Case Report: In Situ and Systemic Immune Response to Mucosal Leishmaniasis in an HIV-Infected Patient

In situ and systemic evaluations of the immune responses of HIV-infected patients to mucosal leishmaniasis have been poorly described. We describe a recently diagnosed HIV-infected patient with mucosal leishmaniasis who was characterized by a CD4 count of 85 cells/mm3 and nasal septum destruction resulting from pruritic and ulcerated nasal mucosa with crust formation and progression over 2 years. In situ and systemic immune evaluations of T cell activation, memory, and exhaustion were conducted using cytofluorometric assays, and sequencing of the Leishmania species was performed. The immune profile of HIV-infected patient with mucosal leishmaniasis shows a mixed Th1/Th2 pattern and an activated and exhausted status.

Thalidomide is Associated With Increased T Cell Activation and Inflammation in Antiretroviral-naive HIV-infected Individuals in a Randomised Clinical Trial of Efficacy and Safety

Trial Design

Open-label, randomised, controlled, pilot proof-of-concept clinical trial.

Methods

Participants: Antiretroviral naïve adult males with CD4 count ≥ 350 cells/mm³.

Interventions: Patients were randomised to receive thalidomide 200 mg QD for 3 weeks (Thalidomide group) or not (Control group) and followed for 48 weeks.

Objective: We hypothesized that short-term Thalidomide use would reduce HIV related inflammation and HIV replication among antiretroviral naïve HIV infected individuals.

Outcome: Viral loads, CD4/CD8 counts, ultra-sensitive C-reactive protein (US-CRP), cell activation markers, and plasma lipopolysaccharide (LPS) were analyzed.

Randomisation: Unrestricted randomisation.

Blinding: No blinding was used.

Results

Numbers randomised: Thirty recruited individuals were randomised to Thalidomide (16 patients) or Control (14 patients) groups.

Recruitment: Patients were recruited from April 2011 to January 2013.

Outcome: Viral loads remained stable in both groups. During thalidomide treatment, a decrease in CD4/CD8 ratio (p = 0.04), a decrease in CD4 count (p = 0.04), an increase in cell activation calculated by the percentage of CD38 ⁺/HLA-DR⁺ CD8 cells (p < 0.05) and an increase in US-CRP (p < 0.01) were observed in the Thalidomide group, with all parameters returning to baseline levels after thalidomide interruption. We confirmed that thalidomide increased HIV replication in vitro of 6 of 7 samples from long-term antiretroviral suppressed individuals.

Harms: No class 3/4 adverse events occurred.

Conclusions

Short-term use of thalidomide led to an intense transient increase in T cell activation and inflammation, with a decrease in the CD4⁺ cell count without changes to the CD8⁺ cell count. We confirmed that thalidomide acts in vitro as a latency reversal agent and speculate that the in vivo results obtained were due to an increase in HIV replication.

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Short-term Thalidomide use lead to intense increase in inflammatory markers among HIV+ antiretroviral naïve individuals.

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Thalidomide use lead to a transitory decrease in CD4⁺ T cells and CD4/CD8 ratios.

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In vitro complementary studies revealed that Thalidomide acts as an HIV Latency Reversal Agent.

Thalidomide in general presents a potent anti-inflammatory effect, and is still being used for a number of inflammatory diseases and infection. Therefore, Thalidomide investigated here in a randomised clinical trial aiming to mitigate HIV related inflammation among antiretroviral naïve individuals. Surprisingly, the HIV related inflammation increased during Thalidomide use, and in vitro studies demonstrated that Thalidomide is efficient in interrupting HIV latency, one of the major's obstacles for the cure of HIV chronic infection.

Immune Activation and Bacterial Translocation: A Link between Impaired Immune Recovery and Frequent Visceral Leishmaniasis Relapses in HIV-Infected Patients

The maintenance of chronic immune activation due to leishmaniasis or even due to microbial translocation is associated with immunosenescence and may contribute to frequent relapses. Our aim was to investigate whether patients with HIV-associated visceral leishmaniasis (VL/HIV) who experience a single episode of VL have different immunological behaviors in comparison to those who experience frequent relapses. VL/HIV patients were allocated to non-relapsing (NR, n = 6) and relapsing (R, n = 11) groups and were followed from the active phase of VL up to 12 months post-treatment (mpt). The patients were receiving highly active antiretroviral therapy (HAART) and secondary prophylaxis after VL therapy. During active VL, the two groups were similar in all immunological parameters, including the parasite load. At 6 and 12 mpt, the NR group showed a significant gain of CD4⁺ T cells, a reduction of lymphocyte activation, and lower soluble CD14 and anti-Leishmania IgG3 levels compared to the R group. The viral load remained low, without correlation with the activation. The two groups showed elevated but similar percentages of senescent T cells. These findings suggest a decreased ability of the R group to downmodulate immune activation compared to the NR group. Such functional impairment of the effector response may be a useful indicator for predicting clinical prognosis and recommending starting or stopping secondary prophylaxis.

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.

Identification of Giardia lamblia Assemblage E in Humans Points to a New Anthropozoonotic Cycle

Giardia lamblia is a pathogen transmitted by water and food that causes infection worldwide. Giardia genotypes are classified into 8 assemblages (A-H). Assemblages A and B are detected in humans, but they are potentially zoonotic because they infect other mammalian hosts. Giardia in samples from 44 children was genotyped. Conserved fragments of the genes encoding β-giardin and glutamate dehydrogenase were sequenced and their alignment were carried out with sequences deposited in GenBank. As expected for Rio de Janeiro, the majority of samples were related to assemblage A. Surprisingly, assemblage E was detected in 15 samples. Detection of assemblage E in humans suggests a new zoonotic route of Giardia transmission.

Effector memory CD4(+) T cells differentially express activation associated molecules depending on the duration of American cutaneous leishmaniasis lesions

A high number of Leishmania-responder T cells is found in cutaneous leishmaniasis lesions, suggesting that important immunological events occur at the site of infection. Although activated, cytotoxic and regulatory T cells infiltrating into lesions may influence disease pathogenesis, the role of the T cell differentiation pattern of lymphocytes in lesions is unknown. Our aim was to investigate whether the phase of lesion development (early or late) is influenced by the functional status of cells present in inflammatory infiltrate. Activation, cytotoxity and T cell differentiation molecules were evaluated in lesion mononuclear cells by flow cytometry. The frequency of T cells was correlated with the lesion area (r = 0·68; P = 0·020). CD4(+) CD25(+) T cells predominated over CD4(+) CD69(+) T cells in early lesions (less than 30 days), whereas late lesions (more than 60 days) exhibited more CD4(+) CD69(+) T cells than CD4(+) CD25(+) T cells. The duration of illness was correlated positively with CD4(+) CD69(+) (r = 0·68; P = 0·005) and negatively with CD4(+) CD25(+) T cells (r = -0·45; P = 0·046). Most CD8(+) T cells expressed cytotoxic-associated molecules (CD244(+) ), and the percentages were correlated with the lesion area (r = 0·52; P = 0·04). Both CD4(+) and CD8(+) effector memory T cells (TEM -CD45RO(+) CCR7(-) ) predominated in CL lesions and were significantly higher than central memory (TCM -CD45RO(+) CCR7(+) ) or naive T cells (CD45RO(-) CCR7(+) ). An enrichment of TEM cells and contraction of naive T cells were observed in lesions in comparison to blood (P = 0·006) for both CD4(+) and CD8(+) T cells. Lesion chronicity is associated with a shift in activation phenotype. The enrichment of TEM and activated cytotoxic cells can contribute to immune-mediated tissue damage.

Antigen-triggered interferon-γ and interleukin-10 pattern in cured mucosal leishmaniasis patients is shaped during the active phase of disease

An exacerbated type 1 response to leishmanial antigens is the basis of tissue destruction observed in mucosal leishmaniasis (ML). After therapy, a persistent production of high levels of inflammatory cytokines can confer a poor prognosis. Herein we investigated whether the clinical conditions defined during the active phase of ML affect the magnitude of long-term anti-Leishmania immune response. Twenty clinically cured ML cases were studied. Peripheral blood mononuclear cells (PBMC) were cultured with L. braziliensis antigens (Lb-Ag), Toxoplasma gondii antigens (Tg-Ag), concanavalin-A (Con-A) or medium alone, and the lymphocyte proliferative response and cytokine secretion were quantified. Medical records were reviewed for Montenegro skin test (MST) during diagnosis, duration of ML disease or time elapsed after clinical cure. The duration of disease was correlated positively with MST (r = 0·61). Lb-Ag induced interferon (IFN)-γ was correlated positively with duration of illness (r = 0·69) as well as the frequency of secreting cells [enzyme-linked immunospot (ELISPOT)] assay. No association was observed for Tg-Ag or Con-A. Disease duration was correlated negatively with interleukin (IL)-10 production (r = −0·76). Moreover, a negative correlation between length of time after clinical cure and TNF levels (r = −0·94) or the IFN-γ : IL-10 ratio (r = −0·89) were also seen. We suggest that the magnitude of the IFN-γ inflammatory response triggered by ML can be driven by the time of leishmanial antigens exposition during the active phase of the disease. This pattern could persist even long-term after cure. However, despite IFN-γ levels, the decrease of the TNF and IFN-γ : IL-10 ratio reflects the control of proinflammatory responses achieved by cure of ML, possibly preventing disease relapses.

Leishmania braziliensis-reactive T cells are down-regulated in long-term cured cutaneous Leishmaniasis, but the renewal capacity of T effector memory compartments is preserved

Leishmania (Viannia) braziliensis control and tissue damage relate to the effector immune response, which in turn affects clinical outcome. Leishmania reactive CD4(+) and CD8(+) T cells are expanded in long-term healed cutaneous leishmaniasis (hCL) patients but their functional characteristics remain to be determined. This study investigates antigen-specific recall in long-term healed CL caused by L. braziliensis infection. Healed CL subjects were grouped according to the time elapsed since the end of therapy: less than two years and two to five years. Activation phenotype (CD69(+) or CD25(+)) and subpopulations of memory T cell phenotypes [central memory (Tcm): CD45RO(+) CCR7(+) or effector memory (Tem): CD45RO(+) CCR7(-)] were quantified in ex vivo blood mononuclear cells and after Leishmania antigens stimuli. A reduction in the percentage of activated Leishmania-responder CD4(+) and CD8(+) T cells in hCL was associated with the time elapsed since clinical cure. Percentage of CD69(+) in TCD4(+) and TCD8(+) cells were negatively correlated with IL-10 levels. Ex vivo analyses showed contracted Tem CD4(+) and Tem CD8(+) compartments from hCL with long time elapsed since clinical cure, although renewal of these compartments was observed following in vitro exposure to leishmanial stimuli. Our results show that healed L. braziliensis infected patients exhibit a recall response to Leishmania antigens with evident expansion of effector memory T cells. Regulated leishmanial-specific response seems to emerge only about two years after initial contact with the parasite antigens.

Microbial translocation induces an intense proinflammatory response in patients with visceral leishmaniasis and HIV type 1 coinfection

BACKGROUND

 Leishmania infection is a cofactor in the heightened cellular activation observed in patients with American visceral leishmaniasis and human immunodeficiency virus type 1 (HIV) infection, with or without progression to AIDS (AVL/HIV). Thus, the persistence of a high parasite load despite antileishmanial therapy could be responsible for the continued immune stimulation.

METHODS

 CD8(+) T cells expressing CD38, parasite load, lipopolysaccharide (LPS), soluble CD14, macrophage migration inhibitory factor (MIF), intestinal fatty acid-binding protein (IFABP), and proinflammatory cytokines (interleukin 1β, interleukin 6, interleukin 8, interleukin 17, interferon γ, and tumor necrosis factor) were measured in 17 patients with AVL/HIV, 16 with HIV, and 14 healthy subjects (HS).

RESULTS

 Lower Leishmania parasitemia was observed after antileishmanial and antiretroviral therapies. However, higher levels of CD38(+) on CD8(+) T cells were observed in both clinical phases of leishmaniasis, compared with HIV cases. AVL/HIV and HIV patients showed higher levels of LPS and IFABP than HS. Proinflammatory cytokine levels were significantly augmented in patients with active coinfection, as well as those with remission of Leishmania infection. LPS levels and Leishmania infection were positively correlated with CD38 expression on CD8(+) T cells and with IL-6 and IL-8 levels.

CONCLUSIONS

 LPS levels along with the immune consequences of Leishmania infection were associated with elevated cellular activation in coinfected patients. As a consequence, secondary chemoprophylaxis for leishmaniasis or even the use of antiinflammatory drugs or antibiotics may be considered for improving the prognosis of AVL/HIV.

Decrease in anti-Leishmania IgG3 and IgG1 after cutaneous leishmaniasis lesion healing is correlated with the time of clinical cure

For better efficiency in the establishment of American tegumentary leishmaniasis clinical cure, the World Health Organization suggests that the clinical criteria are supported by serologic data. The present study aims to investigate the dynamics of IgG subclass production in clinical evolution post-treatment of cutaneous leishmaniasis (CL). Paired sera from 23 subjects with CL resulting from Leishmania braziliensis infection were studied during the active lesion phase (aCL) and after clinical cure post-therapy (hCL), which included an alternative protocol with a low dose of antimony. Anti-Leishmania IgG and its subclasses were measured using ELISA, and the immunoglobulin levels were correlated with patients' clinical data. All of the subjects were clinically healed and did not present relapse during follow-up. Serum levels of anti-Leishmania IgG (r = -0·79; P < 0·0001), IgG1 (r = -0·64, P < 0·001) and IgG3 (r = -0·42, P < 0·045) in hCL were negatively correlated with the duration of clinical cure. After 24 months of clinical cure, 73% of samples were negative for IgG1 and 78% were negative for IgG3. In conclusion, the detection of serum anti-Leishmania IgG1 and IgG3 is an improved laboratory strategy to aid in the decision of interruption of the ambulatory follow-up of CL patients.

Atypical lesions as a sign of cutaneous dissemination of visceral leishmaniasis in a human immunodeficiency virus-positive patient simultaneously infected by two viscerotropic Leishmania species

Leishmaniasis is considered an emerging opportunistic disease in human immunodeficiency virus (HIV)-infected patients who have considerably variable clinical presentation. We report a patient with visceral leishmaniasis who had unexpected clinical aspects (atypical cutaneous lesions appearing after long-term evidence of visceral parasites). The patient had hepatoesplenomegaly in the absence of fever, but was otherwise generally healthy. The HIV viral load was low despite severe immunossupression (low lymphocyte proliferation and low level of interferon-γ, concomitant with a high lymphocyte activation status). Surprisingly, two Leishmania strains were isolated from his bone marrow (typical L. infantum sequence MON-1, type A) and skin (L. donovani MON-2 sequence); this second strain had not been previously identified in Brazil. The association of visceral leishmaniasis and HIV/acquired immunodeficiency syndrome is a largely unknown disease, particularly in areas in which leishmaniasis is not endemic. Such atypical cases indicate that this disease can be undiagnosed in clinical settings.

Evidence that lipopolisaccharide may contribute to the cytokine storm and cellular activation in patients with visceral leishmaniasis

Background

Visceral leishmaniasis (VL) is characterized by parasite-specific immunosuppression besides an intense pro-inflammatory response. Lipopolisaccharide (LPS) has been implicated in the immune activation of T-cell deficient diseases such as HIV/AIDS and idiopathic lymphocytopenia. The source of LPS is gram-negative bacteria that enter the circulation because of immunological mucosal barrier breakdown. As gut parasitization also occurs in VL, it was hypothesized that LPS may be elevated in leishmaniasis, contributing to cell activation.

Methodology/Principal Findings

Flow cytometry analysis and immunoassays (ELISA and luminex micro-beads system) were used to quantify T-cells and soluble factors. Higher LPS and soluble CD14 levels were observed in active VL in comparison to healthy subjects, indicating that LPS was bioactive; there was a positive correlation between these molecules (r = 0.61;p<0.05). Interestingly, LPS was negatively correlated with CD4⁺ (r = −0.71;p<0.01) and CD8⁺ T-cells (r = −0.65;p<0.05). Moreover, higher levels of activation-associated molecules (HLA-DR, CD38, CD25) were seen on T lymphocytes, which were positively associated with LPS levels. Pro-inflammatory cytokines and macrophage migration inhibitory factor (MIF) were also augmented in VL patients. Consistent with the higher immune activation status, LPS levels were positively correlated with the inflammatory cytokines IL-6 (r = 0.63;p<0.05), IL-8 (r = 0.89;p<0.05), and MIF (r = 0.64;p<0.05). Also, higher plasma intestinal fatty acid binding protein (IFABP) levels were observed in VL patients, which correlated with LPS levels (r = 0.57;p<0.05).

Conclusions/Significance

Elevated levels of LPS in VL, in correlation with T-cell activation and elevated pro-inflammatory cytokines and MIF indicate that this bacterial product may contribute to the impairment in immune effector function. The cytokine storm and chronic immune hyperactivation status may contribute to the observed T-cell depletion. LPS probably originates from microbial translocation as suggested by IFABP levels and, along with Leishmania antigen-mediated immune suppression, may play a role in the immunopathogenesis of VL. These findings point to possible benefits of antimicrobial prophylaxis in conjunction with anti-Leishmania therapy.

Visceral leishmaniasis (VL) affects organs rich in lymphocytes, being characterized by intense Leishmania-induced T-cell depletion and reduction in other hematopoietic cells. In other infectious and non-infectious diseases in which the immune system is affected, such as HIV-AIDS and inflammatory bowel disease, damage to gut-associated lymphocyte tissues occurs, enabling luminal bacteria to enter into the circulation. Lipopolisaccharide (LPS) is a bacterial product that stimulates macrophages, leading to the production of pro-inflammatory cytokines and other soluble factors such as MIF, which in turn activate lymphocytes. Continuous and exaggerated stimulation causes exhaustion of the T-cell compartment, contributing to immunosuppression.

Herein, we show that an increment in LPS plasma levels also occurs in VL; the higher the LPS levels, the lower the TCD4⁺ and TCD8⁺ cell count in the blood. This T-cell depletion may affect the mucosal immune system, which, along with intestinal parasitization by amastigotes, may contribute to gut barrier damage and consequent microbial translocation. LPS levels were correlated with T-cell activation, pro-inflammatory cytokine plasma levels, MIF, and IFABP, showing that a bacterial molecule, probably from luminal origin, not associated with Leishmania infection can negatively affect the immune system. These findings points to possible benefits of antimicrobial prophylaxis in conjunction with anti-Leishmania therapy.

High levels of T lymphocyte activation in Leishmania-HIV-1 co-infected individuals despite low HIV viral load

BACKGROUND

Concomitant infections may influence HIV progression by causing chronic activation leading to decline in T-cell function. In the Americas, visceral (AVL) and tegumentary leishmaniasis (ATL) have emerged as important opportunistic infections in HIV-AIDS patients and both of those diseases have been implicated as potentially important co-factors in disease progression. We investigated whether leishmaniasis increases lymphocyte activation in HIV-1 co-infected patients. This might contribute to impaired cellular immune function.

METHODS

To address this issue we analyzed CD4+ T absolute counts and the proportion of CD8+ T cells expressing CD38 in Leishmania/HIV co-infected patients that recovered after anti-leishmanial therapy.

RESULTS

We found that, despite clinical remission of leishmaniasis, AVL co-infected patients presented a more severe immunossupression as suggested by CD4+ T cell counts under 200 cells/mm3, differing from ATL/HIV-AIDS cases that tends to show higher lymphocytes levels (over 350 cells/mm3). Furthermore, five out of nine, AVL/HIV-AIDS presented low CD4+ T cell counts in spite of low or undetectable viral load. Expression of CD38 on CD8+ T lymphocytes was significantly higher in AVL or ATL/HIV-AIDS cases compared to HIV/AIDS patients without leishmaniasis or healthy subjects.

CONCLUSIONS

Leishmania infection can increase the degree of immune system activation in individuals concomitantly infected with HIV. In addition, AVL/HIV-AIDS patients can present low CD4+ T cell counts and higher proportion of activated T lymphocytes even when HIV viral load is suppressed under HAART. This fact can cause a misinterpretation of these laboratorial markers in co-infected patients.

Therapeutic failure in American cutaneous leishmaniasis is associated with gelatinase activity and cytokine expression

Cutaneous lesions caused by Leishmania braziliensis infection occasionally heal spontaneously, but with antimonials therapy heal rapidly in approximately 3 weeks. However, about 15% of the cases require several courses of therapy. Matrix metalloproteinase-2 (MMP-2) and MMP-9 are gelatinases that have been implicated in other chronic cutaneous diseases and skin re-epithelialization. These enzymes are controlled by their natural inhibitors [tissue inhibitors of metalloproteinase (TIMPs)] and by some cytokines. Uncontrolled gelatinase activity may result in intense tissue degradation and, consequently, poorly healing wounds. The present study correlates gelatinase activity to therapeutic failure of cutaneous leishmaniasis (CL) lesions. Our results demonstrate an association between gelatinase activity and increased numbers of cells making interferon (IFN)-γ, interleukin (IL)-10 and transforming growth factor (TGF)-β in lesions from poor responders. Conversely, high levels of MMP-2 mRNA and enhanced MMP-2 : TIMP-2 ratios were associated with a satisfactory response to antimonials treatment. Additionally, high gelatinolytic activity was found in the wound beds, necrotic areas in the dermis and within some granulomatous infiltrates. These results indicate the importance of gelatinase activity in the skin lesions caused by CL. Thus, we hypothesize that the immune response profile may be responsible for the gelatinase activity pattern and may ultimately influence the persistence or cure of CL lesions.

Psoriasis affects individuals of African descent and white Brazilians similarly

INTRODUCTION

Cultural, socio-demographic and environmental factors such as tropical climate and exposure to sun could have an impact on the incidence or clinical course of psoriasis. Here we describe the main clinical aspects of psoriasis in Brazilian patients and also investigate whether any particular feature can distinguish the disease occurring in Brazil from that occurring in other countries.

MATERIAL AND METHODS

We recorded the clinical features of 151 psoriasis patients seen in a Brazilian public dermatological care unit between 2006 and 2008.

RESULTS

Males and females were similarly affected. The reported races were as follows: whites, 47 cases (41.6%), interracial individuals (mixed race), 42 cases (37.2%) and blacks, 24 cases (21.2%). Chronic plaque-type psoriasis was the most prevalent clinical form (110 cases, 72.8%) followed by palm and sole involvement (21 cases, 13.9%).

CONCLUSIONS

We demonstrated that psoriasis in these Brazilian subjects was similar to that observed in subjects from other countries, but interracial and black populations were affected as much as whites. Considering the high rate of interracial populations among Brazilians we cannot exclude the possibility that Afro-descendants may have inherited Caucasian genes associated with psoriasis. Poor socio-economic conditions of Afro-descendants can limit their possibilities of receiving adequate treatments, impairing their health-related quality of life.

The skin homing receptor cutaneous leucocyte-associated antigen (CLA) is up-regulated by Leishmania antigens in T lymphocytes during active cutaneous leishmaniasis

The cutaneous leucocyte-associated antigen receptor (CLA) can direct Leishmania-specific T lymphocytes towards inflamed skin lesions. Homing receptors [CLA, lymphocyte-associated antigen 1 (LFA-1) or CD62L] were analysed in lymphocytes from blood and cutaneous leishmaniasis (CL) lesions. CL patients with active lesions (A-CL) presented lower levels of T lymphocytes expressing the CLA(+) phenotype (T CD4(+) = 10.4% +/- 7.5% and T CD8(+) = 5.8% +/- 3.4%) than did healthy subjects (HS) (T CD4(+) = 19.3% +/- 13.1% and T CD8(+) = 21.6% +/- 8.8%), notably in T CD8(+) (P < 0.001). In clinically cured patients these percentages returned to levels observed in HS. Leishmanial antigens up-regulated CLA in T cells (CLA(+) in T CD4(+) = 33.3% +/- 14.1%; CLA(+) in T CD8(+) = 22.4% +/- 9.4%) from A-CL but not from HS. An enrichment of CLA(+) cells was observed in lesions (CLA(+) in T CD4(+) = 45.9% +/- 22.5%; CLA(+) in T CD8(+) = 46.4% +/- 16.1%) in comparison with blood (CLA(+) in T CD4(+) = 10.4% +/- 7.5%; CLA(+) in T CD8(+) = 5.8% +/- 3.4%). Conversely, LFA-1 was highly expressed in CD8(+) T cells and augmented in CD4(+) T from peripheral blood of A-CL patients. In contrast, CD62L was not affected. These results suggest that Leishmania antigens can modulate molecules responsible for migration to skin lesions, potentially influencing the cell composition of inflammatory infiltrate of leishmaniasis or even the severity of the disease.

T-cell responses associated with resistance to Leishmania infection in individuals from endemic areas for Leishmania (Viannia) braziliensis

Subclinical or asymptomatic infection is documented in individuals living in endemic areas for leishmaniasis suggesting that the development of an appropriate immune response can control parasite replication and maintain tissue integrity. A low morbidity indicates that intrinsic factors could favor resistance to Leishmania infection. Herein, leishmanial T-cell responses induced in subjects with low susceptibility to leishmaniasis as asymptomatic subjects were compared to those observed in cured cutaneous leishmaniasis (CCL) patients, who controlled the disease after antimonial therapy. All of them have shown maintenance of specific long-term immune responses characterized by expansion of higher proportions of CD4+ as compared to CD8+ Leishmania reactive T-lymphocytes. Asymptomatic subjects had lower indexes of in vitro Leishmania induced lymphoproliferative responses and interferon-gamma (IFN-gamma) production in comparison to CCL patients. On the other hand, interleukin (IL-10) production was much higher in asymptomatics than in CCL, while no differences in IL-5 levels were found. In conclusion, long lived T-cell responses achieved by asymptomatic individuals differed from those who had developed symptomatic leishmaniasis in terms of intensity of lymphocyte activation (proliferation or IFN-gamma) and regulatory mechanisms (IL-10). The absence of the disease in asymptomatics could be explained by their intrinsic ability to create a balance between immunoregulatory (IL-10) and effector cytokines (IFN-gamma), leading to parasite destruction without producing skin tissue damage. The establishment of profiles of cell-mediated immune responses associated with resistance against Leishmania infection is likely to make new inroads into understanding the long-lived immune protection against the disease.

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

Suitable levels of interferon (IFN)-gamma and interleukin (IL)-10 seem to favour the outcome of cutaneous leishmaniasis (CL), while high IFN-gamma 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-gamma 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-gamma 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-gamma/IL-10 ratio observed in CML can indicate unfavourable cytokine balance. On the other hand, no significant difference in the IFN-gamma/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-gamma/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-gamma/IL-10 balance observed in CCL, SH and ASY individuals can represent a better-modulated immune response associated with a favourable prognosis.

Flow cytometric analysis of cellular infiltrate from American tegumentary leishmaniasis lesions

BACKGROUND

CD4+ and CD8+ T lymphocytes play different roles in the outcome of leishmaniasis. However, T-cell distribution in lesions shows significant variability in in situ immunocytochemical studies.

OBJECTIVES

In this report flow cytometry was used to determine the predominant T-cell subsets in leishmaniasis lesions, and their relationship with Leishmania-responsive circulating T cells.

PATIENTS AND METHODS

Mononuclear cells from lesions or peripheral blood (PBMC) of 34 cutaneous (CL), four mucosal (ML) and four disseminated leishmaniasis were phenotypically characterized by flow cytometry. Leishmania-responsive T cells were obtained after in vitro stimulation of PBMC with leishmanial antigens.

RESULTS/CONCLUSIONS

Variable amounts of gammadelta lymphocytes were present in all lesions, with no association with duration of illness. The highest percentages of interleukin-2R- and interferon-gammaR-positive cells were observed in ML lesions and could render these T cells more susceptible to the effects of these cytokines. The distribution of intralesional T-lymphocyte subsets was quite variable (CD4+ > CD8+ = 18 cases, CD8+ > CD4+ = 12 cases and CD4+ congruent with CD8+ = 4 cases) without any association with clinical parameters, and could explain the controversy regarding proportions of these T-cell subsets in leishmaniasis lesions. Low percentages of Leishmania-reactive CD8+ T cells were observed in blood while an enrichment of CD8+ cells was shown in the inflammatory infiltrate, suggesting that local immunoregulatory factors could favour the recruitment and/or proliferation of local CD8+ lymphocytes. Increased percentages of CD8+ cells observed in older lesions are consistent with the hypothesis that they can mediate healing, although their involvement in tissue damage cannot be ruled out. It is possible that these mechanisms can influence the clinical outcome or even the response to therapy.

Long-term follow-up of co-infected HIV and Trypanosoma cruzi Brazilian patients

Three cases of Trypanosoma cruzi-HIV co-infected haemophiliacs are described. Parasitological (xenodiagnosis, haemoculture, PCR) and immunological (CD4+ and CD8+ T cell counts, in vitro lymphoproliferative responses) studies were performed. Hybridization of isolated parasites with a specific probe confirmed the T. cruzi aetiology. We observed that despite the high parasitaemia, no clinical or parasitological evidence of T. cruzi reactivation was detected. CD4+ T cells decreased with time in two patients and the lymphocyte proliferative response to T. cruzi was very low in all patients. These data suggest that T. cruzi infection may have a long silent course in immunosuppressed HIV patients. Therefore, this parasitic infection should be investigated in any AIDS patient coming from areas endemic for Chagas' disease.

American tegumentary leishmaniasis (ATL) in Rio de Janeiro State, Brazil: main clinical and epidemiologic characteristics

BACKGROUND

Rio de Janeiro State in Brazil is an endemic area of American tegumentary leishmaniasis (ATL) induced by Leishmania (Viannia) braziliensis. Objective Our purpose was to describe the main clinical and epidemiologic characteristics of the disease in Rio de Janeiro State.

METHODS

Patients from endemic areas of Rio de Janeiro State attending the Evandro Chagas Hospital were included in the study. A general physical, dermatologic, and otorhinolaryngologic examination was performed in all patients, as well as a Leishmanin skin test. Skin biopsy specimens were obtained and utilized for touch preparations (stained with Leishman dye), culture in special media (Nicolle, Nevy and McNeal; NNN), and histopathologic examination after hematoxylin and eosin stain. Positive cultures were identified with regard to species by the isoenzyme technique. Therapy with pentavalent antimonial compounds was employed in all cases. Eco-epidemiologic characteristics were studied through regular field visits to endemic foci.

RESULTS

Cutaneous disease was present in 87.2% of patients, and mucosal disease in only 12.7%. A single ulcerative cutaneous lesion was the most common clinical presentation. Demonstration of the parasite was always difficult and culture in special media gave the best results for diagnosis. The species involved in transmission was Leishmania (Viannia) braziliensis. Vectors included phlebotomine sand flies (Diptera: Psychodidae) of the genus Lutzomyia, and the most common species was Lutzomyia intermedia, captured mainly on the external walls of houses.

CONCLUSIONS

ATL in Rio de Janeiro is mostly a cutaneous disease. In general, the cases showed great sensitivity to antimony. A pattern of peridomestic transmission seems to be the rule.

Detection of early apoptosis and cell death in T CD4+ and CD8+ cells from lesions of patients with localized cutaneous leishmaniasis

Human localized cutaneous leishmaniasis (LCL), induced by Leishmania braziliensis, ranges from a clinically mild, self-healing disease with localized cutaneous lesions to severe forms which can present secondary metastatic lesions. The T cell-mediated immune response is extremely important to define the outcome of the disease; however, the underlying mechanisms involved are not fully understood. A flow cytometric analysis of incorporation of 7-amino actinomycin D and CD4+ or CD8+ T cell surface phenotyping was used to determine whether different frequencies of early apoptosis or accidental cell death occur at different stages of LCL lesions. When all cells obtained from a biopsy sample were analyzed, larger numbers of early apoptotic and dead cells were observed in lesions from patients with active disease (mean = 39.5 +/- 2.7%) as compared with lesions undergoing spontaneous healing (mean = 17.8 +/- 2.2%). Cells displaying normal viability patterns obtained from active LCL lesions showed higher numbers of early apoptotic events among CD8+ than among CD4+ T cells (mean = 28.5 +/- 3.8 and 15.3 +/- 3.0%, respectively). The higher frequency of cell death events in CD8+ T cells from patients with LCL may be associated with an active form of the disease. In addition, low frequencies of early apoptotic events among the CD8+ T cells were observed in two patients with self-healing lesions. Although the number of patients in the latter group was small, it is possible to speculate that, during the immune response, differences in apoptotic events in CD4+ and CD8+ T cell subsets could be responsible for controlling the CD4/CD8 ratio, thus leading to healing or maintenance of disease.

Clinical analysis and parasite genetic diversity in human immunodeficiency virus/Chagas' disease coinfections in Brazil

To evaluate the possible role of parasitemia on Chagas' disease reactivation in Chagas' disease/human immunodeficiency virus (HIV) coinfection cases and the impact of HIV coinfection on Trypanosoma cruzi genetic diversity, 71 patients with Chagas' disease (34 HIV+ and 37 HIV-) were surveyed. Moreover, 92 T. cruzi stocks from 47 chronic chagasic patients (29 HIV+ and 18 HIV-) were isolated and analyzed by multilocus enzyme electrophoresis and a random amplified polymorphic DNA procedure. High parasitemia appeared to play a major role in cases of Chagas' disease reactivation. In HIV+ patients, the genetic diversity and population structure (clonality) of T. cruzi was similar to that previously observed in HIV- patients, which indicates that immunodepression does not modify drastically genotype repartition of the parasite. There was no apparent association between given T. cruzi genotypes and specific clinical forms of Chagas' disease/HIV associations.

Atypical mucocutaneous leishmaniasis caused by Leishmania braziliensis in an acquired immunodeficiency syndrome patient: T-cell responses and remission of lesions associated with antigen immunotherapy

An atypical case of acquired immunodeficiency syndrome-associated mucocutaneous lesions due to Leishmania braziliensis is described. Many vacuolated macrophages laden with amastigote forms of the parasite were found in the lesions. Leishmanin skin test and serology for leishmaniasis were both negative. The patient was resistant to therapy with conventional drugs (antimonial and amphotericin B). Interestingly, remission of lesions was achieved after an alternative combined therapy of antimonial associated with immunotherapy (whole promastigote antigens). Peripheral blood mononuclear cells were separated and stimulated in vitro with Leishmania antigens to test the lymphoproliferative responses (LPR). Before the combined immunochemotherapy, the LPR to leishmanial antigens was negligible (stimulation index - SI=1.4). After the first course of combined therapy it became positive (SI=4.17). The antigen responding cells were predominantly T-cells (47.5%) most of them with CD8+ phenotype (33%). Very low CD4+ cells (2.2%) percentages were detected. The increased T-cell responsiveness to leishmanial antigens after combined therapy was accompanied by interferon-g (IFN-g) production as observed in the cell culture supernatants. In this patient, healing of the leishmaniasis lesions was associated with the induction of a specific T-cell immune response, characterized by the production of IFN-g and the predominance of the CD8+ phenotype among the Leishmania-reactive T-cells.

Leishmania pifanoi amastigote antigen P-4: epitopes involved in T-cell responsiveness in human cutaneous leishmaniasis

In experimental murine cutaneous leishmaniasis, the purified Leishmania pifanoi amastigote protein P-4 has been shown to induce significant protection against infection. Further, recent studies examining the response of peripheral blood mononuclear cells (PBMC) from Leishmania braziliensis-infected human patients have demonstrated that the P-4 protein selectively elicits a significant TH1-like response. Because a TH1-like response is associated with cure, epitope studies were conducted to further evaluate the human response to P-4. PBMC from confirmed cutaneous leishmaniasis patients infected with L. braziliensis in Rio de Janeiro, Brazil, an area where the disease is endemic, were examined for T-cell proliferation and/or cytokine production in response to whole-parasite homogenate, isolated P-4 protein, and/or P-4 peptides. Twenty of the 22 patients (91%) examined responded to the native P-4 protein by proliferation and/or gamma interferon (IFN-gamma) production. According to the proliferation data, PBMC from 14 patients (64%) were found to respond to the intact P-4 protein (stimulation index of >/=2.5). Fifty-seven percent of the P-4-responsive patients studied responded to at least one of the P-4 peptides; 11 individual peptides were found to elicit a proliferative response. Of 17 patients examined for cytokine production, no PBMC produced detectable interleukin-4 in response to P-4 protein or peptides. However, PBMC from 14 patients (82%) produced significant levels of IFN-gamma (>/=20 pg/ml) in response to native P-4 protein. Nineteen of the 23 peptides were found to elicit an IFN-gamma response from at least two patients. These data indicate that multiple epitopes spanning the entire P-4 molecule are responsible for the TH1-like immune response observed, indicating that the intact P-4 amastigote molecule, rather than selected peptides, may prove to be the most useful for leishmaniasis vaccine development.

Chagas' disease and HIV co-infection: genotypic characterization of the Trypanosoma cruzi strain

In the past few years, new aspects of the immunopathology of Chagas' disease have been described in immunosuppressed patients, such as fatal central nervous system lesions related to the reactivation of the parasite. This article is the first description of the genotypic characterization, at the strain level, of Trypanosoma cruzi isolated from a patient with Chagas' disease/AIDS co-infection. The presence of four hypodense lesions was observed in the cranial compute tomographic scan. the diagnosis of AIDS was assessed by the detection of anti-HIV antibodies using enzyme-linked immunosorbent assay (ELISA) and Western blot techniques. The CD4+ lymphocyte counts were maintained under 200 cells/mm3 during one year demonstrating the severity of the state of immunosuppression. Chagas' disease was confirmed by serological and parasitological methods. Trypomastigote forms were visualized in a thick blood smear. The parasite isolated is genotypically similar to the CL strain. The paper reinforces that cerebral Chagas' disease can be considered as another potential opportunistic infection in AIDS resulting from the reactivation of a dormant T. cruzi infection acquired years earlier.

Immunologic patterns associated with cure in human American cutaneous leishmaniasis

Patients with American cutaneous leishmaniasis were studied before therapy (active lesion) and at the end of therapy (cured patients). Assays of lymphocyte proliferative responses of peripheral blood mononuclear cells induced in vitro by Leishmania braziliensis promastigote antigens (Lb) were performed. Antigen-stimulated cells were harvested for CD4 and CD8 phenotype analysis and the levels of gamma interferon (IFN-gamma) and interleukin 4 (IL-4) produced were also determined in the culture supernatants. Two different patterns of Lb-induced T cell responses were observed: a) predominance of responding CD4+ cells and mixed type 1 and type 2 cytokine production (IFN-gamma and IL-4) during the active disease, and b) similar proportions of responding CD4+ and CD8+ cells, and type 1 cytokine production (presence of IFN-gamma and very low IL-4) at the end of therapy (healed lesions). This last pattern is probably associated with a beneficial T cell response.

T-cell responsiveness of American cutaneous leishmaniasis patients to purified Leishmania pifanoi amastigote antigens and Leishmania braziliensis promastigote antigens: immunologic patterns associated with cure

Patients suffering from American cutaneous leishmaniasis were studied before therapy (active lesion) and at the end of therapy (cured patients). Assays of lymphocyte proliferative responses of peripheral blood mononuclear cells induced in vitro by Leishmania braziliensis promastigote antigens (Lb) or by three proteins (A-2/P-2, P-4, and P-8) derived from Leishmania pifanoi amastigotes were performed. Antigen-stimulated cells were harvested for CD4 and CD8 phenotype analysis and the levels of gamma interferon (IFN-gamma), interleukin 2 (IL-2) and interleukin 4 (IL-4) produced were also determined. Results show two different patterns of Lb-induced T cell responses: (a) predominance of responding CD4+ cells and mixed type 1 and type 2 cytokine production (IFN-gamma, IL-2, and IL-4) during the active disease, (b) similar proportions of responding CD4+ and CD8+ cells and type 1 cytokine production (presence of IFN-gamma and IL-2 and very low IL-4) at the end of therapy (healed lesions). Thus, this last pattern is probably associated with a beneficial T cell response. The A-2/P-2 amastigote cysteine proteinase provided only marginal (s.i. approximately or = 2.5) T cell stimulation in 25% of patients studied; in contrast, the L. pifanoi P-4 and P-8 amastigote antigens induced significant stimulation (s.i. approximately or = 5) in approximately 50% of the patients. In comparison to Lb-stimulated cultures, lower proliferative responses of T lymphocytes to P-4 or P-8 were observed. However, the P-4- or P-8-stimulated cultures had similar percentages of reactive CD4+ and CD8+ cells, as well as type 1 cytokines (presence of IFN-gamma and IL-2, and low levels or absence of IL-4) in the supernatants both before and at the end of therapy. The consistent induction of apparently beneficial T cell responses by the P-4 and P-8 amastigote glycoproteins points to the possibility that these molecules be considered as candidates for future defined vaccines against leishmaniasis.

Tumor necrosis factor-alpha in human american tegumentary leishmaniasis

Tumor necrosis factor-alpha (TNF-alpha) is a cytokine produced by activated macrophages and other cells. In order to verify whether the serum levels of TNF-alpha in American tegumentary leishmaniasis patients are associated with the process of cure or aggravation of the disease, 41 patients were studied: 26 cases of cutaneous leishmaniasis (CL) and 15 of mucocutaneous leishmaniasis (MCL). During active disease the serum levels of TNF-alpha of MCL patients were significantly higher than those of CL patients and control subjects (healthy individuals and cutaneous lesions from other etiologies). The MCL patients had serum titers of TNF-alpha significantly lower at the end of antimonial therapy than before therapy. After a six-month follow-up, the MCL patients had serum levels of TNF-alpha similar to those observed at the end of the therapy as well as to those of CL patients and control subjects. No significant variation in the serum levels of TNF-alpha was observed in CL patients throughout the study period (before, at the end of therapy and after a six-month follow-up). The possible relationship between the high TNF-alpha serum levels and severity of the disease is discussed.

Characterization of human T lymphocyte-mediated immune responses induced by a vaccine against American tegumentary leishmaniasis

Forty-three Brazilians were immunized against American tegumentary leishmaniasis using a vaccine made of whole antigens from killed promastigotes of five American dermotropic Leishmania strains. None of the immunized subjects had a positive reaction in the Montenegro skin test (leishmanin) before vaccination, and 74% developed positive reactions in the skin test after vaccination. The proliferative responses of peripheral blood mononuclear cells (PBMC) induced by antigens from dermotropic Leishmania species were significantly higher after vaccination than before vaccination. However, with antigens from L. chagasi (a causative agent of American visceral leishmaniasis), there was no significant difference between the proliferative responses obtained before and after vaccination. Interferon-gamma was detected in the supernatants of L. braziliensis antigen-stimulated PBMC cultures after vaccination (but not before vaccination). One year after vaccination, PBMC were obtained from eight of the immunized individuals and stimulated with L. braziliensis antigens in proliferative response assays. In all cases, the majority of the responding cells were CD8+ T cells, in contrast to the results of a group of patients with active lesions of tegumentary leishmaniasis, whose L. braziliensis-reactive cells were mainly of the CD4+ T cell phenotype.

Leishmania-reactive CD4+ and CD8+ T cells associated with cure of human cutaneous leishmaniasis

Fourteen patients suffering from American cutaneous leishmaniasis were studied. Assays of the lymphocyte proliferative response induced in vitro by Leishmania braziliensis antigens were performed. After 5 days in culture, L. braziliensis-stimulated blast T cells were harvested for CD4+ and CD8+ phenotype analysis. When results before and at the end of therapy were compared, leishmaniasis patients showed an increase in the percentage of CD8+ blast T cells and a decline in the proportion of CD4+ blast T cells in cultures. The levels of gamma interferon in T-cell culture supernatants showed a tendency to increase when the patients were cured. These results show a pattern of higher proportions of Leishmania-reactive CD8+ T cells and lower proportions of Leishmania-reactive CD4+ T cells after cure.

Cellular and humoral immune responses of a patient with American cutaneous leishmaniasis and AIDS

The lymphocyte responsiveness to leishmanial antigens and its influence on the course of cutaneous leishmaniasis was studied in a patient with AIDS-associated American cutaneous leishmaniasis caused by Leishmania braziliensis. The patient had cutaneous disseminated erythematous papules or nodules and mucosal lesions as well as moniliasis and weight loss. The patient had a poor delayed-type hypersensitivity to leishmanial antigens, showing 3 mm of induration. The cellular immune responses were studied in vitro by lymphocyte proliferative assays induced by leishmanial antigens and concanavalin A. The T cell phenotypes were analysed by flow cytometry. The peripheral blood mononuclear cells before proliferation showed an inversion of the CD4/CD8 ratio (0.28:1). The lymphoproliferative responses to antigen and mitogen were very low (indices < 2.5). The blast-like cell phenotypes after antigen stimulation in culture were: CD3+ 44.8%, CD4+ 7.53% and CD8+ 17.45%. In AIDS patients the decrease in the pool of CD4+ cells, and consequent diminution of the CD4/CD8 ratio, produced by HIV infection provokes a generalized immune depression. The patient's disseminated clinical picture was probably related to the inability of his T cell-mediated immune responses to control the spread of Leishmania infection.