Efecto de la ciclofosfamida en la infección por Coccidioides immitis en la rata

Coccidioidomycosis is a systemic mycosis, endemic in arid areas of the American continent. The rat was employed as an experimental host, since it had been shown to reproduce human lesions and present a chronic course of disease with granulomas mainly restricted to lungs. Given the influence of immunosuppressive therapy on the clinical course of human coccidioidomycosis, we studied the effect of cyclophosphamide (CY) in the experimental rat model. Accordingly, animals were inoculated with 400 Coccidioides immitis arthroconidia of the Acosta strain, by intracardiacal route. As single CY doses failed to alter the course of disease, three schedules were used: A) 4 daily doses of 20 mg/kg each, prior to C. immitis inoculation; B) 4 similar daily doses after infection; and C); 6 doses of 20 mg/kg each, given from day +1 to +4, then on days +8 and +9, post infection (pi), taking day 0 as the time of fungal inoculation. The first two schedules inhibited antibody formation up to day 28 pi, without modifying cellular response to coccidioidin as measured by foodpad swelling. Initially, there was greater fungal spread than in controls receiving C. immitis alone, which proved self-limiting in the latter. In contrast, schedule C led to 559r mortality, with both humoral and cellular response abrogation, accompanied by extensive C. immitis dissemination. Histology disclosed significant alterations, such as the persistence of primary infection sporangia, corresponding to the acute stage of coccidioidomycosis in the absence of granuloma development. Therefore, the observed depression in cellular immunity seems responsible for the lack of inflammatory reaction capable of restricting sporangia proliferation in tissues which, in turn, enhances pathogen spread and mortality rate.El propósito de este trabajo fue estudiar el efecto de la inmunosupresión causada por la droga ciclofosfamida (CY) sobre la infección de la rata con Coccidioides immitis por vía intracardíaca. Este huésped fue empleado como modelo experimental, ya que presenta una evolución de la enfermedad semejante a la del hombre, alcanzando una etapa crónica con granulomas principalmente restringidos a los pulmones. Se utilizaron tres esquemas de CY: A) 4 dosis de 20 mg/kg cada una, antes de la inoculación de Ci; B) 4 dosis de igual cantidad de CY, luego de la infección; y C) 6 dosis de 20 mg/kg cada una, administradas desde el día +1 hasta +4 y continuando los días + 8 y +9 post-infección (pi). Los dos primeros esquemas inhibieron la formación de anticuerpos hasta el día 28 pi, sin modificar la respuesta celular a la coccidioidina, medida como hinchazón de la almohadilla plantar. Se observó una mayor diseminación fúngica inicial, autolimi-tándose más tarde. Por el contrario, el esquema C provocó un 55% de mortalidad, disminución de la respuesta humoral y celular, acompañada de una extensa diseminación del Ci. La histología mostró alteraciones significativas, tales como persistencia de esporangios de primoinfección, correspondientes al estadio agudo de la coccidioidomicosis, con ausencia de desarrollo de granulomas. Por lo tanto, la depresión observada en la respuesta celular debido al tratamiento con CY sería la responsable de la ausencia de la reacción inflamatoria capaz de restringir la proliferación de esporangios en los tejidos, lo cual a su vez favorece la diseminación del microorganismo patógeno y el aumento de morta lidad

Evaluación externa del desempeño en el tamizaje de bancos de sangre en Argentina: resultados y estrategias para mejorarlo

OBJETIVOS: Debido a la falta de un programa para la evaluación externa de la calidad del tamizaje de infecciones transmisibles por transfusión (ITT) en los bancos de sangre, el Servicio de Hemoterapia del Hospital Garrahan, de Buenos Aires, Argentina, inició en 1999 un programa continuo con el apoyo de la Organización Panamericana de la Salud (OPS) y la Asociación Argentina de Hemoterapia e Inmunohematología (AAHI). MÉTODOS: Se distribuyó un panel de 12 muestras con reactividad para todos los marcadores tamizados en los bancos de sangre argentinos. El panel se entregó a 52, 102 y 118 laboratorios en 1999, 2000 y 2001, respectivamente. Los laboratorios participantes se clasificaron según su desempeño en: A: menos de 2 resultados positivos falsos (RPF); B: de 2 a 3 PF; C: más de 3 RPF; y D: algún resultado negativo falso. Se efectuaron talleres con los participantes para analizar conjuntamente los resultados. RESULTADOS: Los porcentajes de respuesta de cada año fueron 92,3, 92,2 y 83,9, respectivamente; estos porcentajes de respuesta indican interés en las actividades de evaluación. Sin embargo, el promedio de los laboratorios con clasificación D resultó muy alto (30%), lo que evidencia la presencia de problemas en el desempeño del tamizaje de las ITT. Esto podría asociarse con la dificultad de tomar medidas correctoras en todo el sistema, dado el elevado número de laboratorios involucrados. CONCLUSIONES: Se deben incluir evaluaciones de este tipo en el Programa Nacional de Sangre para el diagnóstico continuo de la situación, la toma de decisiones y el seguimiento de la calidad del tamizaje

Coccidioidomicose experimental em ratos imunossuprimidos

C. immitis inoculated rats are known to develop infection restricted to lung whereas cyclophosphamide (CY) treatment leads to widespread dissemination with considerable mortality. In this study, an attempt was made to elucidate the mechanisms involved in such behaviour. With this aim, spleen cells were transferred from infected CY-treated to infected untreated rats, achieving significant specific inhibition in footpad swelling to coccidioidin in recipients, attributable to a suppressor T cell subpopulation induced by greater fungal antigen concentration arising from widespread C. immitis dissemination in immunosuppressed animals. NK activity proved similar regardless of CY treatment. Lastly, chronically infected rats presented increased colony forming units count after several weekly doses of CY, as happens in immunosuppressed patients harbouring a previous infection.Ratos adultos inoculados com C. immitis desenvolveram infecção circunscrita ao pulmão sem apresentar mortalidade; no entanto, ao serem imunossuprimidos com CY apresentaram disseminação fúngica em vários órgãos, ausência de granulomas e depressão na resposta celular à coccidioidina junto com uma mortalidade de 50%. Tentou-se determinar os mecanismos envolvidos neste comportamento. Para isso foram medidas as atividades dos linfócitos supressores e células NK. Ao serem transferidos esplenócitos de animais infectados e tratados com CY a ratos somente infectados conseguiu-se significativa inibição específica da resposta à coccidioidina. Este efeito seria devido a uma subpopulação de linfócitos T supressores induzida por maior concentração de antígeno nos animais imunossuprimidos. A atividade NK foi semelhante nos ratos infectados independentemente do tratamento com CY. Por outro lado, tentou-se a reativação da infecção crônica com C. immitis. Os animais infectados apresentaram maior quantidade de unidades formadoras de colônias nos pulmões depois de várias doses semanais de CY, assim como ocorre em pacientes que apresentam deficiências a nível imunológico

Relevance of HTLV-1 proviral load in asymptomatic and symptomatic patients living in endemic and non-endemic areas of Argentina.

HTLV-1 proviral load (pVL) in peripheral blood mononuclear cell (PBMCs) is proposed as a marker of disease progression but its role still remains controversial. The aim of this study was to evaluate the levels of HTLV-1 pVL in symptomatic patients and asymptomatic HTLV-1 carriers. In this cross-sectional study the pVL was measured by Real Time PCR in 102 asymptomatic carriers and 22 symptomatic patients (5ATLL, 15 TSP and 2 uveitis). We observed that the HTLV-1 pVL was significantly higher in symptomatic patients (median = 4.99 log10 HTLV-1 copies /106 PBMCs) compared to asymptomatic HTLV-1 carriers (median = 4.38 log10 HTLV-1 copies /106 PBMCs; p = 0.0030). A wide variation on the HTLV-1 pVL levels among asymptomatic HTLV-1 carriers was observed with some pVL as high as those observed in symptomatic patients. The asymptomatic HTLV-1 carriers were divided according to the place of birth and the highest levels of pVL were detected among patients from endemics areas from the North of Argentina. Our results reinforce the usefulness of the proviral load would be a prognostic marker of HTLV-1 disease progression. Moreover, host, viral or socio-environmental factors cannot be excluded as determinant of high proviral load

A comprehensive protocol to evaluate the use of blood and its components in Latin America and the Caribbean

Blood transfusion safety is a critical part of appropriate health care. Considering the limited information available on the use of blood and its components in Latin America and the Caribbean, the Grupo Cooperativo iberoamericano de Medicina Transfusional (Ibero-American Cooperative Group for Transfusion Medicine; GCIAMT), through its Research and International Affairs committees, carried out a project to develop a protocol that would facilitate the evaluation of blood usage at the country, jurisdiction, and institutional levels in varied country contexts. Experts in blood safety from the Pan American Health Organization (Washington, DC, United States), the University of São Paulo (São Paulo, Brazil), the Hemocentro of São Paulo (São Paulo, Brazil), and GCIAMT designed a 2-step comprehensive blood-use evaluation protocol: step 1 collects data from blood requests, and step 2, from medical charts. At a minimum, 1 000 analyzed requests are necessary; as such, study periods vary depending on the number of transfusion requests issued. An Internet-based application, the Modular Research System-Study Management System (MRS-SMS), houses the data and produces reports on how hospitals request blood, how blood is issued, who requires blood and blood components, and as an added benefit, how many blood units are wasted and what the real demand for blood is