Subcutaneous vacuoles with suppuration and granulomas: a histological clue to atypical mycobacterial infection

An 83-year-old woman was referred to the Dermatology department with a papular eruption on her left arm, occurring below the scar site of a malignant melanoma in situ, which had been excised 6 months previously. On physical examination, multiple, tender, violaceous papules and nodules inferior to the scar were noted, with central pustules in some of the lesions.

Heterogeneous Recognition of beta 2-glycoprotein I by Antibodies from Antiphospholipid Syndrome Patients

Beta 2-glycoprotein I plays a pivotal role in the binding of antiphospholipid antibodies to phospholipid in patients with antiphospholipid syndrome. In this study the nature of the epitopes on beta 2-glycoprotein I (β2-GPI) recognised by sera from antiphospholipid syndrome (APS) patients (n = 15) was investigated and compared to rabbit polyclonal and mouse monoclonal anti-β2-GPI antibodies. β2-GPI was only recognised when bound to a high affinity binding support. The antigenic epitope on β2-GPI recognised by all APS patients was also dependent on disulphide bond integrity. Digestion of β2-GPI with elastase rapidly destroyed the epitope(s) on β2-GPI recognised by antibodies in 91% of APS patients. The main cleavage occurred at tryptophan316-lysine317 in the fifth domain. Digestion with staphylococcal V8 protease resulted in a 50% reduction in antibody binding in 81% of patients and the cleavage sites mainly involved the first domain of the molecule. There was considerable variability in the recognition of six different species of β2-GPI by serum from APS patients. The epitopes on β2-GPI bound by APS sera appear conformationally determined in all patients but are quite heterogeneous in the regions of β2-GPI that are recognised.

Allergy in Irish adults: a survey of referrals and outcomes at a major centre

BACKGROUND

There is an increasing demand for specialist public allergy services across Ireland. Little data exist on the patterns of allergic disease in Irish adults. The limited resources available require innovative strategies to ensure quality care delivery.

AIMS

This study aimed to review the types of allergy referrals and diagnostic outcomes at a major Irish centre, and to establish an efficient method of communication with non-specialist practitioners.

METHODS

Demographic data, referral characteristics and diagnostic outcomes from one hundred consecutive new allergy referrals were identified. Additionally, communications to a pilot email service were reviewed over a 12-month period and user satisfaction assessed.

RESULTS

Requests for the investigation of food allergy accounted for 71% of referrals. Despite this, the main diagnostic outcome in this cohort was a non-allergic condition, chronic spontaneous urticaria (56%). immunoglobulin E (IgE)-mediated food allergy was definitively diagnosed in only 9% of patients, with the majority of these presenting with anaphylaxis. The allergy advice email service received 43 requests for assistance over 12 months, mainly for help in the interpretation of an allergy clinical history. Feedback on the email service was universally positive.

CONCLUSIONS

The majority of patients in this cohort did not have IgE-mediated allergic disease. Increased awareness of the features that differentiate allergy from non-allergic conditions such as food intolerance or chronic spontaneous urticaria is required. The allergy advice email service should be developed further to play a key role in education and care delivery in partnership primary care.

Campylobacter jejuni cellulitis in a patient with pan-hypogammaglobulinaemia

The case of a 17-year-old male with recurrent episodes of cellulitis affecting his left shin is presented. The cellulitis had been present on an intermittent basis over an 18-month period despite several courses of both intravenous and oral antibiotics. Each course of antibiotics resulted in a temporary remission, but on four occasions the cellulitis then relapsed. The patient was known to have pan-hypogammaglobulinaemia and was receiving intravenous IgG replacement therapy every 3 weeks. Other than cellulitis, he remained generally well. The organism responsible for the cellulitis was unknown until Campylobacter jejuni was grown in blood cultures during one of the relapse episodes. Based on microbial sensitivity, the patient was treated with ciprofloxacin. This resulted in full resolution of the cellulitis and he remains well. This case illustrates the value of blood cultures in helping microbial identification, particularly in immunocompromised patients with atypical infections.

Cutaneous Fusarium solani infection in childhood acute lymphoblastic leukaemia

Cutaneous involvement is often an initial presentation of infection with Fusarium species, which occurs more commonly in immunocompromised hosts and may be either localized or widespread. Skin lesions typically appear as red or grey macules, which may develop central ulceration and black eschar. Secondary dissemination to extracutaneous organs may occur in immunocompromised hosts, especially those with prolonged and severe neutropenia. We describe a case of widespread cutaneous involvement after infection with Fusarium solani in childhood acute lymphoblastic leukaemia that responded successfully to treatment with prolonged liposomal amphotericin B.

Investigation of molecular markers in the diagnosis of refractory coeliac disease in a large patient cohort: Table 1

Aims:

Some patients with coeliac disease, despite strict adherence to a gluten-free diet, continue to have significant symptoms and/or a severe small intestinal histological lesion. The term “refractory coeliac disease” (rCD) is used to describe this condition. The purpose of this study was to investigate the value of tissue molecular markers reported to help in the diagnosis of rCD.

Methods:

Details on 61 patients with suspected rCD were collected. The clinical and laboratory findings in these patients were carefully evaluated, in part to determine whether patients were adhering to a strict gluten-free diet. The co-expression of CD3 and CD8 on intraepithelial lymphocytes was investigated by monoclonal antibody staining of small intestinal biopsy tissue; a finding of less than 50% CD3+ cells co-expressing CD8 was defined as an aberrant phenotype. T cell receptor gene rearrangement was assessed when a sufficient tissue sample was available.

Results:

A diagnosis of rCD was made in 38 patients based on clinical, laboratory and histological data. An aberrant intraepithelial lymphocyte population was found in 20 of these patients and in this group a clonal T cell population was found in five of seven patients tested. In the remaining 18 patients, the CD3/CD8 ratio was normal and two of seven tested had a clonal T cell population. After detailed monitoring, a diagnosis of rCD was excluded in the remaining 23 patients.

Conclusions:

This study supports the use of phenotypic and T cell clonality investigations in identifying patients with true rCD.

Dermatitis herpetiformis: no evidence of bone disease despite evidence of enteropathy

The majority of patients with dermatitis herpetiformis (DH) have small intestinal enteropathy that may result in bone loss. The objective of this study was to evaluate bone mineral density (BMD) in DH and to examine whether dietary treatment or degree of the small intestinal lesion correlate with BMD. Twenty-five patients with DH (18 men) were investigated. Detailed dietary assessment and duodenal biopsies were performed on all patients before entry into the study. BMD at lumbar spine and femur was determined by DXA scan. Bone biomarkers, vitamin D, and parathyroid status were assessed. Twenty patients had enteropathy. None of the patients had hypovitaminosis D or secondary hyperparathyroidism. Resorption and formation markers were within normal limits. BMD Z-scores were not significantly different from expected (-0.38; CI, -0.84 to 0.07) and femur (0.46; CI, -0.06 to 0.97). There was no relationship between BMD Z-scores and the severity of the degree of enteropathy. We conclude that enteropathy of differing severity is present in 80% of patients with DH, but this is not associated with bone disease.

Serum levels of soluble CD163 correlate with the inflammatory process in coeliac disease

BACKGROUND

In coeliac disease, following the introduction of a gluten-free diet, monitoring mucosal disease activity requires repeated small intestinal biopsies. If a test measuring a circulating inflammatory marker was available, this would be clinically valuable.

AIM

To determine if levels of soluble CD163, a scavenger receptor shed by tissue macrophages, correlated with the inflammatory lesion in coeliac disease.

METHODS

Serum samples were collected from 131 patients with untreated coeliac disease, 40 patients with treated coeliac disease, 92 non-coeliac disease control subjects and 131 healthy controls. A capture enzyme linked immunosorbance assay was established to measure levels of soluble CD163 in sera. The extent of the histological lesion in coeliac biopsies was assessed using a Marsh grading system.

RESULTS

Levels of CD163 in untreated coeliac subjects were significantly elevated when compared with the treated coeliac patients, the disease control group and the healthy control subjects (P < 0.0001 in each instance). Moreover, coeliac patients with the most marked histological lesion (Marsh 3) had significantly higher levels of soluble CD163 than patients with Marsh grade 2 lesions (P < 0.0004), with grade 1 lesions (P < 0.0001) and grade 0 lesions (P < 0.0001).

CONCLUSIONS

Measurement of soluble CD163 may be a useful method of monitoring the inflammatory lesion in coeliac disease.

Circulating levels of beta2-glycoprotein I in thrombotic disorders and in inflammation

Beta2-glycoprotein I (beta2GPI) is a plasma protein suspected to have a role in inhibition of thrombosis. This suspicion is reinforced by the observation that beta2GPI is the major target for autoantibodies in the antiphospholipid syndrome. However, little is known about its circulating levels in common thrombotic diseases or inflammation. We measured beta2GPI levels in 344 healthy controls, 58 normal pregnancies, 102 patients with non-haemorrhagic stroke, 121 patients with acute coronary syndrome and 200 patients with elevated C-reactive protein (CRP). In healthy individuals, we found a strong positive correlation between age and beta2GPI concentration (r = 0.274, P < 0.001) and that beta2GPI levels fall significantly after the eighth week of pregnancy (P = 0.002). We also found significantly reduced levels of beta2GPI in patients with stroke and in elderly patients with myocardial syndrome (P = 0.013 and 0.043). However, in neither group did beta2GPI levels change in the following six months, suggesting that the reduced levels were not a transient post-event phenomenon. In patients with inflammation, beta2GPI levels showed a significant negative correlation with CRP (r = -0.284, P < 0.001) and positively correlated with albumin and transferrin (r = 0.372 and 0.453, respectively with P < 0.001 for both). Furthermore, the largest reduction in beta2GPI levels occurred in patients with the highest CRP values (P < 0.001).

Immunohistochemical analysis of coeliac mucosa following ingestion of oats

There is now considerable clinical evidence that oats do not activate coeliac disease. Nonetheless, a reluctance to include oats in the gluten-free diet remains. Because gluten-induced damage is accompanied by activation of the gastrointestinal immune system, the purpose of this study was to investigate if similar changes were induced by oats ingestion. Small intestinal histological sections from 10 patients who ingested 50 g of oats daily for 3 months were investigated for possible evidence of immune activation. Tissue obtained before and after oats challenge was stained with a series of antibodies directed against the following molecules: human leucocyte antigen D-related (HLA-DR), Ki-67, CD25, CD54 [intercellular adhesion molecule 1 (ICAM-1)] and mast cell tryptase. None of the patients developed clinical or laboratory evidence of adverse effects. The distribution of intestinal HLA-DR expression was not affected by oats ingestion and the crypt epithelium remained unstained. In the pre-oats biopsies, the percentage of Ki-67 positive enterocytes, 29.5 +/- 6.9 [95% confidence interval (CI) 13.9-45.0] did not differ significantly from that found in post-oats biopsies, 41.2 +/- 3.7 (95% CI, 32.8-49.6), P = 0.19, not significant. Furthermore, oats ingestion did not alter the number of CD25 positive and tryptase positive cells. Finally, the distribution and intensity of ICAM-1 staining was unchanged by dietary oats. In summary, detailed immunohistological studies of biopsies from patients ingesting oats for 3 months did not reveal evidence of immune activation. Together with other reported findings, this study strengthens the view that oats can be included safely in the diet of gluten sensitive patients.

Barley and rye prolamins induce an mRNA interferon-gamma response in coeliac mucosa

BACKGROUND

In coeliac disease, wheat, barley and rye are traditionally excluded in the gluten-free diet. However, few studies have examined the small intestinal immune response to barley and rye.

AIM

To investigate the immunogenicity of barley and rye prolamins (hordein and secalin respectively) in comparison with wheat gliadin.

METHODS

Duodenal biopsies from 22 coeliac patients and 23 disease controls were cultured for 4 h with gliadin, hordein or secalin and compared with culture medium alone. Proinflammatory cytokines, interferon-gamma and interleukin-2, were quantified by TaqMan polymerase chain reaction and enzyme-linked immunosorbent assay.

RESULTS

Hordein caused the greatest increase in interferon-gamma mRNA in coeliac patients (median: 3.3-fold) in comparison with control subjects (median: 0.28-fold, P < 0.085). Secalin and gliadin induced similar levels of interferon-gamma mRNA with median fold-changes of 3.4 and 2.8, respectively, in coeliac patients in comparison with 1.6- and 1.1-fold increases in control subjects (P < 0.294 and P < 0.105, respectively). The median fold-changes for interleukin-2 mRNA did not differ between coeliac patients and controls. Cytokine protein was not upregulated.

CONCLUSION

The findings of this study provide evidence that barley and rye cause immune activation in the mucosa of coeliac patients and support the practice that barley and rye should be excluded from the gluten-free diet.

Intestinal T cell responses to cereal proteins in celiac disease

Celiac disease is caused by sensitivity to wheat gluten in genetically susceptible individuals. The etiological role of the other wheat-related cereals, barley, rye, and oats, is still debated. In order to investigate this issue further, in this study we examined the immune response of celiac mucosal T cell lines to fractions from all four cereals. Cell stimulation was assessed by measuring proliferation (employing (3)H-thymidine incorporation) or cytokine (IL-2, IFN-gamma) production. All five T cell lines demonstrated immunoreactivity to protein fractions from the four related cereals. In some cell lines, reactivity to wheat, barley, and rye was only evident when these cereal fractions had been pretreated with tissue transglutaminase. This study confirms the similar T cell antigenic reactivity of these four related cereals and has implications for their exclusion in the gluten-free diet. However, despite oats stimulation of T cell lines, this cereal does not activate a mucosal lesion in most celiac patients.

Haplotypes in the CTLA4 region are associated with coeliac disease in the Irish population

Chromosomal region 2q33 encodes the immune regulatory genes, CTLA4, ICOS and CD28, which are involved in regulation of T-cell activity and has been studied as a candidate gene locus in autoimmune diseases, including coeliac disease (CD). We have investigated whether an association exists between this region and CD in the Irish population using a comprehensive analysis for genetic variation. Using a haplotype-tagging approach, this gene cluster was investigated for disease association in a case-control study comprising 394 CD patients and 421 ethnically matched healthy controls. Several SNPs, including CTLA4_CT60, showed association with disease; however, after correction for multiple-testing, CTLA4-658C/T was the only polymorphism found to show significant association with disease when allele, genotype, or carrier status frequency were analysed (carrier status (Allele C), P = 0.0016). Haplotype analysis revealed a haplotype incorporating the CD28/CTLA4 and two 5' ICOS polymorphisms to be significantly associated with disease (patients 24.1%; controls 31.5%; P = 0.035), as was a shorter haplotype composed of the CTLA4 markers only (30.9 vs 34.9%; P = 0.042). The extended haplotype incorporating CD28/CTLA4 and 5' ICOS is more strongly associated with disease than haplotypes of individual genes. This suggests a causal variant associated with this haplotype may be associated with disease in this population.

The prevalence of coeliac disease among female subjects having bone densitometry

BACKGROUND

Osteoporosis frequently complicates coeliac disease but most studies focus on symptomatic patients at the time of diagnosis. Screening tests have revealed that many individuals with coeliac disease have mild, atypical, or absent symptoms.

AIM

To evaluate the relationship between coeliac disease and osteopenia or osteoporosis in female subjects attending for bone densitometry.

METHODS

We studied 371 female subjects attending for bone densitometry, without secondary causes of osteoporosis and included those with normal and with reduced bone mineral density. Mineral density was measured by dual energy X-ray absorptiometry. Screening for coeliac disease was by measurement of anti-endomysial antibody by indirect immunofluorescence.

RESULTS

Two of 115 (1.7%) female subjects with normal bone density and five of 256 (1.9%) female subjects with sub-normal bone density were positive for endomysial antibody. Five subjects who underwent small bowel biopsy had histological changes suggestive of coeliac disease.

CONCLUSIONS

In females referred for bone densitometry, endomysial antibody positivity was not more prevalent among those with reduced bone mineral density. Examining only patients with clinically detected coeliac disease may overestimate the frequency of complications. This study does not support population screening for coeliac disease in an area with a high frequency of the condition.

Chromosome 5q candidate genes in coeliac disease: Genetic variation at IL4, IL5, IL9, IL13, IL17B and NR3C1

Genetic predisposition to coeliac disease (CD) is determined primarily by alleles at the HLA-DQB locus, and evidence exists implicating other major histocompatibility complex-linked genes (6p21) and the CTLA4 locus on chromosome 2q33. In addition, extensive family studies have provided strong, reproducible evidence for a susceptibility locus on chromosome 5q (CELIAC2). However, the gene responsible has not been identified. We have assayed genetic variation at the IL4, IL5, IL9, IL13, IL17B and NR3C1 (GR) loci, all of which are present on chromosome 5q and have potential or demonstrated involvement in autoimmune and/or inflammatory disease, in a sample of 409 CD cases and 355 controls. Thirteen single nucleotide polymorphisms were chosen on the basis of functional relevance, prior disease association and, where possible, prior knowledge of the haplotype variation present in European populations. There were no statistically significant allele or haplotype frequency differences between cases and controls. Therefore, these results provide no evidence that these loci are associated with CD in this sample population.

Primary Immunodeficiency Disorders in the Republic of Ireland: First Report of the National Registry in Children and Adults

Data collection for the national registry for patients with primary immunodeficiency disorders in the Republic of Ireland commenced in 1996. One hundred and fifteen cases of primary immunodeficiency diseases were registered between December 1996 and February 2003. The most frequent primary immunodeficiency disorders were antibody deficiency (n = 53) and complement deficiency (n = 32). In addition, patients with T cell deficiency (n = 11) and chronic granulomatous disease (n = 11) were identified. A small number of patients with Wiskott-Aldrich syndrome, natural killer cell deficiency, DiGeorge syndrome and chronic mucocutaneous candidiasis were also registered. Comparison of our data with that recently reported in the European registry revealed that complement deficiency was more prevalent in the Republic of Ireland compared to other European countries. Results of our registry point to a significant prevalence of primary immunodeficiency disorders in the Republic of Ireland (2.9 cases per 100,000 population). However, it is likely that these figures underestimate the true prevalence of such cases in the country. We hope, with increased awareness of the national registry among primary care physicians, that more patients will be included and we will be able to identify accurately the frequency and the distribution of these disorders.

Haplotype variation at the IBD5/SLC22A4 locus (5q31) in coeliac disease in the Irish population

In addition to the well-established association of coeliac disease (CD) with HLA-DQ (6p21) and possibly CTLA4 (2q33), there is considerable evidence for a susceptibility locus on chromosome 5q, which contains many potential candidates for inflammatory disease, including a cluster of cytokine genes in 5q31. CD cases and controls were genotyped for four single-nucleotide polymorphism (SNP) markers that together characterize >90% of the haplotype variation at the IBD5 locus encoding, among others, the SLC22A4 gene. IBD5 and SLC22A4 map to 5q31 and have recently been associated with Crohn's disease and rheumatoid arthritis. Haplotype frequencies do not differ significantly between CD cases and controls in the Irish population, and therefore the chromosome 5 CD susceptibility locus most likely lies elsewhere on 5q.

Anti-transglutaminase antibodies and the serological diagnosis of coeliac disease

Tissue transglutaminase (tTG) has recently been identified as the antigenic target recognised by anti-endomysial antibodies in patients with coeliac disease. In this study, an enzyme-linked immunosorbent assay (ELISA) is used to measure IgA, IgG and IgM antibodies to tTG in patients with coeliac disease and a variety of other inflammatory disorders; and is compared to the standard immunofluorescence test used to detect endomysial antibodies (EMA). In the samples tested, 3% control sera (n=146), 83% EMA-positive sera (n=29), 9% patients with Graves' disease (n=94), 12% antimitochondrial antibody-positive sera (n=53), 11% rheumatoid arthritis patients (n=53) and 22% systemic lupus erythematosus (SLE) patients (n=46) were positive for anti-tTG antibodies. In contrast, none of the controls, 1% of patients with Graves' disease, 2% antimitochondrial antibody-positive sera, 2% rheumatoid arthritis patients and none of the SLE patients were positive for EMA. Measurement of IgG or IgM antibodies to tTG was much less reliable than IgA anti-tTG antibody for the serological diagnosis of coeliac disease. The addition of calcium to the coating buffer improved the assay characteristics of the anti-tTG ELISA. However, the IgA anti-tTG ELISA, with and without calcium, performed less well than the standard EMA test used for the serological diagnosis of coeliac disease. In particular, the anti-tTG ELISA gave a higher rate of non-specific positive reactions.

Avenin fails to induce a Th1 response in coeliac tissue following in vitro culture

BACKGROUND

It is well established that the wheat protein gliadin triggers inflammation in coeliac patients. However, the potential toxicity of avenin, the equivalent protein in oats, is debated.

AIM

To investigate the immunogenicity of avenin using the cytokines interferon gamma (IFN-gamma) and interleukin (IL)-2 as markers of immunological activity.

METHODS

Duodenal biopsies from coeliac patients were cultured with 5 mg/ml of peptic tryptic (PT) gliadin (n=9) or 5 mg/ml of PT avenin (n=8) for four hours. Biopsies cultured with RPMI 1640 alone served as controls. Non-coeliac biopsies were also cultured with PT gliadin (n=8) and PT avenin (n=8). Total RNA was extracted from the tissue after culture. Cytokine mRNA was quantified by TaqMan polymerase chain reaction. Secreted cytokine protein was measured in the culture supernatant by enzyme linked immunosorbent assay.

RESULTS

After culture with PT gliadin, an increase in IFN-gamma mRNA was observed in all nine patients with coeliac disease. Increased IFN-gamma protein was also found in four of these patients. Smaller increases in IL-2 mRNA were detected in six subjects with increased IL-2 protein found in two patients. In contrast with PT gliadin, there was no significant IFN-gamma or IL-2 response when coeliac biopsies were cultured with PT avenin. Similarly, biopsies from normal controls did not respond to PT gliadin or PT avenin stimulation.

CONCLUSIONS

The findings of this study suggest that the immunogenic sequences in gliadin are not present in avenin. Moreover, they are in keeping with in vivo studies which report that oats are safe for consumption by coeliac patients.

Tumour necrosis factor blocking agents: a new therapeutic modality for inflammatory disorders

Development of anti-tumour necrosis factor-alpha (anti-TNF alpha) treatment offers the potential to alter radically the course of inflammatory diseases such as rheumatoid arthritis and Crohn's disease using modalities directed against a specific inflammatory mediator. Controlled randomised trials in these diseases demonstrate clinical benefit associated with significant improvement in patients with severe active joint and intestinal disease, often when conventional therapies are unsuccessful. To date, anti-TNF alpha therapy has been well tolerated and shows a favourable safety profile. This review considers the nature of this therapy and current evidence of its clinical benefit and adverse effects.

Selective expansion and partial activation of human NK cells and NK receptor-positive T cells by IL-2 and IL-15

IL-2 and IL-15 are lymphocyte growth factors produced by different cell types with overlapping functions in immune responses. Both cytokines costimulate lymphocyte proliferation and activation, while IL-15 additionally promotes the development and survival of NK cells, NKT cells, and intraepithelial lymphocytes. We have investigated the effects of IL-2 and IL-15 on proliferation, cytotoxicity, and cytokine secretion by human PBMC subpopulations in vitro. Both cytokines selectively induced the proliferation of NK cells and CD56(+) T cells, but not CD56(-) lymphocytes. All NK and CD56(+) T cell subpopulations tested (CD4(+), CD8(+), CD4(-)CD8(-), alphabetaTCR(+), gammadeltaTCR(+), CD16(+), CD161(+), CD158a(+), CD158b(+), KIR3DL1(+), and CD94(+)) expanded in response to both cytokines, whereas all CD56(-) cell subpopulations did not. Therefore, previously reported IL-15-induced gammadelta and CD8(+) T cell expansions reflect proliferations of NK and CD56(+) T cells that most frequently express these phenotypes. IL-15 also expanded CD8alpha(+)beta(-) and Valpha24Vbeta11 TCR(+) T cells. Both cytokines stimulated cytotoxicity by NK and CD56(+) T cells against K562 targets, but not the production of IFN-gamma, TNF-alpha, IL-2, or IL-4. However, they augmented cytokine production in response to phorbol ester stimulation or CD3 cross-linking by inducing the proliferation of NK cells and CD56(+) T cells that produce these cytokines at greater frequencies than other T cells. These results indicate that IL-2 and IL-15 act at different stages of the immune response by expanding and partially activating NK receptor-positive lymphocytes, but, on their own, do not influence the Th1/Th2 balance of adaptive immune responses.

Flow cytometric measurement of intracellular migration inhibition factor and tumour necrosis factor alpha in the mucosa of patients with coeliac disease

There is increasing evidence that proinflammatory cytokines contribute to many of the small intestinal features in coeliac disease. The aim of the study was to investigate the expression of two proinflammatory cytokines, migration inhibition factor (MIF) and tumour necrosis factor alpha (TNF-alpha) in duodenal biopsy specimens from patients with coeliac disease on a gluten-free diet and normal control subjects. A flow cytometric system was used to analyse intracellular protein levels of MIF and TNF-alpha in freshly isolated cells from duodenal biopsies taken from 12 patients with treated coeliac disease and 10 healthy control subjects. From the biopsy specimens, single cell suspensions of the epithelium and lamina propria were prepared using EDTA/DTT and enzymes. Intracellular cytokine expression was studied in intraepithelial lymphocytes (IELs), lamina propria T cells (LP T) and intestinal epithelial cells using different surface labelling antibodies. MIF protein was constitutively expressed in IELs, LP T cells and epithelial cells from normal intestinal mucosa. In contrast, although TNF-alpha was found in LP T cells, this cytokine was virtually undetectable in either IELs or epithelial cells. In coeliac disease, intracellular levels of MIF were significantly higher in epithelial cells compared with control subjects (P = 0.005). Raised levels of TNF-alpha were found in epithelial cells (P = 0.03) as well as IELs (P = 0.045) from coeliac patients compared with controls. The findings from this study show up-regulated expression of MIF and TNF-alpha in IELs and epithelial cells of histologically normal mucosa in patients with coeliac disease. Increased expression of proinflammatory cytokines in cells occupying the epithelial layer could help explain the rapidity with which the coeliac mucosa may respond to gluten challenge.

Flow-cytometric detection of lactase expression in normal and coeliac intestinal epithelium

OBJECTIVE

Enterocyte lactase expression is a useful marker of gluten toxicity. In this study, the technique of flow cytometry was evaluated to quantify lactase expression in coeliac disease (CD).

METHODS

Duodenal enterocyte suspensions were obtained from 23 patients with CD, four patients with dermatitis herpetiformis (DH), and 33 control subjects. The percentage of enterocytes that reacted with anti-lactase monoclonal antibody was determined by flow cytometry. In some subjects, organ culture of duodenal biopsies in the presence of various stimuli (including gluten fractions) was performed before enterocyte analysis.

RESULTS

This study demonstrated that lactase expression can be readily investigated semi-quantitatively using flow cytometry. Moreover, the level of expression correlated with the extent of mucosal damage in gluten-sensitive individuals. However, in organ culture experiments, lactase expression did not change in the presence of gluten or after marked T-cell activation for 48 h.

CONCLUSIONS

Measurement of enterocyte lactase expression by flow cytometry is a useful adjunctive test in the diagnosis and monitoring of gluten-sensitive enteropathy. However, lactase expression is not a suitable marker of gluten-induced toxicity in organ culture.

Analysis and clinical effects of gluten in coeliac disease

The prolamin working group coordinates research on laboratory gluten analysis in food and on clinical evaluation of patient sensitivity to prolamins. As an observer organization to the Codex Alimentarius Commission, the group summarizes current data on analysis and effects of gluten in coeliac disease. All types of gliadin, the ethanol-soluble fraction of gluten, contain the coeliac-active factor. However, coeliac toxicity and immunogenicity (humoral and cellular) of various prolamins are not identical in coeliac patients. There are no conclusive data on the threshold of gluten sensitivity of coeliac patients. Information as to the long-term risk to coeliac patients exposed to small doses of gliadin is lacking. Therefore, every effort should be made to keep the diet of coeliac patients as gluten-free as possible. The prolamin group is currently evaluating a new enzyme-linked immunosorbent assay (ELISA) protocol for gluten analysis that could serve as a basis for further Codex regulations. The group recommends adherence to a single Codex limit for gluten-free foods. The current limit of 200 ppm gluten is questionable and requires reconsideration based on new information that will be available soon.

Impaired IgG responses in a child with homozygous C2 deficiency and recurrent pneumococcal septicaemia

Homozygous deficiency of the second component of complement (C2) is the most common inherited deficiency of complement. Although C2 deficiency has been detected in asymptomatic individuals, patients usually present with either autoimmune disease or recurrent pyogenic infection, particularly due to encapsulated bacteria such as Streptococcus pneumoniae, Haemophilus influenzae type b and Neisseria meningitidis. Interestingly, infection is the most common mode of presentation of C2 deficiency in young children (1). An association between C2 deficiency and IgG subclass deficiency has also been previously described. We now report a female child with C2 deficiency that presented at the age of 3 mo with recurrent pneumococcal septicaemia. Although IgG subclass levels were normal, specific IgG responses to vaccination against S. pneumoniae and H. influenzae were significantly impaired.

Heterogeneous recognition of beta 2-glycoprotein I by antibodies from antiphospholipid syndrome patients

Beta 2-glycoprotein I plays a pivotal role in the binding of antiphospholipid antibodies to phospholipid in patients with antiphospholipid syndrome. In this study the nature of the epitopes on beta 2-glycoprotein I (beta2-GPI) recognised by sera from antiphospholipid syndrome (APS) patients (n = 15) was investigated and compared to rabbit polyclonal and mouse monoclonal anti-beta2-GPI antibodies. beta2-GPI was only recognised when bound to a high affinity binding support. The antigenic epitope on beta2-GPI recognised by all APS patients was also dependent on disulphide bond integrity. Digestion of beta2-GPI with elastase rapidly destroyed the epitope(s) on beta2-GPI recognised by antibodies in 91% of APS patients. The main cleavage occurred at tryptophan316-lysine317 in the fifth domain. Digestion with staphylococcal V8 protease resulted in a 50% reduction in antibody binding in 81% of patients and the cleavage sites mainly involved the first domain of the molecule. There was considerable variability in the recognition of six different species of beta2-GPI by serum from APS patients. The epitopes on beta2-GPI bound by APS sera appear conformationally determined in all patients but are quite heterogeneous in the regions of beta2-GPI that are recognised.

Clinical features of coeliac disease today

Coeliac disease is an inflammatory disorder of the small intestine induced by dietary gluten. This frequently results in malabsorption of a range of important nutrients including iron, folic acid, calcium and fat-soluble vitamins. Coeliac disease in now considered to be a common disorder, possibly affecting 1:300 of the general population. Many patients present in adulthood, have minimal symptoms, and gastrointestinal manifestations are frequently absent. The diagnosis and screening for coeliac disease has been dramatically facilitated by testing for endomysial autoantibodies, although biopsy and demonstration of a characteristic histological lesion remains the definitive diagnostic investigation. Treatment with a gluten-free diet is effective but requires good patient compliance and monitoring to succeed.

Anti-Beta 2-glycoprotein I antibody isotype and IgG subclass in antiphospholipid syndrome patients

Beta 2-glycoprotein I (beta2-GPI) is an antigenic target recognised by antiphospholipid antibodies found in association with the antiphospholipid syndrome (APS). In this study, the prevalence of Immunoglobulin M (IgM) and IgA anti-beta2-GPI antibodies was examined in APS patients and compared with IgG antibodies. In addition the value of measuring antibody isotypes and IgG subclass was investigated in the laboratory diagnosis of APS. A solid phase enzyme linked immunosorbent assay was established to measure IgG, IgM and IgA and IgG subclass antibodies to beta2-GPI in patients with APS and a variety of other thrombotic and non-thrombotic disorders. Raised levels of IgM anti-beta2-GPI antibodies were observed in 65% of patients with APS, 21% with systemic lupus erythematosus (SLE), 23% with rheumatoid factor, 4% with stroke, 5% carotid artery stenosis (CAS), 17% with a biological false positive serology for syphilis, 43% with infectious mononucleosis (IM) and 27% with human immunodeficiency virus (HIV). The median value for IgM antibodies to beta2-GPI for all these groups ranged from 2 to 7 arbitrary units (AU). Elevated levels of IgA antibodies to beta2-GPI were found in patients with APS (47%), SLE (13%), rheumatoid factor (26%), CAS (48%), stroke (25%), VDRL false positive serology for syphilis (33%), IM (47%) and HIV (7%). The median value of IgA antibodies to beta2-GPI in all of these groups ranged from 2 to 4 AU. Conversely the median value for IgG anti-beta2-GPI in APS patients was 112 AU compared to 1-4 AU in the other conditions examined. The presence of IgM and IgA antibodies to beta2-GPI was much less specific and sensitive for APS than IgG, with raised levels of these isotypes seen in a variety of thrombotic and non-thrombotic disorders. Elevated levels of IgG1, IgG2, IgG3 and IgG4 antibodies to beta2-GPI were detected in APS patients. While all four IgG anti-beta2-GPI antibody subclasses were represented in APS patients there appeared to be a significant overall skewing towards to the IgG2 subclass.

Lactase enzyme, detected immunohistochemically, is lost in active celiac disease, but unaffected by oats challenge

OBJECTIVES

The loss of lactase activity that occurs in active celiac disease resolves on adherence to a gluten-free diet that excludes the cereals wheat, barley, rye, and oats. Recently, an immunohistochemical technique has been described to evaluate lactase expression in primary hypolactasia. We have adapted this method to study lactase activity in adult celiac patients and to assess its value as a diagnostic tool. In addition, given the results of two recent studies suggesting the safety of reintroducing oats cereal into the celiac diet, we have also evaluated the response of lactase expression to oats exposure.

METHODS

Duodenal biopsies from 26 patients were stained for lactase expression using an indirect immunoperoxidase method. Eleven disease control patients had normal architecture and nine had features of active celiac disease. Ten patients, who had celiac disease in clinical and histological remission, underwent oats challenge for 12 wk.

RESULTS

Confluent expression of lactase was observed in the 11 control patients with normal histology, whereas staining was absent in the nine patients with active celiac disease. All 10 patients with treated celiac disease had normal lactase expression after exposure to oats.

CONCLUSIONS

The immunohistochemical technique used in this study provides an easy, reliable method of assessing lactase enzyme and confirms the value of this index as a marker of celiac disease activity. The results of two recent studies demonstrating the lack of oats toxicity in adult celiac patients have been further corroborated by our findings, which show the preservation of lactase enzyme after oats challenge.

Increased HLA-DR and CD44 antigen expression in the gut: evidence of extraarticular immunological activity in rheumatoid arthritis

OBJECTIVE

To examine the gastrointestinal (GI) immune system in rheumatoid arthritis (RA) for evidence of activation.

METHODS

Duodenal biopsies from 25 patients with RA were obtained by endoscopy. Single cell suspensions from the epithelial layer and lamina propria were prepared. Flow cytometry was used to examine the expression of CD4, CD8, T cell receptor-gammadelta (TCR-gammadelta), TCR-alphabeta, HLA-DR, CD44, and interleukin 2 receptor on gut T lymphocytes. Fifteen disease control (DC) individuals and 6 patients with osteoarthritis (OA) taking longterm nonsteroidal antiinflammatory drug (NSAID) therapy were also investigated. Peripheral blood T lymphocytes from all individuals were examined for the expression of these surface molecules.

RESULTS

HLA-DR expression was significantly increased on intraepithelial lymphocytes (IEL) and enterocytes from patients with RA (n = 13) compared with the 2 control groups (p<0.01). Immunohistochemistry also revealed increased expression of HLA-DR on enterocytes from patients with RA. RA IEL (n = 6) expressed significantly higher levels of CD44 (p<0.02). In the lamina propria, a small but significant gammadelta T lymphocyte population (mean 5.5%, range 2-12%) was detected in rheumatoid factor positive RA patients (n = 8) compared with RF negative RA patients (n = 8, mean 2%, range 0.4-6%; p<0.01) and the disease control group (n = 15, mean 2%, range 0.5-5%; p<0.01). None of these changes were detectable in peripheral blood lymphocytes from patients with RA.

CONCLUSION

This study demonstrates evidence of activation of specific components of the GI immune system in RA. Peripheral blood T lymphocytes from patients with RA did not show increased expression of activation markers, suggesting that changes in the RA GI tract are not systemic but localized. Moreover, these changes appear to be independent of NSAID therapy.

T cell proliferation, MHC class II restriction and cytokine products of gliadin-stimulated peripheral blood mononuclear cells (PBMC)

The immune response of PBMC to gliadin was investigated in patients with coeliac disease (CoD) by examining proliferation, MHC restriction and cytokine production. Gliadin induced low levels of proliferation in 63% of eight untreated patients, 32% of 28 treated patients and 35% of 31 healthy control subjects. In MHC restriction studies, the proliferative response to gliadin was inhibited (range 47-98% inhibition) in the presence of a MoAb to HLA-DR in each of three coeliac and three control donors studied. Using flow cytometry, increased expression of activation markers (HLA-DR and IL-2R) was demonstrated on gliadin-stimulated T cells from four of nine coeliac patients and three of seven healthy control donors. Cytokines were studied in culture supernatants using ELISA. Gliadin was a potent inducer of IL-6 and IL-10 in 100% of coeliac patients and controls, whereas IL-4 was not produced in either subject group. Gliadin induced IL-2 production in 40% of untreated patients, 42% of treated patients and 35% of healthy control donors. Interferon-gamma (IFN-gamma) in gliadin-stimulated cultures was found only in coeliac patients, observed in 33% of untreated patients and 25% of treated patients. Spontaneous secretion of both IL-2 and IFN-gamma was found more frequently in patients with untreated disease (87% of cases versus 21% of controls for IFN-gamma and 40% versus 0% for IL-2). These results suggest, as manifest by IFN-gamma production, that gliadin stimulates a Th1/Th0-like response in coeliac patients and a Th0-like response in healthy controls.

Characterisation of anti-neutrophil cytoplasmic antibody target antigens using electrophoresis and western blotting techniques

Anti-neutrophil cytoplasmic antibodies (ANCA) are a family of autoantibodies which react with components of phagocytic cells, and are associated with vasculitis and other idiopathic inflammatory disorders. However, the antigenic targets of many of these autoantibodies have not been defined yet. In this study, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing (IEF) were evaluated for characterising the antigenic specificity of unidentified ANCA. The uncharacterised sera included those from patients with ulcerative colitis (n = 21), Crohn's disease (n = 5), cystic fibrosis (n = 16) and sarcoidosis (n = 2). In addition, sera from patients with antibodies to the phagocytic enzymes proteinase 3 (PR3) (n = 11) and myeloperoxidase (MPO) (n = 5) were also included. The sub-cellular localisation of antigens was determined by testing sera against crude neutrophil extract and sub-cellular fractions consisting of azurophilic granules, specific granules and cytosolic, fractions using enzyme-linked immunosorbent assays (ELISAs). All sera reacted with the crude and azurophilic granule extracts. The native system of IEF followed by capillary immunoblotting successfully detected anti-PR3 and anti-MPO in azurophilic granule extracts. In contrast, SDS-PAGE Western blotting failed to detect any reactivity, either to PR3 or MPO, in the crude extract or azurophilic granule extract. However, the antibody specificity of patient sera with uncharacterised autoantibodies could not be detected by IEF/capillary immunoblotting or SDS-PAGE. This study showed that the sub-cellular azurophilic granules are the antigenic target of a variety of uncharacterised ANCA. It also showed that IEF characterised both anti-PR3 and anti-MPO but failed to detect other forms of ANCA. In contrast, the majority of common ANCA were not detected by SDS-PAGE.

Diagnosis of gluten-sensitive enteropathy: is exclusive reliance on histology appropriate?

OBJECTIVE

Coeliac disease is a prevalent disorder but frequently remains undiagnosed because of varied modes of clinical presentation. In this study, methods for the detection of coeliac disease were evaluated in a clinical practice setting.

METHODS

Small intestinal histology, IgA anti-endomysial and IgG anti-gliadin antibody tests were performed on 441 unselected, consecutive patients under investigation for small intestinal disease. Response to treatment and other clinical events were monitored over the ensuing years.

RESULTS

Untreated coeliac disease was diagnosed in 97 patients and was excluded in 344. At clinical presentation, the endomysial antibody test was positive in 84 of the 97 untreated coeliac patients (sensitivity 87%) and negative in 340 of the 344 non-coeliac patients (specificity 99%). A typical histological lesion was found in 83 of the 97 coeliac patients (sensitivity 86%) but was absent in all 344 non-coeliacs (specificity 100%). The sensitivity of the gliadin antibody test was 69% and the specificity was 71%.

CONCLUSIONS

In unselected patients attending a gastroenterology clinic, small bowel histology and endomysial antibody serology show similar predictive value in the diagnosis of coeliac disease. These results emphasize that a combination of clinical, histological and serological criteria are required for effective diagnosis of this disorder. Exclusive reliance on histology or serology will result in failure to make a diagnosis in a significant proportion of patients.

Anti-phagocyte antibodies and infection

Autoantibodies specific to the cytoplasmic components of neutrophils and monocytes are associated with vasculitis and other idiopathic inflammatory disorders. In this study, using enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assays, sera from patients with acute and chronic infection were examined for the presence of anti-neutrophil and anti-monocyte antibodies: cystic fibrosis (n = 23), acute appendicitis (n = 22), tuberculosis (n = 26), acute gastroenteritis (n = 38), bronchiectasis (n = 9) and chronic granulomatous disease (n = 6). Sera from patients with Wegener's granulomatosis (n = 14), rheumatoid factor positive (n = 15) and healthy volunteers (n = 20) were used as positive and negative controls. In patients with chronic infection, using an ELISA assay, antibodies reactive with neutrophil or monocyte components (% reacting with monocyte components in parenthesis) were found in: 70% (39%) of patients with cystic fibrosis, 4% (38%) of patients with tuberculosis, 0% (33%) of patients with bronchiectasis and 0% (17%) of patients with chronic granulomatous disease. When these sera were examined using an immunofluorescence assay, all of the positive samples were found to react with the cytoplasmic component of neutrophils or monocytes. In patients with acute infection no antibodies (either IgG or IgM) were detected against neutrophils or monocytes. These findings imply that antibodies directed against neutrophil cytoplasmic components are predominantly associated with chronic pyogenic infection and antibodies specific to monocyte cytoplasmic components are predominantly associated with chronic granulomatous infection. This mirrors the findings in idiopathic inflammatory disease where anti-monocyte antibodies are associated with granulomatous disorders such as sarcoidosis, and anti-neutrophil antibodies are associated with neutrophilic disorders such as ulcerative colitis. These results suggest that chronic stimulation of phagocytes by infectious agents may result in the generation of a humoral response against phagocyte cytoplasmic components. This furthers our understanding of humoral immune responses against phagocytic cell components during infection.

Antibodies to prothrombin in antiphospholipid syndrome and inflammatory disorders

Antiphospholipid antibodies associated with the antiphospholipid syndrome (APS) have been shown to bind plasma proteins, particularly beta 2-glycoprotein I (beta2-GPI). In this study the incidence of antibodies to solid-phase prothrombin was examined in patients with antiphospholipid syndrome and a variety of other inflammatory disorders. Significantly elevated levels of IgG anti-prothrombin (anti-PT) antibodies were detected in 63% of patients with APS (n = 27, median 22 arbitrary units: AU), 33% with SLE (n = 92, median 14 AU). 45% with rheumatoid factor (n = 22, median 16 AU), 21% with carotid artery stenosis (n = 21, median 15 AU), 32% with stroke (n = 38, median 13 AU). 67% of patients with a false positive serology for syphilis (n = 21, median 24 AU), 37% with HIV (n = 30, median 14 AU), 29% with syphilis (n = 14, median 19 AU) and 3% with infectious mononucleosis (n= 30, median 9 AU). In addition, a group of lupus anticoagulant (LA) positive patients (n = 48) was examined for antibodies to prothrombin, beta2-GPI and cardiolipin. 10 (21%) patients had raised levels of IgG anti-PT antibodies, 30 (62%) had significantly elevated levels of anti-beta2-GPI antibodies and 15 (31%) had elevated levels of anticardiolipin antibodies (ACA). Of the LA-positive patients, 15 (43%) were identified with definite APS, eight (23%) with probable APS, two (6%) with possible APS and 10 (28%) patients had no clinical evidence of APS. In conclusion, antibodies to prothrombin were found in a variety of inflammatory disorders and were therefore not specific for the APS. However, identification of the plasma proteins recognized by antibodies from patients with APS may provide insight into the pathogenic mechanisms involved in the heterogenous clinical manifestations of the APS.