T-cell responses associated with resistance to Leishmania infection in individuals from endemic areas for Leishmania (Viannia) braziliensis

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.

Leishmanial antigens in the diagnosis of active lesions and ancient scars of American tegumentary leishmaniasis patients

Cutaneous biopsies (n = 94) obtained from 88 patients with American tegumentary leishmaniasis were studied by conventional and immunohistochemical techniques...

Pancreatite: um dos efeitos adversos da terapia antimonial na leishmaniose / Pancreatitis: one of the adverse effects of antimonial therapy in leishmaniasis

São relatados dois casos de leishmanioses - forma visceral e forma mucosa - em paciente de 52 anos do sexo masculino e em paciente do sexo feminino de 67 anos, respectivamente. Ambos apresentavam história pregressa de hanseníase. Após a confirmação diagnóstica, foram submetidos a tratamento com antimoniato de meglumina na dose de 20 mg (Caso n.1) e 10 mg de Sb5+/Kg de peso por dia (Caso n.2). Os pacientes evoluíram com mal-estar, astenia e anorexia a partir do sexto e décimo dia de tratamento e elevação de 7 a 22 vezes dos níveis séricos de amilase para cada caso, respectivamente. O caso n.2 apresentou também dor abdominal, náusea, hipotensão, febre, aumento de uréia, cretinina e transaminases, cardiotoxicidade e prurido cutâneo. O tratamento foi interrompido nos dois casos com regressão da sintomatologia e retorno gradual dos níveis séricos de amilase aos valores normais, apesar da reintrodução do tratamento no Caso n.1. Não foi possível reintroduzir o tratamento no caso n.2 devido à associação com outros efeitos adversos e demora na normalização da amilasemia. Ambos evoluíram para cura clínica da leishmaniose. Os autores discutem relatos semelhantes encontrados na literatura e sugerem o monitoramento da função pancreática ao lado dos outros parâmetros de controle da toxicidade do antimônio