Robson da Paixão de Souza

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.

Cytokine and Chemokine Profile in Individuals with Different Degrees of Periportal Fibrosis due to Schistosoma mansoni Infection

Periportal fibrosis in schistosomiasis has been associated to the host immune response to parasite antigens. We evaluated the immune response in S. mansoni infected individuals with different degrees of periportal fibrosis. Cytokine and chemokines were measured in serum and in supernatants of PBMC cultures stimulated with the soluble adult worm (SWAP) or egg (SEA) antigens, using a sandwich ELISA. The levels of IL-5 in response to SEA were higher in individuals with moderate to severe fibrosis (310.9 pg/mL) compared to individuals without fibrosis (36.8 pg/mL; P = 0.0418). There was also a higher production of TNF-α in cultures stimulated with SWAP in patients with insipient fibrosis (1446 pg/mL) compared to those without fibrosis (756.1 pg/mL; P = 0.0319). The serum levels of IL-13 and MIP-1α were higher in subjects without fibrosis than in those with moderate to severe fibrosis. However a positive association between serum levels of IL-13, TNF-α, MIP-1α, and RANTES and S. mansoni parasite burden was found. From these data we conclude that IL-5 and TNF-α may participate in liver pathology in schistosomiasis. The positive association between IL-13, TNF-α, MIP-1α, and RANTES with parasite burden, however, might predict the development of liver pathology.

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.

Impaired Lymphocyte Profile in Schistosomiasis Patients with Periportal Fibrosis

The Th2 immune response in chronic schistosomiasis is associated with the development of periportal fibrosis. However, little is known about the phenotype and activation status of T cells in the process. Objective. To evaluate the profile of T cells in schistosomiasis patients with periportal fibrosis. Methods. It was a cross-sectional study, conducted in the village of Agua Preta, Bahia, Brazil, which included 37 subjects with periportal fibrosis determined by ultrasound. Peripheral blood mononuclear cells were obtained by the Ficcol-hypaque gradient and the frequency of T cells expressing the surface markers CD28, CD69, CD25, and CTLA-4 was determined by flow cytometry. Results. The frequency of CD4+CD28+ T lymphocytes was higher in individuals with moderate to severe fibrosis compared to patients with incipient fibrosis. We did not observe any significant difference in the frequency of CD4+ T cells expressing CD69 among groups of individuals. There was also no significant difference in the frequency of CD8+ T cells expressing CD28 or CD69 among the studied groups. Individuals with moderate to severe fibrosis presented a lower frequency of CD8+ T cells, CD4+CD25high T cells, and CD4+CTLA-4+ T cells when compared to patients without fibrosis or incipient fibrosis. The frequency of CD4+CD25low cells did not differ between groups. Conclusion. The high frequency of activated T cells coinciding with a low frequency of putative Treg cells may account for the development of periportal fibrosis in human schistosomiasis.

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.

Schistosoma mansoni antigens modulate allergic response in vitro in cells of asthmatic individuals

Schistosoma mansoni infection is associated with a low prevalence of asthma and a less severe form of the disease. The mechanisms underlying this association may include the production of regulatory cells and cytokines. The aim of this study was to evaluate the immune response induced by the S. mansoni antigens, Sm22.6, PIII, and Sm29 and their ability to suppress allergen‐specific IL‐5 production by peripheral blood mononuclear cells (PBMC) from asthmatic individuals. PBMCs were stimulated in vitro with S. mansoni antigens in the presence or absence of antigen‐1 of the mite Dermatophagoides pteronyssinus (Der p1). Cytokines were measured in PBMC supernatants by enzyme‐linked immunosorbent assay (ELISA), and the phenotype of cells producing IL‐10 was assessed using flow cytometry. High production of S. mansoni antigen‐specific IL‐10 was observed not only in cells of S. mansoni‐infected individuals, but also in cells of noninfected asthmatic individuals. In the former group, the main cellular sources of IL‐10 were CD4+ CD25+, and CD14+ cells. The levels of IFN‐γ, IL‐5, and IL‐13 in the noninfected asthmatic group were ∼100 pg/ml in response to the antigens. Moreover, when S. mansoni antigens were added to cultures stimulated with Der p1, levels of IL‐10 were increased (Der p1 = 234 ± 118; Der p1 + Sm22.6 = 1189 ± 595; Derp1 + PIII = 799 ± 331; Derp1 + Sm29 = 652 ± 288 pg/ml) with reduced levels of IL‐5 (Der p1 = 286 ± 219; Der p1 + Sm22.6 = 93 ± 153; Derp1 + PIII = 132 ± 188; Derp1 + Sm29 = 96 ± 86 pg/ml). The S. mansoni antigens evaluated in the present study induced the production of the regulatory cytokine IL‐10 and down‐modulated the Th2 immune response that participates in the pathology of asthma. Drug Dev Res 72:538–548, 2011.

Susceptibility of dendritic cells from individuals with schistosomiasis to infection by Leishmania braziliensis

HighlightsCoinfection with leishmaniasis and schistosomiasis is associated with severe forms of cutaneous lesions.Dendritic cells from patients with schistosomiasis are more susceptible to an infection with L. braziliensis.Dendritic cells from patients with schistosomiasis has a lower degree of activation and a regulatory profile. Abstract Coinfection with leishmaniasis and schistosomiasis has been associated with increased time to healing of cutaneous lesions of leishmaniasis. The objective of this study was to evaluate the effect of Leishmania braziliensis infection on co‐cultures of monocyte‐derived dendritic cells (MoDCs) with autologous lymphocytes from patients with schistosomiasis and patients with cutaneous leishmaniasis. MoDCs were differentiated from peripheral blood monocytes, isolated by magnetic beads, infected with L. braziliensis, and co‐cultured with autologous lymphocytes. Expression of HLA‐DR, CD1a, CD83, CD80, CD86, CD40, and the IL‐10 receptor (IL‐10R) on MoDCs as well as CD28, CD40L, CD25, and CTLA‐4 on lymphocytes were evaluated by flow cytometry. The production of the cytokines IL‐10, TNF, IL‐12p40, and IFN‐&ggr; were evaluated by sandwich ELISA of the culture supernatant. The infectivity evaluation was performed by light microscopy after concentration of cells by cytospin and Giemsa staining. It was observed that the frequency of MoDCs expressing CD83, CD80, and CD86 as well as the MFI of HLA‐DR were smaller in the group of patients with schistosomiasis compared to the group of patients with leishmaniasis. On the other hand, the frequency of IL‐10R on MoDCs was higher in patients with schistosomiasis than in patients with leishmaniasis. CD4+ and CD8+ T lymphocytes from patients with schistosomiasis presented a lower frequency of CD28 and a higher frequency of CTLA‐4 compared to lymphocytes from patients with leishmaniasis. Levels of IL‐10 were higher in the supernatants of co‐cultures from individuals with schistosomiasis compared to those with leishmaniasis. However, levels of TNF, IL‐12p40, and IFN‐&ggr; were lower in the group of individuals with schistosomiasis. Regarding the frequency of MoDCs infected by L. braziliensis after 72 h in culture, it was observed that higher frequencies of cells from patients with schistosomiasis were infected compared to cells from patients with leishmaniasis. It was concluded that MoDCs from patients with schistosomiasis are more likely to be infected by L. braziliensis, possibly due to a lower degree of activation and a regulatory profile.

Dr. James Matthew Lipton, 1938-2016

Dr. Jim Lipton died on the 10th of July this year. It was a great loss not only to his family and friends but also to the scientific world. The facts and dates of his life are well expressed in the obituary written by his daughter reprinted above, with permission. Many years ago, when Jim and his buddy, S.M. ‘Don’ McCann were both Professors of Physiology in Dallas, they suggested we start a new NIM journal. I was opposed to the idea, because there were already too many journals proliferating at a dizzying pace. The success of the ISNIM journal proved that they were right and I was wrong. One could not imagine two more disparate personalities, but they always managed to work together harmoniously. Both were geniuses, Jim soft-spoken and modest ... and Don, with an amazing photographic memory, boisterous (Don was first my professor at the University of Pennsylvania, and later, my student and honorary lecturer and awardee of the Novera Spector lectureship). A book needs to be written about Don, but most observers agree that he should have shared at least one Nobel Prize. Both remained my good friends all their lives. At one point I went to an international congress organized by Jim, only to find that he had dedicated this meeting to me! I hope that his friends and especially his wife, Luby, will I have been asked to write an obituary-memoriam for the cofounder of Neuroimmunomodulation (NIM) , who died on the 10th of July this year. Below is an obituary written by Jim’s daughter and reprinted with her permission, followed by some informal remembrances from Luby, his widow, and me.

Immunological Profile in Individuals with Schistosomal Myeloradiculopathy

Background: Schistosomal myeloradiculopathy (SMR) is the most serious ectopic presentation of Schistosoma mansoni infection. The pathogenesis occurs mainly via the host inflammatory response to the eggs of the parasite that are stuck in the central nervous system, and the diagnosis is generally made by the exclusion of other neurological diseases. Objective: We aimed to evaluate the immune status of SMR patients and to identify a marker for SMR diagnosis. Methods: We enrolled 15 patients with a presumptive diagnosis of SMR, and the control groups included 17 patients with myelopathy associated with human T cell lymphotropic virus type 1 (HTLV-1) and 11 with other neurological disorders. The determination of soluble egg antigen-specific IgE and the levels of cytokines from Th1, Th2, Th17 and T-regulatory cell profiles and the chemokines MIP-1a and RANTES were measured in the cerebrospinal fluid (CSF) and serum using an ELISA technique. Results: We observed that SMR leads to an increase in IgE levels in the CSF compared to serum, and the levels of IL-13 and MIP-1α were significantly higher in the CSF and serum of the SMR patients than in the patients with HTLV-1-associated myelopathy. The levels of MIP-1α and RANTES were higher in the CSF than in the serum of the SMR group. The ratio between levels of IL-13, MIP-1α and RANTES over IL-10 was positive in the CSF of the SMR patients. Conclusions: These results indicate that S. mansoni-specific IgE in the CSF is a promising marker for the diagnosis of SMR and that the cytokines and chemokines associated with the Th2 profile may be important factors in the immunopathogenesis of SMR.

Monocyte Subsets in Schistosomiasis Patients with Periportal Fibrosis

A major issue with Schistosoma mansoni infection is the development of periportal fibrosis, which is predominantly caused by the host immune response to egg antigens. Experimental studies have pointed to the participation of monocytes in the pathogenesis of liver fibrosis. The aim of this study was to characterize the subsets of monocytes in individuals with different degrees of periportal fibrosis secondary to schistosomiasis. Monocytes were classified into classical (CD14++CD16−), intermediate (CD14++CD16+), and nonclassical (CD14+CD16++). The expressions of monocyte markers and cytokines were assessed using flow cytometry. The frequency of classical monocytes was higher than the other subsets. The expression of HLA-DR, IL-6, TNF-α, and TGF-β was higher in monocytes from individuals with moderate to severe fibrosis as compared to other groups. Although no differences were observed in receptors expression (IL-4R and IL-10R) between groups of patients, the expression of IL-12 was lower in monocytes from individuals with moderate to severe fibrosis, suggesting a protective role of this cytokine in the development of fibrosis. Our data support the hypothesis that the three different monocyte populations participate in the immunopathogenesis of periportal fibrosis, since they express high levels of proinflammatory and profibrotic cytokines and low levels of regulatory markers.