Jackson Maurício Lopes Costa

Seroconversion against Lutzomyia longipalpis Saliva Concurrent with the Development of Anti–Leishmania chagasi Delayed-Type Hypersensitivity

Antibody responses to salivary gland sonicate (SGS) from Lutzomyia longipalpis were investigated using serum samples from individuals living in an area where visceral leishmaniasis is endemic. Individuals were classified into 2 groups, according to the alteration of their responses to Leishmania chagasi antigen over the course of 6 months. Group 1 included children who experienced anti-L. chagasi seroconversion from negative to positive; group 2 included children who experienced delayed-type hypersensitivity (DTH) response to L. chagasi antigen conversion from negative to positive. Individuals who experienced seroconversion against L. chagasi antigens did not have increased anti-saliva antibody response, whereas those who developed a positive anti-L. chagasi DTH response had increased immunoglobulin (Ig) G, IgG1 and IgE anti-SGS antibody levels. Despite wide variation, serum samples from individuals in group 2 recognized more bands in SGS than did those from individuals in group 1. This simultaneous appearance of anti-saliva humoral response and anti-L. chagasi cell-mediated immunity supports the hypothesis that induction of immune response against SGS can facilitate induction of a protective response against leishmaniasis.

Clinical and immunopathological aspects of disseminated cutaneous leishmaniasis

The clinico-pathological and immunological findings in eight patients from Bahia, Brazil with disseminated cutaneous leishmaniasis are described. This condition differs from anergic diffuse cutaneous leishmaniasis (DCL) and from classical American cutaneous leishmaniasis (ACL). The number of lesions in these patients ranged from 75 to 800 and were characterized by papules and an acneiform type of lesion with a few ulcers rather than nodules that are the main characteristic of DCL. On the other hand the high incidence of mucosal disease (38%) in patients with disseminated cutaneous leishmaniasis make the prevalence of mucosal involvement in this condition higher than that observed in ACL. L. amazonensis (five cases) and L. braziliensis (two cases) were the causal agents in the patients where the infecting agent was characterized. Antibody titers in disseminated cutaneous leishmaniasis were higher than those observed in ACL and patients with the highest antibody titers had mucosal involvement. Abnormalities in cellular immunity that are not observed in ACL such as decrease in CD4+ cells and absence of T cell response to leishmania antigen were observed in several patients with disseminated cutaneous leishmaniasis but restoration of these abnormalities occurred after treatment. In spite of the great number of lesions, the therapeutic response was good in six patients with disappearance of the lesions in a period shorter than that observed in ACL. In the two patients that presented therapeutic failure the causal agent was L. amazonensis. In such patients there was a predominance of ulcerated lesions, and a high titer of antibody was detected.

Balance of IL-10 and Interferon-γ plasma levels in human visceral leishmaniasis: Implications in the pathogenesis

BackgroundLeishmaniasis remains a serious public health problem in several parts of the developing world. Effective prophylactic measurements are hampered by imprecise comprehension of different aspects of the disease, including its immunoregulation. A better comprehension of immunoregulation in human VL may be useful both for designing and evaluating immunoprophylaxis.MethodsTo explore immunoregulatory mechanisms, 20 visceral leishmaniasis (VL) patients were evaluated during active disease and at different periods up to one year after treatment determining their plasma cytokine levels, clinical parameters (palpable spleen and liver) and antibody levels.ResultsElevated plasma levels of IFN-γ and of IL-12 p40 were observed during active disease, significantly decreasing after treatment whereas in vitro Leishmania antigen-stimulated IFN-γ production by PBMC exhibited an inverse pattern being low during disease and increasing steadily thereafter. Absence of IFN-γ activity is a hallmark of VL. The main candidate for blunting IFN-γ activity is IL-10, a cytokine highly elevated in plasma with sharp decrease after treatment. Activity of IL-10 is inferred by high levels of anti-Leishmania specific IgG1 and IgG3. TGF-β had elevated total, but not of active, levels lessening the likelihood of being the IFN-γ counterpart. Spleen or liver size presented a steady decrease but return to normal values at only 120 days after treatment. Anti-Leishmania IgG (total and subclasses) levels and DTH or Leishmania-stimulated lymphocyte proliferation conversion to positive also present a slow decrease after treatment. IL-6 plasma levels were elevated in only a few patients.ConclusionTaken together our results suggest that IFN-γ and IL-10 are the molecules most likely involved in determining fate of disease. After treatment, there is a long delay before the immune profile returns to normal what precludes using plasma cytokine levels as criteria of cure as simpler clinical evaluations, as a palpable spleen or liver, can be used.

Risk factors associated with asymptomatic infection by Leishmania chagasi in north-east Brazil

Various factors have been associated with a predisposition to the development of clinical American visceral leishmaniasis (AVL). However, little information is available about the factors that predispose to asymptomatic infection. To identify the risk factors associated with asymptomatic infection, a study was carried out between July 1997 and June 1998 on children aged 0-5 years in the districts of Vila Nova and Bom Viver in the municipality of Raposa in the island of São Luís, State of Maranhão, Brazil. A questionnaire containing socioeconomic, demographic and epidemiological data was used. The delayed-type hypersensitivity (DTH) test was carried out on 639 children in the first phase, and on 572 in the second, 7 months after the first survey, using Leishmania amazonensis antigen. Infection was determined by enzyme-linked immunosorbent assay (ELISA) in 638 children during the first phase, and in 572 during the second. Six outcome measures were used: initial prevalence, final prevalence and incidence, each determined by DTH and ELISA. The incidence of infection was 10.8% when determined by DTH and 28.5% when determined by ELISA. After adjustment for confounding variables using Cox regression, infection by L. chagasi was associated with childs age (> or = 2 years), location of the dwellings (Vila Nova) and reporting of relatives with AVL. Bathing outside the house and playing outdoors between 18:00 and 20:00 were identified as risk factors in some analyses but not in others. Presence of intra- and peridomestic Lutzomyia sandflies and animals such as dogs or chickens in the house or in the neighbourhood appeared as risk factors in some analyses but in others they unexpectedly seemed to protect from infection. Malnutrition was not found to be associated with infection.

Clinical Utility of Polymerase Chain Reaction—Based Detection of Leishmania in the Diagnosis of American Cutaneous Leishmaniasis

We evaluated the use of polymerase chain reaction (PCR) for diagnosis of American cutaneous leishmaniasis (ACL) in an area in Bahia, Brazil, where Leishmania braziliensis is endemic. Leishmania DNA was detected in 50 cases, yielding a positivity rate of 100%, which was higher than the rates for all of the other diagnostic methods studied--namely, the Montenegro skin test, anti-Leishmania serological testing, and microscopic examination of lesion biopsy specimens. These findings have led us to propose guidelines for the diagnosis of ACL that use PCR as the principal means of parasitological confirmation of cases.

CD8+ Granzyme B+–Mediated Tissue Injury vs. CD4+IFNγ+–Mediated Parasite Killing in Human Cutaneous Leishmaniasis

A protective or deleterious role of CD8+T cells in human cutaneous leishmaniasis (CL) has been debated. The present report explores the participation of CD8+T cells in disease pathogenesis as well as in parasite killing. CD8+T cells accumulated in CL lesions as suggested by a higher frequency of CD8+CD45RO+T cells and CD8+CLA+T cells compared with peripheral blood mononuclear cells. Upon Leishmania braziliensis restimulation, most of the CD8+T cells from the lesion expressed cytolytic markers, CD107a and granzyme B. Granzyme B expression in CL lesions positively correlated with lesion size and percentage of TUNEL-positive cells. We also observed a significantly higher percentage of TUNEL-positive cells and granzyme B expression in the biopsies of patients showing a more intense necrotic process. Furthermore, coculture of infected macrophages and CD8+T lymphocytes resulted in the release of granzyme B, and the use of granzyme B inhibitor, as well as z-VAD, Fas:Fc, or anti-IFN-γ, had no effect upon parasite killing. However, coculture of infected macrophages with CD4+T cells strongly increased parasite killing, which was completely reversed by anti-IFN-γ. Our results reveal a dichotomy in human CL: CD8+ granzyme B+T cells mediate tissue injury, whereas CD4+IFN-γ+T cells mediate parasite killing.

Nível de conhecimentos sobre Leishmaniose Tegumentar Americana (LTA) e uso de terapias alternativas por populações de uma área endêmica da Amazônia do Maranhão, Brasil

Realizou-se estudo visando identificar e comparar que conhecimentos basicos e uso de terapias alternativas relativos a Leishmaniose Tegumentar Americana (LTA), tem populacoes residentes em cinco areas rurais (Sexta Vicinal, Quinta Vicinal, Trilha 410, Vila Uniao e Buritizinho) pertencentes ao municipio de Buriticupu, Maranhao. No periodo de setembro de 1997 a janeiro de 1998, aplicou-se questionarios com perguntas abertas e fechadas, abordando aspectos epidemiologicos, modos de prevencao, clinica e terapeutica alternativa. A populacao estudada foi de 378 (19%) individuos de um total de 1980 habitantes. Na Sexta Vicinal (35 individuos), Quinta Vicinal (63), Trilha 410 (96), Vila Uniao (85) e Buritizinho (99). Dos entrevistados, 72% tinham poucos conhecimentos dos modos de transmissao, 96,9% ja ouviram falar da doenca, a maioria obteve informacoes com amigos, 60,7% conheciam a LTA como lesh. O Glucantime foi a droga mais citada para o tratamento, 29,6% relataram uso de plantas no local da lesao. O Citrus limon (limao) foi a planta mais citada (15,4%) dos entrevistados, o modo de uso mais frequente era o po espalhado sobre a lesao. Conclui-se que o nivel de conhecimento sobre LTA foi incipiente, principalmente na prevencao e terapeutica, situacao similar nas cinco areas estudadas.

Perfil dos pacientes com hanseníase em área hiperendêmica da Amazônia do Maranhão, Brasil

An epidemiological cross-sectional study of 207 patients with leprosy disease, was undertaken between August 1998 to november 2000, aiming at evaluating the socioeconomic, demographic and ambiental profiles of the patients as well as physical incapacity due to the disease. The study was performed in the municipality of Buriticupu-Maranh o state, a hiperendemic leprosy area in the Amazonian Maranh o. The level of incapacity was assessed from parameters established by the Brazilian Health Minister. The clinical evaluation and the results of the physical tests were registered in a standardized form. It was observed a predominance of married people (45,9%), with low level of education (56%), being lend workers (40,1%), with familiar income to the minimum wage (76,3%), aged from 14 to 44 years (63,3%), males (60,9%) and brown (67,6%); 44% living in mud huts, 82,6% deposited their excrements in cesspits and 63,8% do not treat the drinking water, 58% utilized well-water and 51,7% do not use treated water for ingestion. The most affected segments of the body were the feet (62,3%), eyes (51,2%) end hands (7,2%), being the higher percentage of physical incapacitaties found among the patients bearing the borderline form of the disease (93%) mainly hands and feet, and in the virchowian form greatest frequency of eyes incapacities. It is concluded that the hyperendemicity associated with the precarious socioeconomic conditions and with a high level of physical incapacities may be involved with the living quality of the patients.An epidemiological cross-sectional study of 207 patients with leprosy disease, was undertaken between August 1998 to november 2000, aiming at evaluating the socioeconomic, demographic and ambiental profiles of the patients as well as physical incapacity due to the disease. The study was performed in the municipality of Buriticupu-Maranhao state, a hiperendemic leprosy area in the Amazonian Maranhao. The level of incapacity was assessed from parameters established by the Brazilian Health Minister. The clinical evaluation and the results of the physical tests were registered in a standardized form. It was observed a predominance of married people (45,9%), with low level of education (56%), being lend workers (40,1%), with familiar income to the minimum wage (76,3%), aged from 14 to 44 years (63,3%), males (60,9%) and brown (67,6%); 44% living in mud huts, 82,6% deposited their excrements in cesspits and 63,8% do not treat the drinking water, 58% utilized well-water and 51,7% do not use treated water for ingestion. The most affected segments of the body were the feet (62,3%), eyes (51,2%) end hands (7,2%), being the higher percentage of physical incapacitaties found among the patients bearing the borderline form of the disease (93%) mainly hands and feet, and in the virchowian form greatest frequency of eyes incapacities. It is concluded that the hyperendemicity associated with the precarious socioeconomic conditions and with a high level of physical incapacities may be involved with the living quality of the patients.

Infecção por Leishmania (Leishmania) chagasi em crianças de uma área endêmica de leishmaniose visceral americana na Ilha de São Luis-MA, Brasil

Barral, Aldina Maria Prado “Documento produzido em parceria ou por autor vinculado a Fiocruz, mas nao consta a informacao no documento”.A prospective study was undertaken in 648 children with less than 6 years of age in the municipality of Raposa, Maranhao, Brazil, from June 1997 to June 1998, to evaluate the characteristics of the infection by L.(L.)chagasi and verify if there is an association between malnutrition and asymptomatic infection. A standardized questionnaire was used containing socioeconomic, environmental and behavioral data. Montenegro skin reaction (IDRM) with L. amazonensis and Enzyme Linked Immunosorbent Assay (ELISA) test to detect infection, and anthropometric examination were performed. Initial and final prevalence and incidence of infection were 18.6%, 20.6% and 10.8% as measured by IDRM and 13.5%, 34.4% and 28% according to ELISA. The prevalence of chronic malnutrition was 26%. No association was detected between malnutrition and asymptomatic infection by L. (L.) chagasi. More effective control measures are needed in these areas since asymptomatic infection seems to be on the increase.

Lesion Size Correlates with Leishmania Antigen-Stimulated TNF-Levels in Human Cutaneous Leishmaniasis

Cutaneous leishmaniasis (CL) is a worldwide disease endemic in several regions of the globe. The hallmark of CL is skin ulcers likely driven by efforts of the immune system to control Leishmania growth. Cytokines, such as tumor necrosis factor (TNF) and interferon-gamma can control disease progression in animal models. Nevertheless, the impact of these cytokines in CL ulcer outcome is not well established in humans. In this study, 96 CL patients from an endemic area of Leishmania braziliensis were enrolled for a follow-up study that consisted of clinical and immunological evaluations in a 2-year period. Statistical analysis revealed that healing time (P = 0.029), age (P = 0.002), and TNF levels (P = 0.0002) positively correlate with ulcer size at the time of the first clinical evaluation. Our findings suggest that ulcer size correlates with healing time and TNF levels support the use of TNF inhibitors combined with standard therapy to improve healing in CL patients with severe lesions.