Maria Inês Fernandes Pimentel

Multifunctional CD4⁺ T cells in patients with American cutaneous leishmaniasis.

Leishmaniasis is a group of important parasitic diseases affecting millions worldwide. To understand more clearly the quality of T helper type 1 (Th1) response stimulated after Leishmania infection, we applied a multiparametric flow cytometry protocol to evaluate multifunctional T cells induced by crude antigen extracts obtained from promastigotes of Leishmania braziliensis (LbAg) and Leishmania amazonensis (LaAg) in peripheral blood mononuclear cells from healed cutaneous leishmaniasis patients. Although no significant difference was detected in the percentage of total interferon (IFN)‐γ‐producing CD4+T cells induced by both antigens, multiparametric flow cytometry analysis revealed clear differences in the quality of Th1 responses. LbAg induced an important proportion of multifunctional CD4+ T cells (28% of the total Th1 response evaluated), whereas LaAg induced predominantly single‐positive cells (68%), and 57% of those were IFN‐γ single‐positives. Multifunctional CD4+T cells showed the highest mean fluorescence intensity (MFI) for the three Th1 cytokines assessed and MFIs for IFN‐γ and interleukin‐2 from those cells stimulated with LbAg were significantly higher than those obtained after LaAg stimulation. These major differences observed in the generation of multifunctional CD4+ T cells suggest that the quality of the Th1 response induced by L. amazonensis antigens can be involved in the mechanisms responsible for the high susceptibility observed in L. amazonensis‐infected individuals. Ultimately, our results call attention to the importance of studying a Th1 response regarding its quality, not just its magnitude, and indicate that this kind of evaluation might help understanding of the complex and diverse immunopathogenesis of American tegumentary leishmaniasis.

Influence of the nutritional status in the clinical and therapeutical evolution in adults and elderly with American Tegumentary Leishmaniasis

The objective of this study is to describe the nutritional status of adult and elderly patients with American Tegumentary Leishmaniasis (ATL). It was conducted a longitudinal study in 68 adult and elderly patients with ATL treating at the Surveillance Leishmaniasis Laboratory at the Evandro Chagas Clinical Research Institute, Oswaldo Cruz Foundation (Fiocruz), from 2009 to 2012. The nutritional assessment included the body mass index (BMI) and serum albumin levels. The clinical evolution (epithelialization and wound healing) was measured up to two years after ATL treatment. Most of the sample was composed of men (71%), adults (73%), with household income of 1-5 minimum wages (79%), and incomplete elementary school (48.5%). The predominant ATL form was cutaneous (72%), and 39% presented comorbidities, the most frequent was hypertension (30.8%). The most prevalent clinical and nutritional events were: recent decrease in food intake (23.9%); nasal obstruction (22.1%); oral ulcer (14.7%), anorexia and dysphagia (13.2% each) and odynophagia (10.3%). The total healing time was 115.00 (IR=80-230) days for skin lesions, and 120.00 (IR=104.50-223.50) days for mucous membrane lesions. Low body weight in 10%, and hypoalbuminemia in 12% of the patients have been observed. Low body weight was associated with age, mucosal leishmaniasis (ML), nasal obstruction, recent decrease in food intake and hypoalbuminemia. As for serum albumin depletion, association with the ML, dyspnea, dysphagia, odynophagia, recent decrease in food intake, absence of complete healing of the skin lesions, and increased healing time for mucous membrane lesions, was observed. The ML and their events that affect the alimentary intake have been related to the impairment of the nutritional status. Additionally, serum albumin depletion negatively affected the healing of the lesions, suggesting that a nutritional intervention can increase the effectiveness of the ATL treatment.

Are Neutrophil Extracellular Traps Playing a Role in the Parasite Control in Active American Tegumentary Leishmaniasis Lesions

Neutrophil extracellular traps (NETs) have been described as a network of extracellular fibers composed by DNA, histones and various proteins/enzymes. Studies have demonstrated that NETs could be responsible for the trapping and elimination of a variety of infectious agents. In order to verify the presence of NETs in American tegumentary leishmaniasis (ATL) and their relationship with the presence of amastigotes we evaluated active cutaneous lesions of 35 patients before treatment by the detection of parasites, neutrophils (neutrophil elastase) and histones through immunohistochemistry and confocal immunofluorescence. Intact neutrophils could be detected in all ATL lesions. NETs were present in 27 patients (median 1.1; range from 0.1 to 23.5/mm2) with lesion duration ranging from one to seven months. NETs were in close proximity with neutrophils (r = 0.586; p = 0.0001) and amastigotes (r = 0.710; p = 0.0001). Two patterns of NET formation were detected: small homogeneously distributed networks observed in all lesions; and large structures that could be visualized at a lower magnification in lesions presenting at least 20% of neutrophils. Lesions presenting the larger NET formation showed high parasite detection. A correlation between NET size and the number of intact amastigotes was observed (p=0.02). As we detected an association between NET and amastigotes, our results suggest that neutrophil migration and NET formation could be stimulated and maintained by stimuli derived from the parasite burden/parasite antigen in the extracellular environment. The observation of areas containing only antigens not intermingled with NETs (elastase and histone) suggests that the involvement of these structures in the control of parasite burden is a dynamic process in which the formation of NETs is exhausted with the destruction of the parasites. Since NETs were also associated with granulomas, this trapping would favor the activity of macrophages in order to control the parasite burden.

Montenegro skin test and age of skin lesion as predictors of treatment failure in cutaneous leishmaniasis.

A case-control study was conducted to examine the association among the Montenegro skin test (MST), age of skin lesion and therapeutic response in patients with cutaneous leishmaniasis (CL) treated at Evandro Chagas National Institute of Infectious Diseases (INI), Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, Brazil. For each treatment failure (case), two controls showing skin lesion healing following treatment, paired by sex and age, were randomly selected. All patients were treated with 5 mg Sb5+/kg/day of intramuscular meglumine antimoniate (Sb5+) for 30 successive days. Patients with CL were approximately five times more likely to fail when lesions were less than two months old at the first appointment. Patients with treatment failure showed less intense MST reactions than patients progressing to clinical cure. For each 10 mm of increase in MST response, there was a 26% reduction in the chance of treatment failure. An early treatment - defined as a treatment applied for skin lesions, which starts when they are less than two months old at the first appointment -, as well as a poor cellular immune response, reflected by lower reactivity in MST, were associated with treatment failure in cutaneous leishmaniasis.

Endemic tegumentary leishmaniasis in Brazil: correlation between level of endemicity and number of cases of mucosal disease.

The purpose of this study was to establish a correlation between the endemic level of tegumentary leishmaniasis in different regions of Brazil during 2002-2009 and the number of cases of mucosal or mucocutaneous leishmaniasis. The proportion of mucosal leishmaniasis was inversely correlated with prevalence of infection. In areas with a lower infection prevalence, the proportion of mucosal leishmaniasis increased (P < 0.05). The hypothesis of an Amazonian origin and dissemination through human migration is considered. Our results show that in regions with lower prevalence and endemically younger, the proportion of cases that evolve to the mucosal form is higher than in regions with higher prevalence and endemically older.

Acroangiodermatite (pseudossarcoma de Kaposi): uma condição raramente reconhecida. Um caso na planta do pé associado a insuficiência venosa crônica

Acroangiodermatitis, often known as pseudo-Kaposi sarcoma, is an uncommon angioproliferative entity related to chronic venous insufficiency, arteriovenous fistulae, paralysed limbs, amputation stumps, vascular syndromes and conditions associated with thrombosis. It presents most frequently as purple macules, papules or plaques in the dorsal aspects of the feet, especially the toes, and the malleoli. We report a case of acroangiodermatitis in the plantar aspect of the foot, misdiagnosed for two years, in which haematoxylin-eosin hystopathological stain and immunolabeling with CD34 histochemistry examination were decisive for diagnosis. Patient had chronic venous insufficiency. The lesion responded well to the treatment with a combination of leg elevation and compression.

American Tegumentary Leishmaniasis in Older Adults: 44 Cases Treated with an Intermittent Low‐Dose Antimonial Schedule in Rio de Janeiro, Brazil

American tegumentary leishmaniasis (ATL) is a disease affecting the skin and mucosae caused by protozoans of the genus Leishmania transmitted by the bite of female sandflies. Cutaneous leishmaniasis (CL) presents mainly as skin ulcers at exposed body sites. Mucosal leishmaniasis (ML) manifests as chronic and destructive lesions of the nasal, oral, pharyngeal, and laryngeal tissues.1 Pentavalent antimonials are the first-line treatment for ATL. Reports of pentavalent antimonial toxicity include renal tubular dysfunction; cardiac, hepatic, pancreatic, and hematological alterations; and even death.2–6 Adverse effects (AEs) are frequent, and interruption is sometimes needed in patients aged 60 and older, even those receiving low-dose treatment. Observing that lesions continued to heal during withdrawal, it was decided to evaluate the safety and efficacy of an intermittent low-dose meglumine antimonate (MA) regimen for ATL in the elderly.....

Cytotoxic cell involvement in human cutaneous leishmaniasis: assessments in active disease, under therapy and after clinical cure.

Cutaneous leishmaniasis (CL) is an important public health issue worldwide. The control of Leishmania infection depends on cellular immune mechanisms, and the inflammatory response may contribute to pathogenesis. A beneficial role of CD8+ T lymphocytes has been proposed; nevertheless, other studies suggest a cytotoxic role of CD8+ T lymphocytes involved in tissue damage, showing controversial role of these cells. The goal of the current study was to understand the immunopathology of CL and determine the profile of cytotoxic cells – such as CD4+ T, natural killer and natural killer T cells – that might be involved in triggering immunological mechanisms, and may lead to cure or disease progression. The frequencies of cytotoxic cell populations in peripheral blood, obtained from patients with active disease, during treatment and after clinical healing, were assessed by flow cytometry. Cytotoxicity could not be related to a deleterious role in Leishmania braziliensis infection, as patients with active CL showed similar percentages of degranulation to healthy individuals (HI). Cured patients exhibited a lower percentage of degranulating cells, which may be due to a downregulation of the immune response. The understanding of the immunopathological mechanisms involved in CL and the commitment of cytotoxic cells enables improvements in therapeutic strategies.

Intestinal helminth coinfection is associated with mucosal lesions and poor response to therapy in American tegumentary leishmaniasis

The most severe clinical form of American tegumentary leishmaniasis (ATL) due to Leishmania braziliensis is mucosal leishmaniasis (ML), characterized by destructive lesions in the facial mucosa. We performed a retrospective cohort study of 109 ATL patients from Rio de Janeiro State, Brazil, where ATL is caused by L. braziliensis, to evaluate the influence of intestinal parasite coinfections in the clinical course of ATL. Parasitological stool examination (PSE) was performed with samples from all patients by the sedimentation, Kato-Katz and Baermann-Moraes methods. The diagnosis of ATL was made from lesion biopsies by direct observation of amastigotes in Giemsa-stained imprints, isolation of Leishmania promastigotes or histopathological examination. All patients were treated with meglumine antimoniate. Patients with positive PSE had a frequency of mucosal lesions significantly higher than those with negative PSE (p<0.005). The same was observed for infections with helminths in general (p<0.05), with nematodes (p<0.05) and with Ascaris lumbricoides (p<0.05), but not for protozoan infections. Patients with intestinal parasites had poor response to therapy (therapeutic failure or relapse) significantly more frequently than the patients with negative stool examination (p<0.005). A similar difference (p<0.005) was observed between patients with positive and negative results for intestinal helminths, but not for intestinal protozoa. Patients with positive PSE took significantly longer to heal than those with negative PSE (p<0.005). A similar difference was observed for intestinal helminth infections (p<0.005), but not for protozoan infections. Our results indicate a deleterious influence of intestinal helminth infections in the clinical course of ATL and evidence for the first time an association between ML and these coinfections, particularly with nematodes and A. lumbricoides.

Apoptosis and frequency of total and effector CD8 + T lymphocytes from cutaneous leishmaniasis patients during antimonial therapy

BackgroundLeishmaniasis is an important parasitic disease affecting millions worldwide. Human cutaneous leishmaniasis (CL) is endemic in Rio de Janeiro, Brazil, where is caused by Leishmania braziliensis. The adaptive immune response is accountable for the healing of CL and despite of key role of CD8+ T cells in this immune response little is known about the CD8+ T lymphocytes frequencies, apoptosis and antigen-responsive CD8+ T lymphocytes of CL patients during antimonial therapy.MethodsUsing flow cytometry, we examined total and effector CD8+ T cells from CL patients before (PBT), during (PDT) and after (PAT) treatment for apoptosis and frequencies upon isolation and after in vitro L. braziliensis antigens (LbAg)-stimulation culture. Besides, a correlation study between immunological findings and lesion size was done.ResultsPDT showed lower frequencies of total CD8+ T lymphocytes and higher levels of apoptosis of these cells, which were also observed following LbAg-stimulation culture. Regarding effector CD8+ T cells, high frequencies were observed in PDT, while lower frequencies were observed in PAT. Interestingly, PDT showed higher frequencies of apoptotic-effector CD8+ T lymphocytes. Similar results were seen after in vitro antigenic-stimulation assays. Correlation analysis showed that the greater the size of lesion, the smaller the frequency of effector CD8+ T lymphocytes in PDT and PAT, as well as a positive correlation between apoptotic-effector CD8+ T cells frequency and lesion size of PDT.ConclusionsChanges in effector CD8+ T–lymphocyte frequencies, during and after treatment, seem to represent a critical stage to generate an efficient immune response and suggest that these cells would be evolved in the triggering or in the resolution of lesion, under the influence of therapy. This hypothesis opens new perspectives to clarify controversial statements about the protective or deleterious role of CD8+ T cells in the cure or aggravation of CL and the new approach of evaluating patients during treatment proved to be of utmost importance for understanding the immune response in the healing process of human CL.