Subclinical or asymptomatic infection is documented in individuals living in endemic areas for leishmaniasis suggesting that the development of an appropriate immune response can control parasite replication and maintain tissue integrity. A low morbidity indicates that intrinsic factors could favor resistance to Leishmania infection. Herein, leishmanial T-cell responses induced in subjects with low susceptibility to leishmaniasis as asymptomatic subjects were compared to those observed in cured cutaneous leishmaniasis (CCL) patients, who controlled the disease after antimonial therapy. All of them have shown maintenance of specific long-term immune responses characterized by expansion of higher proportions of CD4+ as compared to CD8+ Leishmania reactive T-lymphocytes. Asymptomatic subjects had lower indexes of in vitro Leishmania induced lymphoproliferative responses and interferon-gamma (IFN-gamma) production in comparison to CCL patients. On the other hand, interleukin (IL-10) production was much higher in asymptomatics than in CCL, while no differences in IL-5 levels were found. In conclusion, long lived T-cell responses achieved by asymptomatic individuals differed from those who had developed symptomatic leishmaniasis in terms of intensity of lymphocyte activation (proliferation or IFN-gamma) and regulatory mechanisms (IL-10). The absence of the disease in asymptomatics could be explained by their intrinsic ability to create a balance between immunoregulatory (IL-10) and effector cytokines (IFN-gamma), leading to parasite destruction without producing skin tissue damage. The establishment of profiles of cell-mediated immune responses associated with resistance against Leishmania infection is likely to make new inroads into understanding the long-lived immune protection against the disease.

The author describes and make comments on the favorable conditions that made possible the creation and organization of the first laboratory of flow cytometry in Brazil and South America installed at the Oswaldo Cruz Institute-Fiocruz, Rio de Janeiro, in November 1988.

An atypical case of acquired immunodeficiency syndrome-associated mucocutaneous lesions due to Leishmania braziliensis is described. Many vacuolated macrophages laden with amastigote forms of the parasite were found in the lesions. Leishmanin skin test and serology for leishmaniasis were both negative. The patient was resistant to therapy with conventional drugs (antimonial and amphotericin B). Interestingly, remission of lesions was achieved after an alternative combined therapy of antimonial associated with immunotherapy (whole promastigote antigens). Peripheral blood mononuclear cells were separated and stimulated in vitro with Leishmania antigens to test the lymphoproliferative responses (LPR). Before the combined immunochemotherapy, the LPR to leishmanial antigens was negligible (stimulation index - SI=1.4). After the first course of combined therapy it became positive (SI=4.17). The antigen responding cells were predominantly T-cells (47.5%) most of them with CD8+ phenotype (33%). Very low CD4+ cells (2.2%) percentages were detected. The increased T-cell responsiveness to leishmanial antigens after combined therapy was accompanied by interferon-g (IFN-g) production as observed in the cell culture supernatants. In this patient, healing of the leishmaniasis lesions was associated with the induction of a specific T-cell immune response, characterized by the production of IFN-g and the predominance of the CD8+ phenotype among the Leishmania-reactive T-cells.

Tumor necrosis factor-alpha (TNF-α) is a cytokine produced by activated macrophages and other cells. In order to verify whether the serum levels of TNF-α in American tegumentary leishmaniasis patients are associated with the process of cure or aggravation of the disease, 41 patients were studied: 26 cases of cutaneous leishmaniasis (CL) and 15 of mucocutaneous leishmaniasis (MCL). During active disease the serum levels of TNF-α of MCL patients were significantly higher than those of CL patients and control subjects (healthy individuals and cutaneous lesions from other etiologies). The MCL patients had serum titers of TNF-α significantly lower at the end of antimonial therapy than before therapy. After a six-month follow-up, the MCL patients had serum levels of TNF-α similar to those observed at the end of the therapy as well as to those of CL patients and control subjects. No significant variation in the serum levels of TNF-α was observed in CL patients throughout the study period (before, at the end of therapy and after a six-month follow-up). The possible relationship between the high TNF-α serum levels and severity of the disease is discussed.

O teste de imunofluorescência indireta (IF) para a detecção de anticorpos anti-Leismania nas classes IgG e IgM foi realizado em soros de indivíduos dos seguintes grupos: 214 pacientes com leismaniose cutânea, quatro pacientes com leismaniose mucocutânea, 28 indivíduos sadios com intradermorreação de Montenegro (IDRM) positiva, 29 indivíduos sadios com IDRM negativa e 16 pacientes com leishmaniose visceral. Os indivíduos dos quatro primeiros grupos eram provenientes de uma área da periferia da cidade do Rio de Janeiro (Jacarepaguá) onde a leishmaniose tegumentar causada por Leishmania braziliensis brasiliensis é endêmica. Entre os pacientes com leishmaniose cutânea foi observado que os títulos de IF-IgM foram significantemente mais altos nos casos com menos de quatro meses de evolução do que em pacientes com períodos mais longos de evolução da doença e que os títulos de IF-IgG foram significantemente mais altos em pacientes com lesões múltiplas do que nos portadores de lesão única. Os pacientes com leishmaniose visceral tiveram títulos de IF-IgG significantemente superiores aos dos pacientes com leishamiose cutânea. zum grupo de 28 indivíduos selecionados entre os 214 pacientes com leishmaniose cutânea tiveram seus títulos de IF (IgG e IgM) comparados aos de dois grupos controles constituídos de indivíduos sadio, moradores na área endêmica com IDRM respectivamente positiva e negativa. Títulos de IF-IgG e IF-IgM significantemente superiores foram encontrados no grupo com doença ativa. O mesmo grupo de pacientes apresentou título de IF-IgG significantemente mais baixos após a terapêutica antimonial do que durante a mesma.

The indirect immunofluorescence test (IF) for anti-Leishmania antibodies (IgC and IgM) was performed with sera form the following groups of individuals: 214 cutaneous leishmaniasis patients, 28 healthy subjects with positive Montenegro's skin test (MST), 29 healthy subjects with negativeMST and 16 visceral leishmaniasis patients. The first four groups came from a suburban area of Rio de Janeiro (Jacarepaguá) where cutaneous leishmaniasis caused by Leishmania braziliensis braziliensis is endemic. It was observed that IF-IgM titers were significantly higher amongst the cutaneous leishmaniasis patients with less than four months of disease as compared to those with longer periods and that IF-IgG titers were significantly higher in patients with multiple lesions as compared to those with single lesions. The visceral leishmaniasis patients had IF-IgG titers significantly higher than those from cutaneous leishmaniasis patients. A group of 28 individuals selected amongst the 214 cutaneous leishmaniasis patients had their IF-titers (IgG and IgM) compared to those of the two control groups of healthy subjects from the endemic area, respectively with positive and negative MST. Significantly higher titers of IF-IgG and IF-IgM were found in the group with active disease. The same group of patients showed IF-IgG titers significantly lower at the end of the antimonial therapy than those observed during this tratment.

Quatro cães foram inoculados por via intredérmica com 3 x 10**6 promastigotos de Leishmania brasiliensis braziliensis. Três deles desenvolveram lesões no sítio do inóculo, mas uma úlcera mucosa foi detectada 16 meses após o inóculo. Os achados foram similares áqueles verificados na infecção canina natural, bem como na doença humana. Estes resultados sugerem que o cão pode representar um modelo experimental para a infecção causada pela L. b. brasiliensis.

Four mongrel dogs were intradermically inoculated with 3 x 10**6 Leishmania braziliensis braziliensis promastigotes. Three out of the four animals developed cutaneous lesions respectively 4, 7, and 8 months after. The fourth dog did not develop lesion at the inoculation site, but a mucosal ulcer was seen 16 months after the inoculum. Clinical, histopathological, and serological findings were similar to what is found in natural canine infection as well as in the human disease. These results suggest that dogs may be an useful model for L. b. braziliensis infection.

Foram feitos testes de imunofluorescência (IF) para toxoplasmose em 608 escolares do 1º grau, sendo 166 de Bonsucesso (área urbana do Rio de Janeiro) e 442 da baixa de Jacarepaguá (área com características rurais). Todas as IF-IgM foram não-reagentes, enquanto que 416 escolares (68,4%) foram soro-reagentes na IF-IgG (maior ou igual a 1:16). As percentagens de soro-reagentes em Jacarepaguá foram significantemente superiores às de Bonsucesso, tanto em relação ao número total de escolares, como quando subdivididos segundo as faixas etárias de 6 a 8 anos ou de 12 a 14 anos. Tanto em Jacarepaguá quanto em Bonsucesso, a prevalência de reagentes no grupo etário de 12 a 14 anos foi significantemente maior do que no grupo de 6 a 8 anos de idade. Em Jacarepaguá encontraram-se prevalências significantemente maiores de soro-reagentes entre os escolares que referiam a ingestão de carne crua ou mal cozida, assim como entre o que possuiam gato; isto ocorreu tanto no grupo etário de 6 a 8 anos como no de 12 a 14 anos. Em Bonsucesso só houve diferença significante entre as crianças de 6 a 8 anos que possuiam gatos no domicílio. Verificou-se assim que em área com característica rural o risco de infecção era maior e mais precoce do que em área urbana.

Immunofluorescence tests (IF) for toxoplasmosis were performed on a total of 608 schoolchildren in elementary and junior high grades. 166 being in the Bonsucesso district (an urban region of Rio de Janeiro) and 442 children from locations within the lowlands of Jacarepaguá (with rural characteristics). All the IF-IgM were nonreactive, whilst 416 schoolchildren (68.4%) were IF-IgG serum-reactive ([greater than or equal to] 1:16). The percentages of serum-reactives in Jacarepaguá were significantly higher than in Bonsucesso, both as regards the total number of schoolchildren (p < 0.001), as also when subdivided according to the age-grades from six to eight years (p < 0.001) or from twelve to fourteen (p < 0.05). Both in Jacarepaguá and in Bonsucesso, the prevalence of reactions in the 12 to 14 year age-grade was significantly greater than in the 6 to 8 year age-grade (p < 0.001 in both cases). Expressively larger prevalences of serum reactions were found in Jacarepaguá among schoolchildren who preferred eating raw or undercooked meat, as well as among those having cats as pets; this occurred equally in the 6 to 8 year and in the 12 to 14 year age-grades. In Bonsucesso, the only significant difference was in the 6 to 8 year age-grades that had cats as pets. Thus, it has been verified that the risk of infection is greater and more precocious in localities with rural characteristics than in urban regions.

Durante inquéritos caninos realizados na periferia da cidade do Rio de Janeiro, foram estudados clínica e laboratorialmente 40 cães. Todos apresentavam diagnóstico parasitológico e/ou sorológico de leishmaniose. Dentre esses, 19 procediam de áreas de ocorrência de leishmaniose visceral (LV) - Realengo, Bangu e Senador Camará. Sinais clínicos sugestivos da infecção foram observados em 36,8% deles (incluindo emagrecimento - 100%, linfadenopatia e depilação - 85,7%). Outros 21 cães procediam da área de Campo Grande onde tanto a LV como a leishmaniose tegumentar americana (LTA) ocorrem. Sinais clínicos da infecção por Leishmania, principalmente ulcerações cutâneas e mucocutâneas, foram observadas em 76,2% deles. Em 39 cães foram encontrados leishmanias: 22% em vísceras, 42,5% em vísceras e pele normal e 35% um ulcerações cutâneas ou mucocutâneas. Todos os estoques de Leishmania isolados de cães provenientes das áreas de LV e da área de LV + LTA foram caracterizados como L. donovani (exceto em um caso) conforme seus esquisodemas, zimodemas e serodemas. O único estoque caracterizado como L. braziliensis brazilienzis foi isolado de linfonodo de um cão de Campo Grande, com leishmaniose visceral e sem alterações cutâneas. A tentativa de tratamento pelo antimonial em oito cães positivos para Leishmania donovani não reverteu o curso da doença e um deles apresentou intenso agravamento, morrendo em curto período.

Forty dogs from the periphery of the city of Rio de Janeiro were studied. All dogs where diagnosed as positive for leishmaniasis either parasitologically and/or serologically. Among them, 19 came from areas where only Visceral Leishmaniasis (VL) occurs (Realengo, Bangu, Senador Camará). Clinical signs of the disease were seen in 36.8% of the cases, including emaciation - 100%, lymphadenopathy and depilation - 85.7%. The other 21 dogs came from an area (Campo Grande) where both diseases (VL, and American Cutaneous Leishmaniasis - ACL) occur. Clinical signs of the disease, mainly cutaneous or mucocutaneous ulcers were seen in 76.2% of the cases. Leishmania parasites were found in 39 cases: 22% in viscera, 42.5% in viscera and normal skin and 35% in cutaneous or mucocutaneous ulcers. All the Leishmania stocks isolated from dogs which came from Realengo, Bangu, Senador Camará (VL area), and from Campo Grande (VL + ACL area) were characterized as L. donovani (except in one case) according to their schizodeme, zymodeme and serodeme. The only stock characterized as L. b. braziliensis, was isolated from the lymph node of a dog from Campo Grande with visceral disease and without skin lesions. Antimony therapy attempted in eight Leishmania donovani positive dogs was unsuccessful.

Casos humanos de Leishmaniose Visceral Tegumentar têm sido diagnosticados em áreas periféricas da cidade do Rio de Janeiro. Os parasitais isolados têm sido identificados respectivamente como Leishmania donovani e Leishmania braziliensis braziliensis. Foi feito um inquérito para Leismaniose entre 1.342 cães provenientes daquelas áreas utilizando-se a pesquisa de anticorpos pela imunofluorescência indireta. Dos cães examinados, 616 eram provenientes de áreas de ocorrência de casos humanos de Leishmaniose Visceral, 373 de área de Leishmaniose Tegumentar humana e os restantes 353 de uma região (Campo Grande) onde além de casos humanos de Leishmaniose Visceral, alguns casos de Leishmaniose Tegumentar haviam sido diagnosticados. A prevalência de anticorpos para Leishmania entre os cães provenientes de área de Leishmaniose Tegumentar foi significantemente maior que a observada nas áreas de Leishmaniose Visceral (8,6% vs. 4,3%;p < 0,02). Interessante é que a maior prevalência foi observada entre cães da área onde amboas as doenças ocorreram (12,7%).

There are areas in the periphery of Rio de Janeiro city where human cases of Visceral and/or Cutaneous Leishmaniasis occur. The parasites have been identified as Leishmania donovani and Leishmania braziliensis braziliensis respectively. A survey for Leishmaniasis was done among 1,342 dogs from those areas using an indirect immunofluorescent test. From the dogs, 616 came from areas where only human cases of Visceral Leishmaniasis occurred, 373 from an area where all human cases were of Cutaneous Leishmaniasis and 353 from a third area (Campo Grande) where both visceral and cutaneous human cases were detected. The prevalence of parasite antibody titers among dogs from areas of Cutaneous Leishmaniasis was significantly higher than that of Visceral Leishmaniasis (8.6% vs. 4.3%, p < 0.02). The highest prevalence was observed among dogs from the area where both diseases are present (12.7%).