Background Human and animal studies have demonstrated that helminth infections are associated with a decreased prevalence of type 2 diabetes mellitus (T2DM). However, very little is known about their biochemical and immunological interactions. Methods To assess the relationship between a soil-transmitted helminth, Strongyloides stercoralis (Ss), and T2DM, we examined analytes associated with glycemic control, metabolic processes, and T-cell–driven inflammation at the time of Ss diagnosis and 6 months after definitive anthelmintic treatment. We measured plasma levels of hemoglobin A1c, glucose, insulin, glucagon, adipocytokines, and T-helper (TH) 1-, 2-, and 17- associated cytokines in patients with T2DM with (INF group) or without (UN group) Ss infection. In INF individuals, we again assessed the levels of these analytes 6 months following anthelmintic treatment. Results Compared to UN individuals, INF individuals exhibited significantly diminished levels of insulin and glucagon that increased significantly following therapy. Similarly, INF individuals exhibited significantly diminished levels of adiponectin and adipsin that reversed following therapy. INF individuals also exhibited significantly decreased levels of the TH1- and TH17- associated cytokines in comparison to UN individuals; again, anthelmintic therapy augmented these levels. As expected, INF individuals had elevated levels of TH2-associated and regulatory cytokines that normalized following definitive therapy. Multivariate analysis revealed that these changes were independent of age, sex, body mass index, and liver and renal function. Conclusions Strongyloides stercoralis infection is associated with a significant modulation of glycemic, hormonal, and cytokine parameters in T2DM and its reversal following anthelmintic therapy. Hence, Ss infection has a protective effect on diabetes-related parameters.

BackgroundTh9 cells are a subset of CD4+ T cells that express the protoypical cytokine, IL-9. Th9 cells are known to effect protective immunity in animal models of intestinal helminth infections. However, the role of Th9 cells in human intestinal helminth infections has never been examined.MethodologyTo examine the role of Th9 cells in Strongyloidis stercoralis (Ss), a common intestinal helminth infection, we compared the frequency of Th9 expressing IL-9 either singly (mono-functional) or co-expressing IL-4 or IL-10 (dual-functional) in Ss-infected individuals (INF) to frequencies in uninfected (UN) individuals.Principal FindingsINF individuals exhibited a significant increase in the spontaneously expressed and/or antigen specific frequencies of both mono- and dual-functional Th9 cells as well as Th2 cells expressing IL-9 compared to UN. The differences in Th9 induction between INF and UN individuals was predominantly antigen-specific as the differences were no longer seen following control antigen or mitogen stimulation. In addition, the increased frequency of Th9 cells in response to parasite antigens was dependent on IL-10 and TGFx since neutralization of either of these cytokines resulted in diminished Th9 frequencies. Finally, following successful treatment of Ss infection, the frequencies of antigen-specific Th9 cells diminished in INF individuals, suggesting a role for the Th9 response in active Ss infection. Moreover, IL-9 levels in whole blood culture supernatants following Ss antigen stimulation were higher in INF compared to UN individuals.ConclusionThus, Ss infection is characterized by an IL-10- and TGFβ dependent expansion of Th9 cells, an expansion found to reversible by anti-helmintic treatment.

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Helminth infections are known to modulate cytokine responses in latent tuberculosis (LTB). However, very few studies have examined whether this modulation is reversible upon anthelmintic therapy. We measured the systemic and mycobacterial (TB) antigen-stimulated levels of type 1, type 2, type 17, and regulatory cytokines in individuals with LTB and with or without coexistent Strongyloides stercoralis infection before and after anthelmintic therapy. Our data reveal that individuals with LTB and coexistent S. stercoralis infection have significantly lower levels of systemic and TB antigen-stimulated type 1 (gamma interferon [IFN-␥], tumor necrosis factor alpha [TNF-␣], and interleukin-2 [IL-2]) and type 17 (IL-17A and/or IL-17F) cytokines and significantly higher levels of systemic but not TB antigen-stimulated type 2 (IL-4 and IL-5) and regulatory (transforming growth factor beta [TGF-␤]) cytokines. Anthelmintic therapy resulted in significantly increased systemic levels of type 1 and/or type 17 cytokines and in significantly decreased systemic levels of type 2 and regulatory (IL-10 and TGF-␤) cytokines. In addition, anthelmintic therapy resulted in significantly increased TB antigen-stimulated levels of type 1 cytokines only. Our data therefore confirm that the modulation of systemic and TB antigen-stimulated cytokine responses in S. stercoralis-LTB coinfection is reversible (for the most part) by anthelmintic treatment.

Infection with the helminth parasite Strongyloides stercoralis (Ss) is commonly clinically asymptomatic that is often accompanied by peripheral eosinophilia. Granulocytes are activated during helminth infection and can act as immune effector cells. Plasma levels of eosinophil and neutrophil granular proteins convey an indirect measure of granulocyte degranulation and are prominently augmented in numerous helminth-infected patients. In this study, we sought to examine the levels of eosinophil, neutrophil, and mast cell activation-associated granule proteins in asymptomatic Ss infection and to understand their kinetics following anthelmintic therapy. To this end, we measured the plasma levels of eosinophil cationic protein, eosinophil-derived neurotoxin, eosinophil peroxidase, eosinophil major basic protein, neutrophil elastase, myeloperoxidase, neutrophil proteinase-3, mast cell tryptase, leukotriene C4, and mast cell carboxypeptidase-A3 in individuals with asymptomatic Ss infection or without Ss infection [uninfected (UN)]. We also estimated the levels of all of these analytes in infected individuals following definitive treatment of Ss infection. We demonstrated that those infected individuals have significantly enhanced plasma levels of eosinophil cationic protein, eosinophil-derived neurotoxin, eosinophil peroxidase, eosinophil major basic protein, elastase, myeloperoxidase, mast cell tryptase, leukotriene C4, and carboxypeptidase-A3 compared to UN individuals. Following the treatment of Ss infection, each of these granulocyte-associated proteins drops significantly. Our data suggest that eosinophil, neutrophil, and mast cell activation may play a role in the response to Ss infection.

Alteration in the frequency of monocyte subsets is a hallmark of tuberculosis-diabetes co-morbidity (TB-DM). To study this association, we examined the plasma levels of sCD14, sCD163, C-reactive protein (CRP) and soluble tissue factor (sTF) in individuals with TB-DM, TB or diabetes mellitus (DM), and in healthy controls (HC). Circulating levels of sCD14, sCD163 and sTF were significantly increased in TB-DM and DM compared with TB and HC; however, CRP was significantly increased in TB-DM and TB compared with DM and HC. During longitudinal follow up, sCD14, CRP and sTF levels remained significantly increased in TB-DM compared with TB from baseline (pre-treatment), during treatment (2nd month) and at the completion (6th month) of anti-TB treatment (ATT), whereas sCD163 was significantly higher in TB-DM compared with TB only at baseline. Moreover, the levels of sCD14 and sCD163 were significantly higher in TB-DM individuals with bilateral and cavitary disease and exhibited a significant positive relationship with bacterial burden. Levels of sCD14, sCD163 and CRP exhibited a positive relationship with HbA1c levels. Within the TB-DM group, those with known diabetes before incident TB (KDM) exhibited significantly higher levels of sCD14 and sCD163 compared with individuals with newly diagnosed DM with TB (NDM). Finally, KDM individuals on metformin treatment exhibited significantly lower levels of sCD14, sCD163 and CRP compared with those on non-metformin-containing regimens. Our data demonstrate that systemic monocyte activation marker levels reflect baseline disease severity and extent in TB-DM, differentiate KDM from NDM and are modulated by ATT and metformin therapy.

Microbial translocation, characterized by elevated levels of lipopolysaccharide (LPS) and related markers, is a common occurrence in HIV and some parasitic infections. This is usually associated with extensive inflammation and immune activation. To examine the occurrence of microbial translocation and the associated inflammatory response in asymptomatic Strongyloides stercoralis infection, we measured the plasma levels of LPS and other microbial translocation markers, acutephase proteins, inflammatory markers, and proinflammatory cytokines in individuals with (infected [INF] . Following treatment of S. stercoralis infection, the elevated levels of microbial translocation markers, acute-phase proteins, and inflammatory markers were all diminished. Our data thus show that S. stercoralis infection is characterized by microbial translocation and accompanying increases in levels of acute-phase proteins and markers of inflammation and provide data to suggest that microbial translocation is a feature of asymptomatic S. stercoralis infection and is associated with an inflammatory response.KEYWORDS microbial translocation markers, Strongyloides stercoralis, acute-phase proteins, inflammatory markers, proinflammatory cytokines M icrobial translocation refers to the process by which the translocation of bacterial products results in elevated levels of lipopolysaccharide (LPS) in the circulation without overt bacteremia (1). LPS and 16S rRNA (common to most bacteria) are often used as indicators of bacterial translocation, and endotoxin core IgG antibody (EndoCAb) is also used as a surrogate marker for the measurement of circulating LPS levels (1, 2). iFABP may also reflect a breach in epithelial integrity associated with chronic intestinal infections (3). The prevalence of increased acute-phase protein concentrations during episodes of inflammation is used as a supporting prognostic and diag-

Coexistent helminth infections are known to modulate T cell and cytokine responses in latent infection with Mycobacterium tuberculosis. However, their role in modulating chemokine responses in latent tuberculosis (LTB) has not been explored. Because chemokines play a vital role in the protective immune responses in LTB, we postulated that coexistent helminth infection could modulate chemokine production in helminth-LTB coinfection. To test this, we measured the levels of a panel of CC and CXC chemokines at baseline and following mycobacterial Ag or mitogen stimulation in individuals with LTB with (Strongyloides stercoralis + LTB +) or without S. stercoralis (S. stercoralis 2 LTB +) infection and in individuals without both infections, healthy controls (HC). At baseline (in the absence of a stimulus), S. stercoralis + LTB + individuals exhibited significantly diminished production of CCL1, CCL2, CCL4, CCL11, CXCL9, CXCL10, and CXCL11 in comparison with S. stercoralis 2 LTB + and/or HC individuals. Upon mycobacterial Ag stimulation, S. stercoralis + LTB + individuals exhibited significantly diminished production of CCL1, CCL2, CCL4, CCL11, CXCL2, CXCL9, and CXCL10 in comparison with S. stercoralis 2 LTB + and/or HC individuals. No differences were observed upon mitogen stimulation. Finally, after anthelmintic treatment, the baseline levels of CCL1, CCL2, CCL4, CCL11, and CXCL11 and mycobacterial Ag-stimulated levels of CCL1, CCL2, CCL11, CXCL2, and CXCL10 were significantly increased in S. stercoralis + LTB + individuals. Thus, our data demonstrate that S. stercoralis + LTB + individuals are associated with a compromised ability to express both CC and CXC chemokines and that this defect is at least partially reversible upon treatment. Hence, coexistent helminth infection induces downmodulation of chemokine responses in LTB individuals with likely potential effects on tuberculosis pathogenesis.