To elucidate the role of innate immune responses in celiac disease, we investigated the effect of gliadin on blood monocytes from patients with celiac disease. Gliadin induced substantial TNF-alpha and IL-8 production by monocytes from patients with active celiac disease, lower levels by monocytes from patients with inactive celiac disease, and even lower levels by monocytes from healthy donors. In healthy donor monocytes gliadin induced IL-8 from monocytes expressing HLA-DQ2 and increased monocyte expression of the costimulatory molecules CD80 and CD86, the dendritic cell marker CD83, and the activation marker CD40. Gliadin also increased DNA binding activity of NF-kappaB p50 and p65 subunits in monocytes from celiac patients, and NF-kappaB inhibitors reduced both DNA binding activity and cytokine production. Thus, gliadin activation of HLA-DQ2(+) monocytes leading to chemokine and proinflammatory cytokine production may contribute to the host innate immune response in celiac disease.

Celiac disease (CD) is a gluten-responsive, chronic inflammatory enteropathy. IL-1 cytokine family members IL-1β and IL-18 have been associated with the inflammatory conditions in CD patients. However, the mechanisms of IL-1 molecule activation in CD have not yet been elucidated. We show in this study that peripheral blood mononuclear cells (PBMC) and monocytes from celiac patients responded to pepsin digest of wheat gliadin fraction (PDWGF) by a robust secretion of IL-1β and IL-1α and a slightly elevated production of IL-18. The analysis of the upstream mechanisms underlying PDWGF-induced IL-1β production in celiac PBMC show that PDWGF-induced de novo pro-IL-1β synthesis, followed by a caspase-1 dependent processing and the secretion of mature IL-1β. This was promoted by K+ efflux and oxidative stress, and was independent of P2X7 receptor signaling. The PDWGF-induced IL-1β release was dependent on Nod-like receptor family containing pyrin domain 3 (NLRP3) and apoptosis-associated speck like protein (ASC) as shown by stimulation of bone marrow derived dendritic cells (BMDC) from NLRP3−/− and ASC−/− knockout mice. Moreover, treatment of human PBMC as well as MyD88−/− and Toll-interleukin-1 receptor domain-containing adaptor-inducing interferon-β (TRIF)−/− BMDC illustrated that prior to the activation of caspase-1, the PDWGF-triggered signal constitutes the activation of the MyD88/TRIF/MAPK/NF-κB pathway. Moreover, our results indicate that the combined action of TLR2 and TLR4 may be required for optimal induction of IL-1β in response to PDWGF. Thus, innate immune pathways, such as TLR2/4/MyD88/TRIF/MAPK/NF-κB and an NLRP3 inflammasome activation are involved in wheat proteins signaling and may play an important role in the pathogenesis of CD.

The prevalence of celiac disease (CD) was determined in healthy blood donors and in high-risk groups of adults (a total of 1835 adults--randomly selected 1312 healthy blood donors, 102 patients with primary osteoporosis, 58 patients with autoimmune diseases and 365 infertile women). It was calculated on the basis of a two-step serologic screening method--in the first step IgA and IgG antigliadin antibodies (AGA) and IgA anti-gamma-glutamyltransferase ('transglutaminase') antibodies (ATG) were estimated, in the second step sera positive for IgA AGA and/or IgA ATG were examined for antiendomysial IgA (AEA) antibodies. Immunoenzymic assay (ELISA) was used for determining of AGA and ATG antibodies; immunofluorescence method, performed on human umbilical cord tissue, was used for assaying of AEA antibodies. Total serum IgA level in only IgG AGA positive subjects was measured by routine turbidimetric method. 0.45% of healthy blood donors, 0.98% of osteoporotic patients, 2.7% of patients suffering from autoimmune disease and 1.13% of women with infertility considered as immunologically mediated were found to be positive in both steps of serologic screening (AGA and/or ATG and antiendomysium positive). The presumed high prevalence of seropositivity for CD in apparently healthy Czech adult population was confirmed. In the high-risk groups, the prevalence of seropositivity for CD was approximately 2-4 times higher than in healthy blood donors. The real prevalence of CD in the tested groups, however, can be estimated after performing small intestinal biopsy in the seropositive patients.

Serology markers of coeliac disease (CD) - antigliadin IgA/IgG antibodies (AGA/AGG) with purified alpha-gliadin, antiendomysium IgA antibodies (EmA) and anti-tissue transglutaminase (atTG) IgA/IgG antibodies--determined in 1451 serum samples, were analysed with respect to different screening algorithms. Determination of atTG using five ELISA methods was compared taking into account the impact of human recombinant antigen and IgG class of atTG. A subgroup of 119 patients undergoing small intestinal biopsy was used to calculate sensitivity and specificity of CD markers. The highest sensitivity (94%) was obtained for AGG, and the highest specificity (93.5%) was obtained for EmA. All coeliac disease patients were detected using the combination of all four CD markers, resulting in 100% sensitivity. CD and type 1 diabetes mellitus autoantigens were determined in 139 diabetic patients. The atTG IgA mean value (16.7 IU/ml) was higher in the antiglutamate dehydrogenase antibody (GAD)-positive subgroup, where at least one CD marker was positive in 83.6% subjects. In the GAD-negative subgroup atTG IgA was 8.73 lU/ml and at least one CD marker was positive in 57.4% subjects. atTG in IgA and IgG classes could be recommended as valuable serological markers of CD in the differential diagnosis of malabsorption as well as in various screening algorithms. ELISA determination of atTG with human antigen could increase the specificity, especially in patients with other autoimmune diseases.

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