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Biomedical subjects

R Troncone

Publications and source records attributed to R Troncone.

At least 91 records · Page 5Linked to original sources

Early prediction of relapse during gluten challenge in childhood celiac disease.

Thirty-seven children, in whom celiac disease had been diagnosed because of flat mucosa on a gluten-containing diet and recovery on a gluten-free diet, were challenged with gluten powder, 10 g/day, in addition to an otherwise gluten-free diet. A small intestinal biopsy was performed before the challenge; clinical symptoms, a 1-h blood xylose test, and gliadin antibody measurement were used to establish the timing of the confirmatory biopsy. All but one case relapsed within 205 days (mode, 60 days). In no case was the relapse clinically evident. Raised levels of gliadin antibodies, a fall in xylose absorption, or both predicted the relapse in 37%, 7%, and 57% of cases, respectively. Evaluated individually, each test gave a considerable rate of false negative results. Discriminant coefficients produced for each test were used to compute a score that allowed the classification of patients into relapse/no relapse categories with a good degree of accuracy. The discriminant score rose sharply after only 15 days of challenge, indicating that it is possible to predict the relapse long before any clinical symptom appears.

Antibodies↗

Gluten-sensitive enteropathy in childhood.

Genetic and environmental factors (breast feeding, probably viral infections) play a role in the expression of the disease. Prevalence of GSE in childhood did not substantially decrease in the last 15 years in all European countries, where GSE is still more common in infantile age and presents frequently gastrointestinal symptoms. A decrease has been reported in childhood in several United Kingdom areas and in Finland, where the clinical presentation is changing, shifting upward with age and coming closer to the adult type of the disease. The following clinical problems have been reported in the recent literature: enamel hypoplasia; monosymptomatic short stature; arthritis and other immunologic diseases; association with diabetes, atopy, Iga deficiency, and probably Down's syndrome. Delay in puberty and other peculiar problems of the disease have been described in adolescents. Tests assessing the permeability of the small intestine and the blood levels of antigliadin antibodies have recently gained success as noninvasive tools for the diagnosis of the GSE. The gluten should be withdrawn from the diet and the challenge with gluten should be performed not before 12 months of gluten-free diet with an accurate timing of the biopsy on the basis of the antigliadin and antireticulin antibodies, to avoid clinical and growth damage. Celiac children do require a permanent gluten-free (and not poor) diet. In reality, too many celiac adolescents are off-diet.

Adolescent↗

Prevalence of atopy is unrelated to presence of inflammatory bowel disease.

The prevalence of atopy (assessed by prick testing and serum IgE measurement), and of symptoms associated with atopy, has been defined in 122 patients with inflammatory bowel disease (IBD) and 103 age-matched controls. History analysis for atopic symptoms, and serum IgE levels, showed no differences between controls and IBD patients, or IBD subgroups (Crohn's disease, ulcerative colitis, ulcerative proctitis). Both in controls and in IBD patients, the prevalence of positive skin tests was higher in young people (aged less than 30) than in others; taking account of age distribution within the groups, there were no differences between controls and IBD patients, or subgroups, in the prevalence of positive skin tests. Our finding do not support the hypothesis that reaginic hypersensitivity plays a significant role in the pathogenesis of IBD.

Adolescent↗

Gliadin presented via the gut induces oral tolerance in mice.

When an antigen is first presented via the gut, either priming or suppression of the systemic immune response may result. Many factors influence the outcome, including physico-chemical properties of the antigen. The aim of this study is to establish if wheat gliadin behaves as an oral immunogen or tolerogen. Mice reared on a gluten-free diet were fed gliadin, either as wheat flour in a standard rodent diet or as the purified molecule. Immune status (tolerant or sensitized) was then defined by measuring specific systemic immune responses after parenteral immunization of gliadin-fed and control mice. A single feed of 25 or 125 mg of purified gliadin resulted in a dose-dependent suppression of both cell-mediated and humoral immune responses. Similar oral tolerance was achieved by feeding mice with a gluten-containing diet for a week. Finally, mice reared on a normal, gluten-containing diet showed evidence of established oral tolerance, with significantly lower systemic immune response to gliadin than mice reared on gluten-free diet. These results indicate that gliadin is an effective oral tolerogen. In vivo studies on the immunogenicity of gliadins should be conducted in animals from gluten-free colonies.

Administration, Oral↗

In mice, gluten in maternal diet primes systemic immune responses to gliadin in offspring.

We have demonstrated recently immunological tolerance to gliadin in mice maintained on a diet that contains gluten. The aim of this study was to investigate whether oral tolerance is recreated in each generation by the ingestion of dietary gluten at weaning, or whether it is transferred from mother to young (as immune status or via passage of antigen) before birth or during lactation. Surprisingly, instead of transfer of tolerance we found priming of the immune response to gliadin in young mice. Mice born to mothers from normal, gluten-containing diet colonies had significantly greater systemic immune responses to gliadin after parenteral immunization than mice born to mothers from a gluten-free diet colony. Furthermore, feeding mothers gluten-containing diet for defined periods before and during pregnancy and during lactation also resulted in priming of the specific systemic immune responses of the offspring. These findings indicate that, in mice, sensitization to maternal dietary antigens readily occurs in utero or shortly after birth. This animal model should allow investigation of the immunological mechanisms concerned.

Animals↗

Passage of gliadin into human breast milk.

Samples of breast milk were taken from 53 women following the ingestion of 20 g of gluten. The samples were analysed for the presence of gliadin by a double-antibody sandwich enzyme immunoassay. Gliadin (5-95 ng/ml) was detected in 54/80 samples collected at various stages of lactation. Maximum levels in milk were found 2-4 hours after ingestion; gliadin could not be detected in serum. The transfer of gliadin from mother to infant might be critical for the development of an appropriate specific immune response to gliadin later in life.

Administration, Oral↗

In vitro gliadin antibody production by peripheral blood mononuclear cells from patients with coeliac disease.

In vitro spontaneous IgG gliadin antibody production was shown in peripheral blood mononuclear cell (PBMC) cultures from 12/14 patients with active coeliac disease; in most cases no increase and sometimes a marked reduction of the in vitro synthesis was observed after pokeweed mitogen (PWM) addition. Lower levels of gliadin antibodies were also detected in PBMC cultures from 7/12 coeliac patients in remission; in all the cases the synthesis was increased by PWM. In vitro production was confirmed by higher levels in 7-day culture supernatants than in 0-day frozen-thawed cell pellets and by the inhibitory effect of cycloheximide. Spontaneous release of antibodies occurred within the first 3 days of culture, while PWM-induced antibody production reached a plateau after 7-9 days. The analysis of the in vitro gliadin antibody production is a promising technique to assess the regulatory mechanisms involved in the humoral immune response to gliadin.

Adolescent↗

A sandwich enzyme immunoassay for wheat gliadin.

A sandwich double antibody solid-phase enzyme immunoassay (EIA) that can detect and quantitate gliadin is described. Quantitative analysis could be carried out in the range of 5-400 ng/ml and the assay was more sensitive than inhibition EIA. Gliadin possessed weak cross-reactivity with oats, maize and rice prolamines. In the presence of anti-gliadin antibody (serum from a patient with active coeliac disease) gliadin could not be detected, but the sensitivity of the assay was restored by heat treatment of the serum. This EIA can therefore be employed to assess the gliadin content of biological fluids where specific antibody may coexist.

Antibody Specificity↗

Impaired suppressor activity in children affected by coeliac disease.

Immunoregulatory cells were enumerated in 19 coeliac disease children on a gluten free diet by means of monoclonal antibodies that define total T lymphocytes (T3), helper/inducer T cells (T4), suppressor/cytotoxic T cells (T8) and monocytes (M1), as well as by means of surface receptors for Fc fragments of IgM and IgG (T mu and T gamma, respectively). In addition, suppressor cell function was assessed in 17 coeliac disease patients by examining the ability of concanavalin-A (Con-A)-activated suppressor cells to inhibit autologous cell response to mitogenic stimulus as compared with age-matched controls. No statistically significant differences were found in the percentages of subsets defined by monoclonal antibodies between coeliac disease patients and age-matched controls, whereas coeliac disease patients had a significant decrease of the subpopulation bearing membrane receptor for Fc fragment of IgG. Mean value was 8.5% in coeliac patients versus 13.4% in age-matched controls. In the functional assay, mononuclear cells from 10 out of 17 coeliac disease patients either totally or partially failed to suppress responder cells after Con-A-activation. This defect is not related to HLA-DR status, because no difference was found between patients-HLA-matched and unmatched normal individuals. In this assay, mononuclear cells of three coeliac disease patients with low suppressor activity were able to inhibit responder cells to the same extent as controls, when indomethacin was used to block prostaglandin production in the induction phase of Con-A-activated suppressor cells. Our results suggest that an abnormality in immunoregulation may play a role in the pathogenesis of coeliac disease.

Adult↗

A solid-phase radioimmunoassay for IgG gliadin antibodies using 125I-labelled staphylococcal protein A.

A sensitive radioimmunoassay for IgG gliadin antibodies is described. Serum specimens were added to wells of plastic microtitre plates coated with gliadin. After removal of the unbound material, gliadin antibodies were detected by adding 125I-labelled staphylococcal protein A (125I-SpA). Serum specimens from coeliac patients on a normal diet or on a gluten-free diet were tested, as well as sera from an age-matched control group. Measurements to obtain precise quantitative values were made with gliadin antibody-rich serum as reference standard. High titres of gliadin antibodies were found in 18 out of 19 coeliac patients on a normal diet (95%); in patients on a strict gluten-free diet serum values did not exceed 2 S.D. of the control mean. Due to the high sensitivity of the method a low but detectable amount of gliadin antibody was present in the sera of all controls.

Adolescent↗

Immunoregulatory T subsets in chronic active viral hepatitis: characterization by monoclonal antibodies.

Immunoregulatory T subsets, defined by monoclonal antibodies, were enumerated in children affected by HBsAg-positive chronic active hepatitis. The helper to suppressor/cytotoxic cells ratio was lower in patients than in age-matched controls. The lower ratio was mainly due to an increase of lymphocytes of the suppressor/cytotoxic phenotype. Helper cells were even fewer in severe chronic hepatitis patients, thereby lowering still further the helper/suppressor ratio. Therapy seemed to influence the ratio in patients affected by moderate active chronic hepatitis, for four of eight children treated with azathioprine and prednisone had a ratio within -1 SD of normal values. The increase of the suppressor/cytotoxic cells in patients affected by chronic hepatitis might be a means for limiting virus-induced cell hyperactivity.

Adolescent↗

Characterization of the inflammatory infiltrate in peptic oesophagitis.

BACKGROUND: The diagnosis of oesophagitis is mainly based on histology, but interpretation of endoscopic biopsies is often difficult. We performed immunohistochemical studies on oesophageal biopsies to see if better characterization of the inflammatory cell infiltrate would improve the accuracy of the histologic diagnosis of gastro-oesophageal reflux disease. METHODS: The study groups consisted of 40 consecutive children (mean age +/- SD: 79.6 +/- 5l.9 months; 20 boys) with gastro-oesophageal reflux disease and 7 symptomatic children (mean age +/- SD: 52.6 +/- 37.0 months; 3 boys) without gastro-oesophageal reflux disease. All patients underwent upper gastrointestinal endoscopy with oesophageal biopsies. The diagnosis of gastro-oesophageal reflux disease was established by conventional endoscopic and histologic criteria. In each mucosal biopsy specimen, the number of intraepithelial CD3+, CD25+ (IL2 receptor+), ICAM+, HLA-DR+ and mucosal mast cells were determined. RESULTS: Conventional histology was in close agreement with endoscopic findings (p<0.001) and reflected the clinical score even more than endoscopic findings. Conventional histology significantly correlated with each inflammatory immunohistochemical marker (<0.05 for each), but the markers were not predictive of symptom severity. Immunohistochemical markers were always abnormal in the gastro-oesophageal reflux disease patients, even in the mildest cases of oesophagitis. CONCLUSIONS: Although there is a good correlation between symptoms and histology, in a subset of patients, immunohistochemical studies appear useful in supporting the histological diagnosis of gastro-oesophageal reflux disease.

Biopsy↗

An analysis of cereals that react with serum antibodies in patients with coeliac disease.

Sera from six children with active coeliac disease, and elevated titres against gliadins and from six age-matched controls, were examined for IgG antibodies against different cereal proteins by a solid-phase radioimmunoassay. Antibodies to the major wheat proteins and the prolamines of other cereals were present in low titre in all control sera. In coeliac sera, significantly higher titres were found against A-gliadin, as well as against hexaploid and tetraploid wheat whole gliadins. Gliadin peptic-tryptic digest retained a significant antigenic activity, completely lost by peptic-tryptic-pancreatic digest. High titres were also found when coeliac sera were tested against wheat glutenins, albumins, and globulins, as well as against barley, oats, and maize prolamines; rice prolamines gave lower titres. Serum from whole gliadins and A-gliadin immunized rabbits showed a similar spectrum of reactivity against prolamines as coeliac sera. Our results indicate a dissociation between immunogenic properties of cereal proteins and toxicity in coeliac disease.

Antibodies↗