Adaptation of a Cell-Based High Content Screening System for the In-Depth Analysis of Celiac Biopsy Tissue

The IN Cell Analyzer 1000 possesses several distinguishing features that make it a valuable tool in research today. This fully automated high content screening (HCS) system introduced quantitative fluorescent microscopy with computerized image analysis for use in cell-based analysis. Previous studies have focused on live cell assays, where it has proven to be a powerful and robust method capable of providing reproducible, quantitative data. Using HCS as a tool to investigate antigen expression in duodenal biopsies, we developed a novel approach to tissue positioning and mapping. We adapted IN Cell Analyzer 1000's image acquisition and analysis software for the investigation of tissue transglutaminase (tTG) and smooth muscle alpha-actin (SM α-actin) staining in paraffin-embedded duodenal tissue sections from celiac patients and healthy controls. These innovations allowed a quantitative analysis of cellular structure and protein expression. The results from routine biopsy material indicated the intensity of protein expression was altered in celiac disease compared to normal biopsy material.

Twenty-Four Hour Ex Vivo Culture of Celiac Duodenal Biopsies

Organ culture is a valuable technique in celiac disease research. It provides the opportunity to examine interactions between different cell types during the disease process without the need for invasive in vivo studies. Biopsies are maintained in an oxygen-rich environment, in contact with, but not submerged in, culture medium. A very straightforward and successful method of organ culture is described here.

Celiac Disease: Diagnosis

Historically the diagnosis of celiac disease has relied upon clinical, serological, and histological evidence. In recent years the use of sensitive serological methods has meant an increase in the diagnosis of celiac disease. The heterogeneous nature of the disorder presents a challenge in the study and diagnosis of the disease with patients varying from subclinical or latent disease to patients with overt symptoms. Furthermore the related gluten-sensitive disease dermatitis herpetiformis, while distinct in some respects, shares clinical and serological features with celiac disease. Here we summarize current best practice for the diagnosis of celiac disease and briefly discuss newer approaches. The advent of next-generation assays for diagnosis and newer clinical protocols may result in more sensitive screening and ultimately the possible replacement of the intestinal biopsy as the gold standard for celiac disease diagnosis.

Immunological indicators of coeliac disease activity are not altered by long-term oats challenge

Coeliac disease is a gluten-sensitive enteropathy that develops in genetically susceptible individuals. The disease exhibits many features of an autoimmune disorder. These include the production of highly specific anti-endomysial autoantibodies directed against the enzyme tissue transglutaminase. It is well accepted that wheat-, barley- and rye-based foods should be excluded in the gluten-free diet. Although several studies report that oats ingestion is safe in this diet, the potential toxicity of oats remains controversial. In the current study, 46 coeliac patients ingested oats for 1 year and were investigated for a potential immunogenic or toxic effect. Stringent clinical monitoring of these patients was performed and none experienced adverse effects, despite ingestion of a mean of 286 g of oats each week. Routine histological analysis of intestinal biopsies showed improvement or no change in 95% of the samples examined. Furthermore, tissue transglutaminase expression in biopsy samples, determined quantitatively using the IN Cell Analyzer, was unchanged. Employing immunohistochemistry, oats ingestion was not associated with changes in intraepithelial lymphocyte numbers or with enterocyte proliferation as assessed by Ki-67 staining. Finally, despite the potential for tissue transglutaminase to interact with oats, neither endomysial nor tissue transglutaminase antibodies were generated in any of the patients throughout the study. To conclude, this study reaffirms the lack of oats immunogenicity and toxicity to coeliac patients. It also suggests that the antigenic stimulus caused by wheat exposure differs fundamentally from that caused by oats.

Peptic duodenitis--does it exist in the second part of the duodenum?

AIM

To re-evaluate all patients diagnosed histologically as having peptic duodenitis who had known endomysial antibody (EMA) test results to find out whether they would still be classified as peptic duodenitis on histological analysis and to review their subsequent clinical course.

METHODS

All mucosal biopsy specimens of the second part of the duodenum which were reported as showing features of peptic duodenitis and on which a serum EMA test had been done between January 1990 and January 1995 were reviewed. The number of intraepithelial lymphocytes (IELs) per 500 epithelial cells was also counted. The cases were re-assigned to one of three clinical categories: normal, coeliac disease or peptic duodenitis. Clinical details were reviewed for any cases where the re-assigned diagnosis and the EMA test result did not correlate.

RESULTS

Of the 24 cases, 21 showed a correlation between morphology and immunology-that is, if the biopsy specimen was characteristic of coeliac disease, the EMA was positive and if the biopsy specimen was normal or characteristic of peptic duodenitis, the EMA was negative. Three cases had a negative correlation: two had a positive EMA test but a biopsy diagnosis of peptic duodenitis and one had a normal duodenal biopsy specimen with a positive EMA test. On review of their clinical details, two of the three patients were diagnosed with coeliac disease and the other with silent coeliac disease. EMA test results and IEL counts correlated with the final diagnosis in all cases.

CONCLUSIONS

The diagnosis of peptic duodenitis on biopsy specimens of the second part of the duodenum was not substantiated in 92% of cases. On review of 24 cases, a histological diagnosis of peptic duodenitis was reached in four. In difficult cases, the histological appearances should be correlated with the EMA test result and the IEL count. Correlation of this kind should leave no cases of coeliac disease undiagnosed.

Changes in levels of IgM RF and alpha 2 PAG correlate with increased disease activity in rheumatoid arthritis during the puerperium

In this prospective study of 24 pregnant patients with rheumatoid arthritis, quiescent disease activity in 21 patients (88%) during gestation was followed by more active disease in the puerperium in 19 patients (79%). Increased disease activity was reflected in a deterioration in manual dexterity and this was found to correlate with a post-partum rise in IgM rheumatoid factor (IgM RF) (r = 0.86) and a post-partum decline in pregnancy associated alpha-2 glycoprotein (PAG) (r = 0.44). The increase in IgM RF also correlated with increased disease activity measured by a visual analogue scale (r = 0.44). Changes in IgA RF were not observed. These results suggest that PAG and IgM RF could contribute to the modulation and pathogenesis of rheumatoid arthritis during pregnancy.

Mucosal and systemic IgA anti-gliadin antibody in celiac disease. Contrasting patterns of response in serum, saliva, and intestinal secretions

Serum IgA anti-gliadin antibody estimation is a recognized screening method for celiac disease. However, celiac disease is primarily a small intestinal mucosal disorder, and so we have examined the possibility that secreted, mucosal IgA anti-gliadin antibody might provide a more relevant measure of gluten sensitivity than that obtained from serum tests. Serum IgA anti-gliadin antibody and serum, salivary, and small intestinal aspirate IgA anti-gliadin antibody were measured by enzyme-linked immunosorbent assay. Serum IgA and IgG anti-gliadin antibody were markedly increased in untreated celiacs (N = 31) as compared to normals (N = 20) or disease controls (N = 39) (P less than 0.0001). Levels were lower in treated (N = 30) than untreated celiacs (P less than 0.001). In intestinal aspirates both untreated and treated patients had similar levels of IgA anti-gliadin antibody (P = 0.48), but both were significantly higher than in controls (P less than 0.01). Salivary IgA anti-gliadin antibody, by contrast, was not increased in celiac patients as compared to controls. Serum IgA anti-gliadin antibody was the most sensitive (84%) and specific (95%) test for detecting untreated celiac disease. It was also the most useful in patient follow-up where it provides an early objective indicator of adherence to a gluten-free diet. Mucosal IgA responses to gliadin in celiac disease appear to be compartmentalized, with different portions of the gastrointestinal tract functioning as separate immunological organs. Our results also demonstrate that serum and secretory IgA production are under independent control.

Effect of cyclosporin on immune complex deposition in murine glomerulonephritis

Chronic glomerulonephritis (GN) was induced in N/M mice by daily injections of human serum albumin (HSA). The glomerular lesion was similar to that observed in human membranous GN and was characterized by intense mesangial and capillary loop immunofluorescent staining for HSA, IgG and C3. Electron microscopic examination revealed numerous electron-dense deposits in the mesangium and along the subepithelial side of the glomerular basement membrane, the latter deposits being associated with membranous spikes. Chronically injected mice that had been treated with cyclosporin (CsA) from Day 1 had different patterns of immune complex deposition. Mesangial deposition was apparently unaltered but no subepithelial deposits or spikes were evident. In addition, only two out of 21 HSA-injected mice which began CsA treatment on Day 21 had subepithelial deposits. There was no significant difference in serum levels of HSA-specific IgG between the three groups of mice. CsA treatment would therefore appear to ameliorate the immunopathology of antigen-induced glomerulonephritis in this model without affecting serum antibody levels, and may be of therapeutic value in the treatment of human membranous GN.

Complement activation within the coeliac small intestine is localised to Brunner's glands

Complement activation may play an important role in the pathogenesis of coeliac disease. In the present study immunohistochemical localisation of C3 and of a neoantigen exposed only on the terminal C5b-9 complement complex has been performed on small intestinal biopsy sections from newly diagnosed untreated coeliac patients, from coeliac patients on long-term gluten-free diet and from disease controls. Levels of C3 were markedly increased in treated coeliac patients compared with controls. Staining of C3 was concentrated subepithelially and within the centre of the lamina propria. No staining was detected at these sites using antibody to the neoantigen, however, strongly suggesting that the increased levels of C3 seen in the coeliac patients was the result of increased extravasation of serum proteins rather than complement activation. Surprisingly, complement activation was detected within the glands of Brunner. Positive staining using anti-C5b-9 neoantigen was found in all coeliac patients, both treated and untreated. Three of the 13 disease controls also showed reactivity with this antibody. This novel finding suggests that Brunner's glands, hitherto largely neglected structures, may play an important role in the development of coeliac disease.

Suppressor-cell activity in coeliac disease induced by alpha-gliadin, a dietary antigen

The wheat protein antigen alpha-gliadin, a fraction derived from gluten of molecular weight 60 000, activated suppressor cells from patients with coeliac disease but not from normal subjects or patients with Crohn's disease. Two other dietary antigens, casein and beta-lactoglobulin, failed to produce suppressor-cell activation. Since this phenomenon appears to be specific to coeliac disease, it may be of pathogenetic significance.

Cell mediated cytotoxicity against HLA-D region products expressed in monocytes and B lymphocytes. III. Inhibition by monoclonal antibodies and study of an HLA-B/DR recombinant

Attempts to further define the antigens recognized by HLA-D-region specific cytotoxic lymphocytes were undertaken using monocytes and transformed B cell lines as target cells. Monoclonal antibody against framework determinants of HLA-DR antigens partially blocked cell mediated lysis, suggesting that at least a portion of the D-region specific cytotoxic cells recognized the HLA-DR determinants. The study of a family with an HLA-B/DR recombinant showed that the determinants recognized by allogeneic anti-HLA-D-region cytotoxic lymphocytes are encoded outside of HLA-B. In addition, cytotoxic lymphocytes specific for the HLA-D region could be generated with cells identical throughout the interval from HLA-A to B and disparate only to the left of HLA-B.

Cell-mediated cytotoxicity against HLA-D-region products expressed in monocytes and B lymphocytes. II. HLA-A- or B-antigen compatibility is not required for HLA-D-region directed cytotoxicity

When effector cells were produced by sensitization in vitro with HLA-A- and B-compatible but HLA-D/DR-incompatible stimulator cells, cytotoxicity apparently was directed against a product of genes closely associated with HLA-D. For effective killing to occur with effector cells against certain minor histocompatibility antigens it is necessary that the effector cells and the target cells be matched for HLA-A or B. We have, therefore, investigated whether sharing of HLA-A or B antigens is needed to obtain efficient lysis with effector cells primed against HLA-D. Good killing was observed with effector cells against HLA-D/DRw3 and against HLA-D/DRw4 whether or not the HLA-A or B antigens were matched. The results indicated that compatibility at HLA-A or B is not required for cell-mediated cytotoxicity against a product of the HLA-D region. The HLA-D region appears to code for products that behave as strong histocompatibility antigens that can by themselves cause cell-mediated killing.

Cell-mediated cytotoxicity against HLA-D-region products expressed in monocytes and B lymphocytes. I. Blocking by Unlabelled cells and inhibition by antisera

Cytotoxic effector cells against HLA-D-region produts were generated in cultures with HLA-A- and B-matched, HLA-D-mismatched stimulating cells. Monocytes from unrelated donors sharing HLA-D/DR antigens with the primary stimulator were used as target cells. Lysis of target cells was inhibited by addition of unlabelled monocytes having the same HLA-D/DR antigens. Inhibition of cytotoxicity was also observed with unlabelled B cells, but T lymphocytes had little effect. The distribution of the target antigens, therefore, fits the known distribution of the products of HLA-D. In other experiments, a human alloantiserum specific for HLA-DRw3 was found to inhibit cellular cytotoxicity specific for HLA-D/DRw3. Lysis by HLA-D/DRw3-specific effector cells was not inhibited by sera against HLA-DRw2 or DRw7 or by antibodies against HLA-B8 using HLA-B8 positive, DRw3 positive targer cells. A xenogeneic serum against human Ia antigens, produced in rabbits, blocked cytotoxicity directed at DRw2, DRw3 and DRw4. These results suggest that cell-mediated cyctotoxicity was directed against HLA-D/DR or very closely associated determinants.

Specific inhibition of T-cell-mediated cytolosis by alloantiserum against HLA-D-related (DR) antigens

Lymphocytes sensitized against HLA-A and B region-compatible, HLA-D region-incompatible stimulators were cytotoxic for target cells having the correct HLA-D antigens. This form of cytotoxicity was inhibited by platelet-absorbed pregnancy sera containing antibodies to the HLA-DR antigens of the target cells but not by sera with antibodies against other DR antigens. This form of CML was also inhibited by unlabeled monocytes and B cells of the relevant HLA-D specificity but not by T lymphocytes from the same donors.