Assessing the relative impact of lupus nephritis on mortality in a population-based systemic lupus erythematosus cohort.

OBJECTIVE: There is limited knowledge on the relative impact of lupus nephritis (LN) on morbidity and mortality in population-based systemic lupus erythematous (SLE) cohorts. Here, the primary aim was to compare mortality rates between patients with and without LN in a population-based SLE cohort. METHODS: The study cohort included all SLE patients resident in the city of Oslo during 1999-2008. Follow-up time was median 14 (0-15) years. Presence of LN was defined according to the 1987 American College of Rheumatology classification criteria for SLE. LN class was determined by renal biopsy. Data on kidney function, including presence of end-stage renal disease (ESRD), were obtained from patient charts. Standardized mortality ratios (SMRs) were estimated by comparing deaths in the SLE cohort with age- and gender-matched population controls. RESULTS: We found that 98/325 SLE patients (30%) developed LN, 92% of whom had occurrence within the first five years from disease onset. Incidence rate of ESRD was 2.3 per 1000 patient-years. A total of 56 deaths occurred during the study period, corresponding to an overall SMR in the SLE cohort of 2.1 (95% confidence interval (CI) 1.2-3.4). Estimated SMR for LN patients was 3.8 (95% CI 2.1-6.2), and for SLE patients without LN it was 1.7 (95% CI 0.9-2.7). CONCLUSION: In this population-based SLE cohort, we found that LN was associated with increased morbidity and mortality, whereas SLE patients who did not develop LN had good overall prognoses regarding survival.

Plasma vitamin D levels and inflammation in the aortic wall of patients with coronary artery disease with and without inflammatory rheumatic disease.

OBJECTIVES: Vitamin D modulates inflammation, and this may explain the observed associations between vitamin D status and disorders driven by systemic inflammation, such as coronary artery disease (CAD) and inflammatory rheumatic diseases (IRDs). The aims of this study were to assess vitamin D status in patients with CAD alone and in patients with CAD and IRD, and to explore potential associations between vitamin D status and the presence of mononuclear cell infiltrates (MCIs) in the aortic adventitia of these patients. METHOD: Plasma levels of 25-hydroxyvitamin D3 [(25(OH)D3] were determined by radioimmunoassay and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] by enzyme immunoassay in the 121 patients from the Feiring Heart Biopsy Study (FHBS) who had available histology data on adventitial MCIs; 53 of these had CAD alone and 68 had CAD and IRD. RESULTS: In the crude analysis, vitamin D levels were similar in CAD patients with and without IRD. After adjustment for potential confounders, IRD was associated with an increase of 8.8 nmol/L [95% confidence interval (CI) 1.0-16.6; p = 0.027] in 25(OH)D3 and an increase of 18.8 pmol/L (95% CI 4.3-33.3; p = 0.012) in 1,25(OH)2D3, while MCIs in the aortic adventitia were associated with lower levels of 1,25(OH)2D3 (ß = -18.8, 95% CI -33.6 to -4.0; p = 0.014). CONCLUSIONS: IRD was associated with higher levels of both 25(OH)D3 and 1,25(OH)2D3. These findings argue against the hypothesis that patients with high systemic inflammatory burden (CAD+IRD) should have lower vitamin D levels than those with less inflammation (CAD only). Of note, when controlled for potential confounders, low 1,25(OH)2D3 levels were associated with adventitial aortic inflammation.

High prevalence of inclusion body myositis in Norway; a population-based clinical epidemiology study.

BACKGROUND AND PURPOSE: Knowledge about the occurrence of sporadic inclusion body myositis (sIBM) in the general population is limited. Here, our aim was to identify and characterize every sIBM patient living in southeast Norway (population 2.64 million) from 2003 to 2012. METHOD: Two sIBM case finding strategies were applied. First, all hospital databases in southeast Norway were screened to identify cases with sIBM-compatible International Classification of Diseases 10 (ICD-10) codes. These cases were then manually chart reviewed. Secondly, all muscle histology reports encoded with inflammation were independently reviewed. Finally, cases were classified according to the 1997 and the 2011 European Neuro-Muscular Centre (ENMC) Research Diagnostic Criteria for sIBM. RESULTS: The combined case finding strategy identified 3160 patients with sIBM compatible ICD-10 codes, and a largely overlapping cohort of 500 patients having muscle biopsies encoded with inflammation. Detailed retrospective review of chart and histology data showed that 95 patients met the 2011 ENMC sIBM criteria and 92 met the 1997 criteria. Estimated point prevalence of sIBM was 33/1 000 000, equal with both criteria sets. Mean age at diagnosis was 66.9 years and mean diagnostic delay was 5.6 years. Chart review revealed higher frequencies of dysphagia (94% vs. 65%) and anti-Sjøgren syndrome A antibodies (39% vs. 12%) in female sIBM patients (n = 40) than in males. Coexisting rheumatic diseases were present in 25% of sIBM cases, with Sjøgren's syndrome in 10%. CONCLUSION: An estimated point prevalence of sIBM seven times higher than previously observed in Europe is reported. Our data show considerable diagnostic delay, a major challenge with new sIBM treatments in the pipeline.

Influence of the IL17A locus in giant cell arteritis susceptibility.

OBJECTIVE: Different lines of evidence have highlighted the role of IL-17A in the inflammatory process occurring in giant cell arteritis (GCA). The aim of the present study was to assess whether the IL17A locus influences GCA susceptibility and its clinical subphenotypes. METHODS: We carried out a large meta-analysis including a total of 1266 biopsy-proven GCA patients and 3779 healthy controls from four European populations (Spain, Italy, Germany and Norway). Five IL17A polymorphisms (rs4711998, rs8193036, rs3819024, rs2275913 and rs7747909) were selected by tagging and genotyped using TaqMan assays. Allelic combination and dependency tests were also performed. RESULTS: In the pooled analysis, two of the five analysed polymorphisms showed evidence of association with GCA (rs2275913: PMH=1.85E-03, OR=1.17 (1.06-1.29); rs7747909: PMH=8.49E-03, OR=1.15 (1.04-1.27)). A clear trend of association was also found for the rs4711998 variant (PMH=0.059, OR=1.11 (1.00-1.23)). An independent effect of rs2275913 and rs4711998 was evident by conditional regression analysis. In addition, the haplotype harbouring the risk alleles better explained the observed association than the polymorphisms independently (likelihood p value <10(-05)). CONCLUSIONS: Polymorphisms within the IL17A locus show a novel association with GCA. This finding supports the relevant role of the Th17 cells in this vasculitis pathophysiology.

Identification of the PTPN22 functional variant R620W as susceptibility genetic factor for giant cell arteritis.

OBJECTIVE: To analyse the role of the PTPN22 and CSK genes, previously associated with autoimmunity, in the predisposition and clinical phenotypes of giant cell arteritis (GCA). METHODS: Our study population was composed of 911 patients diagnosed with biopsy-proven GCA and 8136 unaffected controls from a Spanish discovery cohort and three additional independent replication cohorts from Germany, Norway and the UK. Two functional PTPN22 polymorphisms (rs2476601/R620W and rs33996649/R263Q) and two variants of the CSK gene (rs1378942 and rs34933034) were genotyped using predesigned TaqMan assays. RESULTS: The analysis of the discovery cohort provided evidence of association of PTPN22 rs2476601/R620W with GCA (PFDR=1.06E-04, OR=1.62, CI 95% 1.29 to 2.04). The association did not appear to follow a specific GCA subphenotype. No statistically significant differences between allele frequencies for the other PTPN22 and CSK genetic variants were evident either in the case/control or in stratified case analysis. To confirm the detected PTPN22 association, three replication cohorts were genotyped, and a consistent association between the PTPN22 rs2476601/R620W variant and GCA was evident in the overall meta-analysis (PMH=2.00E-06, OR=1.51, CI 95% 1.28 to 1.79). CONCLUSIONS: Our results suggest that the PTPN22 polymorphism rs2476601/R620W plays an important role in the genetic risk to GCA.

Interleukin-15 induces interleukin-17 production by synovial T cell lines from patients with rheumatoid arthritis.

IL-17-producing T cells (Th17 cells) are believed to contribute to local inflammation and joint damage in rheumatoid arthritis (RA). Limited data exist on Th17 cells located within the inflamed synovial tissue (ST) of patients with RA. Here, we aimed to generate polyclonal T cell lines (TCLs) from the RA ST and assess their cytokine production, including the effects of exogenous IL-15 on IL-17 production in vitro. For five patients with RA, polyclonal TCLs were established from ST obtained by joint surgery. Synovial TCLs were expanded and stimulated by anti-CD3/CD28 microbeads and exogenous cytokines. Cytokine production was assessed by culture supernatant analyses and intracellular flow cytometry, and TCLs were sorted based on their surface expression of CCR6. In addition to IL-17, we detected IL-6, IL-10, IFN-γ and TNF-α in the synovial TCL culture supernatants. Exogenous IL-15 increased the production of IL-17 as well as the other cytokines except IFN-γ. For IL-17, this effect was more pronounced after prolonged culture times. Intracellular flow cytometry confirmed the presence of IL-17+ and IL-17+ IFN-γ+ CD4+ T cells in the TCLs. IL-17+ and IL-17+ IFN-γ+ T cells were enriched in the CD4+ CCR6+ population. In conclusion, Th17 cells can be detected after polyclonal expansion and stimulation of RA synovial TCLs generated by joint surgery. The Th17 cells from the RA ST were enriched in the CD4+ CCR6+ population, and they were sensitive to exogenous IL-15. Th17 cells present within the synovial compartment may contribute to the RA pathogenesis and local joint damage.

Tissue transglutaminase selectively modifies gliadin peptides that are recognized by gut-derived T cells in celiac disease.

The action of tissue Transglutaminase (TGase) on specific protein-bound glutamine residues plays a critical role in numerous biological processes. Here we provide evidence for a new role of this enzyme in the common, HLA-DQ2 (and DQ8) associated enteropathy, celiac disease (CD). The intestinal inflammation in CD is precipitated by exposure to wheat gliadin in the diet and is associated with increased mucosal activity of TGase. This enzyme has also been identified as the main target for CD-associated anti-endomysium autoantibodies, and is known to accept gliadin as one of its few substrates. We have examined the possibility that TGase could be involved in modulating the reactivity of gliadin specific T cells. This could establish a link between previous reports of the role of TGase in CD and the prevailing view of CD as a T-cell mediated disorder. We found a specific effect of TGase on T-cell recognition of gliadin. This effect was limited to gliadin-specific T cells isolated from intestinal CD lesions. We demonstrate that TGase mediates its effect through an ordered and specific deamidation of gliadins. This deamidation creates an epitope that binds efficiently to DQ2 and is recognized by gut-derived T cells. Generation of epitopes by enzymatic modification is a new mechanism that may be relevant for breaking of tolerance and initiation of autoimmune disease.

The intestinal T cell response to alpha-gliadin in adult celiac disease is focused on a single deamidated glutamine targeted by tissue transglutaminase.

The great majority of patients that are intolerant of wheat gluten protein due to celiac disease (CD) are human histocompatibility leukocyte antigen (HLA)-DQ2(+), and the remaining few normally express HLA-DQ8. These two class II molecules are chiefly responsible for the presentation of gluten peptides to the gluten-specific T cells that are found only in the gut of CD patients but not of controls. Interestingly, tissue transglutaminase (tTG)-mediated deamidation of gliadin plays an important role in recognition of this food antigen by intestinal T cells. Here we have used recombinant antigens to demonstrate that the intestinal T cell response to alpha-gliadin in adult CD is focused on two immunodominant, DQ2-restricted peptides that overlap by a seven-residue fragment of gliadin. We show that tTG converts a glutamine residue within this fragment into glutamic acid and that this process is critical for T cell recognition. Gluten-specific T cell lines from 16 different adult patients all responded to one or both of these deamidated peptides, indicating that these epitopes are highly relevant to disease pathology. Binding studies showed that the deamidated peptides displayed an increased affinity for DQ2, a molecule known to preferentially bind peptides containing negatively charged residues. Interestingly, the modified glutamine is accommodated in different pockets of DQ2 for the different epitopes. These results suggest modifications of anchor residues that lead to an improved affinity for major histocompatibility complex (MHC), and altered conformation of the peptide-MHC complex may be a critical factor leading to T cell responses to gliadin and the oral intolerance of gluten found in CD.

Serum IgG antibodies to peptidylarginine deiminase 4 predict radiographic progression in patients with rheumatoid arthritis treated with tumour necrosis factor-alpha blocking agents.

BACKGROUND: Peptidylarginine deiminase 4 (PAD4) may generate epitopes targeted by anticitrullinated protein antibodies in rheumatoid arthritis (RA). A subset of patients with RA has serum autoantibodies to human recombinant PAD4 (hPAD4). Here, we assessed whether anti-hPAD4 status in RA predicted disease outcome after antitumour necrosis factor (anti-TNF)-alpha therapy. METHODS: We analysed RA sera obtained at baseline (n = 40) and after 1 year on anti-TNF-alpha therapy (n = 33) for anti-hPAD4 IgG. Association analyses between baseline anti-hPAD status and disease progression were performed. RESULTS: We found that 17 of 40 patients (42.5%) were serum anti-hPAD4 positive at baseline, and the anti-hPAD4 IgG levels were stable over 1 year on anti-TNF-alpha therapy. At baseline, there were indications that anti-hPAD4 positive patients had more severe disease than the negative patients. After 1 year on anti-TNF-alpha therapy, the anti-hPAD4 positive patients displayed a persistently elevated disease activity score using 28 joint counts score and increased progression in the van der Heijde-modified Sharp erosion score. Accordingly, more anti-hPAD4 positive than negative patients presented an increase in van der Heijde-modified Sharp erosion scores >0 over 1 year. CONCLUSIONS: Anti-hPAD4 IgG can be detected in a subset of RA sera and the levels are stable after initiation of anti-TNF-alpha therapy. Serum anti-hPAD4 may predict persistent disease activity and radiographic progression in patients with RA receiving anti-TNF-alpha therapy.

Serum IgG antibodies to peptidylarginine deiminase 4 in rheumatoid arthritis and associations with disease severity.

BACKGROUND: Antibodies targeting citrullinated antigens are specific for rheumatoid arthritis (RA). Citrullination is catalysed by the peptidylarginine deiminase (PAD) enzyme family. Critical enzymes are often targeted by disease-specific antibodies in complex immune-mediated diseases. Here, we have tested for autoantibodies against human recombinant PAD4 (hPAD4) in Caucasian RA patients. METHODS: A time-resolved fluorometric immunoassay based on hPAD4 was developed to analyse sera from two RA cohorts (n = 237 and n = 177), one systemic lupus erythaematosus (SLE) cohort (n = 84) and 148 healthy controls. Simple and multiple analyses were performed to examine possible associations between anti-hPAD4 and disease variables. RESULTS: Raised levels of anti-hPAD4 IgG were found in both RA cohorts compared to the controls, and 23% of the RA patients were anti-hPAD4 IgG positive. Anti-hPAD4 was associated with anti-cyclic citrullinated peptide (CCP) and rheumatoid factor (RF), as well as increased physical disability. Anti-hPAD4 was also associated with higher longitudinal radiographic damage scores and increased clinical joint pathology, but weaker than anti-CCP. No associations were found between anti-hPAD4 and selected Human leukocyte antigen (HLA)-DRB1 variants. CONCLUSIONS: Approximately 23% of Caucasian RA patients have serum IgG antibodies against hPAD4. The presence of serum anti-hPAD4 IgG was in simple analyses associated with a more severe disease phenotype, and the association with physical disability was maintained in multiple analyses.

Studies of gliadin-specific T-cells in celiac disease.

Celiac disease is an immune-mediated disorder that primarily affects the small intestinal mucosa. It is one of the few human disorders of which it is possible, and ethically acceptable, to obtain samples from the disease-affected tissue. This chapter describes how small intestinal biopsy specimens are utilized for studies of cell-mediated immune responses in celiac disease. The focus is mainly on practical procedures for isolation, growth under sterile conditions, and subsequent analyses of gliadin-specific T-cells derived from the small biopsy specimens. This chapter also provides guidelines for the preparation of different gliadin antigens suitable for T-cell analysis. Note that most of the T-cell assays described necessitate serological and/or genomic HLA typing of the celiac disease patients from whom the T-cells are derived.

Surface expression of transglutaminase 2 by dendritic cells and its potential role for uptake and presentation of gluten peptides to T cells.

Celiac disease is a chronic small intestinal inflammation driven by gluten-reactive T cells of the intestinal mucosa. These T cells are HLA-DQ2 or -DQ8 restricted, and predominantly recognize gluten peptides that are deamidated by the enzyme transglutaminase 2 (TG2). Our recent results strongly suggest that duodenal CD11c(+) dendritic cells (DC) are directly involved in T cell activation in the celiac lesion. The aim of this study was to investigate whether surface-associated TG2 could be involved in receptor-mediated endocytosis of gluten peptides, a process that may contribute to the preferential recognition of deamidated peptides. We found that both monocyte-derived DC and local CD11c(+) DC in the duodenal mucosa expressed cell surface-associated TG2. As phenotypic characterization of CD11c(+) DC in the celiac lesion suggests that these cells may be derived from circulating monocytes, we used monocyte-derived DC in functional in vitro studies. Using a functional T cell assay, we obtained evidence that cell surface-associated TG2 is endocytosed by monocyte-derived DC. However, we were unable to obtain evidence for a role of surface TG2 in the loading and subsequent generation of deamidated gluten peptides in these cells.

The effects of atorvastatin on gluten-induced intestinal T cell responses in coeliac disease.

Various experimental models suggest that the cholesterol-lowering drugs statins may also modulate immune responses. Cellular level studies on human disorders are needed, however, to provide a rational basis for clinical testing of statins as immune therapy. Coeliac disease, a chronic small intestinal inflammation driven by HLA-DQ2 restricted mucosal T cells that are specific for ingested wheat gluten peptides, is in many ways ideal for this purpose. In addition, there is a need for alternative treatment to the gluten-free diet in this disorder. Here we have assessed the effects of atorvastatin on gluten-reactive T cells, dendritic cells and the coeliac mucosa by in vitro culture of biopsies. Atorvastatin inhibited gluten-induced proliferation and specific cytokine production of human intestinal gluten-reactive T cell clones and lines. Dendritic cells exposed to atorvastatin displayed a reduced expression of the costimulatory molecule CD83 upon maturation with lipopolysaccharide. Incubation of intestinal biopsy specimens with atorvastatin in vitro, however, did not influence gluten-induced cytokine release. In conclusion, atorvastatin has specific effects on isolated gluten-reactive T cells and dendritic cells, but does not shut down the gluten-induced production of proinflammatory cytokines in intestinal biopsies.

Gliadin specific, HLA DQ2-restricted T cells are commonly found in small intestinal biopsies from coeliac disease patients, but not from controls.

The authors have analysed gliadin specific, CD4+ T cells isolated from small intestinal biopsies of 23 adult coeliac disease patients (20 on a gluten-free diet and three untreated) and nine control patients. The biopsies were stimulated ex vivo with a peptic/tryptic digest of gliadin for 24 h, and activated T cells were positively selected with paramagnetic beads coated with an antibody against the interleukin-2 receptor. The T cells were expanded and tested for gliadin reactivity and HLA restriction. Gliadin specific, polyclonal T cell lines were recovered from biopsies of all 23 patients. Inhibition studies of T cell lines from 21 patients with anti-HLA monoclonal antibodies indicated predominant presentation of the gliadin antigen by HLA-DQ2 in T cell lines from 11 patients (lines from seven patients with complete MoAb inhibition, the remaining with incomplete inhibition) and incomplete inhibition by HLA-DR3 in lines from three patients. Nine gliadin specific T cell clones from six patients were established; all of these were HLA-DQ2 restricted. Gliadin specific T cells were not found in biopsies from the non-coeliac controls. Our findings demonstrate that gliadin reactive T cells are commonly found in the intestinal mucosa of CD patients and they support the notion that the majority of T cells recognize gliadin peptide(s) when presented by the disease associated DQ2 molecules.

Production of a panel of recombinant gliadins for the characterisation of T cell reactivity in coeliac disease.

BACKGROUND/AIMS: Coeliac disease is a chronic intestinal disorder most probably caused by an abnormal immune reaction to wheat gliadin. The identification of the HLA-DQ2 and HLA-DQ8 as the molecules responsible for the HLA association in coeliac disease strongly implicates a role for CD4 T cells in disease pathogenesis. Indeed, CD4 T cells specific for gliadin have been isolated from the small intestine of patients with coeliac disease. However, identification of T cell epitopes within gliadin has been hampered by the heterogeneous nature of the gliadin antigen. To aid the characterisation of gliadin T cell epitopes, multiple recombinant gliadins have been produced from a commercial Nordic wheat cultivar. METHODS: The alpha-gliadin and gamma-gliadin genes were amplified by polymerase chain reaction from cDNA and genomic DNA, cloned into a pET expression vector, and sequenced. Genes encoding mature gliadins were expressed in Escherichia coli and tested for recognition by T cells. RESULTS: In total, 16 alpha-gliadin genes with complete open reading frames were sequenced. These genes encoded 11 distinct gliadin proteins, only one of which was found in the Swiss-Prot database. Expression of these gliadin genes produced a panel of recombinant alpha-gliadin proteins of purity suitable for use as an antigen for T cell stimulation. CONCLUSION: This study provides an insight into the complexity of the gliadin antigen present in a wheat strain and has defined a panel of pure gliadin antigens that should prove invaluable for the future mapping of epitopes recognised by intestinal T cells in coeliac disease.

Gliadin specific, HLA DQ2-restricted T cells are commonly found in small intestinal biopsies from coeliac disease patients, but not from controls.

The authors have analysed gliadin specific, CD4+ T cells isolated from small intestinal biopsies of 23 adult coeliac disease patients (20 on a gluten-free diet and three untreated) and nine control patients. The biopsies were stimulated ex vivo with a peptic/tryptic digest of gliadin for 24 h, and activated T cells were positively selected with paramagnetic beads coated with an antibody against the interleukin-2 receptor. The T cells were expanded and tested for gliadin reactivity and HLA restriction. Gliadin specific, polyclonal T cell lines were recovered from biopsies of all 23 patients. Inhibition studies of T cell lines from 21 patients with anti-HLA monoclonal antibodies indicated predominant presentation of the gliadin antigen by HLA-DQ2 in T cell lines from 11 patients (lines from seven patients with complete MoAb inhibition, the remaining with incomplete inhibition) and incomplete inhibition by HLA-DR3 in lines from three patients. Nine gliadin specific T cell clones from six patients were established; all of these were HLA-DQ2 restricted. Gliadin specific T cells were not found in biopsies from the non-coeliac controls. Our findings demonstrate that gliadin reactive T cells are commonly found in the intestinal mucosa of CD patients and they support the notion that the majority of T cell recognize gliadin peptide(s) when presented by the disease associated DQ2 molecules.

HLA binding and T cell recognition of a tissue transglutaminase-modified gliadin epitope.

DQ2 confers susceptibility to celiac disease (CD) and intestinal CD4(+) T cells of DQ2(+) CD patients preferentially recognize deamidated gliadin peptides. This modification can be mediated by tissue transglutaminase (tTG). We have investigated what role the tTG-modified residues play in DQ2 binding and T cell presentation using a model gamma-gliadin peptide (residues 134 - 153). Treatment of this peptide with tTG resulted in deamidation of Gln residues at positions 140, 148 and 150. Two of these residues act as DQ2 anchors at position P7 (148) and P9 (150) and increased the affinity of the modified peptide for DQ2 50-fold. Testing of a mutant DQ2 molecule demonstrated that the Lys residue at beta71 of DQ2 is important for binding of the deamidated peptide. A variant DQ2 molecule (with the same beta-chain but different alpha-chain) that does not confer susceptibility to CD was capable of presenting the gliadin peptide, but not pepsin/trypsin-digested gliadin, equally well to a T cell. This suggests that processing events might be involved in the preferential presentation of the gliadin peptide by the DQ2 molecule. Substitution of Gln with Glu in some positions not targeted by tTG, but in positions likely to be deamidated via non-enzymatic mechanisms, disrupted T cell recognition. This provides additional evidence that tTG is responsible for modification of gliadin in vivo.

Heterogeneous reactivity patterns of HLA-DQ-restricted, small intestinal T-cell clones from patients with celiac disease.

BACKGROUND & AIMS: T-cell immune reactions toward wheat gliadins seem important in the pathogenesis of celiac disease. We have previously shown that gliadin-specific T-cell clones (TCCs) from the small intestinal mucosa of patients with celiac disease are predominantly restricted by the celiac disease-associated HLA-DQ2 and HLA-DQ8 molecules, suggesting a link between the HLA association and immunopathogenesis. The aim of the present study was to investigate the nature of the stimulating gliadin antigens. METHODS: Three different pools of gliadins and one purified alpha-type and two purified gamma-type gliadin preparations were prepared by ion exchange chromatography and tested for recognition by a panel of small intestinal gliadin-specific TCCs. RESULTS: Evidence suggested that enzymatic digestion and heating of the gliadins influenced TCC stimulation. Most of the TCCs recognized all three gliadin pools, but some had distinct reactivity patterns. Thirteen of 21 TCCs responded to one or more of the three purified gliadins discerning highly discriminative patterns. CONCLUSIONS: Small intestinal, gliadin-specific T cells from patients with celiac disease show diverse reactivity patterns. Stimulation of large numbers of different gliadin-specific T cells in the small intestinal mucosa of patients with celiac disease may occur; this may be an important immunopathogenic step in the disease.

CD4+ T cells with specific reactivity against astrovirus isolated from normal human small intestine.

BACKGROUND & AIMS: The gut is the largest immunologic organ in the human body, but little is known about the antigen specificity of mucosal T cells. This study sought to determine whether T cells resident in the duodenal mucosa could recognize astrovirus, a common and clinically important gastroenteritis virus. Serum antibodies against astrovirus are prevalent, indicating frequent viral exposure and postinfectious induction of systemic immune responses. Mucosal immune responses may conceivably mediate protection on astroviral reinfections. METHODS: Small intestinal biopsy specimens with normal histology were obtained from 8 adults and challenged in an organ culture system with inactivated human astrovirus. T cells activated by the viral challenge were isolated either by immunomagnetic positive selection of mucosal resident cells or by collecting cells emigrating into the culture supernatant. RESULTS: Astrovirus-specific, mucosal T-cell lines were isolated from all 8 subjects. Analysis of 29 CD4+ T-cell clones from 3 subjects showed predominant HLA-DR restriction of astrovirus responses. Most of the T-cell clones showed a Th1-like cytokine profile when restimulated with astrovirus. CONCLUSIONS: Helper T cells residing in normal, duodenal mucosa of adult subjects recognize a common enteropathogenic virus. These mucosal CD4+ T cells are presumably important in mucosal defense against recurrent astroviral infections.