Phenotyping of peripheral blood lymphocytes in adult coeliac disease

Single-cell approaches to dissect adaptive immune responses involved in autoimmunity: the case of celiac disease

Single-cell analysis is a powerful technology that has found widespread use in recent years. For diseases with involvement of adaptive immunity, single-cell analysis of antigen-specific T cells and B cells is particularly informative. In autoimmune diseases, the adaptive immune system is obviously at play, yet the ability to identify the culprit T and B cells recognizing disease-relevant antigen can be difficult. Celiac disease, a widespread disorder with autoimmune components, is unique in that disease-relevant antigens for both T cells and B cells are well defined. Furthermore, the celiac disease gut lesion is readily accessible allowing for sampling of tissue-resident cells. Thus, disease-relevant T cells and B cells from the gut and blood can be studied at the level of single cells. Here we review single-cell studies providing information on such adaptive immune cells and outline some future perspectives in the area of single-cell analysis in autoimmune diseases.

Double-blind, randomised, placebo-controlled intervention trial to evaluate the effects of Bifidobacterium longum CECT 7347 in children with newly diagnosed coeliac disease

Interactions between the immune system and the intestinal microbiota may play a role in coeliac disease (CD). In the present study, the potential effects of Bifidobacterium longum CECT 7347 in children with newly diagnosed CD were evaluated. A double-blind, randomised, placebo-controlled trial was conducted in thirty-three children who received a capsule containing either B. longum CECT 7347 (10⁹ colony-forming units) or placebo (excipients) daily for 3 months together with a gluten-free diet (GFD). Outcome measures (baseline and post-intervention) included immune phenotype of peripheral blood cells, serum cytokine concentration, faecal secretory IgA (sIgA) content, anthropometric parameters and intestinal microbiota composition. Comparisons between the groups revealed greater height percentile increases (P= 0·048) in the B. longum CECT 7347 group than in the placebo group, as well as decreased peripheral CD3⁺ T lymphocytes (P= 0·004) and slightly reduced TNF-α concentration (P= 0·067). Within-group comparisons of baseline and final values did not reveal any differences in T lymphocytes and cytokines in the placebo group, while decreased CD3⁺ (P =0·013) and human leucocyte antigen (HLA)-DR⁺ T lymphocytes (P =0·029) and slightly reduced TNF-α concentration (P= 0·085) were detected in the B. longum CECT 7347 group. Comparison between the groups showed that the administration of B. longum CECT 7347 reduced the numbers of the Bacteroides fragilis group (P= 0·020) and the content of sIgA in stools (P= 0·011) compared with the administration of placebo. Although this is a first exploratory intervention with limitations, the findings suggest that B. longum CECT 7347 could help improve the health status of CD patients who tend to show alterations in gut microbiota composition and a biased immune response even on a GFD.

Immune phenotype of children with newly diagnosed and gluten-free diet-treated celiac disease

BACKGROUND

Recent data suggest the involvement of both the adaptive and the innate immune system in celiac disease (CD). However, little is known about the immune phenotype of children with CD and its alteration upon dietary intervention.

AIMS

We characterized the prevalence of major interacting members of the adaptive and innate immune system in peripheral blood of newly diagnosed children with CD and tested its alteration with the improvement of clinical signs after the introduction of gluten-free diet (GFD).

METHODS

Peripheral blood was taken from ten children with biopsy-proven CD at the time of diagnosis and after the resolution of clinical symptoms following GFD. As controls, 15 children with functional abdominal pain were enrolled. The prevalence of the cells of adaptive and innate immunity was measured with labeled antibodies against surface markers and intracellular FoxP3 using a flow cytometer.

RESULTS

Patients with CD were found to have lower T helper, Th1 and natural killer (NK), NKT and invariant NKT cell prevalence and with higher prevalence of activated CD4(+) cells, myeloid dendritic cells (DC) and Toll-like receptor (TLR) 2 and TLR-4 positive DCs and monocytes compared to controls. After resolution of symptoms on GFD, the majority of these changes normalized, although the prevalence of NK and NKT cell, DC and TLR-2 expressing DCs and monocytes remained abnormal.

CONCLUSIONS

The immune phenotype in childhood CD indicates the implication of both adaptive and innate immune system. The normalization of immune abnormalities occurs on GFD, but the kinetics of this process probably differs among different cell types.

Flow cytometry of intestinal intraepithelial lymphocytes in celiac disease

This article reviews the multiple uses of flow cytometry in the diagnosis, monitoring and research of celiac disease, the most prevalent chronic autoimmune gastrointestinal disease. The phenotyping of intraepithelial lymphocytes (IELs) is of clinical relevance in the diagnosis of the disease given the characteristic features of elevated CD3+ IELs (αβ and γδ TcR) and the decrease in CD3- IELs. IEL biomarkers are also useful in the assessment of the response to the gluten-free diet and, importantly, in the diagnosis of the severe complications of celiac disease: refractory celiac disease and enteropathy-associated T-cell lymphoma. Novel applications of flow cytometry for the detection of anti-transglutaminase antibodies (a validated biomarker of celiac disease) and of gluten (the triggering antigen of the autoimmune process) are also discussed. The assessment of diagnostic and prognostic biomarkers by flow cytometry in celiac disease is performed routinely in a growing number of centers and it is an example of the versatility of this technique and its applicability to the research and clinical study of solid tissues.

Systematic review: The evidence base for long-term management of coeliac disease

BACKGROUND

While gluten-free diet is an effective treatment for coeliac disease, the need for and goals of long-term management of patients are poorly defined.

AIM

To review systematically the complications and associations of coeliac disease, to identify potential risk factors, to define ways of assessing risk factors and to provide a strategy for management.

METHODS

Review of medical literature from 1975.

RESULTS

There is an increasing list of potential complications and/or conditions associated with coeliac disease, in particular, autoimmune disease, malignancy and bone disease. Risk factors that may predict or influence long-term outcomes include genetic susceptibility, environmental factors predominantly gluten ingestion, persistent small intestinal inflammation/injury and nutritional deficiencies. Genotyping of patients is yet to have an established clinical role in long-term management. Assessment of adherence to the gluten-free diet largely relies upon skilled dietary history, but the ultimate test is duodenal histopathology, which is the only currently established means of assessing healing. Symptoms, serology or other non-invasive means are poor predictors of healing and the likelihood of complications.

CONCLUSION

Evidence (albeit limited) that adherence to a gluten-free diet and mucosal healing prevent and/or ameliorate complications indicates that a planned long-term strategy for follow-up is essential.

Deficiency of invariant natural killer T cells in coeliac disease

BACKGROUND

Immunoregulatory invariant natural killer (iNK) T cells rapidly produce interleukin (IL)-4 and other cytokines that suppress a Th1 response and are deficient in some autoimmune diseases.

AIM

The aim of this study was to investigate any deficiency of iNK T cells in coeliac disease.

METHODS

Blood was collected from 86 subjects with coeliac disease and from 152 healthy control subjects for investigation of Valpha24+ T cells by flow cytometry. iNK T cells were assessed by Valpha24 and alpha-galactosylceramide/CD1d tetramer markers in 23 normal controls and 13 subjects with coeliac disease. Intracellular IL-4 was measured after anti-CD3 antibody stimulation. Duodenal biopsies were obtained in a subgroup of subjects with coeliac disease and control subjects for Valpha24 mRNA expression using relative PCR and for Valpha24+ T cells by immunofluorescence.

RESULTS

The mean numbers of circulating Valpha24+ T cells and iNK T cells in coeliac disease were 27% (p<0.001) and 16% (p<0.001), respectively, of levels in control subjects. After in vitro anti-CD3 stimulation, numbers of IL-4+ producing iNK T cells from subjects with coeliac disease were unchanged but increased by 21% in control subjects. In subjects with coeliac disease, Valpha24 mRNA intestinal expression was reduced to 17% (p<0.001) by relative PCR and numbers of intestinal Valpha24+ T cells were 16% (p<0.01) of levels in control subjects.

CONCLUSIONS

We conclude that Valpha24+ T cells and iNK T cells are deficient in coeliac disease. We speculate that this deficiency could contribute to the failure of immunological oral tolerance that seems to underlie this disease.

A decapeptide from durum wheat prevents celiac peripheral blood lymphocytes from activation by gliadin peptides

Identifying antagonist peptides able to inhibit the abnormal immune response triggered by gliadin peptides in celiac disease (CD) is an alternative therapeutic strategy for CD. The aim of this study was to evaluate the antagonist effect of 10mer, a decapeptide (sequence QQPQDAVQPF) from alcohol-soluble protein fraction of durum wheat, assessing its ability to prevent celiac peripheral blood lymphocytes from activation by gliadin peptides. Peripheral blood mononuclear cells (PBMC) were obtained from DQ2-positive untreated coeliac children and from healthy controls and incubated with the peptic-tryptic digest of bread wheat gliadin (GLP) and peptide 62-75 from alpha-gliadin both alone and with 10mer simultaneously. PBMC proliferation, release of pro-inflammatory Th1 cytokines interferon-gamma and tumor necrosis factor-alpha, release of immunoregulatory cytokine IL-10, and analysis of CD25 expression as indexes of lymphocytes activation were carried out. Enhanced lymphocytes activation was seen after exposure to GLP and p62-75, whereas the simultaneous incubation with 10mer inhibits the lymphocytes response. These data indicate that a peptide naturally occurring in durum wheat exerts in vitro an antagonist effect against gliadin toxicity and could have a protective effect in CD disease.

Coeliac disease and risk of renal disease-a general population cohort study

BACKGROUND

Coeliac disease (CD) may be a risk factor for renal disease.

METHODS

We investigated the risk of any form of glomerulonephritis (GN) (acute, chronic and non-specified), chronic glomerulonephritis (CGN) and renal replacement therapy including dialysis treatment and kidney transplantation (KT) in patients with CD in a general population-based cohort study. We used Cox regression to assess the risk of renal disease in 14,336 patients who had received a diagnosis of CD (1964-2003) and 69,875 reference individuals matched for age, calendar year, sex and county. Patients were identified using the Swedish Hospital Discharge Registry. Follow-up began 1 year after study entry.

RESULTS

CD was associated with an increased risk of any form of GN (hazard ratio (HR) = 1.64; 95% confidence intervals (CI) = 1.01-2.66; P = 0.046; 89 events), CGN (HR = 2.65; 95% CI = 1.34-5.24; P = 0.005; 39 events), dialysis (HR = 3.48; 95% CI = 2.26-5.37; P < 0.001; 102 positive events) and KT (HR = 3.15; 95% CI = 1.29-7.71; P = 0.012; 22 events).

CONCLUSION

We suggest that immune characteristics associated with CD increase the risk of chronic renal disease. Individuals with CD may also be at a moderately increased risk of any form of GN.

Lymphopenia in occupational pulmonary silicosis with or without autoimmune disease

An increased prevalence of autoimmune diseases such as rheumatoid arthritis has been demonstrated in silica-exposed patients. The aim of this study was to determine the peripheral blood lymphocyte phenotype in a population of silicotic workers employed in the slate mines of the district. Silicosis was assessed in 58 patients according to the International Labor Office's criteria. Clinical and biological data including flow cytometric evaluation of the lymphocyte subsets were compared with those from 41 healthy volunteers. The silicotic patients had a higher prevalence of autoimmune diseases (6/58 versus 0/41: P < 0.05) and of elevated antinuclear antibody titres compared to the control group. A very significant decrease of total lymphocyte count (P < 0.001) involving B, T and Natural Killer cells was found in silicotic patients as compared with matched healthy volunteers. A significant increase in the percentage of activated T cells (12.3%) was observed in the silicotic group as compared to 6.5% in the control group (P = 5 x 10(-5)). Our results show that in silicotic patients, the absolute number of circulating lymphocytes is diminished with an increased proportion of activated T cells. Whether these findings could predispose to the development of autoimmune disorders is discussed.

Apoptosis and peripheral blood lymphocyte depletion in coeliac disease

In coeliac disease (CD) immunological abnormalities are not confined to the small bowel and it has been suggested that changes in peripheral blood lymphocytes (PBL), such as lymphopenia and increased T-cell activation, may predispose to malignant or autoimmune complications of this condition. In the light of the recent findings about the Fas-Fas ligand (FasL) system in regulating lymphocyte homeostasis, the aim of the present study was to investigate peripheral lymphocyte Fas-mediated apoptosis in CD to establish whether the homeostatic role of apoptosis in peripheral T-cell selection is maintained. Moreover, because a soluble form of Fas has been described to be functionally implicated in the Fas signalling system, suggesting a relationship between some disorders and soluble Fas function, we measured levels of soluble Fas in sera of coeliac patients and analysed the relationship between these levels and the proportions of apoptotic and Fas(+) PBL to further explore the function of the Fas-FasL pathway in this condition. Finally, we evaluated whether the increased prevalence of anticardiolipin antibodies, recently described in CD, could be related to PBL apoptosis in this condition. We demonstrated an increased apoptosis and higher levels of Fas and FasL expression in PBL isolated from untreated coeliac patients when compared to treated coeliac patients and controls. In addition, low levels of soluble Fas and a significant positive correlation between anticardiolipin antibodies and PBL apoptosis were found in untreated CD. Then, our results showed an increased susceptibility of PBL to undergo Fas-mediated apoptosis in active CD. This increased apoptosis could be responsible for both lymphopenia and immunogenic exposure of phospholipids with subsequent production of autoantibodies.