A secondary wave of neutrophil infiltration causes necrosis and ulceration in lesions of experimental American cutaneous leishmaniasis.

We evaluated the importance of neutrophils in the development of chronic lesions caused by L. Viannia spp. using the hamster as experimental model of American Cutaneous Leishmaniasis (ACL). Neutrophils infiltrated the lesion within the first six hours post-infection. Inhibition of this early infiltration using a polyclonal antibody or cyclophosphamide was associated with transient parasite control but the protective effect vanished when lesions became clinically apparent. At lesion onset (approximately 10 days p.i.), there was an increased proportion of both uninfected and infected macrophages, and subsequently a second wave of neutrophils infiltrated the lesion (after 19 days p.i.) This second neutrophil infiltration was associated with lesion necrosis and ulceration (R2 = 0.75) and maximum parasite burden. Intradermal delivery of N-formylmethionyl-leucyl-phenylalanine (fMLP), aimed to increase neutrophil infiltration, resulted in larger lesions with marked necrosis and higher parasite burden than in mock treated groups (p<0.001 each). In contrast, reduced neutrophil infiltration via cyclophosphamide-mediated depletion led to more benign lesions and lower parasite loads compared to controls (p<0.001 each). Neutrophils of the second wave expressed significantly lower GM-CSF, reactive oxygen species and nitric oxide than those of the first wave, suggesting that they had less efficient anti-leishmania activity. However, there was increased inflammatory cytokines and expression of neutrophil proteases (myeloperoxidase, cathepsin G and elastase) in lesions during the second wave of neutrophil infiltration compared with the levels reached during the first wave (6h p.i.). This suggests that augmented neutrophil proteases and inflammatory cytokines during the secondary wave of neutrophils could contribute to skin inflammation, ulceration and necrosis in ACL. The overall results indicate that neutrophils were unable to clear the infection in this model, and that the second wave of neutrophils played an important role in the severity of ACL.

[Ethics review committees for human research: the challenge of strengthening this process in Colombia]. / Comités de etica de investigación en humanos: el desafío de su fortalecimiento en Colombia.

INTRODUCTION: Ethics committees are a necessary resource to guarantee ethical integrity in human research; they must apply international standards in their ethical evaluation of research projects involving human subjects. OBJECTIVE: The ethics committees for human research of Colombia were characterized, and recommendations for strengthening them were formulated. MATERIALS AND METHODS: In 2003, 280 groups with research projects involving human subjects were selected from a list of research groups which form part of the science and technology network of Colciencias. (Colciencias is the Colombian national agency that promotes and funds science and technology.) Eighty percent (224) of the projects were associated with 40 institutions, consisting of universities, hospitals, and public or private research centers. Thirty of these institutions had at least one ethics committee for evaluating use of human subjects. A questionnaire was mailed to each of these Committees, requesting information concerning its their compostition, regulations, multidisciplinarity, plurality, representativity and independence. The World Health Organization's Operational Guidelines for Ethic Committees that Evaluate Biomedical Research (TDR/PRD/ETHICS/2000) was used as reference for the analysis. In 5 of the cities, supplemental information was obtained by direct discussions with members of the ethics committees. RESULTS: Twenty-six committees responded to the questionnaire. The results indicated that 47% of the committee members were physicians, but only 23% of the committees had representatives from the community. In 60% of the Committees, members were not independent from the organization in which it was based. Seventy percent had established operating procedures. Lack of national regulations and limited education in research ethics were mentioned as the main drawbacks in providing effective guidance. CONCLUSIONS: These observations led to the conclusion that national guidelines must be established for ethics committees that correspond to international standards. Committee members must be trained before accepting committee responsibilities. Finally, new committees must be created along with the improvement of the currently existing committees for reinforcing and promoting the importance of ethical integrity in research.

Comparative immunohistological analysis of the Montenegro skin test reaction in asymptomatic infection and in acute and chronic cutaneous leishmaniasis.

INTRODUCTION: The Montenegro skin test reaction and leishmaniasis lesions share fundamental characteristics of a delayed type hypersensitivity reaction. OBJECTIVES: To determine whether the Montenegro skin test reaction (response to leishmanin) might approximate and thereby provide insight into the early inflammatory and immune response to Leishmania infection. MATERIALS AND METHODS: We compared the inflammatory response in biopsies of acute (evolution time < or = one month), and chronic lesions (evolution time > or = 6 months) with the Montenegro skin test reaction in the corresponding patients, and with the Montenegro skin test of asymptomatically infected volunteers. RESULTS: The proportion of CD4+ and CD8+ T lymphocytes, mononuclear phagocytes and granulocytes were similar in acute lesions and in their corresponding Montenegro skin test reactions. In contrast, CD4+ lymphocytes (32.6%) represented a significantly lower, and B cells (20%) and macrophages (27%) a significantly higher proportion of the cellular infiltrate in chronic lesions as compared to reactions in the corresponding skin test site (CD4+: 43.7%, B cells: 0.9%; macrophages: 17.5%). CD8+ T lymphocytes and macrophages were positively associated (P = 0.038) in the Montenegro skin test of asymptomatically infected individuals whereas CD8+ and CD4+ T cells were positively associated in the Montenegro skin test of chronic patients (P = 0.002). Notably, B cells were markedly more frequent in chronic lesions (20%) than in acute lesions (5.3%) (P = 0.002). CONCLUSION: The Montenegro skin test distinguished the cellular immune response to Leishmania in asymptomatic infection and chronic disease and may provide a surrogate of the early response to infection.

Performance of OptiMAL(R) in the diagnosis of Plasmodium vivax and Plasmodium falciparum infections in a malaria referral center in Colombia.

Alternative, non-microscopic methods for the diagnosis of malaria have recently become available. Among these, rapid dipstick methods stand out. One such test, OptiMAL(R), is based on the immunochromatographic detection of Plasmodium lactate dehydrogenase (pLDH) and has the capacity to detect and distinguish infections caused by P. falciparum and Plasmodium sp. This capacity is particularly important in countries where different species of Plasmodium co-exist. In this study we evaluated the performance of OptiMAL(R) in an urban referral center for malaria diagnosis. Two sets of patients were included: one (n = 112) having predetermined infections with P. falciparum or P. vivax and individuals with negative blood smears; and another consisting of all eligible consecutive patients (n = 80) consulting for diagnosis at the referral center during one month. The overall diagnostic efficiency of OptiMAL(R) for both sets of patients was 96.9%. Efficiency was higher for P. vivax (98.1%) than for P. falciparum (94.9%). These results corroborate the diagnostic utility of OptiMAL(R) in settings where P. vivax and P. falciparum co-exist and support its implementation where microscopic diagnosis is unavailable and in circumstances that exceed the capacity of the local microscopic diagnosis facility.

Comités de ética de investigación en humanos: el desafío de su fortalecimiento en Colombia / Ethics review committees for human research: the challenge of strengthening this process in Colombia

Introducción. Los comités de ética de investigación en humanos que aplican los estándares internacionales en la evaluación ética de proyectos de investigación son un recurso indispensable para garantizar la integridad ética de la investigación en humanos. Objetivo. El presente trabajo se propuso conocer las características de los comités de ética de investigación en humanos y sus necesidades con miras a su fortalecimiento en Colombia. Materiales y métodos. En el 2003, se seleccionaron 280 grupos de investigación en humanos de un listado de grupos de investigación que acudieron a la convocatoria del año 2002 de la Red de Ciencia y Tecnología de Colciencias. El 80 por ciento de estos grupos pertenecía a 40 instituciones entre universidades, hospitales y centros de investigación públicos y privados. Treinta de 40 instituciones tenían comité de ética. Se les envió un cuestionario que indagaba sobre la constitución, reglamentación, composición multidisciplinaria, pluralidad, representatividad e independencia de los comités. Las respuestas se analizaron utilizando como referencia las Guías operacionales para comités de ética de investigación biomédica (TDR/PRD/ETHICS/2000). Se complementó la información obtenida mediante discusiones con miembros de estos comités en cinco ciudades del país. Resultados. Veintiséis comités respondieron la encuesta. El 47 por ciento de los miembros eran médicos, 23 por ciento de los comités tenía un miembro representante de la comunidad, 40 por ciento tenía un miembro independiente, 70 por ciento tenía manual de operaciones. Mencionaron la necesidad de mejorar la constitución de los comités, la capacitación de sus miembros, la regulación y las guías nacionales. Conclusión. Es urgente que en Colombia se elaboren guías nacionales para los comités de ética de investigación basados en estándares internacionales, se capacite a sus miembros y se promueva la integridad ética de la investigación.

Comparative immunohistological analysis of the Montenegro skin test reaction in asymptomatic infection and in acute and chronic cutaneous leishmaniasis / Análisis inmunohistopatológico comparativo de la reacción a la prueba cutánea de Montenegro en infección asintomática y en leishmaniasis cutánea aguda y crónica

Introducción. La reacción a la prueba cutánea de Montenegro (a leishmanina) y la lesión de leishmaniasis comparten características fundamentales de la reacción de hipersensibilidad de tipo retardado. Objetivos. Determinar si la respuesta cutánea a leishmanina se aproxima y podría modelar la respuesta inflamatoria e inmune temprana a la infección por Leishmania. Materiales y métodos. Este estudio comparó la respuesta inflamatoria de biopsias de lesiones agudas (tiempo de evolución £1 mes) y lesiones crónicas (tiempo de evolución ³6 meses) con su respectiva reacción a la prueba cutánea de Montenegro, y con la reacción a la prueba de Montenegro de individuos infectados asintomáticos. Resultados. La proporción de linfocitos T CD4+ y CD8+, células fagocíticas mononucleares y granulocitos fue similar entre lesiones agudas y sus reacciones a la prueba cutánea a leishmanina. En contraste, los linfocitos CD4+ (32,6 por ciento) representaron una proporción significativamente mas baja, y los linfocitos B (20 por ciento) y macrófagos (27 por ciento) una proporción significativamente más alta del infiltrado celular en lesiones crónicas que en sus correspondientes reacciones a la prueba cutánea de Montenegro (CD4+: 43,7 por ciento, linfocitos B: 0.9 por ciento; macrófagos: 17,5 por ciento). Se encontró una asociación positiva entre linfocitos T CD8+ y macrófagos ( P=0,038) en la reacción a la prueba cutánea de Montenegro de los individuos con infección asintomática, mientras que los linfocitos T CD8+ y CD4+ estuvieron asociados positivamente en las reacciones a la prueba cutánea de Montenegro de pacientes crónicos ( P=0,002). Adicionalmente, la proporción de linfocitos B en lesiones crónicas (20 por ciento) fue más alta que en lesiones agudas (5,3 por ciento) ( P=0,002). Conclusión. La reacción cutánea de Montenegro permitió diferenciar la respuesta celular inmune entre infección asintomática y enfermedad crónica, y simula la respuesta temprana a la infección.

Introduction. The Montenegro skin test reaction and leishmaniasis lesions share fundamental characteristics of a delayed type hypersensitivity reaction. Objectives. To determine whether the Montenegro skin test reaction (response to leishmanin) might approximate and thereby provide insight into the early inflammatory and immune response to Leishmania infection. Materials and methods. We compared the inflammatory response in biopsies of acute (evolution time £one month), and chronic lesions (evolution time ³6 months) with the Montenegro skin test reaction in the corresponding patients, and with the Montenegro skin test of asymptomatically infected volunteers. Results. The proportion of CD4+ and CD8+ T lymphocytes, mononuclear phagocytes and granulocytes were similar in acute lesions and in their corresponding Montenegro skin test reactions. In contrast, CD4+ lymphocytes (32.6%) represented a significantly lower, and B cells (20%) and macrophages (27%) a significantly higher proportion of the cellular infiltrate in chronic lesions as compared to reactions in the corresponding skin test site (CD4+: 43.7%, B cells: 0.9%; macrophages: 17.5%). CD8+ T lymphocytes and macrophages were positively associated ( P=0.038) in the Montenegro skin test of asymptomatically infected individuals whereas CD8+ and CD4+ T cells were positively associated in the Montenegro skin test of chronic patients ( P=0.002). Notably, B cells were markedly more frequent in chronic lesions (20%) than in acute lesions (5.3%) ( P=0.002). Conclusion. The Montenegro skin test distinguished the cellular immune response to Leishmania in asymptomatic infection and chronic disease and may provide a surrogate of the early response to infection.

Performance of OptiMAL® in the diagnosis of Plasmodium vivax and Plasmodium falciparum infections in a malaria referral center in Colombia

Alternative, non-microscopic methods for the diagnosis of malaria have recently become available. Among these, rapid dipstick methods stand out. One such test, OptiMAL®, is based on the immunochromatographic detection of Plasmodium lactate dehydrogenase (pLDH) and has the capacity to detect and distinguish infections caused by P. falciparum and Plasmodium sp. This capacity is particularly important in countries where different species of Plasmodium co-exist. In this study we evaluated the performance of OptiMAL® in an urban referral center for malaria diagnosis. Two sets of patients were included: one (n = 112) having predetermined infections with P. falciparum or P. vivax and individuals with negative blood smears; and another consisting of all eligible consecutive patients (n = 80) consulting for diagnosis at the referral center during one month. The overall diagnostic efficiency of OptiMAL® for both sets of patients was 96.9 percent. Efficiency was higher for P. vivax (98.1 percent) than for P. falciparum (94.9 percent). These results corroborate the diagnostic utility of OptiMAL® in settings where P. vivax and P. falciparum co-exist and support its implementation where microscopic diagnosis is unavailable and in circumstances that exceed the capacity of the local microscopic diagnosis facility

Oncocercosis en Colombia? una revaluación del foco de López de Micay / Onchocerciasis in Colombia? Follow-up of the in López of Micay focus

En 1965 se describió el primer foco de oncocercosis humana en Colombia en López de Micay, en la costa pacífica. Doce años después, una visita de seguimiento mostró que la prevalencia de infección había disminuído del 15 al 7,5 por ciento. Ya que no se volviron a reportar pacientes, se consideró extinguido el foco hasta 1989, cuando un niño con queratitis ocular fue remitido al Hospital Universitario de Cali. Se confirmó el diagnóstico de oncocercosis con una biopsia de piel. En julio de 1989 se hizo una visita al área y se tomaron muestras a 170 personas. La prevalencia de infección detectada por biopsia de piel fue de 4,1 por ciento (7/170). Se detectaron microfilarias (mf) en piel en 10 por ciento de los hombres muestreados y 0,9 por ciento de las mujeres. La microfilarodermia varió entre 0,5 mf por miligramo de piel y 47mf/mg y estaba directamente relacionada con la edad. No se encontraron nódulos subcutáneos palpables ni alteraciones dérmicas atribuibles al parásito en ningún paciente. Dos pacientes presentaron cambios oculares: queratitis bilateral y degeneración de la retina, respectivamente. Durante la visita, la actividad de los simúlidos fue muy baja y no se intentaron capturas. Es probable que la transmisión ocurra en sitios río arriba, donde la actividad de los vectores es mayor. Con la construcción de vías de acceso y una planta hidroeléctrica se espera un aumento de la población no inmmune en área. Cabe preguntar, cúal será el impacto de esta población susceptible sobre este foco hopoendémico