IFN-gamma, IL-4, IL-10 and IL-12 gene expression in BCG-Leishmania vaccination of Trypanosoma cruzi-infected mice.

We have previously shown that vaccination of BALB/c mice with a combination of BCG plus killed Leishmania promastigotes, applied by the i.p. route 10 and 3 days before Trypanosoma cruzi inoculation, prolonged their survival and decreased their parasitaemia. In the present study we show that the BCG-Leishmania vaccine induced higher levels of circulating IFN-gamma in acute and chronic infection of mice [on day 25 and 40 post-infection (p.i.) respectively], in comparison to unvaccinated animals (PBS-treated). Though the IFN-gamma mRNA content of spleen cells of vaccinated and infected mice (on day 25 p.i.) was similar to that of unvaccinated animals, the BCG-Leishmania vaccine enhanced significantly the production of IFN-gamma by spleen cells stimulated with T. cruzi antigens. This effect was observed to a lower extent in BCG- and Leishmania-treated mice. The BCG-Leishmania vaccine reduced the expression of the IL-10 mRNA of splenocytes as soon as day 12 p.i., before the peak parasitaemia. Such this effect was not observed in BCG- or Leishmania-treated animals. On day 25 p.i., the BCG plus Leishmania- or BCG-treatment of mice abolished the capacity of spleen cells to produce IL-10 in response to T. cruzi antigens. The levels of mIL-4 RNA and protein production were not modified in any group of mice. T. cruzi infection in BCG-Leishmania-vaccined mice stimulated an early and high production of IL-12 transcripts in spleen cells during the acute phase of the infection, that was prolonged during the chronic phase of infection. This effect was weaker or absent in BCG- and Leishmania-treated animals, respectively. These results indicate that the BCG-Leishmania vaccine stimulates the production of IL-12 and IFN-gamma, but inhibits that of IL-10 and is without effect on IL-4 when mice are infected with T. cruzi. This highlights the key role of endogenously produced IFN-gamma, IL-10 and IL-12 in the control of T. cruzi acute and chronic infection in mice and the favorable modulation of their balance by a vaccination combining BCG and Leishmania.

Immunotherapy with live BCG plus heat killed Leishmania induces a T helper 1-like response in American cutaneous leishmaniasis patients.

Previous work has shown that American cutaneous leishmaniasis (ACL) patients treated with viable BCG plus heat killed promastigotes of Leishmania amazonensis show the same rate of cure as patients receiving conventional chemotherapy. The treatment is safe and economical, but the immunological correlates of cure have not been examined. In the present study, T cell responses have been analysed in 43 ACL patients, including patient groups sampled before and after therapy, and in 10 endemic controls. Lymphocyte proliferation, interferon (IFN)-gamma and interleukin (IL)-5 responses to crude antigen (L. amazonensis, MEL; Mycobacterium tuberculosis PPD; M. bovis BCG) stimulation, and serum IL-5 levels, were analysed. In endemic volunteers, proliferative responses to BCG were high and IFN-gamma responses low. In contrast, localized cutaneous (LCL) and mucocutaneous (MCL) patients showed low proliferative and high IFN-gamma responses to BCG. Treatment enhanced the IFN-gamma response and further decreased the proliferative response to BCG, especially in MCL patients. LCL and MCL patients showed an increase in proliferative and IFN-gamma responses to MEL with treatment, but the response was not exaggerated in MCL patients, either before or after treatment, compared to LCL patients. IL-5 production was low in T cell assays, and > 62% of untreated patients had very low serum IL-5 levels. There were no significant changes in serum IL-5 with treatment. Overall results show enhanced antigen-specific IFN-gamma responses to the two components of the immunotherapy, live M. bovis BCG and heat killed L. amazonensis, which is consistent with a shift in balance of T cell response towards a T helper 1 response and clinical cure mediated by IFN-gamma.

Immunological changes associated with clinical improvement of asthmatic children subjected to psychosocial intervention.

In the present study we evaluated the impact of a program of psychosocial intervention (PSI) on the immunological status and the clinical management of a group of asthmatic children of an island population in Venezuela. We studied a total of 35 asthmatic children who belonged to either a PSI group (19 patients) or a control group (16 patients), both of which received conventional antiasthmatic treatment. The PSI group received, in addition, a 6-month psychosocial intervention program which included relaxation, guided imagery, and self-esteem workshops. During the PSI period, the number of asthmatic episodes and the use of bronchodilator medication were significantly reduced, and pulmonary function was significantly improved, compared to the 6 months before intervention. There was also a significant reduction in the specific IgE responses against the most important allergen in these children, the intestinal parasite Ascaris lumbricoides. PSI resulted in a significant increase of NK cells, an augmented expression of the T-cell receptor for IL-2, and a significant decrease of leukocytes with low affinity receptors for IgE. In fact, these surface markers became similar to those of nonasthmatic children from both Coche Island and the mainland. None of these clinical or immunological changes were seen in the control group of asthmatics who did not undergo PSI. These results are consistent with the possibility that PSI induces immunological alterations that are responsible for the clinical and physiological improvements observed in the study group.

Vaccination of mice with a combination of BCG and killed Leishmania promastigotes reduces acute Trypanosoma cruzi infection by promoting an IFN-gamma response.

The combination of BCG with killed Leishmania promastigotes, demonstrated to be efficient in the cure of patients suffering American cutaneous leishmaniasis and in the induction of a long-term immune response in healthy vaccinated volunteers, was tested in BALB/c mice infected with Trypanosoma cruzi, in comparison to BCG or Leishmania alone, and a vehicle (PBS) control. BCG-Leishmania vaccination, applied intra-peritoneally 10 and 3 days before T. cruzi trypomastigote inoculation, prolonged the survival, and reduced blood parasitaemia of infected animals. Proliferation studies indicated that splenocytes of mice vaccinated with BCG-Leishmania and harvested in the acute phase of T. cruzi infection displayed stimulation indices higher than cells from PBS-treated mice when stimulated with PHA mitogen, PPD, Leishmania or T. cruzi antigens. Injections of a monoclonal antibody able to neutralise IFN-gamma into BCG-Leishmania vaccinated mice increased parasitaemia to levels similar to those of control animals (treated with PBS) and reversed the beneficial effect of vaccination on the proliferative response to T. cruzi antigen. These results show that vaccination of mice with BCG plus killed Leishmania promastigotes delayed acute T. cruzi infection, stimulated a T-cell response to T. cruzi antigen and promoted IFN-gamma production.

[Immunopathology of American tegumentary leishmaniasis]. / Inmunopatología de la leishmaniasis tegumentaria Americana.

The complex cell mediated immune response in parasitic diseases can be evaluated in different body compartments. In the present work we describe the results of studies of peripheral blood lymphocytes and the cutaneous lesions in the three clinical forms of tegumentary leishmaniasis. These clinical forms, that constitute a clinical, histological and immunological spectrum, are: localized cutaneous leishmaniasis (LCL), diffuse cutaneous (DCL9, and the intermediate forms that include mucous and verrocous leishmaniasis (MCL). The overall results suggest that the cytokine pattern of lymphocytes in the blood and lesions of LCL, the self-limiting form of the disease, is T-helper type 1. This leads to the cure of the lesions in these patients, either spontaneously or after appropriate therapy. The disseminated disease in DCL patients is resistant to chemotherapy, and is characterized by a Th2 cytokine pattern, with a an absence of IL-2 AND ifn-gamma production when the lymphocytes are specifically stimulated by leishmanial antigen. This is probably why these patients are unable to control the infection, and allows the cutaneous dissemination of the parasite. The intermediate MCL form is characterized by destructive lesions of the oral and nasopahryngeal mucosas, with a tendency to the chronicity of the infection. The cytokine pattern of MCL patients is a mixture of Type 1 and Type 2 responses. This may be responsible for the progression of the disease in these patients, as it is possible that when both types of cytokines are produced, the Type 2 responses can predominate over the Type 1 and the disease is maintained in a chronic, although activated, state. The examination of the cutaneous lesions demonstrated that the epidermis in the DCL lesions is deficient in ICAM-1 accessory signals and MHC-II expression by keratinocytes, and presents a variable number of Langerhans cells. In MCL lesions, the expression of ICAM-1 and MHC-II is elevated, and Langerhans cells are absent in the damaged epithelium. The epidermis of LCL lesions show ICAM-1 in patches and MHC uniformly expressed by keratinocytes. DCL lesions are characterized by low CD4/CD8 and memory/naive T cell ratios, low numbers of T gamma delta cells, and an apparent defect in the expression of LFA-1 directional receptors. The cytokine patterns are Th1 and Th2, with the latter predominating. MCL granulomas manifest high CD4/CD8 and memory/naive Tcel ratios, low numbers of T gamma delta, a high coefficients of cellular adhesion, with a mixed Th1/Th2 cytokine pattern. LCL granulomas are characterized by a normal CD4/CD8 ratio, a high memory/naive cell ratio, numerous groups of T gamma delta, a high expression of directional receptors, and Th1/Th0 cytokine patterns. We discuss the results in the context of the immunological effects, both in immunotherapy and immunoprophylasis, of the combined vaccine of BCG plus promastigotes of Leishmania. In immunotherapy we demonstrate that the combined vaccine simulates a Th1 response in LCL patients. As an immunoprophylactic vaccine in healthy individuals from an endemic area of leishmaniasis, it stimulates a Th1 response (positivity in the Montenegro cutaneous reactions, proliferative responses in vitro and production of IFN-gamma), with a low specific antibody response. This demonstrates that the combined vaccine is potentially useful both in the treatment of LCL patients, as well as being potentially protective applied as immunoprophylaxis in the control of leishmaniasis.

Polymorphism in tumor necrosis factor genes associated with mucocutaneous leishmaniasis.

Recent studies have shown that mucocutaneous leishmaniasis (MCL), a severe and debilitating form of American cutaneous leishmaniasis (ACL) caused by Leishmania braziliensis infection, is accompanied by high circulating levels of tumor necrosis factor (TNF)-alpha. Analysis of TNF polymorphisms in Venezuelan ACL patients and endemic unaffected controls demonstrates a high relative risk (RR) of 7.5 (P < 0.001) of MCL disease in homozygotes for allele 2 of a polymorphism in intron 2 of the TNF-beta gene, especially in females (RR = 9.5; P < 0.001) compared with males (RR = 4; P < 0.05). A significantly higher frequency (P < 0.05) of allele 2 at the -308-basepair TNF-alpha gene polymorphism was also observed in MCL patients (0.18) compared with endemic control subjects (0.069), again associated with a high relative risk of disease (RR = 3.5; P < 0.05) even in the heterozygous condition. Because both the TNF-alpha and TNF-beta polymorphisms have previously been linked with functional differences in TNF-alpha levels, these data suggest that susceptibility to the mucocutaneous form of disease may be directly associated with regulatory polymorphisms affecting TNF-alpha production.

Immune response in healthy volunteers vaccinated with BCG plus killed leishmanial promastigotes: antibody responses to mycobacterial and leishmanial antigens.

Antibody (IgG) responses to mycobacterial (BCG; PPD; Mycobacterium leprae soluble antigen, MLSA) and leishmanial (Leishmania mexicana LV4) antigens were measured in 208 initially PPD and leishmanin skin-test negative volunteers divided into four vaccine groups as follows: 68 received BCG plus killed promastigotes (group A), 47 received BCG alone (group B), 47 received killed promastigotes alone (group C), and 46 formed the diluent control (placebo, group D). Three vaccine doses were administered at 8-12 week intervals. Vaccinees were bled immediately prior to each vaccination, and again at 3- and 12-month follow-up. Skin tests were performed prevaccination, and again at the 3- and 12-month follow-up. Anti-BCG, anti-PPD and anti-MLSA IgG levels increased significantly in groups A and B receiving BCG. The presence of leishmanial antigen (with BCG) in the inoculum suppressed the IgG response to Mycobacterium tuberculosis/Mycobacterium bovis-related (PPD and BCG), but not M. leprae-related (MLSA)-related, antigens. A small but significant increase (relative to prevaccination level) in response to MLSA, but not to BCG or PPD was observed in the non-BCG-vaccinated groups. The background level of response to mycobacterial and leishmanial antigens was higher in the Venezuelan vaccinees than in non-endemic (British) volunteers. Responses to leishmanial antigen were not enhanced in the two vaccine groups receiving killed promastigotes (with/without BCG) compared with the BCG alone and placebo groups. Instead, all vaccine groups showed a pattern of response consistent with either (i) a response to the skin-test antigen or, more likely, (ii) seasonal endemic exposure to leishmanial antigen. Interestingly, this endemic response to leishmanial antigen was enhanced in the vaccine groups receiving BCG, despite the fact that group B received no leishmanial antigen in the vaccine inoculum. When prevaccination IgG levels (mean + 3 standard deviations) were used to determine a negative cut-off, a low percentage (< 38%) of vaccinees converted to responder status for either anti-mycobacterial or anti-leishmanial responses, and those who did would be classified as 'low-responder' status compared with titres observed in severe forms of disease. Hence, although there was evidence for a background endemic response to both leishmanial and mycobacterial antigens, there was no evidence that vaccination per se led to a potentially disease exacerbatory level of TH2-associated antibody response especially with respect to the anti-leishmanial response.(ABSTRACT TRUNCATED AT 400 WORDS)

Immune response in healthy volunteers vaccinated with killed leishmanial promastigotes plus BCG. I: Skin-test reactivity, T-cell proliferation and interferon-gamma production.

This study reports the results of a vaccine trial established to study the cellular immune responses in vivo (skin-test reactivity) and in vitro (T-cell proliferation and interferon-gamma production) to both leishmanial and mycobacterial antigens following vaccination of healthy volunteers from a leishmaniasis-endemic area with killed leishmanial promastigotes, with or without BCG (Bacille Calmètte-Guerin). Skin tests were performed using purified protein derivative of tuberculin (PPD) and leishmanial antigen in 692 volunteers, and 208 doubly negative subjects (< or = 7 mm induration) were selected to participate in the trial. The study subjects were divided into four vaccine groups: (A) killed promastigotes plus BCG, (B) BCG alone, (C) killed promastigotes alone, and (D) placebo. Three vaccine doses were administered at 6-10-week intervals. The skin-test responses to PPD and leishmanial antigen were reassessed at 4-6- and 12-18-month follow-ups. The results of this trial demonstrated that the combined vaccine, i.e. killed promastigotes of Leishmania plus BCG, results in the stimulation of an immune response to both leishmania and mycobacterial antigens in a high percentage of vaccines (> 85%), manifested either by skin-test conversion, lymphocyte proliferation and/or interferon-gamma production. This was evident after the first dose of vaccine for lymphocyte proliferation and interferon-gamma production and was maintained for a year after the three doses of vaccine. Group B (which received BCG alone), responded as well as group A to PPD but not as well to leishmanial antigen. The reverse was true for group C which received promastigotes alone. Group A attained a 38% leishmanin skin-test conversion at the 4-6-month follow-up, which was associated with double PPD/leishmanial antigen responder status. In contrast, a 35% skin-test conversion was found at the 12-18-month follow-up in group C (promastigotes alone), but this was not associated with responses to PPD. A significant percentage of conversion was observed in the placebo group at the 12-18-month follow-up, both to PPD (58%) and leishmanial (21%) antigens, which suggests either environmental exposure to mycobacterial or leishmanial antigens during the vaccine trial or, more probably, a response to the repeated leishmanial skin tests. Further studies are required to determine whether the presence of proliferative and/or interferon-gamma responses in the absence of a skin-test response are sufficient indicators of potential vaccine success.

The clinical and immunological spectrum of American cutaneous leishmaniasis.

American cutaneous leishmaniasis is characterized by a spectrum of clinical manifestations. These include localized, often self-healing single lesions, intermediate forms which frequently produce mucosal lesions and often show exaggerated delayed-type hypersensitivity (DTH), and the rare diffuse cutaneous leishmaniasis in which no reaction of protective cell-mediated immunity or DTH can be demonstrated. Clinical, pathological and immunological studies have begun to unravel some of the mechanisms associated with different disease manifestations, dependent on complex interactions between the host immune response, measured in terms of indices including lymphocyte subsets and lymphokines in vitro and within active lesions, and different species of Leishmania.

Leishmania colombiensis in Venezuela.

Flagellate parasites isolated in Venezuela from bone marrow aspirates of a human (MHOM/VE/70/Chuao) and a dog (MCAN/VE/72/Talisman2) were subsequently identified by isozyme analysis as Leishmania colombiensis. Data are presented describing genetic similarity among Panama, Colombia, and Venezuela populations of this species.

Serum levels of tumor necrosis factor in patients with American cutaneous leishmaniasis.

The purpose of this study was to evaluate serum levels of TNF-alpha in patients with either of the three clinical forms of American cutaneous leishmaniasis. The 86 patients examined were classified as having either the localized (LCL: 22 patients), mucocutaneous (MCL: 45 patients), or the rare diffuse (DCL: 19 patients) form of the disease. Our results show a significant increase in the mean level of TNF-alpha in the three groups of patients when compared to controls. MCL patients produce significantly higher levels of TNF-alpha than DCL patients. The proportion of individuals positive for serum TNF-alpha was significantly higher in both MCL and DCL patients than in the controls. No significant differences were found in the level of TNF-alpha when compared between before and after cure of 12 patients with MCL. There were no significant correlations between the level of TNF-alpha and the skin test diameter. The results will be discussed in terms of the pathogenesis of the disease in its different clinical forms.

Evaluation of serum levels of tumour necrosis factor-alpha (TNF-alpha) and soluble IL-2 receptor (sIL-2R) and CD4, CD8 and natural killer (NK) populations during infrared pulsed laser device (IPLD) treatment.

The purpose of this study was to evaluate serum levels of TNF-alpha, sIL-2R and distribution of peripheral leucocyte subsets in patients with advanced neoplastic disease undergoing IPLD treatment. Fifteen cancer patients with evidence of persistent disease were further divided in two groups according to outcome at the end of the period of clinical evaluation: group 1 patients were still alive and group 2 patients had died. Our results show: (i) an increase in the initial level of TNF-alpha in both groups; (ii) a decrease in TNF-alpha levels during the follow up of group 1 patients; (iii) a significant increase in serum levels of sIL-2R in patients in group 2 compared with those in group 1; (iv) a progressive and constant increase in TNF-alpha levels in group 2; (v) a decrease in CD4+CD45RA+ subpopulation in both groups; (vi) an increase in CD25+ cells; (vii) an increase in CD4+, CD4+CD45RA+ and CD25+ cells during the follow up of group 2 patients. The data generated here form the basis for further investigations on the use of IPLD as a single agent and in combination with other biological response modifiers in cancer patients.

Bronchial challenge of tropical asthmatics with Ascaris lumbricoides.

Despite the fact that helminthic parasites can stimulate strong immediate hypersensitivity reactions, it is uncertain whether these are relevant to the development of allergic disease in infected patients. In order to examine this possibility, we tested 20 informed chronic asthmatic patients from an Ascaris-endemic area by bronchial challenge with a partially purified extract of this parasite. Sequential measurements were made of both the forced expiratory volume in the first second (FEV1) and the peak expiratory flow rate (PEFR) up to 6 h postchallenge, then of PEFR from 6 to 14 h and at 24 h. These were compared to the effect of control inhalations of saline. Extremely low doses of Ascaris antigen that did not exceed 10 PNU (6 x 10(-7) g of protein) induced significant reductions (> 20%) in FEV1 within 30 min in 3 (15%) patients, and in PEFR in 5 cases (25%). By 6 h postchallenge, 5 (25%) subjects showed significant alterations in FEV1, and 10 (50%) in PEFR. Significant changes in PEFR were recorded between 6 and 24 h in 12 (60%) patients. The challenge of nonasthmatic subjects from the same Ascaris-endemic area did not produce notable changes in pulmonary function, and although asthmatics with no evidence of prior contact with the parasite showed a certain degree of immediate bronchial reactivity to the parasite extract, the late responses were significantly less frequent than in the infected patients. No correlations were detected between the bronchial responses and skin test reactivities to the Ascaris extract, or serum levels of specific IgE or IgG antibody.(ABSTRACT TRUNCATED AT 250 WORDS)

Leishmania chagasi antigens recognized in cured visceral leishmaniasis and asymptomatic infection.

Active visceral leishmaniasis is associated with antigen-specific immuno-suppression. However, cured patients develop a cellular immune response associated with resistance to reinfection. Recent studies have identified patients with asymptomatic or subclinical infections, which are also accompanied by an immune response. In order to identify subjects immune to Leishmania chagasi, we performed a skin-test survey in an endemic area in eastern Venezuela. The delayed-type hypersensitivity (DTH) response was assessed in patients cured of visceral leishmaniasis, as well as in their relatives and neighbors. Of the latter, 36 (34.2%) of 105 were positive and 26 (24.7%) of 105 gave intermediate responses. The DTH reaction correlated with age. The antigens recognized by a subgroup of cured patients, those with positive skin-test results, and controls (skin-test negative) were assessed by Western blotting with sera, and T cell immunoblotting with peripheral blood mononuclear cells. No consistent differences between the groups were noted in Western blots with L. chagasi antigens. T cell blots were performed on five patients from each group. For the cured patients and skin-test positive contacts, a significant proliferative response to fraction 12 (less than 20.5 kDa) was noted in four of five patients in each group. Cells from three of five cured patients and two of five skin-test-positive patients proliferated in response to fraction 4 (73-115 kDa). The response to other fractions was variable, with only a minority of patients responding to any one fraction. These data suggest that the antigens recognized by patients with evidence of immunity to L. chagasi are quite variable.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunotherapy of localized, intermediate, and diffuse forms of American cutaneous leishmaniasis.

The clinical efficacy of immunotherapy for localized American cutaneous leishmaniasis with a combination of heat-killed Leishmania mexicana amazonensis promastigotes and viable BCG (bacille Calmette Guérin) has been compared with meglumine antimoniate chemotherapy and with BCG alone in a controlled clinical study in 217 patients. The results in the first two groups were comparable, with greater than 90% clinical cures with an average time of 16-18 w required for healing. The cure rate was considerably lower (42%) and more prolonged in the group receiving BCG alone. Secondary effects were observed in less than 5% of the patients receiving combined immunotherapy or BCG alone. In contrast, 49% of the patients receiving chemotherapy showed side effects. High therapeutic efficacy was also observed using combined immunotherapy in patients with intermediate and diffuse cutaneous leishmaniasis who were previously unresponsive to chemotherapy. Cure or clinical improvement was seen in all 11 patients with intermediate forms of the disease, and marked clinical improvement was observed in 9 of 10 patients with diffuse disease. The results on the efficacy of the combined vaccine in immunotherapy for American cutaneous leishmaniasis provide a strong rationale for studying its effectiveness in prophylactic trials.

Cell-mediated immunity in localized cutaneous leishmaniasis patients before and after treatment with immunotherapy or chemotherapy.

In previous studies of the treatment of localized cutaneous leishmaniasis (LCL) we demonstrated that the therapeutic efficiency of immunotherapy (BCG plus promastigotes of Leishmania mexicana) is equal to that of chemotherapy (Glucantime), without causing the serious side-effects of the drug treatment. In the present study, various aspects of cell-mediated immunity, including the lymphoproliferative response, and leucocyte subpopulations were evaluated both before treatment and after cure in 39 LCL patients who had received immunotherapy (IT), in 34 submitted to chemotherapy (CT), and in 14 patients cured by the administration of BCG alone. We demonstrated evident signs of T-cell activation in cured patients who had received either CT or IT. For example, an increased expression of IL-2 receptors was observed in such patients, compared to their pretreatment values. Also, a significant percentage of patients showed augmented in-vitro responses to mitogen, and both in-vitro and in-vivo reactivity to leishmanial antigen. No evidence was found for the development of an exaggerated immune response to Leishmania parasites in the IT group, because the final level of immunological reactivity was comparable to the CT group. Neither was there any difference in terms of the final immune response between the patients cured by BCG treatment alone and the other groups. However, the therapeutic efficiency of BCG was lower and the mean cure time was longer. We conclude that IT is very useful in the treatment of LCL patients because of its high efficiency, low propensity to produce side-effects, and the fact that it does not induce a state of hyper-reactivity.

Inmunorregulación y subpoblaciones leucocitarias en pacientes con leishmaniasis cutánea americana / Immunorregulation and population leukositarias in patients with leishmaniasis cutanea americana

En el presente trabajo nos hemos propuesto dos objetivos principales, primero la evaluación de ciertos aspectos de la regulación de la respuesta inmune en pacientes examinados indirectamente, el papel de las prostaglandinas mediante el uso de indometacina la cual es un inhibidor de su síntesis. En segundo término la cuantificación de diferentes poblaciones de células linfoides: linfocitos T, así como de células no linfoides: monocitos (MO2) mediante el uso de anticuerpos monoclonales y la técnica de inmunoperoxidasa. Para el estudio se utilizaron 84 pacientes con LCA.

Estudio del interferón en pacientes con leishmaniasis cutánea americana / Study of interferon in patients with american cutaneous leishmania

Se investigaron algunos aspectos sobre el efecto inmunomodulador del interferón * en la respuesta linfoproliferativa frente a mitógenos y antígenos de Leishmania, de las células mononucleares provenientes de los pacientes con leishmaniasis cutánea localizada (LCL) y leishmaniasis cutánea mucosa (LCM). Asimismo se evaluó la producción de IFN ipsilón en sobrenadantes estimulados con PHA y antígenos del parásito, preparados a partir de las células de estos mismos pacientes. Nuestros resultados sugieren que los pacientes con LCM no parecen ser susceptibles al efecto modulador del IFN * en respuesta a mitógenos y antígenos, como sí parecen serlo los pacientes con LCL. Además, se encontró que los pacientes con LCL y LCM producen niveles significativos de IFN ipsilón en los sobrenadantes estimulados con PHA y antígenos parasitarios, comparados con los sobrenadantes no estimulados. Sin embargo, la producción de IFN ipsilón en los sobrenadantes de los pacientes con LCM fue significativamente mayor que en los pacientes con LCL. Estos resultados pueden ayudar a explicar parcialmente el estado de hipersensibilidad y daño en las mucosas que presentan los pacientes con LCM

Estudio del interferón en pacientes con leishmaniasis cutánea americana / Study of interferon in patients with american cutaneous leishmania

Se investigaron algunos aspectos sobre el efecto inmunomodulador del interferón * en la respuesta linfoproliferativa frente a mitógenos y antígenos de Leishmania, de las células mononucleares provenientes de los pacientes con leishmaniasis cutánea localizada (LCL) y leishmaniasis cutánea mucosa (LCM). Asimismo se evaluó la producción de IFN ipsilón en sobrenadantes estimulados con PHA y antígenos del parásito, preparados a partir de las células de estos mismos pacientes. Nuestros resultados sugieren que los pacientes con LCM no parecen ser susceptibles al efecto modulador del IFN * en respuesta a mitógenos y antígenos, como sí parecen serlo los pacientes con LCL. Además, se encontró que los pacientes con LCL y LCM producen niveles significativos de IFN ipsilón en los sobrenadantes estimulados con PHA y antígenos parasitarios, comparados con los sobrenadantes no estimulados. Sin embargo, la producción de IFN ipsilón en los sobrenadantes de los pacientes con LCM fue significativamente mayor que en los pacientes con LCL. Estos resultados pueden ayudar a explicar parcialmente el estado de hipersensibilidad y daño en las mucosas que presentan los pacientes con LCM

T-cell subpopulations, expression of interleukin-2 receptor, and production of interleukin-2 and gamma interferon in human American cutaneous leishmaniasis.

Leukocyte subpopulations, the expression of the interleukin-2 (IL-2) receptor, and the production of IL-2 and gamma interferon (IFN-gamma) were studied in the peripheral blood mononuclear cells of American cutaneous leishmaniasis patients that had been stimulated in vitro with either leishmanial antigen or mitogen (phytohemagglutinin M). The 75 patients examined were classified as having either the localized (LCL; 66 patients), mucocutaneous (MCL; 5 patients), or the rare diffuse (DCL; 4 patients) form of the disease. Patients with DCL, who are characterized by their defective cell-mediated immune response to leishmanial antigen, failed to express the IL-2 receptor and did not produce IFN-gamma when exposed to the antigen but did so when stimulated by phytohemagglutinin M. Both LCL and MCL patients showed strong proliferative responses to leishmanial antigen; these were by far the greatest in MCL patients. Both groups had significantly increased IL-2 receptor expression and IFN-gamma production after exposure to either antigen or mitogen, and these were highest in the MCL patients. Concerning the leukocyte subpopulations evaluated (CD2, CD4, CD8, CD20, MO2), the most significant findings were a decrease of both CD4+ cells and the CD4/CD8 ratio in MCL patients compared with the other groups. Considering IL-2 production, in response to phytohemagglutinin M both MCL and LCL patients showed amounts of IL-2 comparable to those of the controls. Our results help explain the anergy of T cells from DCL patients to leishmanial antigen, which could lead to a defective production of IFN-gamma and possibly contribute to their incapacity to kill the Leishmania parasite. Concerning MCL patients, the significantly increased expression of IL-2 receptor, decreased expression of the CD4 (helper-inducer of suppression) phenotype, and elevated IFV-gamma production might partially explains the state of hypersensitivity and mucosal damage exhibited by these patients.