T cell responses to crude and defined leishmanial antigens in patients from the Lower Amazon region of Brazil infected with different species of Leishmania of the subgenera Leishmania and Viannia

Amazonian localized cutaneous leishmaniasis (LCL) is caused by parasites of the subgenera Leishmania and Viannia . Respectively, these parasites may cause diffuse cutaneous leishmaniasis (DCL) and mucocutaneous leishmaniasis (MCL). This, together with differing skin test responses, suggests some species-specificity in cell mediated immunity. In this study, T cell responses (proliferative and interferon-γ) to crude and defined antigens were examined in paired samples pre and post chemotherapy. Untreated L. (L.) amazonensis LCL patients showed lower responses to crude leishmanial antigens than the L. (V.) spp. group . L. (V.) braziliensis antigen was a more potent stimulator of T cell responses than L. (L.) amazonensis antigen in all patient groups. Few positive responses were seen to the L. (L.) amazonensis glycoprotein GP46. A substantial proportion of LCL patients did respond to the L. (L.) pifanoi amastigote antigens A2, and the surface membrane glycoprotein P8. DCL patients were poor responders to all leishmanial antigens, except GP46. In contrast, MCL patients were good responders to all antigens except GP46 and A2. A significant rise in the response to P8 and A2 antigen was seen post treatment across all LCL and MCL patients, indicating that these antigens might provide suitable vaccine candidates .     

American tegumentary leishmaniasis: a quantitative analysis of Langerhans cells presents important differences between L. (L.) amazonensis and Viannia subgenus

A quantitative study was conducted on the density of Langerhans cells (LCs) CD1a+ in specimens obtained from patients with American tegumentary leishmaniasis (ATL) lesions without previous treatment, as well as from control healthy individuals. LC density was significantly higher among infected patients when compared to controls and also higher in longer term ones. Regarding parasite quantities, these were proportionally inverse and diminished in chronic patients. Localized cutaneous leishmaniasis (LCL) showed an increase in cell population when compared to diffuse cutaneous leishmaniasis (DCL). A tendency towards density increase was observed in LC Leishmania (Leishmania) amazonensis patients when compared to Leishmania (Viannia) sp. Regarding the delayed hypersensitivity test (DTH, Montenegro skin test), L. (L.) amazonensis demonstrated a peculiar behavior because it is a poor cell immune inducer, presenting--among LCL patients--higher density in negative Montenegro patients than in positive ones. Negative DTH responses are usually poor in LC, although this was not evidenced in this study, possibly due to cell reposition, in order to stimulate immune response. Such results confirm the important role of LC in ATL, while suggesting that L. (L.) amazonensis may be a good model for LC studies as APC in ATL, due to its spectral immunological and clinical behavior.     

Usefulness of sampling with cotton swab for PCR-diagnosis of cutaneous leishmaniasis in the New World

In this study, we tested the polymerase chain reaction (PCR)-method to diagnose cutaneous leishmaniasis (CL) by taking exudate materials from lesions with cotton swabs, using our previously tested (PCR) panel comprised of Leishmania (Viannia) panamensis, L. (V.) braziliensis, L. (V.) guyanensis, L. (Leishmania) mexicana and L. (L.) amazonensis. The objectives of the present study were to improve the sampling method convenient for the patients and to test the usefulness of samples taken with cotton swabs. Sixteen patients were clinically diagnosed to have CL including one case of diffuse cutaneous leishmaniasis (DCL) in Ecuador and the causative Leishmania parasites were identified by PCR. All the 12 samples from CL patients of La Mana, positive for Leishmania DNA, were identified as L. (V.) panamensis, while two from CL of Huigra and one from DCL of San Ignacio were L. (L.) mexicana. In the field condition, taking biopsy material is not only painful but sometimes causes iatrogenic bacterial infections. Considering the sensitivity of the test, and convenient sampling procedure, it may be suggested that collection of exudates using cotton swabs may be a better alternative to biopsy sample for PCR-diagnosis of CL.     

Leishmaniasis in Bahia, Brazil: evidence that Leishmania amazonensis produces a wide spectrum of clinical disease

One hundred fourteen Leishmania isolates from patients with different clinical forms of leishmaniasis in the State of Bahia, Brazil, were characterized by indirect radioimmune binding assay using specific monoclonal antibodies (serodeme analysis). Seventy-five of these isolates were also analyzed by enzyme electrophoresis, based on 11 enzyme loci; parasite species were compared, according to their characteristic zymodemes, to those of WHO Leishmania reference strains. All isolates could be classified into one of three species: Leishmania amazonensis (n = 40), L. braziliensis (n = 39) or L. chagasi (n = 35). The most interesting information obtained from this study is the realization that L. amazonensis is capable of producing a wide spectrum of disease in humans. Infection with this parasite was associated with many different clinical presentations, including cutaneous leishmaniasis [CL] (20/49 cases), mucocutaneous leishmaniasis [MCL] (5/13 cases) and, of special note, visceral leishmaniasis [VL] (11/46 cases), as well as four cases of post kalaazar dermal leishmaniasis [PKDL]. In situ tissue parasite characterization, by immunoperoxidase assay and employing anti-L. amazonensis amastigote monoclonal antibodies, confirmed the infection with this species in two cases of CL, one case of DCL, one case of MCL and one case of PKDL. Our results also demonstrate the difficulty of parasite differentiation based on clinical grounds, since at least L. amazonensis infection can be associated with all types of leishmanial diseases, and different Leishmania species may be associated with indistinguishable clinical presentations. Since leishmanial parasites may vary in their biological behavior or in their response to treatment, it is important that their identification be made by reliable methods.     

Immunopathogenic competences of Leishmania (V.) braziliensis and L. (L.) amazonensis in American cutaneous leishmaniasis

The immunopathogenic competences of Leishmania (V.) braziliensis and L. (L.) amazonensis were reviewed in the light of more recent features found in the clinical and immunopathological spectrum of American cutaneous leishmaniasis. It was shown a dichotomy in the interaction between these Leishmania species and human T-cell immune response; while L. (V.) braziliensis shows a clear tendency to lead infection from the localized cutaneous leishmaniasis (LCL), a moderate T-cell hypersensitivity form at the centre of the spectrum, toward to the mucocutaneous leishmaniasis (MCL) at the T-cell hypersensitivity pole and with a prominent Th1-type immune response, L. (L.) amazonensis shows an opposite tendency, leading infection to the anergic diffuse cutaneous leishmaniasis (ADCL) at the T-cell hyposensitivity pole and with a marked Th2-type immune response. Between the central LCL and the two polar MCL and ADCL, the infection can present an intermediary form known as borderline disseminated cutaneous leishmaniasis, characterized by an incomplete inhibition of T-cell hypersensitivity but with a evident supremacy of Th1 over Th2 immune response (Th1 ≥ Th2). These are probably the main immunopathogenic competences of L. (V.) braziliensis and L. (L.) amazonensis regarding the immune response dichotomy that modulates human infection outcome by these Leishmania parasites.     

Diffuse cutaneous leishmaniasis in Mexico

In Mexico, 6 cases of diffuse cutaneous leishmaniasis (DCL) were found in widely separated geographic regions. Information was also available on 2 other cases. In addition to the typical clinical features, half of the patients had evidence of nasopharyngeal mucosal involvement. All isolates from the DCL patients were identified as Leishmania mexicana mexicana by isoenzyme analysis and monoclonal antibody typing. In 1 region of Tabasco state where DCL was found, uncomplicated cutaneous leishmaniasis appeared to be highly endemic, and isolates from a few such patients were identified as L. mexicana mexicana. An incidental finding was the recovery of an isolate of L. braziliensis braziliensis from a patient with chiclero ulcer in Oaxaca state. The clinical and epidemiological significance of the reported cases are discussed.     

Divergent expression of inflammatory dermal chemokines in cutaneous leishmaniasis

Human leishmaniasis is caused by protozoan Leishmania (L.) parasites and comprises a heterogeneous group of clinical appearances ranging from visceral to cutaneous leishmaniasis. In the New World, L. mexicana mediates American cutaneous leishmaniasis, one of the most common forms of this disease. Two different disease progressions can be observed: (i) self-healing localized cutaneous leishmaniasis (LCL) and (ii) progressive diffuse cutaneous leishmaniasis (DCL). These different forms are associated with a T helper 1 (Th1) or Th2 response, respectively, and are additionally characterized by opposing dermal chemokine profiles. Lesions of LCL show high expression of CCL2/MCP-1, CXCL9/MIG, CXCL10/IP-10 and only low amounts of CCL3/MIP-1alpha. In contrast, lesions of chronic DCL are dominated by the expression of CCL3/MIP-1alpha. This finding implies that CCL2/MCP-1 contributes to the healing process. Indeed, CCL2/MCP-1 induces leishmanicidal activities in human monocytes in contrast to CCL3/MIP-1alpha. This effect is enhanced by interferon-gamma and abrogated by interleukin-4. In the murine model of leishmaniasis, the impact of CCL2/MCP-1 is well documented. Normally resistant mice become susceptible for Leishmania infections if CCR2, the receptor for CCL2/MCP-1, is knocked out. Based on this evidence, we propose that tissue specific expression of these small molecules actively regulates cell traffic and tissue localization of effector cells and, additionally, has direct immunological effects.     

Monocyte cytokine and costimulatory molecule expression in patients infected with Leishmania mexicana

Leishmania mexicana causes localized and diffuse cutaneous leishmaniasis. Patients with localized cutaneous leishmaniasis (LCL) develop a benign disease, whereas patients with diffuse cutaneous leishmaniasis (DCL) suffer from a progressive disease associated with anergy of the cellular response towards Leishmania antigens. We evaluated the production of the interleukins (IL) IL-12, IL-15, IL-18 and tumour necrosis factor-alpha (TNF-alpha) and the expression of the costimulatory molecules CD40, B7-1 and B7-2 in monocytes from LCL and DCL patients, stimulated in vitro with Leishmania mexicana lipophosphoglycan (LPG) for 18 h. LCL monocytes significantly increased TNF-alpha, IL-15 and IL-18 production, and this increase was associated with reduced amounts of IL-12. DCL monocytes produced no IL-15 or IL-18 and showed a decreasing tendency of TNF-alpha and IL-12 production as the severity of the disease increased. No difference was observed in the expression of CD40 and B7-1 between both groups of patients, yet B7-2 expression was significantly augmented in DCL patients. It remains to be established if this elevated B7-2 expression in DCL patients is cause or consequence of the Th2-type immune response that characterizes these patients. These data suggest that the diminished ability of the monocytes from DCL patients to produce cell-activating innate proinflammatory cytokines when stimulated with LPG is a possible cause for disease progression.     

Cross-immunity experiments between different species or strains of Leishmania in rhesus macaques (Macaca mulatta)

This study evaluates cross-immunity in rhesus monkeys (Macaca mulatta) previously infected with one species of Leishmania and have had self-cured disease or were cured by antimony-based therapy upon development of full-blown disease. We found that a self-healing cutaneous leishmaniasis (CL) following experimental infection with Leishmania (Leishmania) major induces significant protection for L. (L.) amazonensis and L. (Viannia) guyanensis, and was dependent on time of re-challenge by L (L.) amazonensis after animals had recovered from primary lesions, but lacked protection against L. (V.) braziliensis. In contrast, monkeys that recovered from L. (V.) braziliensis CL or L. (L.) chagasi visceral leishmaniasis following chemotherapeutic intervention were protected by challenge with L. (V.) braziliensis and L (L.) amazonensis. These findings indicate the relative variability in protection after self-cure or drug-cured experimental leishmaniasis to challenge by heterologous leishmanial parasites. Further studying the immune response may provide information regarding relevant factors influencing cross-protective immunity.     

A patient presenting with diffuse cutaneous leishmaniasis (DCL) as a first indicator of HIV infection in India

Opportunistic parasitic infections such as leishmaniasis are common in human immunodeficiency virus (HIV)-infected patients and are usually acquired several days after initial diagnosis of HIV infection. Here, we report on a patient who presented with diffuse cutaneous leishmaniasis (DCL) caused by Leishmania tropica as the first and only clinical manifestation of HIV infection. To the best of our knowledge, this is the first case that illustrates that DCL could be the first clinical indicator of HIV infection. Cutaneous leishmaniasis (CL) and DCL are becoming frequent opportunistic infections in HIV-infected individuals throughout the world. To date, all documented cases of CL and HIV coinfections have been reported in patients who were known cases of HIV and who subsequently developed CL. In this report, we present a case that illustrates that DCL could be the first clinical indicator of HIV infection.     

Variations in the serum levels of soluble CD23, nitric oxide and IgE across the spectrum of American cutaneous leishmaniasis

Serum IgE levels and the expression of low affinity receptor for IgE (Fc epsilon RII/CD23) are increased in cutaneous leishmaniasis. The ligation of CD23 receptor by IgE-anti-IgE immune complexes results in nitric oxide (NO) production, which is a critical leishmanicidal factor. Human monocytes/macrophages express Fc epsilon RII/CD23 after activation with IFN-gamma and IL-4. In the present study, we assessed the relationship between NO, total and Leishmania-specific IgE and soluble CD23 across the clinical spectrum of American cutaneous leishmaniasis (ACL). Sixty-nine ACL patients and 22 endemic controls were studied. NO concentration was estimated using the Greiss method. Soluble CD23, total IgE and anti-Leishmania IgE levels were measured using ELISA. Soluble CD23 was increased in the four patient groups (0.001相似文献   

Disseminated cutaneous leishmaniasis due to Leishmania(Leishmania) amazonensis in human immunodeficiency virus(HIV)-infected patients: A report of two cases

Rationale: Co-infection of human immunodeficiency virus(HIV) and Leishmania spp. has impact on clinical and therapeutic outcomes of leishmaniases. Most studies do not present the identification of Leishmania species causing American tegumentary leishmaniasis in co-infections. In the Americas, Leishmania(L.) Viannia(V.) braziliensis and L.(V.) guyanensis have been identified. Patient concerns: In this study, two cases of American tegumentary leishmaniasis in patients infected with HIV are described. Patients presented several lesions with rapid dissemination and mucosal involvement. Diagnosis: Disseminated cutaneous leishmaniasis caused by L. amazonensis was identified by molecular test. Interventions: The patients were treated with conventional therapies for HIV infection and American tegumentary leishmaniasis. Outcomes: In co-infection, the clinical manifestations are atypical and the treatment response can be impaired. Lessons: These cases show that HIV infection impacts L. amazonensis infection and point to the relevance of identifying Leishmania species, which can lead to a better patient management.     

Observations on local heat treatment for cutaneous leishmaniasis

Local heat treatment was tested and found effective in three patients with diffuse cutaneous leishmaniasis (DCL), a form of disease poorly responsive to the usual chemotherapy. A water bath that circulated water through a pad wrapped around the lesion provided a temperature of 39 degrees C to 41 degrees C for a cumulative time of at least 20 hours, over a period of several days. In the DCL patients beneficial effect of heat treatment was documented by pre- and post-treatment biopsies and cultures. Several other patients with ordinary cutaneous leishmaniasis did not respond to the same form of treatment. It was concluded that different strains and/or species of leishmanial parasites vary in their sensitivity to elevated temperature. While local heat treatment may be curative in certain cases of cutaneous leishmaniasis, such therapy is still experimental and should be monitored by quantitative parasitological studies to document its usefulness.     

The IgG isotypes of specific antibodies in patients with American cutaneous leishmaniasis; relationship to the cell-mediated immune response

American cutaneous leishmaniasis (ACL) presents a spectrum of clinical and immunological manifestations. Since the nature of the cellular response appears to play a fundamental role in determining the characteristics of the immunoglobulin isotype of specific antibody responses, we have compared the relative levels of specific antibodies of the four IgG isotypes against Leishmania in sera from patients with different clinical manifestations of ACL. Using a specific antibody capture assay, significant levels of antibodies of the IgG1, 2 and 3 isotypes were detected in localized cutaneous leishmaniasis (LCL); the average level of IgG4 antibodies was low and they were not detected in 10/20 sera. Sera from muco-cutaneous leishmaniasis (MCL) gave a comparatively strong IgG1 response. Sera from diffuse cutaneous leishmaniasis (DCL), the rare form characterized by antigen-specific anergy of cell-mediated immunity, showed highly significant levels of IgG4 antibodies compared to antibody levels of this isotype in the other groups; IgG1 and IgG2 levels were also elevated. Based on other studies of the relationship between the IgG isotype response and cell-mediated immunity, these results confirm a Th1-like CD4⁺ T cell response in LCL and MCL and a significant Th2-like response in DCL.     

Disseminated cutaneous leishmaniasis in a field clinic in Bahia, Brazil: a report of eight cases

Eight Bahian patients with cutaneous leishmaniasis who had 20 or more ulcerative lesions of short duration are described. Of five identifications of isolated parasites, four were Leishmania braziliensis braziliensis and one was L. mexicana amazonensis. All but one had positive Montenegro tests initially, and all did after treatment. All had circulating anti-leishmanial antibodies and five responded well to glucantime therapy suggesting a functioning immune response. This is quite different to the anergic hansenoid leishmaniasis seen with L. mexicana amazonensis infections in Brazil. Possible reasons for the occurrence of this type of leishmaniasis are briefly discussed.     

Unusual presentation of disseminated cutaneous leishmaniasis due to Leishmania major: Case reports of four Iranian patients

We report four disseminated cutaneous leishmaniasis(DCL) cases referred to leishmaniasis laboratory at the School of Public Health, Tehran University of Medical Sciences with multiple nodular, ulcerative and crusted lesions extended on the face, trunk, and extremities. None of the patients had any complication and historical involvement in their immunological system conditions that suggest as the criteria for DCL. Direct smears of ulcers were positive for Leishmania parasite. The parasite was isolated from the active lesions and identified as Leishmania major (L. major) using PCR-RFLP assay and sequencing analysis.     

Isolation of Leishmania mexicana amazonensis from the bone marrow in a case of American visceral leishmaniasis

The first documented human case of visceral leishmaniasis caused by L. mexicana amazonensis is reported. Leishmania were isolated from bone marrow aspirate material from a typical visceral leishmaniasis patient. Further characterization by isoenzyme electrophoresis and by a panel of species- and subspecies-specific monoclonal antibodies established its classification as L. m. amazonensis.     

Potential utility of hyperbaric oxygen therapy and propolis in enhancing the leishmanicidal activity of glucantime

In this study we investigated the efficacy of hyperbaric oxygen (HBO) therapy, alone or combined with the pentavalent antimonial glucantime on Leishmania amazonensis infection. In parallel, the effect of Brazilian red propolis gel (propain) alone or combined with glucantime on L. amazonensis infection was evaluated. The inhibition of the infection in macrophages treated with glucantime in combination with HBO exposition was greater than that of macrophages treated with glucantime alone or HBO alone. The susceptible mouse strain BALB/c infected in the shaved rump with L. amazonensis treated with glucantime and exposed to HBO showed: time points in the course of the disease in which lesions were smaller than those of mice treated with glucantime alone and revascularization of the skin in the lesion site; interferon-gamma (IFN-g) levels were not elevated in lymph node cells from these animals. Propain alone was not efficient against lesions, although less exudative lesions were observed in animals treated with propain alone or combined with glucantime. These results reveal the potential value of HBO and red propolis in combination with glucantime for treating cutaneous leishmaniasis and encourage further studies on the effect of more aggressive HBO, propolis and glucantime therapies on different mouse models of leishmaniasis.     

Herbicides to curb human parasitic infections: in vitro and in vivo effects of trifluralin on the trypanosomatid protozoans.

Leishmaniasis is a major tropical disease for which current chemotherapies, pentavalent antimonials, are inadequate and cause severe side effects. It has been reported that trifluralin, a microtubule-disrupting herbicide, is inhibitory to Leishmania amazonensis. In this study, the in vitro effect of trifluralin on different species of trypanosomatid protozoans was determined. In addition to L. amazonensis, trifluralin is effective against Leishmania major and Leishmania tropica, which cause cutaneous infections, Leishmania donovani, which causes visceral disease, Leishmania panamensis, which may cause mucocutaneous infection, and Trypanosoma brucei, an important human and veterinary pathogen. Moreover, most encouragingly, trifluralin is effective in vivo as a topical ointment against L. major and Leishmania mexicana murine cutaneous leishmaniasis. Thus, trifluralin is a promising lead drug for several related, prevalent tropical diseases: leishmaniasis, trypanosomiasis of animals, and, possibly, African trypanosomiasis in humans.     

Foxp3 expression in lesions of the different clinical forms of American tegumentary leishmaniasis

As the diversity in clinical presentation of American tegumentary leishmaniasis (ATL) is determined mainly by the immune response of host, our aim was to evaluate the in situ expression of Foxp3 [marker of regulatory T (Treg) cell] in lesions of the different clinical forms of ATL. Foxp3⁺ cells were observed in 39·5% (32/81) of the samples and the number of positive cells was low in all the clinical forms. Even presenting a significantly lower number of CD4⁺ T cells, diffuse cutaneous leishmaniasis (DCL) showed a higher expression of Foxp3 when compared with localized cutaneous leishmaniasis (LCL) and mucocutaneous leishmaniasis (MCL). In LCL and MCL, the number of Foxp3⁺ cells correlated positively with the number of apoptotic cells (active caspase-3⁺ cells). A positive correlation was also observed between the expression of active caspase-3 and FasL in these clinical forms. Our data suggest that increased number of Treg cells may be associated to the hyporesponsiveness observed in DCL and also indicate that the apoptosis may be a possible mechanism of action of Foxp3⁺ Treg cell in LCL and MCL. However, further studies are required to better understand the mechanism of action of Treg cell.