Screening by anti-endomysium antibodies for celiac disease in Tunisian children with type 1 diabetes mellitus.

AIM: Celiac disease (CD) and type 1 diabetes mellitus (DM1) can frequently coexist, presumably due to a common genetic predisposition. The present study was designed to evaluate the frequency of CD among Tunisian children with DM1. PATIENTS AND METHODS: A total of 205 diabetic children (92 girls, 113 boys, age range 6 months-15 years, median 11 years) were screened for CD by determination of IgA anti-endomysium antibodies (EMA). RESULTS: EMA were positive in 17 out of 205 (8.3%) children with DM1. The median age of DM1 at onset was significantly lower in patients with EMA than those without EMA (P<10(-7)). In 13 of 17 EMA-positive patients, duodenal biopsy could be performed and a destructive type of CD was confirmed in 11 of them: 8 patients showed total villous atrophy, 3 patients showed a partial villous atrophy. The other two patients showed a normal histological picture with normal number of intraepithelial lymphocytes. Parents of the remaining EMA-positive children refused endoscopy. Thus the prevalence of biopsy-proven CD was 5.3% (11/205). It was 7.6% (7/92) in girls and 3.5% (4/113) in boys but the difference was not statistically significant. Seventy three percent of patients with CD were asymptomatic. CONCLUSIONS: The prevalence of clinically unrecognized CD, found by EMA screening, is high in Tunisian children with DM1. We suggest that children with diabetes should be screened for CD.

Screening for celiac disease in Tunisian patients with Graves' disease using anti-endomysium and anti-tissue transglutaminase antibodies.

OBJECTIVE: Celiac disease (CD) can be associated with autoimmune thyroid diseases. The aim of this study was to screen for CD in patients with Graves' disease in Tunisia. PATIENTS AND METHODS: Sera from 161 patients with Graves' disease were tested for IgA class anti-endomysium antibodies (AEA) using indirect immunofluorescence on cryostat sections of human umbilical cord and for IgA class anti-human tissue transglutaminase antibodies (AtTG) by ELISA. RESULTS: AEA were positive in 6 out of 161 (3.7%) patients with Graves' disease and all 6 patients were also positive for AtTG. Four of these 6 patients with positive serological markers of CD underwent duodenal biopsy; three had marked villous atrophy, one has normal histological picture and two did not agree to undergo biopsy. The prevalence of biopsy confirmed CD in patients with Graves' disease was 1.86% (3/161). CONCLUSION: Patients with Graves' disease are at substantial risk of CD and therefore antibody screening for CD may be included in the work-up of these patients. Either AEA or AtTG may be used.

Prior exposure to the carrier regulates rat immune responses to a conjugate vaccine.

Small vaccine antigens including peptides generally need to be linked to larger molecules or carriers in order to induce high levels of immune responses. The potential of unwanted immune responses to the carriers represents a major drawback for the conjugated vaccines. The carriers could also regulate the immune responses to the haptens and these effects need to be prevented in order to achieve adequate responses to the vaccines. We examined means to reduce the unwanted reactions to the carrier. For this purpose, we investigated whether prior exposure of rats to a human IgG(1) (hIgG(1)) carrier would affect their subsequent responses to an OVA peptide (i.e., OVA(173-196)). Prior exposure to the hIgG(1) carrier did not affect the T cell responses to the peptide antigen. However, IgG(1) Ab responses to the peptide antigen were enhanced while IgE Abs were reduced. These results show that responses to the hapten are not systematically relevant to the carrier pre-immunization and that the conjugate could achieve desired responses by selective immune responses suppression. Such models of vaccines with enhanced anti-hapten responses and reduced levels of potentially harmful responses could be of great interest for the development of new immune therapies.

The [173-196] fragment of ovalbumin suppresses ovalbumin-specific rat IgE responses.

Peptides and protein hydrolysates are attractive tools for the induction of tolerance or regulation of targeted B and/or T cell responses. In vivo, peptides are mainly produced by the action of digestive enzymes or following the processing of exogenous antigens by antigen-presenting cells (APCs). In vitro, these molecules are generally produced by enzymatic digestion and chemical hydrolysis of proteins. We investigated the T and B cell determinants of the major food allergen ovalbumin (nOVA) in rat by analyzing (1) the stimulatory effect of nOVA peptides generated by cyanogen bromide (CNBr) cleavage on nOVA-specific T cells, and (2) the potential of CNBr-derived OVA fractions to induce oral tolerance to nOVA. Peptide fractions of the CNBr-hydrolysated OVA were isolated by high-pressure liquid chromatography and tested for their ability to stimulate nOVA-specific T cells isolated from rats parenterally immunized with nOVA. The nOVA fractions containing the stimulatory determinants were then intragastrically administered to rat to test their potential to induce oral tolerance. The hole CNBr hydolysate stimulated proliferation of nOVA-specific T cells. Three out of the five HPLC-purified peptidic fractions were also able to stimulate proliferation and cytokine production by nOVA-specific T cells. A peptide fraction exhibiting a single peak by HPLC contained the 173-196 nOVA segment and stimulated nOVA-specific T cells. This segment also promoted oral tolerance to nOVA and reduced IgE responses. CNBr hydrolysis releases several peptides with stimulatory effect on nOVA-specific T cells including a new nOVA [173-196] T cell determinant which induces oral tolerance to nOVA.

Anti-Saccharomyces cerevisiae antibodies are frequent in type 1 diabetes.

Anti-Saccharomyces cerevisiae antibodies (ASCA) have been described in many autoimmune diseases in which there is an increased intestinal permeability. Also in type 1 diabetes (T1D), there is an increased intestinal permeability. Since no data are available about ASCA in T1D, we evaluated, retrospectively, the frequency of ASCA in this disease. ASCA, IgG, and IgA, were determined by ELISA in sera of 224 T1D patients in which coeliac disease has been excluded and 157 healthy control group. The frequency of ASCA (IgG or IgA) was significantly higher in T1D patients than in the control group (24.5% vs. 2.5%, p < 10(-7)). The same observation was found in children and in adult patients when we compare them to healthy children and blood donors group respectively. Compared to children, adult patients with T1D showed significantly higher frequencies of ASCA of any isotype (38% vs. 13.7%, p < 10(-4)), both ASCA IgG and IgA (12% vs. 1.6%, p = 0.002), ASCA IgG (35% vs. 9.8%, p < 10(-5)) and ASCA IgA (15% vs. 5.6%, p = 0.001). The frequency of ASCA was statistically higher in females of all T1D than in males (30.8% vs.17.7%, p = 0.03), in girls than in boys (22% vs.6.2%, p = 0.017), and significantly higher in men than in boys (35.7% vs. 6.2%, p < 10(-4)). The frequency of ASCA IgG was significantly higher than that of ASCA IgA in all T1D patients (21% vs. 9.8%, p < 0.002), in all females (26.5% vs. 10.2%, p < 0.002), in women (37.9% vs. 12%, p < 0.001). The frequency of ASCA was significantly higher in all long-term T1D than in an inaugural T1D (29% vs. 14.5%, p = 0.019). The same observation was found in adults (45.8% vs. 17.8%, p = 0.01). In long-term T1D patients, ASCA were significantly more frequent in adults than children (45.8% vs. 14.5%, p < 10(-4)). The frequency of ASCA IgG was significantly higher in long-term T1D than in an inaugural T1D (25.2% vs. 11.6%, p = 0.03). Patients with T1D had a high frequency of ASCA.

Anti-Saccharomyces cerevisiae antibodies in primary biliary cirrhosis.

AIM: The aim of this study was to evaluate, retrospectively, the frequency of anti-Saccharomyces cerevisiae antibodies (ASCA) in patients with primary biliary cirrhosis (PBC). METHODS: ASCA, IgG, and IgA, were determined by ELISA in sera of 95 PBC patients; 80 healthy blood donors served as controls. RESULTS: The frequency of ASCA (IgG or IgA) was significantly higher in PBC patients than in the control group (24.2% vs 3.7%, P = 0.0001). The frequency of ASCA IgG and ASCA IgA in PBC patients was also significantly higher than that found in the control group (18.9% vs 2.5%, P = 0.0006 and 11.6% vs 1.2%, P = 0.007, respectively). Six patients out of 95 (6.3%) had both ASCA IgG and ASCA IgA; in contrast, none of the control group had both isotypes (P = 0.02). There was no correlation between ASCA levels and mitochondrial autoantibodies (AMA) titres in PBC patients. CONCLUSION: We conclude that ASCA are common in patients with PBC.

Thyroid-related autoantibodies in Tunisian patients with coeliac disease.

BACKGROUND: The aim of our study was to evaluate, retrospectively, the frequency of anti-thyroid antibodies (ATA) in coeliac disease (CD) patients. METHODS: ELISA was used to determine the frequency of anti-thyroid stimulating hormone receptor antibodies, thyroperoxidase antibodies and thyroglobulin antibodies in sera of 104 adult patients with CD. Patients were divided into three groups: group I, 56 untreated patients; group II, 21 patients on a strict gluten-free diet (GFD); and group III, 27 patients who did not comply with a GFD. Sera of 189 healthy blood donors served as controls. RESULTS: Out of 104 patients with CD, five (4.8%) had ATA. The frequency of ATA found in the control group (1.6%) was not significantly different from that found in all CD patients. However, the frequency of ATA in CD patients on a GFD was significantly higher than that found in the control group (8.3% vs. 1.6%, p=0.03). The frequency of ATA in groups I, II and III was 1.8%, 9.5% and 7.4%, respectively. CONCLUSIONS: ATA were found in CD patients even on a GFD.

Anti-Saccharomyces cerevisiae antibodies in coeliac disease.

OBJECTIVE: To evaluate, retrospectively, the frequency of anti-Saccharomyces cerevisiae antibodies (ASCA) in patients with coeliac disease. MATERIAL AND METHODS: ASCA, IgG and IgA were determined by ELISA in sera of 238 coeliac patients. The patients were divided into three groups: group I - 125 untreated patients; group II - 42 patients under a strict gluten-free diet (GFD); and group III - 71 patients who did not comply with a GFD. Sera of 80 healthy blood donors served as controls. RESULTS: The frequency of ASCA (IgG or IgA) was significantly higher in untreated coeliac patients than in the control group (27.2% versus 3.7%, p=10(-5)). In 238 coeliac patients, the frequency of ASCA was significantly higher in adults than in children (35.4% versus 21.1%, p=0.01). In group III, the frequency of ASCA was significantly higher in adults than in children (60% versus 26.1%, p=0.004). In 238 coeliac patients, ASCA IgG were significantly more frequent than ASCA IgA in both children (19% versus 6.3%, p=0.001) and adults (33.3% versus 12.5%, p=5.10(-4)). In children, ASCA IgG were negative in group II and positive in 20% of group I (p=0.01). In adults, the frequency of ASCA IgG was also significantly lower in group II than in group I (9.5% versus 34%, p=0.03). CONCLUSIONS: A high frequency of ASCA has been found in coeliac patients. The frequency of ASCA was not statistically different between patients with successful adherence to GFD and healthy controls.

Anti-thyroid-stimulating hormone receptor antibodies determined by second-generation assay.

BACKGROUND: The aim of our study was to determine the frequency of anti-thyroid-stimulating hormone (TSH) receptor antibodies (TRAb) in Tunisian patients with Graves' disease (GD) and to compare the validity of TRAb to that of thyroperoxidase (TPO-Ab) and thyroglobulin antibodies (TG-Ab). METHODS: ELISA was used to determine the frequency of TRAb, TPO-Ab and TG-Ab in sera of 190 patients with GD. Patients were divided into four groups: those with untreated active GD (group A, n=71), those receiving treatment with anti-thyroid drugs (group B, n=85), those in relapse (group C, n=15) and those in remission (group D, n=19). Sera of 100 healthy blood donors served as controls. RESULTS: The sensitivity of TRAb for the diagnosis of GD (95.8%) was significantly higher than that of TPO-Ab (73.2%) and TG-Ab (42.2%) (p=0.0005 and p<10(-7), respectively). The positive rate for TRAb was lower in group B than in group A (70.6% and 95.8%, respectively; p=0.0001). The levels of TRAb were significantly higher in group A than in group B (mean 30.1 and 14.2 IU/L, respectively; p=0.006). CONCLUSIONS: TRAb, but neither TPO-Ab nor TG-Ab, is valuable in the diagnosis and management of patients with GD.