Enterobius vermicularis in Brazil: An integrative review

Enterobius vermicularis, an intestinal helminth, is transmitted through the ingestion of eggs found in food, water, dust, or other fomites, including infected individuals. This review aimed to examine the frequency and distribution of E. vermicularis infections in Brazil between 1991 and 2022. The conducted bibliographic survey revealed that the frequency of E. vermicularis infections in Brazil ranged from 0.1 to 26.1%, depending on factors such as population ethnicity, individual age group, geographic area, time frame, and diagnostic method. However, these findings were based on a limited number of publications, suggesting that the actual prevalence rates of E. vermicularis infection may still be unknown and potentially underestimated.

Giardia lamblia-infected preschoolers present growth delays independent of the assemblage A, B or E

BACKGROUND

Intestinal parasite Giardia can affect children's physical development mainly stunting even in asymptomatic cases. The protozoa G. lamblia is divided into assemblages A-H. However, it is still unclear whether clinical manifestations and pathogenesis may vary according to the infecting assemblage.

OBJECTIVES

To investigate whether G. lamblia assemblages influence differently the physical development of preschoolers from a community of Rio de Janeiro, Brazil.

METHODS

Anthropometric parameters were analysed from children attending a daycare centre and stool samples were obtained for the G. lamblia diagnosis. G. lamblia isolates from positive samples were genotyped. Data were analysed in order to verify whether there is a relationship between G. lamblia infection and the physical development of children according to the assemblage.

FINDINGS

Herein we demonstrated that although eutrophic, G. lamblia-infected daycare preschoolers from a low-income community presented growth delay compared to non-infected ones. This effect was observed for the three assemblages (A, B or E) found infecting humans.

MAIN CONCLUSION

G. lamblia causes growth delays on children independent of infecting assemblage (A, B or E).

Identification of Immunodominant Proteins of the Leishmania (Viannia) naiffi SubProteome as Pan-Specific Vaccine Targets against Leishmaniasis

Leishmaniasis is a wide-spectrum disease caused by parasites from Leishmania genus. A well-modulated immune response that is established after the long-lasting clinical cure of leishmaniasis can represent a standard requirement for a vaccine. Previous studies demonstrated that Leishmania (Viannia) naiffi causes benign disease and its antigens induce well-modulated immune responses in vitro. In this work we aimed to identify the immunodominant proteins present in the soluble extract of L. naiffi (sLnAg) as candidates for composing a pan-specific anti-leishmaniasis vaccine. After immunoblotting using cured patients of cutaneous leishmaniasis sera and proteomics approaches, we identified a group of antigenic proteins from the sLnAg. In silico analyses allowed us to select mildly similar proteins to the host; in addition, we evaluated the binding potential and degree of promiscuity of the protein epitopes to HLA molecules and to B-cell receptors. We selected 24 immunodominant proteins from a sub-proteome with 328 proteins. Homology analysis allowed the identification of 13 proteins with the most orthologues among seven Leishmania species. This work demonstrated the potential of these proteins as promising vaccine targets capable of inducing humoral and cellular pan-specific immune responses in humans, which may in the future contribute to the control of leishmaniasis.

Low doses of 3-phenyl-lawsone or meglumine antimoniate delivery by tattooing route are successful in reducing parasite load in cutaneous lesions of Leishmania (Viannia) braziliensis-infected hamsters

Current therapeutic ways adopted for the treatment of leishmaniasis are toxic and expensive including parasite resistance is a growing problem. Given this scenario, it is urgent to explore treatment alternatives for leishmaniasis. The aim of this study was to evaluate the effect of 3-phenyl-lawsone (3-PL) naphthoquinone on Leishmania (Viannia) braziliensis infection, both in vitro and in vivo, using two local routes of administration: subcutaneous (higher dose) and tattoo (lower dose). In vitro 3-PL showed low toxicity for macrophages (CC₅₀ >3200 µM/48h) and activity against intracellular amastigotes (IC₅₀ = 193 ± 19 µM/48h) and promastigotes (IC₅₀ = 116 ± 26 µM/72h), in which induced increased ROS generation. Additionally, 3-PL up-regulated the production of cytokines such as tumor necrosis factor alpha (TNF-α), monocyte chemotactic protein 1 (MCP-1), interleukin-6 (IL-6) and IL-10 in infected macrophages. However, the anti-amastigote action was independent of nitric oxide production. Treatment of hamsters infected with L. (V.) braziliensis from one week after infection with 3-PL by subcutaneous (25 µg/Kg) or tattooing (2.5 µg/Kg) route, during 3 weeks (3 times/week) or 2 weeks (2 times/week) significantly decreased the parasite load (p<0.001) in the lesion. The reduction of parasite load by 3-PL treatment was comparable to reference drug meglumine antimoniate administered by the same routes (subcutaneous 1mg/Kg and tattoo 0.1mg/Kg). In addition, treatment started from five weeks after infection with 3-PL per tattoo also decreased the parasite load. These results show the anti-leishmanial effect of 3-PL against L. (V.) braziliensis and its efficacy by subcutaneous (higher dose) and tattoo (lower dose) routes. In addition, this study shows that drug delivery by tattooing the lesion allows the use of lower doses than the conventional subcutaneous route, which may support the development of a new therapeutic strategy that can be adopted for leishmaniasis.

DC-SIGN receptor is expressed by cells from cutaneous leishmaniasis lesions and differentially binds to Leishmania (Viannia) braziliensis and L. (Leishmania) amazonensis promastigotes

BACKGROUND

Dendritic cells (DCs) specific intercellular adhesion molecule (ICAM)-3-grabbing non integrin receptor (DC-SIGN) binds to subgenera Leishmania promastigotes mediating its interaction with DC and neutrophils, potentially influencing the infection outcome.

OBJECTIVES

In this work, we investigated whether DC-SIGN receptor is expressed in cells from cutaneous leishmaniasis (CL) lesions as well as the in vitro binding pattern of Leishmania (Viannia) braziliensis (Lb) and L. (L.) amazonensis (La) promastigotes.

METHODS

DC-SIGN receptor was labeled by immunohistochemistry in cryopreserved CL tissue fragments. In vitro binding assay with CFSE-labeled Lb or La promastigotes and RAJI-transfecting cells expressing DC-SIGN (DC-SIGN^POS) or mock-transfected (DC-SIGN^NEG) were monitored by flow cytometry at 2 h, 24 h and 48 h in co-culture.

RESULTS

In CL lesion infiltrate, DC-SIGN^POS cells were present in the dermis and near the epidermis. Both Lb and La bind to DC-SIGN^POS cells, while binding to DC-SIGN^NEG was low. La showed precocious and higher affinity to DC-SIGN^hi population than to DC-SIGN^low, while Lb binding was similar in these populations.

CONCLUSION

Our results demonstrate that DC-SIGN receptor is present in L. braziliensis CL lesions and interact with Lb promastigotes. Moreover, the differences in the binding pattern to Lb and La suggest DC-SIGN can influence in a difference way the intake of the parasites at the first hours after Leishmania infection. These results raise the hypothesis that DC-SIGN receptor could participate in the immunopathogenesis of American tegumentary leishmaniasis accounting for the differences in the outcome of the Leishmania spp. infection.

Different inoculum of Leishmania braziliensis concentrations influence immunopathogenesis and clinical evolution in the ear dermis hamster model of cutaneous leishmaniasis

The golden hamster (Mesocricetus auratus) is commonly used as a promising model for Leishmania braziliensis infection developing skin-ulcerated lesions. However, different protocols using high concentration of parasites inoculated in the footpad result in severe clinical disease. Here, we further investigate the outcome of the site of infection and concentration of L. braziliensis parasites inoculated on the immunopathogenesis and clinical evolution. Initially, hamsters were infected in the ear dermis or hind footpad with a concentration of 1x10⁵ parasites. Animals infected in the ear dermis developed a disease, with an increased parasite load that more closely resembled human CL lesions comparing to the group infected in the footpad. Next, we evaluated if different parasite concentrations (10⁴ , 10⁵ and 10⁶ ) inoculated in the ear dermis would impact the course and clinical aspects of infection. Hamsters infected with 10⁴ and 10⁵ parasites developed mild lesions compared to the group infected with 10⁶ that presented severe and persistent lesions. The parasite load varied between the different parasite concentrations. The inflammatory response was more intense when infection was initiated with 10⁶ parasites accompanied by an increased initial expression of IL-4, IL-10 and arginase in the lymph node followed by expression of both pro-and anti-inflammatory cytokines comparing to groups infected with 10⁴ and 10⁵ parasites. In conclusion, the number of parasites inoculated, and the initial site of infection could influence the inflammatory response, and clinical presentation. Our results suggest that the ear dermis infection model induces a chronic disease that relate to immunopathological aspects of CL natural infection.

Increased levels of cortisol are associated with the severity of experimental visceral leishmaniasis in a Leishmania (L.) infantum-hamster model

Background

Several infectious diseases are associated with hypothalamic-pituitary-adrenal (HPA) axis disorders by elevating circulating glucocorticoids (GCs), which are known to have an immunosuppressive potential. We conducted this study in golden hamsters, a suitable model for human visceral leishmaniasis (VL), to investigate the relationship of Leishmania (L.) infantum infection on cortisol production and VL severity.

Methods

L. infantum-infected (n = 42) and uninfected hamsters (n = 30) were followed-up at 30, 120, and 180 days post-infection (dpi). Plasma cortisol was analyzed by radioimmunoassay and cytokines, inducible nitric oxide synthase (iNOS), and arginase by RT-qPCR.

Results

All hamsters showed splenomegaly at 180 dpi. Increased parasite burden was associated with higher arginase expression and lower iNOS induction. Cortisol levels were elevated in infected animals in all-time points evaluated. Except for monocytes, all other leucocytes showed a strong negative correlation with cortisol, while transaminases were positively correlated. Immunological markers as interleukin (IL)-6, IL-1β, IL-10, and transforming growth-factor-β (TGF-β) were positively correlated to cortisol production, while interferon-γ (IFN-γ) presented a negative correlation. A network analysis showed cortisol as an important knot linking clinical status and immunological parameters.

Conclusions

These results suggest that L. infantum increases the systemic levels of cortisol, which showed to be associated with hematological, biochemical, and immunological parameters associated to VL severity.

Visceral leishmaniasis (VL) is an infectious disease that is common in most tropical countries. VL has high morbidity and leads to death if not properly treated. In Brazil, Leishmania (Leishmania) infantum is the main causative agent of VL. Golden hamsters have proven to be a suitable model for VL. Despite the importance of hypothalamic-pituitary-adrenal (HPA) axis disturbances in infectious disease, few studies have addressed this issue in VL. In this study, we showed that L. infantum-infected hamsters present augmented levels of plasmatic cortisol in association with increased spleen parasite burden. Indeed, a strong positive correlation was observed between cortisol and biochemical parameters (AST/ALT/ALP) related to liver damage, as well as pro-inflammatory cytokines (IL-6 and IL-1β), anti-inflammatory cytokines (IL-10 and TGF-β), and the arginase enzyme that may favor the progression of infection. On the other side, cortisol was negatively correlated with leucocytes, except monocytes, and with IFN-γ and iNOS, which are involved in parasite-killing macrophage function. These results shed light on an unexplored aspect of VL pathogenesis, which is the importance of cortisol production in the disease-associated immune dysfunction.

Corrigendum to "Nitazoxanide superiority to placebo to treat moderate COVID-19 - A Pilot prove of concept randomized double-blind clinical trial." [EClinicalMedicine 37 (2021) 100981]

[This corrects the article DOI: 10.1016/j.eclinm.2021.100981.].

Biomarkers of disease severity in patients with visceral leishmaniasis co-infected with HIV

Visceral leishmaniasis (VL) is caused by the protozoan Leishmania spp, transmitted by sand fly bites. VL is one of the deadliest tropical infection diseases, yet the coinfection with HIV virus drastically increases relapses, treatment failure and mortality. The concomitant action of these two pathogens leads to high cellular activation independently of the progression to AIDS. In addition, microbial translocation and bacterial infections are thought to contribute worsening the clinical picture. Identifying biomarkers associated with disease severity is of interest for clinical management of patients with VL-HIV/AIDS. Thus, we analyzed in the sera several markers including interleukins (IL-1β, IL-6, IL-8, and IL-17), interferon-γ (IFN- γ), tumor necrosis factor (TNF), lipopolysaccharide (LPS), soluble CD14 (sCD14), macrophage migration inhibitory factor (MIF) and intestinal fatty acid-binding protein (IFABP). These markers were compared with disease severity in 24 patients with VL/HIV presenting different clinical outcomes. Disease severity was defined by the probability of death calculated using a score set system derived by the Kala-Cal® software. Probability of death ranged from 3.7% to 97.9%, with median of 28.8%. Five patients died (20%). At the univariate analysis, disease severity was correlated with TNF, IFN-γ and sCD14. LPS was positively correlated with sCD14 specifically in patients with low CD4⁺ count (CD4⁺ T-cell <200 cells/mL). Most importantly, the multivariate analysis including LPS, CD4⁺count and sCD14 showed that sCD14 was the only independent predictor for disease severity and death. Altogether, our results indicated that sCD14 is a powerful marker of pathogenicity and death for patients with VL-HIV/AIDS.

Nitazoxanide superiority to placebo to treat moderate COVID-19 - A Pilot prove of concept randomized double-blind clinical trial

BACKGROUND

The absence of specific antivirals to treat COVID-19 leads to the repositioning of candidates' drugs. Nitazoxanide (NTZ) has a broad antiviral effect.

METHODS

This was a randomized, double-blind pilot clinical trial comparing NTZ 600 mg BID versus Placebo for seven days among 50 individuals (25 each arm) with SARS-COV-2 RT-PCR+ (PCR) that were hospitalized with mild respiratory insufficiency from May 20^th, 2020, to September 21^st, 2020 (ClinicalTrials.gov NCT04348409). Clinical and virologic endpoints and inflammatory biomarkers were evaluated. A five-point scale for disease severity (SSD) was used.

FINDINGS

Two patients died in the NTZ arm compared to 6 in the placebo arm (p = 0.564). NTZ was superior to placebo when considering SSD (p < 0001), the mean time for hospital discharge (6.6 vs. 14 days, p = 0.021), and negative PCR at day 21 (p = 0.035), whereas the placebo group presented more adverse events (p = 0.04). Among adverse events likely related to the study drug, 14 were detected in the NTZ group and 22 in placebo (p = 0.24). Among the 30 adverse events unlikely related, 21 occurred in the placebo group (p = 0.04). A decrease from baseline was higher in the NTZ group for d-Dimer (p = 0.001), US-RCP (p < 0.002), TNF (p < 0.038), IL-6 (p < 0.001), IL-8 (p = 0.014), HLA DR. on CD4⁺ T lymphocytes (p < 0.05), CD38 in CD4⁺ and CD8⁺ T (both p < 0.05), and CD38 and HLA-DR. on CD4+ (p < 0.01).

INTERPRETATION

Compared to placebo in clinical and virologic outcomes and improvement of inflammatory outcomes, the superiority of NTZ warrants further investigation of this drug for moderate COVID-19 in larger clinical trials. A higher incidence of adverse events in the placebo arm might be attributed to COVID-19 related symptoms.

A Cytokine Network Balance Influences the Fate of Leishmania (Viannia) braziliensis Infection in a Cutaneous Leishmaniasis Hamster Model

The golden hamster is a suitable model for studying cutaneous leishmaniasis (CL) due to Leishmania (Viannia) braziliensis. Immunopathological mechanisms are well established in the L. (L.) major-mouse model, in which IL-4 instructs a Th2 response towards progressive infection. In the present study, we evaluated the natural history of L. braziliensis infection from its first stages up to lesion establishment, with the aim of identifying immunological parameters associated with the disease outcome and parasitism fate. To this end, hamsters infected with 10⁴, 10⁵, or 10⁶ promastigotes were monitored during the first hours (4h, 24h), early (15 days, 30 days) and late (50 days) post-infection (pi) phases. Cytokines, iNOS and arginase gene expression were quantified in the established lesions by reverse transcription-quantitative PCR. Compared to the 10⁵ or 10⁶ groups, 10⁴ animals presented lower lesions sizes, less tissue damage, and lower IgG levels. Basal gene expression in normal skin was high for TGF-β, and intermediary for TNF, IL-6, and IL-4. At 4hpi, no cytokine induction was observed in the 10⁴ group, while an upregulation of IL-6, IL-10, and IL-4 was observed in the 10⁶ group. At 15dpi, lesion appearance was accompanied by an increased expression of all assessed cytokines, markedly in the 10⁵ and 10⁶ groups. Upregulation of all investigated cytokines was observed in the late phase, although less expressive in the 10⁴ group. IFN-γ was the depending variable influencing tissue damage, while IL-6 was associated to parasite load. The network correlating gene expression and clinical and laboratorial parameters indicated inoculum-independent associations at 15 and 30dpi. A strong positive network correlation was observed in the 10⁴ group, but not in the 10⁵ or 10⁶ groups. In conclusion, IL-4, IL-6, IL-10, and TGF-β are linked o L. braziliensis progression. However, a balanced cytokine network is the key for an immune response able to reduce the ongoing infection and reduce pathological damage.

High Frequency of Cryptosporidium hominis Infecting Infants Points to A Potential Anthroponotic Transmission in Maputo, Mozambique

Cryptosporidium is one of the most important causes of diarrhea in children less than 2 years of age. In this study, we report the frequency, risk factors and species of Cryptosporidium detected by molecular diagnostic methods in children admitted to two public hospitals in Maputo City, Mozambique. We studied 319 patients under the age of five years who were admitted due to diarrhea between April 2015 and February 2016. Single stool samples were examined for the presence of Cryptosporidium spp. oocysts, microscopically by using a Modified Ziehl-Neelsen (mZN) staining method and by using Polymerase Chain Reaction and Restriction Fragment Length Polymorphism (PCR-RFLP) technique using 18S ribosomal RNA gene as a target. Overall, 57.7% (184/319) were males, the median age (Interquartile range, IQR) was 11.0 (7-15) months. Cryptosporidium spp. oocysts were detected in 11.0% (35/319) by microscopy and in 35.4% (68/192) using PCR-RFLP. The most affected age group were children older than two years, [adjusted odds ratio (aOR): 5.861; 95% confidence interval (CI): 1.532-22.417; p-value < 0.05]. Children with illiterate caregivers had higher risk of infection (aOR: 1.688; 95% CI: 1.001-2.845; p-value < 0.05). An anthroponotic species C. hominis was found in 93.0% (27/29) of samples. Our findings demonstrated that cryptosporidiosis in children with diarrhea might be caused by anthroponomic transmission.

Epidemiology of Giardia duodenalis assemblages in Brazil: there is still a long way to go

Giardia duodenalis infection is distributed worldwide and can achieve prevalence around 60%, especially in developing countries. This protozoan is divided into eight assemblages, in which A and B have high zoonotic potential, whereas C to H are host-specific. This scenario is changing as molecular studies progress, highlighting that knowledge on host-specificity still has a long way to go. Understanding the players involved in transmission routes enables rational designs of control strategies. Considering the high prevalence of giardiasis, this review aims to gather together the data on available studies on the distribution of G. duodenalis assemblages in Brazil until September 2020.

Recirculation of Giardia lamblia Assemblage A After Metronidazole Treatment in an Area With Assemblages A, B, and E Sympatric Circulation

Giardia lamblia is an intestinal protozoan subdivided into eight assemblages, labeled alphabetically from A to H. Assemblages A, B, and E infect humans and can have a sympatric circulation. We investigated the assemblage recirculation in children living within a high prevalence area of Giardia infection. One hundred and ninety-four children were evaluated and 85 tested positive for Giardia by PCR. These infected individuals were recruited, treated with metronidazole and then reexamined for infections at 20 and 40 days after treatment that included PCR and the genotyping was performed by sequencing beta-giardin and glutamate dehydrogenase gene targets. Giardia assemblages A (n = 43), B (n = 21), E (n = 17), and A/E (n = 4) were identified in infected children. Assemblage A was found in all reoccurrences of infection, including four that had been infected by assemblages B and E. Since both persistence and reinfection could account for the results, the level of nucleotide homology was determined before and after treatment. Most suggested that reinfections were by the same strain, but four presented a distinct genotypic profile. The results suggest that the differences in the genotypic profiles were due to reinfections, which appear to occur with frequency in high Giardia burden areas and soon after the end of therapy. It is not yet possible to define whether the recurrent cases were related to parasite resistance. However, the evidence of rapid reinfections and ready availability of treatment raises the potential for creating resistant strains. This highlights the need to address how Giardia burden is maintained within high prevalence areas.

In vitro-induction of metronidazole-resistant Giardia duodenalis is not associated with nucleotide alterations in the genes involved in pro-drug activation

Giardiasis is an infectious disease caused by Giardia duodenalis. The pro-drug metronidazole (MTZ) is the first-line treatment for giardiasis. Parasite’s proteins as pyruvate:ferredoxin oxidoreductase (PFOR), ferredoxin (Fd), nitroreductase-1 (NR-1) and thioredoxin reductase (TrxR) participate in MTZ activation. Here, we showed Giardia trophozoites long-term exposed to MTZ presented higher IC₅₀ than controls, showing the drug influenced the parasite survival. That reduction in MTZ’s susceptibility does not seem to be related to mutations in the genes pfor, fd, nr-1 or trxr. It points that different mechanism as alterations in other metabolic pathways can account for Giardia resistance to MTZ therapy.

Impaired Thymic Output Can Be Related to the Low Immune Reconstitution and T Cell Repertoire Disturbances in Relapsing Visceral Leishmaniasis Associated HIV/AIDS Patients

Background: Visceral leishmaniasis/HIV-co-infected patients (VL/HIV) accounts for around 8% of VL reported cases in Brazil. Relapses of Leishmania infection after anti-leishmanial treatment constitute a great challenge in the clinical practice because of the disease severity and drug resistance. We have shown that non-relapsing-VL/HIV (NR-) evolved with increase of CD4⁺ T-cell counts and reduction of activated CD4⁺ and CD8⁺ T cells after anti-leishmanial treatment. This immune profile was not observed in relapsing-VL/HIV patients (R-), indicating a more severe immunological compromising degree. Elevated activation status may be related to a deficient immune reconstitution and could help to explain the frequent relapses in VL/HIV co-infection. Our aim was to evaluate if this gain of T cells was related to changes in the peripheral TCRVβ repertoire and inflammatory status, as well as the possible thymus involvement in the replenishment of these newly formed T lymphocytes.

Methods: VL/HIV patients, grouped into non-relapsing (NR- = 6) and relapsing (R- = 12) were evaluated from the active phase up to 12 months post-treatment (mpt). HIV-infected patients (non-VL) and healthy subjects (HS) were included. The TCRVβ repertoire was evaluated ex vivo by flow cytometry, whereas the plasmatic cytokine levels were assessed by Luminex assay. To evaluate the thymic output, DNA was extracted from PBMCs for TCR rearrangement excision circles (TREC) quantification by qPCR.

Results: VL/HIV cases presented an altered mobilization profile (expansions or retractions) of the TCRVβ families when compared to HS independent of the follow-up phase (p < 0.05). TCRVβ repertoire on CD4⁺ T-cells was more homogeneous in the NR-VL/HIV cases, but heterogeneous on CD8⁺ T-cells, since different Vβ-families were mobilized. NR-VL/HIV had the inflammatory pattern reduced after 6 mpt. Importantly, VL/HIV patients showed number of TREC copies lower than controls during all follow-up. An increase of recent thymic emigrants was observed in NR-VL/HIV individuals at 10 mpt compared to R- patients (p < 0.01), who maintained lower TREC contents than the HIV controls.

Conclusions: VL/HIV patients that maintain the thymic function, thus generating new T-cells, seem able to replenish the T lymphocyte compartment with effector cells, then enabling parasite control.

CD49d Is Upregulated in Circulating T Lymphocytes from HTLV-1-Infected Patients

INTRODUCTION

HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic progressive myelopathy associated with an inflammation of the central nervous system (CNS), being characterized by perivascular infiltration of inflammatory cells. HTLV-1-infected cells have the capacity to migrate through endothelial layers by enhancing adhesion receptor expression and corresponding ligands. T cells interact with the extracellular matrix via integrin receptors and these interactions affect both cell migration and proliferation. The importance of these interactions in retrovirus-induced diseases, however, remains less clear.

METHODS

Herein we studied the expression of 3 integrin alpha chains (CD49d, CD49e, and CD49f) on the membrane of T-cell subsets in patients infected by HTLV-1, both HAM/TSP patients and oligo/asymptomatic subjects who were asymptomatic or presented slight manifestations related to the virus infection.

RESULTS

We observed higher peripheral blood frequency of CD49dhiCD4+ and CD49dhiCD8+ T cells in HTLV-1-infected patients.

CONCLUSION

Our findings suggest that the increased expression of adhesion molecules, such as CD49d on T lymphocytes from HTLV-1-infected patients may contribute to the pathogenesis of the disease, in both oligo/asymptomatic and HAM/TSP-infected subjects. Accordingly, it is conceivable that there is a potential use of CD49d as target for a therapeutic approach aiming at blocking migration of activated T cells from HTLV-1-infected patients into the CNS, thus avoiding the progression to HAM/TSP.

Ascaris lumbricoides coinfection reduces tissue damage by decreasing IL-6 levels without altering clinical evolution of pulmonary tuberculosis or Th1/Th2/Th17 cytokine profile

INTRODUCTION

Immunological control of Mycobacterium tuberculosis infection is dependent on the cellular immune response, mediated predominantly by Th1 type CD4+ T cells. Polarization of the immune response to Th2 can inhibit the host immune protection against pathogens. Patients with tuberculosis coinfected with helminths demonstrate more severe pulmonary symptoms, a deficiency in the immune response against tuberculosis, and an impaired response to anti-tuberculosis therapy.

METHODS

We evaluated the cellular immune response and the impact of the presence of Ascaris lumbricoides on the immune and clinical response in pulmonary tuberculosis patients. Ninety-one individuals were included in the study: 38 tuberculosis patients, 11 tuberculosis patients coinfected with Ascaris lumbricoides and other helminths, 10 Ascaris lumbricoides patients, and 34 non-infected control individuals. Clinical evolution of pulmonary tuberculosis was studied on 0, 30, 60, and 90 days post-diagnosis of Mycobacterium tuberculosis and Ascaris lumbricoides. Furthermore, immune cells and plasma cytokine profiles were examined in mono/coinfection by Mycobacterium tuberculosis and Ascaris lumbricoides using flow cytometry.

RESULTS

There were no statistical differences in any of the evaluated parameters and the results indicated that Ascaris lumbricoides infection does not lead to significant clinical repercussions in the presentation and evolution of pulmonary tuberculosis.

CONCLUSIONS

The association with Ascaris lumbricoides did not influence the Th1, Th2, and Th17 type responses, or the proportions of T lymphocyte subpopulations. However, higher serum levels of IL-6 in tuberculosis patients may explain the pulmonary parenchymal damage.

First report of treatment failure in a patient with cutaneous leishmaniasis infected by Leishmania (Viannia) naiffi carrying Leishmania RNA virus: a fortuitous combination?

We report the case of a 32-year-old man from Rio de Janeiro, who was infected in the Amazon region of Brazil by Leishmania (Viannia) naiffi. Generally, patients with L. naiffi cutaneous leishmaniasis exhibit a good therapeutic response to either pentavalent antimonials or pentamidine. However, after pentamidine treatment, this patient's infection evolved to therapeutic failure. To understand this clinical outcome, we investigated the presence of the Leishmania RNA virus (LRV) in parasites isolated from the cutaneous lesion; herein, we discuss the possible association between a poor response to pentamidine therapy and the presence of the LRV.

The presence of Giardia lamblia assemblage A in dogs suggests an anthropozoonotic cycle of the parasite in Rio de Janeiro, Brazil

BACKGROUND

Giardia lamblia is a zoonotic protozoan that is classified into 8 genotypes and is distributed worldwide. Assemblages A and B were found to infect dogs and humans, whereas assemblages C and D are dog host-specific. Our objective was to investigate the G. lamblia genotypes circulating in a canine population in Rio de Janeiro, RJ.

RESULTS

Sixty stool samples positive for G. lamblia from street dogs were characterized. Fragments of the conserved genes encoding beta-giardin (β-gia) and glutamate dehydrogenase (gdh) were used as targets. The sequences from beta-giardin and glutamate dehydrogenase genes obtained from all 60 dog samples were 100% similar to G. lamblia genotype A.

CONCLUSION

The detection of genotype A suggests that G. lamblia transmission in Rio de Janeiro has a predominantly anthropozoonotic cycle.

CD3+CD4negCD8neg (double negative) T lymphocytes and NKT cells as the main cytotoxic-related-CD107a+ cells in lesions of cutaneous leishmaniasis caused by Leishmania (Viannia) braziliensis

Background

Cutaneous leishmaniasis (CL) is caused by Leishmania (Viannia) braziliensis, which infects dermal macrophages and dendritic cells, causing an intense immune-mediated-tissue inflammation and a skin ulcer with elevated borders that can heal spontaneously or after antimonial therapy. The resolution of lesions depends on an adaptive immune response, and cytotoxic cells seem to have a fundamental role in this process. The aim of this study is to better understand the role of cytotoxicity mediated mechanisms that occur during the immune response in the CL lesion milieu, considering distinct cytotoxic-related CD107a⁺ cells, such as CD8⁺, CD4⁺, CD4^neg CD8^neg (double-negative, DN) and CD4⁺CD8⁺ (double-positive, DP) T lymphocytes, as well as NK and NKT cells.

Methods

Lesion derived cells were assessed for T cell subpopulations and NK cells, as well as CD107a expression by flow cytometry. In addition, cytometric bead array (CBA) was used to quantify cytokines and granzyme B concentrations in supernatants from macerated lesions.

Results

Flow cytometry analyses revealed that NKT cells are the major CD107a-expressing cell population committed to cytotoxicity in CL lesion, although we also observed high frequencies of CD4⁺ and DN T cells expressing CD107a. Analysing the pool of CD107a⁺-cell populations, we found a higher distribution of DN T cells (44%), followed by approximately 25% of NKT cells. Interestingly, NK and CD8⁺ T cells represented only 3 and 4% of the total-CD107a⁺-cell pool, respectively.

Conclusions

The cytotoxicity activity that occurs in the lesion milieu of CL patients seems to be dominated by DN T and NKT cells. These findings suggest the need for a reevaluation of the role of classical-cytotoxic NK and CD8⁺ T cells in the pathogenesis of CL, implicating an important role for other T cell subpopulations.

Functional complementation of Leishmania (Leishmania) amazonensis AP endonuclease gene (lamap) in Escherichia coli mutant strains challenged with DNA damage agents

During its life cycle Leishmania spp. face several stress conditions that can cause DNA damages. Base Excision Repair plays an important role in DNA maintenance and it is one of the most conserved mechanisms in all living organisms. DNA repair in trypanosomatids has been reported only for Old World Leishmania species. Here the AP endonuclease from Leishmania (L.) amazonensis was cloned, expressed in Escherichia coli mutants defective on the DNA repair machinery, that were submitted to different stress conditions, showing ability to survive in comparison to the triple null mutant parental strain BW535. Phylogenetic and multiple sequence analyses also confirmed that LAMAP belongs to the AP endonuclease class of proteins.

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.

Development of real-time PCR assays for evaluation of immune response and parasite load in golden hamster (Mesocricetus auratus) infected by Leishmania (Viannia) braziliensis

Background

Cutaneous leishmaniasis (CL) is a neglected disease with a broad spectrum of clinical manifestations, ranging from small cutaneous nodules to severe mucosal tissue destruction. Leishmania (Viannia) braziliensis is the main species attributed to CL in the Americas. However, studies of experimental infection are limited in the murine model due to the self-resolutive pattern of the disease. Previously, our group demonstrated that the hamster model reproduces many of the clinical and histopathological features observed in humans. Herein, we standardized a RT-qPCR gene expression assay to evaluate a panel of immunological markers and a qPCR assay in order to quantify with high sensitivity and reproducibility the parasite load in skin lesions.

Methods

Hamsters were intradermally infected in the footpad with 10⁵ promastigotes of L. (V.) braziliensis and 110 days post-infection skin lesions and popliteal lymph nodes were removed for RNA and DNA extraction, both from the same tissue fragment. Gene expression of IFN-ɣ, IL-10, TGF-β TNF, IL-4, IL-6, iNOS and arginase were measured using non-infected animal tissue as a calibrator. Parasite load was quantified from DNA extracted from lesions by qPCR targeting Leishmania kDNA and normalized by hamster GAPDH, using a SYBR Green-based absolute quantification methodology.

Results

A relative quantification RT-qPCR assay was standardized for the evaluation of mRNA levels from skin and lymph node samples of golden hamsters, with PCR efficiencies ranging from 92.3 to 116.4 %. In uninfected animals, higher basal mRNA levels in lymph nodes were observed for IFN-ɣ, TGF-β, TNF and IL-4 (111.4 ± 92.2; 5.6 ± 1.2; 5.3 ± 1.7; and 60.3 ± 26.8, respectively) in comparison to skin. In golden hamsters infected with L. (V.) braziliensis, an increase in the expression of all immunological markers evaluated was observed, ranging from 2.7 ± 0.2 for TGF-β to 1018.5 ± 809.0 for iNOS in skin lesions, and 2.4 ± 1.6 for TGF-β to 600.2 ± 666.4 for iNOS in popliteal lymph nodes. Interestingly, significantly higher levels of IFN-ɣ, TNF and IL-10 mRNA were observed in skin in comparison to lymph nodes, while a lower significant level of arginase mRNA was observed in skin. In parallel, parasite loads were quantified by qPCR from the skin lesions of infected animals, ranging from 27.0 to 6647.0, with a median of 553.4 (416.7–1504.0) parasites/mg skin equivalents, whereas lesion size varied from 0.3 to 3.1 mm. Despite the tendency of larger lesions to present higher parasite load, the correlation observed was not statistically significant.

Conclusions

In this study, we describe for the first time a sensitive, reproducible and cheaper molecular assay to quantify from the same tissue fragment the gene expression of immunological markers and the parasite load in skin lesions, observing a mixed profile of immune response in the hamster model infected by L. (V.) braziliensis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-016-1647-6) contains supplementary material, which is available to authorized users.

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.

Leishmania (Viannia) naiffi: rare enough to be neglected?

In the Brazilian Amazon, American tegumentary leishmaniasis (ATL) is endemic and presents a wide spectrum of clinical manifestations due, in part, to the circulation of at least seven Leishmania species. Few reports of Leishmania (Viannia) naiffi infection suggest that its occurrence is uncommon and the reported cases present a benign clinical course and a good response to treatment. This study aimed to strengthen the clinical and epidemiological importance of L. (V.) naiffi in the Amazon Region (Manaus, state of Amazonas) and to report therapeutic failure in patients infected with this species. Thirty Leishmania spp samples isolated from cutaneous lesions were characterised by multilocus enzyme electrophoresis. As expected, the most common species was Leishmania (V.) guyanensis (20 cases). However, a relevant number ofL. (V.) naiffi patients (8 cases) was observed, thus demonstrating that this species is not uncommon in the region. No patient infected withL. (V.) naiffi evolved to spontaneous cure until the start of treatment, which indicated that this species may not have a self-limiting nature. In addition, two of the patients experienced a poor response to antimonial or pentamidine therapy. Thus, either ATL cases due to L. (V.) naiffi cannot be as uncommon as previously thought or this species is currently expanding in this region.

Tegumentary leishmaniasis in the State of Amazonas: what have we learned and what do we need?

This study evaluated the occurrence of American tegumentary leishmaniasis (ATL) in the State of Amazonas, Brazil, in the last 30 years with emphasis on the last 10 years (2001 to 2010). The disease was predominantly observed in males (76.2%), in the 21- to 30-year-old age group (26.6%) and in extractive workers (43.7%); 3.3% of the cases were the mucosal form. The endemic channel shows the disease seasonality, with a predominance of cases at the beginning and end of each year. The number of cases by municipality in the period of 2001-2010 shows the maintenance of the endemic in the localities where the highest numbers of cases have always been registered, namely, Manaus, Rio Preto da Eva, Itacoatiara and Presidente Figueiredo. The comparison of data from 2001 to 2005 and from 2006 to 2010 showed the emergence of this disease in municipalities that had been previously unaffected. In the last years, there has been a significant increase in the activities of control, diagnosis and treatment of leishmaniasis in the State of Amazonas. In conclusion, the historical series of ATL analyzed in this study suggests that the transmission foci remain and are even expanding, though without continuous transmission in the intra- or peridomicile settings. Moreover, the disease will persist in the Amazon while the factors associated with infection acquisition relative to forest exploitation continue to have economic appeal. There is a real expectation of wide variations in disease incidence that can be influenced by climate and economic aspects.

T-cell receptor Vβ repertoire of CD8+ T-lymphocyte subpopulations in cutaneous leishmaniasis patients from the state of Rio de Janeiro, Brazil

In human cutaneous leishmaniasis (CL), the immune response is mainly mediated by T-cells. The role of CD8⁺ T-lymphocytes, which are related to healing or deleterious functions, in affecting clinical outcome is controversial. The aim of this study was to evaluate T-cell receptor diversity in late-differentiated effector (LDE) and memory CD8⁺ T-cell subsets in order to create a profile of specific clones engaged in deleterious or protective CL immune responses. Healthy subjects, patients with active disease (PAD) and clinically cured patients were enrolled in the study. Total CD8⁺ T-lymphocytes showed a disturbance in the expression of the Vβ2, Vβ9, Vβ13.2, Vβ18 and Vβ23 families. The analyses of CD8⁺T-lymphocyte subsets showed high frequencies of LDE CD8⁺T-lymphocytes expressing Vβ12 and Vβ22 in PAD, as well as effector-memory CD8⁺ T-cells expressing Vβ22. We also observed low frequencies of effector and central-memory CD8⁺ T-cells expressing Vβ2 in PAD, which correlated with a greater lesion size. Particular Vβ expansions point to CD8⁺ T-cell clones that are selected during CL immune responses, suggesting that CD8⁺ T-lymphocytes expressing Vβ12 or Vβ22 are involved in a LDE response and that Vβ2 contractions in memory CD8⁺T-cells are associated with larger lesions.

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

BACKGROUND

Leishmaniasis is an important parasitic disease affecting millions worldwide. Human cutaneous leishmaniasis (CL) is endemic in Rio de Janeiro, Brazil, where is caused by Leishmania braziliensis. The adaptive immune response is accountable for the healing of CL and despite of key role of CD8+ T cells in this immune response little is known about the CD8+ T lymphocytes frequencies, apoptosis and antigen-responsive CD8+ T lymphocytes of CL patients during antimonial therapy.

METHODS

Using flow cytometry, we examined total and effector CD8+ T cells from CL patients before (PBT), during (PDT) and after (PAT) treatment for apoptosis and frequencies upon isolation and after in vitro L. braziliensis antigens (LbAg)-stimulation culture. Besides, a correlation study between immunological findings and lesion size was done.

RESULTS

PDT showed lower frequencies of total CD8+ T lymphocytes and higher levels of apoptosis of these cells, which were also observed following LbAg-stimulation culture. Regarding effector CD8+ T cells, high frequencies were observed in PDT, while lower frequencies were observed in PAT. Interestingly, PDT showed higher frequencies of apoptotic-effector CD8+ T lymphocytes. Similar results were seen after in vitro antigenic-stimulation assays. Correlation analysis showed that the greater the size of lesion, the smaller the frequency of effector CD8+ T lymphocytes in PDT and PAT, as well as a positive correlation between apoptotic-effector CD8+ T cells frequency and lesion size of PDT.

CONCLUSIONS

Changes in effector CD8+ T-lymphocyte frequencies, during and after treatment, seem to represent a critical stage to generate an efficient immune response and suggest that these cells would be evolved in the triggering or in the resolution of lesion, under the influence of therapy. This hypothesis opens new perspectives to clarify controversial statements about the protective or deleterious role of CD8+ T cells in the cure or aggravation of CL and the new approach of evaluating patients during treatment proved to be of utmost importance for understanding the immune response in the healing process of human CL.

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.

Enhanced T cell activation in Plasmodium falciparum malaria-infected human immunodeficiency virus-1 patients from Mozambique

Human immunodeficiency virus (HIV)-1 infection has an important impact on malaria. Plasmodium falciparum and HIV-1 co-infected patients (Pf/HIV) present with a high degree of anaemia, enhanced parasitaemia and decreased CD4⁺ T cell counts, which increase the risk of developing severe malaria. In addition, infection with either Pf or HIV-1 alone causes extensive immune activation. Our hypothesis was that lymphocyte activation is potentiated in Pf/HIV co-infected patients, consequently worsening their immunosuppressed state. To test this hypothesis, 22 Pf/HIV patients, 34 malaria patients, 29 HIV/AIDS patients and 10 healthy controls without malaria or HIV/acquired immune deficiency syndrome (AIDS) from Maputo/Mozambique were recruited for this study. As expected, anaemia was most prevalent in the Pf/HIV group. A significant variation in parasite density was observed in the Pf/HIV co-infected group (110-75,000 parasites/µL), although the median values were similar to those of the malaria only patients. The CD4⁺ T cell counts were significantly lower in the Pf/HIV group than in the HIV/AIDS only or malaria only patients. Lymphocyte activation was evaluated by the percentage of activation-associated molecules [CD38 expression on CD8⁺ and human leukocyte antigen-DR expression on CD3⁺ T cells]. The highest CD38 expression was detected in the Pf/HIV co-infected patients (median = 78.2%). The malaria only (median = 50%) and HIV/AIDS only (median = 52%) patients also exhibited elevated levels of these molecules, although the values were lower than those of the Pf/HIV co-infected cases. Our findings suggest that enhanced T-cell activation in co-infected patients can worsen the immune response to both diseases.

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.

HIV/AIDS-associated visceral leishmaniasis in patients from an endemic area in Central-west Brazil

An increase in morbidity associated with visceral leishmaniasis (VL) in human immunodeficiency virus (HIV)/AIDS patients has been described in Africa and the Mediterranean. Despite the high endemicity of VL and HIV-1/AIDS in Brazil, this association has not been thoroughly investigated. Our aim was to evaluate the epidemiologic and clinical characteristics of VL-HIV-1/AIDS cases from Central-west [Mato Grosso do Sul (MS)] Brazil. Medical records of 23 VL-HIV-1/AIDS patients were reviewed. Patients were predominantly adult males (87%) and 34.8% of the patients were intravenous drug users (IVDU). Leishmaniasis was the first opportunistic infection in 60% of the HIV-1 patients. Fever occurred in all patients, although splenomegaly and hepatomegaly were absent in 21.7% of the cases. CD4+ T-cell counts were below 200 cells/mm(3) in 80% of the cases and the counts did not increase after clinical remission despite antiretroviral therapy. The first drug chosen to treat the cases was antimonial, but the therapeutic regimen was altered to amphotericin B in 12 of 17 cases due to side effects. Relapses were reported in 56.5% of the patients. IVDU may constitute an important risk factor for the transmission of both diseases in MS. VL-HIV-1/AIDS patients in MS share similar clinical characteristics as those from other endemic regions worldwide. Thus, these findings are critical for improving the surveillance of VL-HIV/AIDS 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.

Differences in the antigenic profile and infectivity of murine macrophages of Leishmania (Viannia) parasites

The antigenic profile and infectivity were compared between 3 recent Leishmania (Viannia) isolates from the Amazonian region (Instituto Nacional de Pesquisas da Amazonia [INPA] strains) and 3 World Health Organization (WHO) reference species (Leishmania guyanensis, Leishmania braziliensis, and Leishmania naiffi). Differences were observed in the peak and extent of promastigote growth. The WHO reference strains exhibited significantly higher exponential growth as promastigotes than INPA strains. In the immunoblot analyses, the INPA strains revealed several specific peptide fragments, as well as the greatest recognition frequencies by sera from Leishmania sp.-infected patients; among the latter, antigens derived from L. naiffi were the most frequently recognized. In vitro infection was carried out using mice peritoneal macrophages; all strains were able to enter the macrophages, but only L. amazonensis was able to reproduce. A striking observation was that L. naiffi exhibited the longest survival time inside the macrophages. Our data strongly suggest the application of recently isolated parasites as sources of antigen for diagnosis procedures. Moreover, L. naiffi species possesses several characteristics relevant for its use as a source of novel antigens to be explored in the design of diagnostic tools and vaccines.

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.

Leishmania (Viannia) guyanensis induces low immunologic responsiveness in leishmaniasis patients from an endemic area of the Brazilian Amazon Highland

Cutaneous leishmaniasis caused by Leishmania (Viannia) guyanensis (CL-Lguy) is endemic in the Brazilian Amazon, differing from L. braziliensis infection in clinical, diagnostic, and therapeutic aspects. T-cell reactivity to leishmanial antigens possibly involved in the pathogenesis of CL-Lguy was studied herein. Variable lymphoproliferative responses (LPRs) to Leishmania antigens were found among the 23 studied patients, and 50% of them showed low or no response to these antigens. Active disease was associated with an enrichment of leishmanial-reactive T lymphocytes, mainly TCD4(+). High and low interferon (IFN)-gamma producers were observed. TNF-alpha, interleukin (IL)-10, and IL-5 were consistently detected. CL-Lguy displayed low antibody response in comparison to L. braziliensis patients. CL caused by L. braziliensis presented positive LPRs and higher IFN-gamma production but undetectable IL-5. L. guyanensis seems to induce a down-regulation of the immune system compared with L. braziliensis. This finding could explain some aspects of clinical presentation of CL-Lguy, such as high tissue parasite burden and frequent resistance to therapy.

Clinical features of cutaneous and disseminated cutaneous leishmaniasis caused by Leishmania (Viannia) braziliensis in Paraty, Rio de Janeiro

BACKGROUND

American tegumentary leishmaniasis (ATL) caused by Leishmania (Viannia) braziliensis is endemic in Rio de Janeiro State (RJ), where the disease shows epidemiologic and clinical characteristics distinct from those of ATL in other Brazilian regions. Paraty is the second most important endemic area in RJ; however, reports on leishmaniasis in this region refer to the occurrence of the disease without describing its characteristics.

METHODS

The clinical features of 71 cases of ATL reported between 1991 and 1997 in Paraty are presented. Thirty patients were re-evaluated 10 years later.

RESULTS

Males and females were affected in similar proportions, and the disease was more prevalent in patients aged between 10 and 49 years (63.4%). Cutaneous leishmaniasis was the most prevalent clinical form observed. Unique lesions were present in 69% of cases, 91.6% of which displayed an ulcerated aspect. Although mucosal leishmaniasis was not observed, severe clinical manifestations, such as disseminated cutaneous lesions caused by L. braziliensis, were diagnosed in two patients. These patients presented skin lesions with different clinical aspects spread throughout the body, as well as low cellular immune responses. Montenegro skin test (92% positivity) and serology (8% IgM and 56% IgG anti-Leishmania positive results) were the most utilized tests for supporting the diagnosis of leishmaniasis. Parasites, detected in 27 of the 33 cases analyzed, were characterized as L. braziliensis.

CONCLUSION

ATL in Paraty shares the clinical and laboratory characteristics reported for ATL in other regions of RJ, probably because of the similar epidemiologic context related to the Atlantic rainforest region.

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.

Parasitological and immunological follow-up of American tegumentary leishmaniasis patients

A long-term evaluation of human American tegumentary leishmaniasis patients was conducted to detect immunological and/or parasitological indicators associated with cure or protection against leishmaniasis. Cutaneous leishmaniasis (CL) and mucosal leishmaniasis (ML) patients from endemic areas of Leishmania braziliensis infection in Brazil were studied during the active disease, at the end of therapy, and up to 10 years after the end of therapy. For immunological studies, lymphocyte proliferative responses, phenotypic characterization of CD4+ and CD8+ T cells reactive to L. braziliensis and cytokine production in vitro were assayed. In CL, with its tendency for healing lesions, at or shortly after the completion of therapy the ratio of CD4+ to CD8+ T cells was approximately one and production of interferon gamma (IFN gamma) remained roughly constant. In ML, these apparently beneficial CD4+/CD8+ ratios and cytokine patterns appeared later. The long-term memory T cell responses were associated with preferential induction of CD4+ subpopulations and IFN gamma production that probably led to protection against relapses or reinfection. Deoxyribonucleic acid (DNA) was isolated from peripheral blood and oligonucleotides that amplify the conserved region of the minicircle molecules of Leishmania were used in a 'hot-start' polymerase chain reaction (PCR). Leishmania DNA was found in about one-quarter of the patients with active disease as well as in individuals who had received chemotherapy. The PCR was also positive in one-third of the individuals with a positive skin test but no past or present history of leishmaniasis. The well-modulated T cell response leading to long-term protection observed in CL patients could result from a favourable host genetic background and/or a particular parasite genotype, leading to a beneficial T cell immune response even in the presence of parasite antigens. The possibility of parasite persistence after clinical cure suggests that the immune response can control, but not fully eliminate, the infection. It could prevent the parasite from causing disease, maintaining a leishmanial antigen-specific response and hampering reinfection.

T-cell-mediated immune responses in patients with cutaneous or mucosal leishmaniasis: long-term evaluation after therapy

T-cell immune responses in patients with cutaneous leishmaniasis (CL) and mucosal leishmaniasis (ML) were studied during the active disease, at the end of therapy, and 1 to 17 years posttherapy (long-term follow-up). Lymphocyte proliferative responses, phenotypic characterization of CD4(+) and CD8(+) Leishmania-reactive T cells, and cytokine production were assayed. Patients with active ML and CL showed higher proportions of CD4(+) than CD8(+) T cells. In CL, the healing process was associated with a decrease of CD4(+) and an increase of CD8(+), leading to similar CD4(+) and CD8(+) proportions. This pattern was only seen in ML after long-term therapy. Long-term follow-up of patients with CL showed a positive CD4(+)/CD8(+) ratio as observed during the active disease, although the percentages of these T cell subsets were significantly lower. Patients with CL did not show significant differences between gamma interferon (IFN-gamma) and interleukin-5 (IL-5) production during the period of study. Patients with active ML presented higher IFN-gamma and IL-5 levels compared to patients with active CL. IL-4 was only detected during active disease. Patients long term after cure from ML showed increasing production of IFN-gamma, significant decrease of IL-5, and no IL-4 production. Two apparently beneficial immunological parameters were detected in tegumentary leishmaniasis: (i) decreasing proportions of CD4(+) Leishmania-reactive T cells in the absence of IL-4 production associated with cure of CL and ML and (ii) decreasing levels of IL-5 long after cure, better detected in patients with ML. The observed T-cell responses maintained for a long period in healed patients could be relevant for immunoprotection against reinfection and used as a parameter for determining the prognosis of patients and selecting future vaccine preparations.