A prospective study on the dynamics of the clinical and immunological evolution of human Leishmania (L.) infantum chagasi infection in the Brazilian Amazon region

Abstract

This prospective study was carried out from October 2003 to December 2005 and involved a cohort of 946 individuals of both genders, aged 1-89 years, from an endemic area for American visceral leishmaniasis (AVL), in Pará State, Brazil. The aim of the study was to analyze the dynamics of the clinical and immunological evolution of human Leishmania (L.) infantum chagasi infection represented by the following clinical-immunological profiles: asymptomatic infection (AI); symptomatic infection (SI=AVL); subclinical oligosymptomatic infection (SOI); subclinical resistant infection (SRI); and indeterminate initial infection (III). Infection diagnosis was determined by the indirect fluorescent antibody test and leishmanin skin test. In total, 231 cases of infection were diagnosed: the AI profile was the most frequent (73.2%), followed by SRI (12.1%), III (9.9%), SI (2.6%) and SOI (2.2%). The major conclusion regarding evolution dynamics was that the III profile plays a pivotal role from which the cases evolve to either the resistant, SRI and AI, or susceptible, SOI and SI, profiles; only one of the 23 III cases evolved to SI, while most evolved to either SRI (nine cases) or SOI (five cases) and eight cases remained as III.

Severe visceral leishmaniasis in children: the relationship between cytokine patterns and clinical features

“…VL patients' clinical manifestations and laboratory abnormalities permit the diagnosis of the most severe cases and cases at greater risk of disease progression 8,17,18 . Our clinical and laboratory fi ndings agree with those reported by previous studies, as a combination of fever, hepatosplenomegaly, anemia, and leukopenia was frequently observed and led to the suspicion of VL in such cases, particularly in children 19 .…”

“…However, studies have shown that there is no dichotomy in the production of cytokines in VL, but rather a predominance of elevated levels of a pool of cytokines 17,18,24,25 .…”

“…However, despite a highly activated immune system, patients exhibit Leishmania antigenspecifi c immunosuppression 12 . Additionally, interleukin 10 (IL-10) and TGF-β activity in splenic and liver macrophages induces parasite proliferation; therefore, these cytokines can be characterized as immune response regulators [13][14][15][16][17][18] . It has been suggested that the main risk factors for death in VL are related to the fact that such high systemic pro-infl ammatory cytokine production greatly compromises organs and systems 10 .…”

Diagnosing Neglected Tropical Diseases in HIV Coinfection

“…Classically, VL is characterized by splenomegaly, hepatomegaly, fever, and pancytopenia. 78,79 Tegumentary leishmaniasis presents distinct forms and the main ones are as follows: 1) localized cutaneous leishmaniasis, characterized by a simple or multiple ulcer, can be caused by all dermotropic Leishmania species; 2) disseminated cutaneous leishmaniasis, characterized by multiple small ulcers; 3) diffuse cutaneous leishmaniasis is the anergic form of TL, characterized by multiple nodules or papules, generally presenting no ulceration; 4) mucosal leishmaniasis is mainly characterized by nasal involvement, presenting perforation or ulceration, which can also involve the palate and pharynx. 12 The spreading of HIV infection to rural areas and the urbanization of leishmaniasis has influenced the clinical progression and diagnosis of leishmaniasis.…”

Novas evidências sobre o valor diagnóstico da reação de imunofluorescência indireta e reação intradérmica de hipersensibilidade tardia na infecção humana por Leishmania (L.) infantum chagasi na Amazônia, Brasil

“…We designed the current study in a similar manner as 28 our two previous studies; one has already been published 29 and the other was accepted for publication .…”