Asymptomatic Leishmania chagasi infection in relatives and neighbors of patients with visceral leishmaniasis

The frequency of asymptomatic infection among relatives and neighbors of cases of visceral leishmaniasis (VL) was compared and characterization of the immunological response in these subjects was performed. Cases were from a new endemic area, close to the beach and near Salvador, capital of the state of Bahia, Brazil. The characterization of asymptomatic infection was made using a skin reaction test and detection of antibody to Leishmania chagasi by the ELISA test. To characterize the immunological response of these subjects with asymptomatic L. chagasi infection the cytokines profile and the lymphoproliferative response were determined after stimulation of lymphocytes by L.chagasi antigen. There was no difference in the frequency of L. chagasi infection in relatives (45 per cent) and in neighbors (27 per cent) of cases of VL (P>0.05). The immunological response from these subjects was characterized by high production of IFN-µ and a low production of IL-10 and a good lymphoproliferative response to L.chagasi antigen.

Estudo evolutivo da leishmaniose mucosa (7 a 17 anos de seguimento) causada por Leishmania (Viannia) braziliensis em Três Braços, Bahia / Follow-up of 7-17 years of patients with mucosal leishmaniases caused by Leishmania (Viannia) braziliensis in Três Braços, Bahia

Seventy seven (68 per cent) patients with mucosal leishmaniasis recorded during the period 1976-1986 in the region of Três Braços, Bahia were traced and re-evaluated clinically, diagnostically and therapeutically. Sixty-five patients were alive. The families of 12 dead patients were interviewed about probable cause of death. The 65 patients had a fresh clinical examination supplemented when necessary by a skilled ENT examination. All had a titre of circulating immunofluorescent antibodies estimated at the time. Eight patients with active mucosal lesions had triturated biopsies which were cultivated in NNN medium and inoculated in hamsters to attempt to recover Leishmania. The isolates were identified by monoclonal antibodies as Leishmania (Viannia) braziliensis. Fifty-six (86 per cent) patients were judged clinically cured. Nine (13 per cent) had active lesions. Of the 12 patients who died 5 (41 per cent) had no signs of activity at death. Mucosal leishmaniasis was thought to be the direct cause of death in 3 patients. The field treatment programme at Três Braços has managed to clinically cure 61 patients (79 per cent) during 17 years. Follow-up periods were a mean of 10 years (range 7-17).

Imunidade humoral e celular em indivíduos curados de leishmaniose visceral / Humoral and cellular immunity in subjects cured of visceral leishmaniasis

Foi realizada avaliaçäo imunológica em 48 indivíduos com história pregressa de leishmaniose visceral (L.V.) e em seis pacientes durante a fase aguda da doença e após o tratamento. Títulos significativos de anticorpos determinados pela técnica de imunofluorescência e/ou ELISA foram observados em 32 (67%) dos 48 casos. A avaliaçäo da resposta imune humoral e celular nos seis pacientes durante a fase ativa da doença demonstrou títulos elevados de anticorpos (média 9536 + ou - 7169) e resposta linfoproliferativa ausente (323 + ou - 24). Após o tratamento (3 e 6 meses) os títulos de anticorpos só caíram em três dos seis pacientes, ao passo que linfócitos passaram a responder "in vitro" a antígenos de leishmânia (11909 + ou - 5637). Estes dados demonstram que os indivíduos que adquirem leishmaniose visceral näo säo geneticamente incapacitados de responder a antígeno de leishmânia e que a persistência de títulos elevados de anticorpos anos após o tratamento, sugere que o parasita permaneça no hospedeiro após a cura clínica da doença