Profile of T and B lymphocytes in individuals resistant to Schistosoma mansoni infection.

The mechanisms involved in the development of resistance to infection/reinfection by Schistosoma mansoni still arouse great interest and controversy. Some authors demonstrate that resistance to infection is attributed to a mixed Th1 and Th2 response and resistance to reinfection after repeated treatments through mechanisms associated with the Th2 response. Through flow cytometry, the phenotypic characterization of B and T lymphocytes in individuals residing in endemic areas with low parasite loads over 10 years was evaluated for the first time in humans. In this study, individuals with low parasite loads for Schistosoma mansoni had a higher proportion of Th1 and Th2 cells. In addition, lymphocytes from these individuals showed a higher degree of expression of costimulatory molecules CD28 and CTLA-4 and regulatory molecules FoxP3 and IL-10, when compared to individuals with high parasite loads. Our data indicate that the control of the parasite load of S. mansoni must be associated with a Th1, Th2, and regulatory response, and that further studies are needed to elucidate the possibility of mechanisms associated with the hyporesponsiveness of lymphocytes from individuals with high parasite loads.

Phenotypic Characterization of CD4+ T Lymphocytes in Periportal Fibrosis Secondary to Schistosomiasis.

Schistosomiasis is a parasitic disease that affects about 166 million people around the world. It is estimated that 5%-10% of individuals with schistosomiasis develop severe forms of the disease, which are characterized by pulmonary hypertension, ascites, periportal fibrosis, and other significant complications. The chronic phase of the disease is associated with a Th2 type immune response, but evidence also suggests there are roles for Th1 and Th17 in the development of severe disease. The aim of this study was to evaluate the CD4+ T lymphocyte profile of patients with different degrees of periportal fibrosis secondary to schistosomiasis. These individuals had been treated for schistosomiasis, but since they live in a S. mansoni endemic area, they are at risk of reinfection. They were evaluated in relation to the degree of periportal fibrosis and classified into three groups: without fibrosis or with incipient fibrosis (WF/IFNE), n=12, possible periportal fibrosis/periportal fibrosis, n=13, and advanced periportal fibrosis/advanced periportal fibrosis with portal hypertension, n=4. We observed in the group without fibrosis a balance between the low expression of Th2 cytokines and high expression of T reg cells. As has already been described in the literature, we found an increase of the Th2 cytokines IL-4, IL-5, and IL-13 in the group with periportal fibrosis. In addition, this group showed higher expression of IL-17 and IL-10 but lower IL-10/IL-13 ratio than patients in the WF/IFNE group. Cells from individuals who present any level of fibrosis expressed more TGF-ß compared to the WF/IFNE group and a positive correlation with left lobe enlargement and portal vein wall thickness. There was a negative correlation between IL-17 and the thickness of the portal vein wall, but more studies are necessary in order to explore the possible protective role of this cytokine. Despite the fibrosis group having presented a higher expression of pro-fibrotic molecules compared to WF/IFNE patients, it seems there is a regulation through IL-10 and T reg cells that is able to maintain the low morbidity of this group.

Characterization of memory T cells in individuals resistant to Schistosoma mansoni infection.

Schistosomiasis affects about 240 million people worldwide and is estimated that about 700 million people live in areas at risk of infection. In the context of immune response associated with infection by Schistosoma mansoni, the role of memory T cells is not well understood. AIM: To evaluate the frequency of memory CD4+ and CD8+ T cells from individuals resistant and susceptible to Schistosoma mansoni infection. METHODS AND RESULTS: We selected individuals with low (resistant) and high (susceptible) parasite burden using databases generated during previous studies carried out in the same endemic area. The cell surface markers were performed using flow cytometry. In this study, the resistant individuals showed an increase in the CD4+ memory T-cell pool associated with an increase in the central memory cell (TCM) and a decrease in the effector memory cell (TEM ). Individuals susceptible to infection had higher frequencies of effector memory cells compared to resistant individuals. CONCLUSIONS: These data suggest that resistance to S mansoni infection may be associated with an increase in the number of CD4+ memory T cells and susceptibility to infection is associated with a decrease in the central memory cell as well as high proportions of effector memory cells.

Helminths and Asthma: Risk and Protection.

Helminth infections may inhibit the development of allergic diseases, including asthma. On the other hand, some helminth species may induce or worsen symptoms of asthma. This article discusses the impact of helminth infections on asthma as well as the potencial of helminth-derived molecules with regulatory characteristics in the prevention or treatment of this disease. The ability to induce regulation has been observed in animal models of asthma or cells of asthmatic individuals in vitro. Potential future clinical applications of helminth antigens or infection for prevention of asthma merit further translational research.

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

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-γ 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-γ were lower in the group of individuals with schistosomiasis. Regarding the frequency of MoDCs infected by L. braziliensis after 72h 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.

Schistosoma mansoni rSm29 Antigen Induces a Regulatory Phenotype on Dendritic Cells and Lymphocytes From Patients With Cutaneous Leishmaniasis.

The immune response induced by Schistosma mansoni antigens is able to prevent immune-mediated diseases. Conversely, the inflammatory response in cutaneous leishmaniasis (CL), although responsible for controlling the infection, is also associated with the pathogenesis of disease. The aim of this study was to evaluate the potential of the S. mansoni Sm29 antigen to change certain aspects of the profiles of monocyte derived dendritic cells (MoDCs) and lymphocytes from subjects with CL in vitro. Expression of surface molecules and intracellular cytokines in the MoDCs and lymphocytes as well as the proliferation of Leishmania braziliensis were evaluated by flow cytometry. Levels of cytokines were evaluated in culture supernatants by ELISA. It was observed that stimulation by rSm29 increased the frequency of expression of CD83, CD80, CD86, and IL-10R in MoDCs compared to non-stimulated cultures. Additionally rSm29 decreased the frequency CD4+ and CD8+ T cells expressing CD28 and increased the frequency of CD4+CD25hi and CD4+CTLA-4+ T lymphocytes. Addition of rSm29 to cultures increased IL-10 levels and decreased levels of IL-12p40 and IFN-γ, while not altering TNF levels compared to non-stimulated cultures. This study showed that rSm29 induced a regulatory profile in MoDCs and lymphocytes and thereby regulated the exaggerated inflammation observed in CL. Considering that there are few therapeutic options for leishmaniasis, the use of rSm29 may be an alternative to current treatment and may be an important strategy to reduce the healing time of lesions in patients with CL.

Schistosoma antigens downregulate CXCL9 production by PBMC of HTLV-1-infected individuals.

HTLV-1 is the causal agent of Adult T cell Leukemia/lymphoma (ATLL) and HTLV-1-associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP). The immune response to HTLV-1-infection is polarized to the Th1-type, and the presence of CXCL9/CXCL10 chemokines may lead to an increase in the recruitment of pro-inflammatory molecules in spinal cord tissue, contributing to the damage observed in the development of HAM/TSP. It has been observed that in chronic helminth-infections, such as schistosomiasis, there is a deviation toward the Th2/regulatory immune response. OBJECTIVE: To evaluate the ability of Schistosoma spp. proteins to decrease the in vitro CXCL9 and CXCL10 production by PBMC of HTLV-1-infected individuals. METHODS: The Schistosoma proteins rSm29, rSh-TSP-2 and PIII were added to PBMC cultures of HTLV-1-infected individuals and the levels of chemokines in the supernatants were measured using a sandwich ELISA method. RESULTS: The addition of rSm29 to the cultures resulted in decreased production of CXCL9 in all the analyzed individuals and HAM/TSP group (18167±9727pg/mL, p=0.044; 20237±6023pg/mL, p=0.028, respectively) compared to the levels in unstimulated cultures (19745±9729pg/mL; 25078±2392pg/mL, respectively). The addition of rSh-TSP-2 decreased the production of CXCL9 in all studied individuals and carriers group (16136±9233pg/mL, p=0.031; 13977±8857pg/mL, p=0.026) vs unstimulated cultures (19745±9729pg/mL; 18121±10508pg/mL, respectively). Addition of PIII did not alter the results. There was no significant change in the levels of CXCL10 by the addition of the studied proteins. CONCLUSION: The Schistosoma proteins used in this study were able to down modulate the production of CXCL9, a chemokine associated with the inflammatory process in HTLV-1-infection.

Schistosoma mansoni antigens alter activation markers and cytokine profile in lymphocytes of patients with asthma.

Asthma is a chronic disease characterized by airway inflammation, obstruction and hyperresponsiveness. Severe asthma affects a small proportion of subjects but results in most of the morbidity, costs and mortality associated with the disease. Studies have suggested that Schistosoma mansoni infection reduces the severity of asthma and prevent atopy. OBJECTIVE: We evaluated the ability of S. mansoni antigens, Sm29 and Sm29TSP-2 to modulate lymphocyte activation status in response to the allergen of the mite Dermatophagoides pteronyssinus (Der p1) in cell cultures of individuals with asthma. METHODS: Thirty four patients were enrolled in this study: seventeen patients with severe asthma (SA group), seventeen patients with mild asthma (MA group) and six controls with no asthma. Peripheral blood mononuclear cells (PBMC) were obtained and stimulated with Sm29 and Sm29TSP-2 in the presence or absence of Der p1. The expression of surface markers and cytokines on lymphocytes was evaluated by flow cytometry and the levels of IL-10 in the culture supernatant were determined by ELISA. RESULTS: The addition of Sm29 and Sm29TSP-2 antigens to PBMC cultures from both groups of subjects with asthma stimulated with Der p1 reduced the frequency of CD4+CD25low cells whereas and increased frequency of CD4+CD25high population was observed compared to unstimulated cultures. Moreover, cultures stimulated with Sm29TSP-2 showed a reduction in the frequency of T cells expressing CD69, IFN-γ, TNF and TGF-ß in the MA group and an increase in the frequency of CD4+TSLPR+ T cells in the SA group. The addition of Sm29 to the cultures reduced the frequency of CD4+CD69+ and CD4+IL-5+ T cells in all asthmatic groups, and reduced the frequency of CD4+ T cells expressing IL-13 in the MA group. The cultures stimulated with Sm29 and Sm29TSP-2 showed an increase in the level of IL-10 in the supernatants. CONCLUSION: These results suggest that the addition of Sm29 and Sm29TSP-2 to the cells cultures from subjects with asthma reduced cell activation markers and altered the cytokine production pattern in a way that can potentialy control the inflammatory response associated with asthma.

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.

Dendritic cell profile induced by Schistosoma mansoni antigen in cutaneous leishmaniasis patients.

The inflammatory response in cutaneous leishmaniasis (CL), although responsible for controlling the infection, is associated with the pathogenesis of disease. Conversely, the immune response induced by S. mansoni antigens is able to prevent immune-mediated diseases. The aim of this study was to evaluate the potential of the S. mansoni Sm29 antigen to change the profile of monocyte-derived dendritic cells (MoDCs) from subjects with cutaneous leishmaniasis (CL) in vitro. Monocytes derived from the peripheral blood mononuclear cells of twelve patients were cultured with GM-CSF and IL-4 for differentiation into dendritic cells and then stimulated with soluble Leishmania antigen (SLA) in the presence or absence of Sm29 antigen. The expression of surface molecules associated with maturation and activation (HLA-DR, CD40, CD83, CD80, and CD86), inflammation (IL-12, TNF), and downregulation (IL-10, IL-10R) was evaluated using flow cytometry. We observed that the frequencies of HLA-DR, CD83, CD80, and CD86 as well as of IL-10 and IL-10R on MoDCs were higher in cultures stimulated with Sm29, compared to the unstimulated cell cultures. Our results indicate that the Sm29 antigen is able to activate regulatory MoDCs in patients with cutaneous leishmaniasis. It might be useful to control the inflammatory process associated with this disease.

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-ß 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.

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(+)CD25(high) T cells, and CD4(+)CTLA-4(+) T cells when compared to patients without fibrosis or incipient fibrosis. The frequency of CD4(+)CD25(low) 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.

Schistosoma antigens downmodulate the in vitro inflammatory response in individuals infected with human T cell lymphotropic virus type 1.

UNLABELLED: Human T cell lymphotropic virus type 1 (HTLV-1) is the causal agent of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). While the immune response to HTLV-1 infection is polarized to the Th1-type, chronic helminth infections drive the Th2- and T regulatory-type, and are able to downregulate the inflammatory response in some autoimmune diseases. OBJECTIVE: To evaluate whether Schistosoma spp. antigens alter the in vitro cytokine response in HTLV-1 infection. METHODS: The recombinant Schistosoma antigens Sm29 and ShTSP2 (tetraspanin) and PIII, a fraction of the Schistosoma mansoni adult worm antigen were added to peripheral blood mononuclear cell (PBMC) cultures of HTLV-1-infected individuals and the levels of interferon (IFN)-γ and interleukin (IL)-10 in the supernatants were measured using the ELISA sandwich technique. RESULTS: Compared to the levels of cytokine in nonstimulated cultures, the levels of IFN-γ were reduced in 50, 47 and 50% of patients by the presence of Sm29, ShTsp2 and PIII, respectively. The downregulation of IFN-γ production in the presence of Sm29 antigen was observed mainly in subjects who had lower basal levels of this cytokine. The levels of IL-10, however, increased by the addition of the three antigens in the cultures in 74, 62 and 44% of individuals, respectively. In addition, there was a decrease in the ratio of IFN-γ/IL-10 levels in cultures stimulated with Sm29 and ShTSP2 when compared to nonstimulated ones. CONCLUSIONS: The Schistosoma spp. antigens used in this study were able to downmodulate IFN-γ production in vitro in HTLV-1 infection. This may be associated with the increased levels of IL-10 induced by the antigens.

Changes in T-Cell and Monocyte Phenotypes In Vitro by Schistosoma mansoni Antigens in Cutaneous Leishmaniasis Patients.

High levels of proinflammatory cytokines such as IFN-γ and TNF are associated with tissue lesions in cutaneous leishmaniasis (CL). We previously demonstrated that Schistosoma mansoni antigens downmodulate the in vitro cytokine response in CL. In the current study we evaluated whether S. mansoni antigens alter monocyte and T-lymphocyte phenotypes in leishmaniasis. Peripheral blood mononuclear cells of CL patients were cultured with L. braziliensis antigen in the presence or absence of the S. mansoni antigens rSm29, rSmTSP-2- and PIII. Cells were stained with fluorochrome conjugated antibodies and analyzed by flow cytometry. The addition of rSm29 to the cultures decreased the expression of HLA-DR in nonclassical (CD14(+)CD16(++)) monocytes, while the addition of PIII diminished the expression of this molecule in classical (CD14(++)CD16(-)) and intermediate (CD14(++)CD16(+)) monocytes. The addition of PIII and rSmTSP-2 resulted in downmodulation of CD80 expression in nonclassical and CD86 expression in intermediate monocytes, respectively. These two antigens increased the expression of CTLA-4 in CD4(+) T cells and they also expanded the frequency of CD4(+)CD25(high)Foxp3(+) T cells. Taken together, we show that S. mansoni antigens, mainly rSmTSP-2 and PIII, are able to decrease the activation status of monocytes and also to upregulate the expression of modulatory molecules in T lymphocytes.

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.

Schistosoma mansoni antigens alter the cytokine response in vitro during cutaneous leishmaniasis.

Schistosoma mansoni infection or associated products are able to down-modulate the type 1 CD4+ T cell inflammatory response characteristic of autoimmune diseases. In this study, we evaluated how S. mansoni antigens altered the immune response that was induced by the soluble Leishmania antigen (SLA) from cutaneous leishmaniasis (CL) patients. Cytokines were measured from the supernatants of peripheral blood mononuclear cell cultures stimulated with SLA. This was performed using the sandwich enzyme linked immunosorbent assay technique in the presence or absence of S. mansoni recombinant antigens Sm29, SmTSP-2 and PIII. The addition of S. mansoni antigens to the cultures resulted in the reduction of interferon gamma (IFN-γ) levels in 37-50% of patients. Although to a lesser extent, the antigens were also able to decrease the production of tumour necrosis factor-alpha (TNF-α). We compared patients that either had or did not have reduction in IFN-γ and TNF-α production in cultures stimulated with SLA in the presence of S. mansoni antigens. We found that there was no significant difference in the levels of interleukin (IL)-10 and IL-5 in response to S. mansoni antigens between the groups. The antigens used in this study down-modulated the in vitro proinflammatory response induced by SLA in a group of CL patients through a currently undefined mechanism.

Schistosoma mansoni antigens alter the cytokine response in vitro during cutaneous leishmaniasis

Schistosoma mansoni infection or associated products are able to down-modulate the type 1 CD4+ T cell inflammatory response characteristic of autoimmune diseases. In this study, we evaluated how S. mansoni antigens altered the immune response that was induced by the soluble Leishmania antigen (SLA) from cutaneous leishmaniasis (CL) patients. Cytokines were measured from the supernatants of peripheral blood mononuclear cell cultures stimulated with SLA. This was performed using the sandwich enzyme linked immunosorbent assay technique in the presence or absence of S. mansoni recombinant antigens Sm29, SmTSP-2 and PIII. The addition of S. mansoni antigens to the cultures resulted in the reduction of interferon gamma (IFN-γ) levels in 37-50 percent of patients. Although to a lesser extent, the antigens were also able to decrease the production of tumour necrosis factor-alpha (TNF-α). We compared patients that either had or did not have reduction in IFN-γ and TNF-α production in cultures stimulated with SLA in the presence of S. mansoni antigens. We found that there was no significant difference in the levels of interleukin (IL)-10 and IL-5 in response to S. mansoni antigens between the groups. The antigens used in this study down-modulated the in vitro proinflammatory response induced by SLA in a group of CL patients through a currently undefined mechanism.

Skin test reactivity and Der p-induced interleukin 10 production in patients with asthma or rhinitis infected with Ascaris.

BACKGROUND: Helminth infections have been associated with reduced reactivity to aeroallergens, which could be related to interleukin 10 (IL-10) production, as reported in schistosomiasis. OBJECTIVE: To compare skin responses to aeroallergens with Der p specific IL-10 production in patients with asthma or rhinitis according to Ascaris infection status. METHODS: Cross-sectional study of 113 patients with asthma or rhinitis from a region endemic for geohelminths. Stool examinations and skin prick tests to aeroallergens were performed in all the patients. Der p specific IL-10 production was measured in the supernatant of peripheral blood mononuclear cell (PBMC) cultures of a subsample of 53 patients. RESULTS: Forty-seven patients had Ascaris in their stool samples. Skin test results were positive in 77% of Ascaris-infected patients and in 71% of uninfected individuals. Median levels of Der p specific IL- 10 in PBMC cultures of infected and uninfected patients were similar (7.8 and 8.4 pg/mL, respectively). The lack of association remained when parasite load was taken into account and when patients with evidence of previous infection were removed from the uninfected group. CONCLUSIONS: In patients with asthma or rhinitis living in an urban area endemic for geohelminths, we found no association between Ascaris infection and skin reactivity to aeroallergens. Furthermore, there was no difference in Der p specific IL-10 production by PBMCs. These negative findings indicate that different from what is observed in Schistosoma infection, Ascaris lumbricoides infection in individuals living in an urban area does not induce strong regulatory responses.