Valdir Sabbaga Amato

Treatment of New World cutaneous leishmaniasis: a systematic review with a meta-analysis

Background  New World leishmaniasis is an important endemic disease and public health problem in developing countries. The increase in ecologic tourism has extended this problem to developed countries. Few drugs have emerged over the past 50 years, and drug resistance has increased, such that the cure rate is no better than 80% in large studies. Despite these data, there has been no systematic review with a meta‐analysis of the therapy used in this important tropical disease. The aim of this study was to determine the best drug management in the treatment of cutaneous leishmaniasis (CL) in Latin America based on the best studies published in the medical literature.

Toll-like receptors and leishmaniasis

More than 10 million people around the world are currently affected by Leishmania sp. (33). Infection with this protozoan parasite continues to be a problem in underdeveloped countries and is a continuous worry in developed countries due to the possibility of the disease afflicting tourists returning from countries where the organism is endemic (82). Leishmaniasis is a neglected infectious disease, and it affects poor and marginalized populations. It is distributed, in its visceral, mucosal, and cutaneous forms, throughout more than 90 countries in Africa, the Americas, Asia, and Europe (5). It constitutes a serious public health problem and causes significant morbidity and mortality. In recent years, economic globalization and the increase in travel have extended the distribution of the disease to developed countries. Approximately 350 million people live in areas where there is active parasite transmission of zoonotic and anthroponotic leishmaniasis. Zoonotic transmission occurs in rural and periurban environments, whereas anthroponotic transmission occurs in urban environments (7). From a strictly biological point of view, de Almeida et al. described humans as just one of the actors in the leishmaniasis drama (23). Also involved are the parasite, the insect, and other hosts. Several immunological studies have increased our understanding of the adaptive response in leishmaniasis. Thus, this disease has been used as a model of Th1 and Th2 responses. Unfortunately, there are still several aspects of the initial steps of Leishmania infection in humans that are largely unknown.

Mucosal Leishmaniasis Caused by Leishmania (Viannia) braziliensis and Leishmania (Viannia) guyanensis in the Brazilian Amazon

Background Leishmania (Viannia) braziliensis is a parasite recognized as the most important etiologic agent of mucosal leishmaniasis (ML) in the New World. In Amazonia, seven different species of Leishmania, etiologic agents of human Cutaneous Leishmaniasis, have been described. Isolated cases of ML have been described for several different species of Leishmania: L. (V.) panamensis, L. (V.) guyanensis and L. (L.) amazonensis. Methodology Leishmania species were characterized by polymerase chain reaction (PCR) of tissues taken from mucosal biopsies of Amazonian patients who were diagnosed with ML and treated at the Tropical Medicine Foundation of Amazonas (FMTAM) in Manaus, Amazonas state, Brazil. Samples were obtained retrospectively from the pathology laboratory and prospectively from patients attending the aforementioned tertiary care unit. Results This study reports 46 cases of ML along with their geographical origin, 30 cases caused by L. (V.) braziliensis and 16 cases by L. (V.) guyanensis. This is the first record of ML cases in 16 different municipalities in the state of Amazonas and of simultaneous detection of both species in 4 municipalities of this state. It is also the first record of ML caused by L. (V.) guyanensis in the states of Pará, Acre, and Rondônia and cases of ML caused by L. (V.) braziliensis in the state of Rondônia. Conclusions/Significance L. (V.) braziliensis is the predominant species that causes ML in the Amazon region. However, contrary to previous studies, L. (V.) guyanensis is also a significant causative agent of ML within the region. The clinical and epidemiological expression of ML in the Manaus region is similar to the rest of the country, although the majority of ML cases are found south of the Amazon River.

Can interferon‐γ and interleukin‐10 balance be associated with severity of human Leishmania (Viannia) braziliensis infection?

Suitable levels of interferon (IFN)‐γ and interleukin (IL)‐10 seem to favour the outcome of cutaneous leishmaniasis (CL), while high IFN‐γ and low IL‐10 production are associated with severity of mucosal leishmaniasis (ML). Considering that cytokine balance is important for the maintenance of protective responses in leishmaniasis, our aim was to investigate leishmanial antigens‐induced IFN‐γ and IL‐10 levels maintained in healed individuals who had different clinical outcomes of Leishmania infection. Thirty‐three individuals who recovered from L. braziliensis infection were studied: cured CL (CCL), cured ML (CML), spontaneous healing of CL (SH) or asymptomatic individuals (ASY). Cytokines were quantified by enzyme‐linked immunosorbent assay (ELISA) in culture supernatants of L. braziliensis‐stimulated peripheral blood mononuclear cells (PBMC). IFN‐γ levels were higher in CML (7593 ±  5994 pg/ml) in comparison to SH (3163 ± 1526 pg/ml), ASY (1313 ±  1048 pg/ml) or CCL (1897 ± 2087 pg/ml). Moreover, cured ML cases maintained significantly lower production of IL‐10 (127 ± 57·8 pg/ml) in comparison to SH (1373 ± 244 pg/ml), ASY (734 ± 233 pg/ml) or CCL (542 ±  375 pg/ml). Thus, a high IFN‐γ/IL‐10 ratio observed in CML can indicate unfavourable cytokine balance. On the other hand, no significant difference in the IFN‐γ/IL‐10 ratio was observed when CCL individuals were compared to SH or ASY subjects. In conclusion, even after clinical healing, ML patients maintained a high IFN‐γ/IL‐10 secretion profile in response to leishmanial antigens. This finding can explain a delayed down‐modulation of exacerbated inflammatory responses, which can be related in turn to the necessity of prolonged therapy in ML management. Conversely, lower IFN‐γ/IL‐10 balance observed in CCL, SH and ASY individuals can represent a better‐modulated immune response associated with a favourable prognosis.

Mucosal leishmaniasis: description of case management approaches and analysis of risk factors for treatment failure in a cohort of 140 patients in Brazil.

Background  Mucosal leishmaniasis is caused mainly by Leishmania braziliensis and it occurs months or years after cutaneous lesions. This progressive disease destroys cartilages and osseous structures from face, pharynx and larynx.

Mucosal leishmaniasis: in situ characterization of the host inflammatory response, before and after treatment

Mucosal leishmaniasis (ML) generally shows progressive tissue destruction, not yet fully elucidated, associated with an intense inflammatory response. To contribute to the understanding of this process and of how treatment interferes with it, we studied several anatomopathological parameters, including those analyzed by immunohistochemistry, such as Leishmania antigens, cells participating in the immune response and cytokine expression. Biopsies were taken from 20 patients with ML before and after treatment. A mixed Th1 and Th2 pattern response occurred inside ML before treatment, persist after treatment. Nevertheless, this mixed response was smaller than in active lesions, with reduced but present numbers of cells expressing TNF-alpha, IFN-gamma and IL-4 and sustained numbers of cells expressing IL-10. We may conclude that specific treatment causes a reduction of inflammatory lesions and disappearance of amastigote forms of Leishmania although the factors related to the pathogenesis of the lesion, such as T CD4+ and T CD8+ lymphocytes and Leishmania antigens, persist in treated lesions. The maintenance of these inflammatory patterns may be due to a specific host-parasite relationship response, strongly indicating the need for continuous surveillance of LM patients at risk of reactivation, despite effective cicatrization after therapy.

Cutaneous leishmaniasis reactivation 2 years after treatment caused by systemic corticosteroids - first report.

American tegumentary leishmaniasis (ATL), an endemic anthropozoonosis in various countries in the world, is caused by parasites of the genus Leishmania. Despite reports on ATL reactivation as a result of immunosuppression, to the best of our knowledge, this paper describes the first case of ATL reactivation in its localized form (cutaneous leishmaniasis) associated with the administration of systemic corticosteroids. The possible action of corticosteroids on the host immune response to the parasite in patients with localized cutaneous leishmaniasis is discussed. This report demonstrates the possibility of ATL reactivation in patients using corticosteroids, an observation that should be considered in individuals treated with this medication.

IFNG +874T/A polymorphism is not associated with American tegumentary leishmaniasis susceptibility but can influence Leishmania induced IFN-γ production

BackgroundInterferon-gamma is a key cytokine in the protective responses against intracellular pathogens. A single nucleotide polymorphism (SNP) located in the first intron of the human IFN-γ gene can putatively influence the secretion of cytokine with an impact on infection outcome as demonstrated for tuberculosis and other complex diseases. Our aim was to investigate the putative association of IFNG+874T/A SNP with American tegumentary leishmaniasis (ATL) and also the influence of this SNP in the secretion of IFN-γ in vitro.MethodsBrazilian ATL patients (78 cutaneous, CL, and 58 mucosal leishmaniasis, ML) and 609 healthy volunteers were evaluated. The genotype of +874 region in the IFN-γ gene was carried out by Amplification Refractory Mutational System (ARMS-PCR). Leishmania-induced IFN-γ production on peripheral blood mononuclear cell (PBMC) culture supernatants was assessed by ELISA.ResultsThere are no differences between +874T/A SNP frequency in cases and controls or in ML versus CL patients. Cutaneous leishmaniasis cases exhibiting AA genotype produced lower levels of IFN-γ than TA/TT genotypes. In mucosal cases, high and low IFN-γ producers were clearly demonstrated but no differences in the cytokine production was observed among the IFNG +874T or A carriers.ConclusionOur results suggest that +874T/A polymorphism was not associated with either susceptibility or severity to leishmaniasis. Despite this, IFNG +874T/A SNP could be involved in the pathogenesis of leishmaniasis by influencing the amount of cytokine released by CL patients, although it could not prevent disease development. On the other hand, it is possible that in ML cases, other potential polymorphic regulatory genes such as TNF-α and IL-10 are also involved thus interfering with IFN-γ secretion.

Use of itraconazole in the treatment of mucocutaneous Leishmaniasis: A pilot study.

OBJECTIVE Mucocutaneous leishmaniasis is widely distributed in Brazil, with Leishmania (Viannia) braziliensis being the major etiologic agent. The currently recommended therapy is limited by its parenteral use, high toxicity, and variable efficacy. A clinical pilot study was conducted to analyze itraconazole as an oral alternative for the treatment of mucocutaneous leishmaniasis. METHODS Ten patients were enrolled to receive 4 mg/kg per day (up to 400 mg/d) itraconazole for 6 weeks on an outpatient regimen. Diagnosis was based on clinical otorhinolaryngologic examination, followed by a specific serologic reaction, the Montenegro test and pathologic analysis with immunohistochemical reaction. Healing of the lesions was confirmed by clinical otorhinolaryngologic examination. Side effects were monitored by general clinical assessment, hemoglobin determination, leukocyte counts, and liver function tests, all performed before, during, and 1 month after the end of treatment. RESULTS Six of 10 patients presented healed lesions 3 months after treatment, with a sustained therapeutic response for at least a median period of 14.5 months (range, 12-18 mo). Side effects were not observed. CONCLUSIONS This pilot study demonstrated that itraconazole can be an effective and well-tolerated alternative for the treatment of mucocutaneous leishmaniasis. Further randomized studies and double blind controlled trials are needed to assess the benefits of this drug in the treatment of mucocutaneous leishmaniasis.

Busca retrospectiva da transmissão maternal da infecção chagásica em pacientes na fase crônica

Maternal transmission of Trypanosoma cruzi from 278 children of 145 mothers, chronically infected with this protozoan, to their offspring was investigated. This study was based upon serological tests. In only two cases (2/278 = 0.70%), such mode of transmission was demonstrated to have occurred. However, as according to extant records both patients had also been breast-fed, and the contribution of this factor could not be ruled out. In any case, maternal transmission, an alternative mode of acquiring the infection with Trypanosoma cruzi, was demonstrated. The methodology used is a further contribution to the evaluation of the prevalence of this propagating mechanism of T. cruzi; in addition to those aimed at the main objective of the investigation, records were kept about pregnancy, parturition, puerperium, abortion, prematurity, perinatal deaths and breast-feeding, which might contribute to a better interpretation of the subject.