Immune response markers in sera of children infected with Giardia duodenalis AI and AII subassemblages.

In this study, we evaluated serum markers of immune responses in children infected with G. duodenalis and compared them with the characterized parasite isolates. The reactivity indexes (RI) of IgG (1.503 ± 0.819) and IgA (2.308 ± 1.935) antibodies were significantly higher (P < 0.001) in infected children than in non-infected children. There were also statistically significantly higher serum levels (P < 0.05) of IFN-γ (393.10 ± 983.90 pg/mL) as well as serum (30.03 ± 10.92 µmol/L) and saliva nitric oxid derivatives (NOx) (192.4 ± 151.2 µmol/L) in children infected with G. duodenalis compared to the group of non-parasitized children (127.4 ± 274.30 pg/mL; 25.82 ± 7.74 µmol/L and 122.5 ± 105.90 µmol/L, respectively). Regarding the characterized genetic variants of G. duodenalis and the immune response profiles, no differences were observed in terms of antibody reactivity or levels of serum cytokine and NOx among children infected with AI or AII subassemblages. The elevated levels of IFN-γ and NOx indicate that G. duodenalis intestinal infection in humans induces a cellular immune response detectable at the systemic level. Moreover, no significant differences in the antibody reactivity profile or the cytokine and NOx production in the sera of children infected with AI or AII G. duodenalis variants were observed, suggesting that subtypes of the parasite do not influence the immune response profile.

Impaired immunoregulatory network of the CD4 T lymphocytes in refractory asthma.

BACKGROUND: The immunopathogenesis of severe asthma has been associated with an inefficient regulatory response. There are a few studies about the CD4 T cells profile among individuals with severe asthma refractory to treatment. OBJECTIVE: To evaluate the CD4 T lymphocyte profile from individuals with severe asthma according to their response to treatment, relating to their atopy status and age of asthma onset. METHODS: We evaluated nineteen individuals with severe asthma refractory to treatment (SAR), 21 with well-controlled or partly controlled severe asthma (CSA) and 23 with mild-to-moderate asthma (MMA). Lymphocytes were obtained from PBMC, and the frequency of expression of different molecules in this population was assessed using the flow cytometry. RESULTS: We observed the frequency of CD4+ IFN-γ+ T cells was higher in atopic individuals with SAR than with CSA. In addition, among the atopic and early-onset asthma (EOA), the frequency of CD4+ CTLA-4+ T cells was lower in the SAR group than the CSA group. In relation to non-atopic and late-onset asthma (LOA) phenotypes, we noted the frequency of CD4+ FoxP3+ T cells was lower in individuals with SAR than with CSA. We also observed among the LOA patients, the frequency of CD4+ TGF-ß+ T cells was decreased in SAR group than the in CSA group. CONCLUSION AND CLINICAL RELEVANCE: Our data suggest that refractoriness to treatment in asthma is associated with a lower expression of distinct regulatory molecules by CD4 T cells between those who are atopic and have EOA and those who are non-atopic and have LOA. Thus, these results may contribute to the identification of new regulatory strategies to treat asthma according to their phenotypes.

Local and systemic production of proinflammatory chemokines in the pathogenesis of HAM/TSP.

BACKGROUND: HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) is related with high proviral load, high proinflammatory cytokine levels, and passage of infected cell from the blood to the central nervous system. We aimed to evaluate the participation of chemokines and adhesion molecules in HAM/TSP pathogenesis. METHODS: CXCL9, CXCL10, sICAM-1, and sVCAM-1 were determined by ELISA in serum and cerebrospinal fluid (CSF) of HTLV-1 infected individuals. The frequency and median fluorescence intensity (MFI) of lymphocytes and monocytes expressing ligands of adhesion molecules (CD11a and CD49d) and a chemokine receptor (CXCR3) were analyzed by flow cytometry. RESULTS: The levels of CXCL9 and CXCL10 in serum of definite HAM/TSP were higher than in serum of probable HAM/TSP and HTLV-1 carriers. Considering the production of chemokines by patients with definite HAM/TSP, CXCL9 levels were higher in serum than in CSF, and CXCL10 production was higher in CSF than in serum. Levels of adhesion molecules in serum and CSF of HTLV-1 infected individuals did not differ. The MFI of CD11a on CD4+, CD8+ and CD14+ cells was lower in definite HAM/TSP than in HTLV-1 carriers and did not differ from probable HAM/TSP and healthy subjects (HS). The frequency of lymphocytes expressing CXCR3 was lower in definite HAM/TSP than in cells of probable HAM/TSP and did not differ from carrier and HS. CONCLUSION: These data point to the participation of proinflammatory chemokines, especially CXCL10, in the pathogenesis of definite HAM/TSP.

Citologia do escarro induzido em asmáticos infectados pelo Schistosoma mansoni / Induced sputum cytology in asthmatics infected with Schistosoma mansoni

A infecção pelo Schistosoma mansoni inibe manifestação da asma. A avaliação do escarro induzido em pacientes infectados pelo parasita pode trazer informações importantes sobre a relação entre doenças alérgicas e parasitoses. Objetivo: Avaliar a celularidade do escarro em asmáticos em uma área endêmica em esquistossomose na Bahia. Métodos: Estudo randomizado, duplo cego, controlado com placebo, incluindo asmáticos infectados pelo S. mansoni e um grupo de asmáticos não infectados. Foi utilizada a celularidade do escarro induzido, em contagens sequenciais pré (D0) e pós-tratamento (D7, D60 e D90), para avaliar os efeitos do tratamento da parasitose com praziquantel sobre a asma. Resultados: Avaliados 22 indivíduos asmáticos infectados pelo S. mansoni e grupo controle adicional composto por oito asmáticos não infectados. O grupo que usou praziquantel não diferiu do grupo placebo quando comparada a celularidade do escarro. Houve aumento no número de eosinófilos nos D7, D60 e D90 no grupo placebo, quando comparados ao basal, e no D60 no grupo praziquantel. O número total de células aumentou em relação ao basal no D7 e no D90 para o grupo placebo, e no D90 para o grupo praziquantel. O grupo que usou praziquantel apresentou uma redução do volume expiratório forçado no 1º segundo (VEF1) no D7, D60 e D90. Não houve associação entre a eosinofilia e a gravidade da asma. Conclusão: No presente estudo não foi encontrada correlação entre os tipos celulares encontrados e a gravidade da asma, nem houve variação significativa do percentualde eosinófilos em resposta ao tratamento da esquistossomose...

Schistosoma mansoni infection inhibits asthma symptoms. Assessment of induced sputum in infected patients may shed light on the relationship between allergic diseases and parasite infections. Objective: To assess the cellularity of induced sputum in asthmatic patients living in an endemic area of schistosomiasis in the Brazilian state Bahia. Methods: This randomized, double blind, placebo-controlled study included asthmatic patients infected with S. mansoni and a group of non-infected asthmatics (controls). Cellularity of induced sputum was analyzed based on cell counts before (D0) and after treatment (D7, D60, and D90), to evaluate the effects of treatment with praziquantel on asthma. Results: A total of 22 asthmatics infected with S. mansoni and 8 controls were assessed. Induced sputum cellularity in the group treated with praziquantel did not differ from that of the group treated with placebo. However, compared to baseline counts, a higher number of eosinophils was found in the placebo group on D7, D60, and D90, and on D60 in the treatment group. Total cell counts increased from baseline to D7 and D90 in the placebo group, and from baseline to D90 in the treatment group. Moreover, the treatment group showed a reduction in forced expiratory volume in 1 second (FEV1) on D7, D60, and D90. There was no association between eosinophilia and asthma severity. Conclusion: In the present study, there was no correlation between asthma severity and the cell types found during cellularity assessment, nor was there an association between treatment of schistosomiasis and sputum eosinophilia...

Risk factors for asthma in a helminth endemic area in bahia, Brazil.

Protective factors associated with atopy or asthma in rural areas include socioeconomic level, overcrowding, and helminth infection. However, little epidemiological information was originated from schistosomiasis areas. This study aimed to investigate factors associated with asthma in a schistosomiasis endemic area. A questionnaire was used to obtain information on demographics, socioeconomic, and environmental features. The ISAAC questionnaire was used to identify individuals with asthma. Parasitological exam was done in all participants and skin prick test to aeroallergens in all asthmatics. Prevalence of Schistosoma mansoni infection was 57.4% and Ascaris lumbricoides, 30.8%. Asthma was found in 13.1% of the population, and 35.1% of them had a positive SPT. Active and passive smoking was positively associated with asthma, whereas A. lumbricoides was negatively associated. In a schistosomiasis hyperendemic region, current infection with A. lumbricoides is protective against asthma. However, we cannot rule out the involvement of S. mansoni infection in this process.

The effect of antihelminthic treatment on subjects with asthma from an endemic area of schistosomiasis: a randomized, double-blinded, and placebo-controlled trial.

This is a prospective, double-blinded, and placebo-controlled trial evaluating the influence of antihelminthic treatments on asthma severity in individuals living in an endemic area of schistosomiasis. Patients from group 1 received placebo of Albendazole or of Praziquantel and from group 2 received Albendazole and Praziquantel. Asthma severity was assessed by clinical scores and by pulmonary function test. There was no significant difference in the asthma scores from D0 to D1-D7 after Albendazole or Praziquantel and from D0 to D30-90 after Albendazole or Praziquantel in both, group 1 and 2. It was observed, however, a clinical worsening of the overall studied population after 6 months and 12 months of antihelminthic treatments. Additionally, we observed increased frequency of forced expiratory volume in 1 second (FEV1) <80% on 12 and 18 months after treatment. The worsening of asthma severity after repeated antihelminthic treatments is consistent with the hypothesis of the protective role conferred by helminths in atopic diseases.

Factors associated with resistance to Schistosoma mansoni infection in an endemic area of Bahia, Brazil.

Detailed knowledge of factors associated with resistance to Schistosoma mansoni infection in endemic areas might facilitate more effective schistosomiasis control. We conducted a cross-sectional study of persons resistant to schistosomiasis and found no association between socioeconomic status and resistance to infection. Mononuclear cells of resistant subjects produced higher levels of interleukin-5 (IL-5), IL-13 and interferon-γ upon stimulation with soluble egg antigen (SEA) compared with infected persons. When stimulated with Sm21.6 or Sm22.6, levels of IL-10 were higher in cell culture of resistant persons. Levels of IgE against soluble adult worm antigen (SWAP) and against interleukin-4-inducing principle from S. mansoni eggs (IPSE) and levels of IgG4 against SWAP, SEA, and Sm22.6 were lower in the resistant group compared with the susceptible group. Our data suggest that socioeconomic status could not fully explain resistance to S. mansoni infection observed in the studied area. However, a mixture of Th1 and Th2 immune responses and low levels of specific IgG4 against parasite antigens could be mediating resistance to infection.

Immunomodulation of the allergic inflammatory response: new developments.

Studies of the molecular mechanisms associated with allergic diseases have lead to a better understanding of the complex processes that underlie their pathogenesis. These mechanisms involve Th2- and Th1-type cells and also some recently described cytokines, such as IL-25 and IL-33. Regulatory mechanisms of allergic inflammation have also been identified. For instance, IL-10, a cytokine produced by many cell types, promotes a decrease in IgE production, and inhibits the release of histamine and other inflammatory mediators by mast cells. Recently, a variety of regulatory cells have been discovered, which, either by direct contact or through the production of IL-10 and/or TGF-beta, can inhibit the allergic inflammatory response. IL-10 is produced in high levels by cells of helminth-infected individuals. There is some evidence that such infections protect against the development of allergic diseases. In asthmatic individuals living in endemic areas of schistosomiasis, it has been shown in in vitro studies that there is a modulation of the Th2 response, both by mechanisms involving IL-10, which is produced mainly by monocytes and CD4+CD25+ T regulatory cells, and also by the expression of cytotoxic T-lymphocyte antigen 4 (CTLA-4) in CD4+ T cells. Studies using parasite antigens to induce the modulation of allergic inflammatory response are being conducted by several groups of researchers and represent new perspectives for the treatment of allergic diseases.

Schistosoma mansoni infection alters co-stimulatory molecule expression and cell activation in asthma.

Chronic schistosomiasis induces Th2/T regulatory responses which are able to down-modulate allergic inflammation and asthma. Because co-stimulatory molecules and IL-10 are essential for inducing tolerance, the aim of this study was to determine by flow cytometry, the expression of CD28, CTLA4, CD40L, CD80, CD86, HLA-DR, IL-10 and IL-10 receptor, by mononuclear cells from asthmatic individuals infected with Schistosoma mansoni and compare with non-infected individuals. Peripheral blood mononuclear cells were stained with fluorochrome conjugated antibodies for the expression of co-stimulatory molecules, and for intracellular CTLA4 and IL-10 expression. There was no significant difference in the frequency of T cells expressing CD28 between the two groups. However, the frequency of TCD4(+) cells expressing CTLA4 and CD40L was higher in infected asthmatics. The frequency of monocytes expressing CD80 and CD86 did not differ between groups, while the expression of HLA-DR and IL-10 receptor was higher on monocytes of infected individuals. Furthermore, monocytes and CD4(+)CD25(+) cells of infected individuals expressed higher levels of IL-10. We conclude that, besides alternatively-activated monocytes that are, together with CD4(+)CD25(+) cells, important sources of IL-10, CTLA4 and CD40L expression may also participate in the down-modulation of inflammatory allergic response in S. mansoni-infected asthmatics.

Schistosoma mansoni antigens modulate experimental allergic asthma in a murine model: a major role for CD4+ CD25+ Foxp3+ T cells independent of interleukin-10.

In areas where schistosomiasis is endemic, a negative correlation is observed between atopy and helminth infection, associated with a low prevalence of asthma. We investigated whether Schistosoma mansoni infection or injection of parasite eggs can modulate airway allergic inflammation in mice, examining the mechanisms of such regulation. We infected BALB/c mice with 30 S. mansoni cercariae or intraperitoneally injected 2,500 schistosome eggs, and experimental asthma was induced by ovalbumin (OVA). The number of eosinophils in bronchoalveolar lavage fluid was higher in the asthmatic group than in asthmatic mice infected with S. mansoni or treated with parasite eggs. Reduced Th2 cytokine production, characterized by lower levels of interleukin-4 (IL-4), IL-5, and immunoglobulin E, was observed in both S. mansoni-treated groups compared to the asthmatic group. There was a reduction in the number of inflammatory cells in lungs of S. mansoni-infected and egg-treated mice, demonstrating that both S. mansoni infection and the egg treatment modulated the lung inflammatory response to OVA. Only allergic animals that were treated with parasite eggs had increased numbers of CD4(+) CD25(+) Foxp3(+) T cells and increased levels of IL-10 and decreased production of CCL2, CCL3, and CCL5 in the lungs compared to the asthmatic group. Neutralization of IL-10 receptor or depletion of CD25(+) T cells in vivo confirmed the critical role of CD4(+) CD25(+) Foxp3(+) regulatory T cells in experimental asthma modulation independent of IL-10.

Polymyxin B as inhibitor of LPS contamination of Schistosoma mansoni recombinant proteins in human cytokine analysis.

BACKGROUND: Recombinant proteins expressed in Escherichia coli vectors are generally contaminated with endotoxin. In this study, we evaluated the ability of Polymyxin B to neutralize the effect of LPS present as contaminant on Schistosoma mansoni recombinant proteins produced in E. coli in inducing TNF-alpha and IL-10. Peripheral blood mononuclear cells from individuals chronically infected with S. mansoni were stimulated in vitro with recombinant Sm22.6, Sm14 and P24 antigens (10 microg/mL) in the presence of Polymyxin B (10 microg/mL). RESULTS: The levels of cytokines were measured using ELISA. There was greater than 90% reduction (p < 0.05) in the levels of TNF-alpha and IL-10 when Polymyxin B was added to the cultures stimulated with LPS. In cultures stimulated with S. mansoni recombinant proteins in the presence of Polymyxin B, a reduction in the levels of TNF-alpha and IL-10 was also observed. However, the percentage of reduction was lower when compared to the cultures stimulated with LPS, probably because these proteins are able to induce the production of these cytokines by themselves. CONCLUSION: This study showed that Polymyxin B was able to neutralize the effect of endotoxin, as contaminant in S. mansoni recombinant antigens produced in E. coli, in inducing TNF-alpha and IL-10 production.

Schistosoma mansoni antigen-driven interleukin-10 production in infected asthmatic individuals

Asthmatics infected with Schistosoma mansoni have a less severe course of asthma and an inhibition of the Th2 inflammatory response that seems to be mediated by interleukin (IL-10). The objective of this study was to evaluate the capacity of some S. mansoni antigens to stimulate IL-10 production in vitro by cells of asthmatic infected individuals. Peripheral bloods mononuclear cells were stimulated with the S. mansoni recombinant antigens Sm22.6, Sm14, P24, and PIII antigen. IL-10 was measured in the supernatants of cultures. As the recombinant antigens were cloned in Escherichia coli, we blocked contaminant endotoxin with polymyxin B added to the cultures. We demonstrated that all antigens used drove high production of IL-10 in S. mansoni infected individuals (n = 13, 408 ± 514 and 401 ± 383 pg/ml, 484 ± 245 pg/ml, 579 ± 468 pg/ml, respectively). In asthmatics infected with S. mansoni (n = 21) rP24 induced higher levels of IL-10 (565 ± 377 pg/ml) when compared to PIII, rSm14 and rSm22.6 (184 ± 209 pg/ml; 292 ± 243 pg/ml; 156 ± 247 pg/ml, respectively). Conclusion: the S. mansoni antigens evaluated in this study stimulated IL-10 production by cells from infected individuals and therefore they have the potential to be used as a modulator of the inflammatory response in asthma.

Aluminum hydroxide associated to Schistosoma mansoni 22.6 kDa protein abrogates partial protection against experimental infection but not alter interleukin-10 production

The need to develop a vaccine against schistosomiasis led several researches and our group to investigate proteins from Schistosoma mansoni as vaccine candidates. Sm22.6 is a protein from S. mansoni that shows high identity with Sj22.6 and Sh22.6 (79 and 91 percent, respectively). These proteins are associated with high levels of IgE and protection to reinfection. Previously, we have shown that Sm22.6 induced a partial protection of 34.5 percent when used together with Freund's adjuvant and produced a Th0 type of immune response with interferon-g and interleukin-4. In this work, mice were immunized with Sm22.6 alone or with aluminum hydroxide adjuvant and high levels of IgG, IgG1, and IgG2a were measured. Unfortunately, no protection was detected. Since IL-10 is a modulating cytokine in schistosomiasis, we also observed a high level of this molecule in splenocytes of vaccinated mice. In conclusion, we did not observe the adjuvant effect of aluminum hydroxide associated with rSm22.6 in protective immunity.

Schistosoma mansoni antigen-driven interleukin-10 production in infected asthmatic individuals.

UNLABELLED: Asthmatics infected with Schistosoma mansoni have a less severe course of asthma and an inhibition of the Th2 inflammatory response that seems to be mediated by interleukin (IL-10). The objective of this study was to evaluate the capacity of some S. mansoni antigens to stimulate IL-10 production in vitro by cells of asthmatic infected individuals. Peripheral bloods mononuclear cells were stimulated with the S. mansoni recombinant antigens Sm22.6, Sm14, P24, and PIII antigen. IL-10 was measured in the supernatants of cultures. As the recombinant antigens were cloned in Escherichia coli, we blocked contaminant endotoxin with polymyxin B added to the cultures. We demonstrated that all antigens used drove high production of IL-10 in S. mansoni infected individuals (n = 13, 408 +/- 514 and 401 +/- 383 pg/ml, 484 +/- 245 pg/ml, 579 +/- 468 pg/ml, respectively). In asthmatics infected with S. mansoni (n = 21) rP24 induced higher levels of IL-10 (565 +/- 377 pg/ml) when compared to PIII, rSm14 and rSm22.6 (184 +/- 209 pg/ml; 292 +/- 243 pg/ml; 156 +/- 247 pg/ml, respectively). CONCLUSION: the S. mansoni antigens evaluated in this study stimulated IL-10 production by cells from infected individuals and therefore they have the potential to be used as a modulator of the inflammatory response in asthma.

Aluminum hydroxide associated to Schistosoma mansoni 22.6 kDa protein abrogates partial protection against experimental infection but not alter interleukin-10 production.

The need to develop a vaccine against schistosomiasis led several researches and our group to investigate proteins from Schistosoma mansoni as vaccine candidates. Sm22.6 is a protein from S. mansoni that shows high identity with Sj22.6 and Sh22.6 (79 and 91%, respectively). These proteins are associated with high levels of IgE and protection to reinfection. Previously, we have shown that Sm22.6 induced a partial protection of 34.5% when used together with Freund's adjuvant and produced a Th0 type of immune response with interferon-g and interleukin-4. In this work, mice were immunized with Sm22.6 alone or with aluminum hydroxide adjuvant and high levels of IgG, IgG1, and IgG2a were measured. Unfortunately, no protection was detected. Since IL-10 is a modulating cytokine in schistosomiasis, we also observed a high level of this molecule in splenocytes of vaccinated mice. In conclusion, we did not observe the adjuvant effect of aluminum hydroxide associated with rSm22.6 in protective immunity.