote-shed antigen. Determination of antigenuria proved valuable for early diagnosis of Chagas' disease and also for diagnosis of chronic cases with conflicting serology.

An iron-binding Trypanosoma cruzi urinary antigen.

An 80-kDa Trypanosoma cruzi urinary antigen (UAg) was affinity-purified from the urine of infected dogs. We demonstrated that UAg is structurally and functionally related to proteins belonging to the transferrin family, as shown by amino acid sequence and iron binding experiments. Nevertheless, monoclonal antibodies raised against UAg specifically and selectively recognized this parasite's circulating antigen. The existence of an 80-kDa T. cruzi antigen co-migrating with UAg could be confirmed when epimastigotes were metabolically labelled with [35S] methionine and then immunoprecipitated with the above mentioned antibodies. We conclude that UAg is an iron-binding T. cruzi component eliminated in the urine of the infected host.

Congenital Chagas' disease: diagnostic and clinical aspects.

The diagnostic and clinical aspects of congenital Chagas' disease were studied in 71 children in Buenos Aires. The children's ages ranged from 2 days to 10 years. In infants < 6 months old, the disease was diagnosed by detection of Trypanosoma cruzi in the blood; the microhematocrit test was positive in 38 (97.4%) of 39 cases. This test was the fastest and most reliable diagnostic method in this group, whereas two conventional serological methods were useful in children > or = 6 months of age. Forty-six (64.8%) of the 71 children had no clinical signs of infection. The clinical sign most frequently documented was hepatomegaly (18.3%). Three children were coinfected with human immunodeficiency virus; the latter infection was severe in two instances. Nifurtimox (10-15 mg/[kg.d] for 2 months) was used for parasiticidal treatment, and use of this drug resulted in mild adverse effects.

Outcome of infection with different strains of Trypanosoma cruzi in mice lacking CD4 and/or CD8.

Mice lacking CD4 and/or CD8 gene expression, generated by embryonic stem-cell technology, were used to study the role of CD4+ and CD8+ cells in the resistance to the acute infection with virulent (Tulahuén and RA) or mild (CA-I) strains of Trypanosoma cruzi. The presence of both CD4+ and CD8+ cells contributed to the survival of mice infected with T. cruzi, and each T-cell subtype was able to sustain protective functions in the absence of the other one. However, in certain host-parasite combinations, CD8+ cell-independent mechanisms were able to control the parasite load. Moreover, CD8- mice chronically infected with a low virulent strain of T. cruzi were protected from an otherwise lethal challenge with the parasite. A different organ distribution of parasite nests was observed when mutant (but not wild type) animals infected with different parasite strains were compared. CD4- mice produced high levels of IgG antibodies against peptide antigens or a whole homogenate from the parasite after infection with CA-I strain. A dramatic enhancement of IgG1- and IgG2a-specific antibodies was observed.