An electrochemical immunoassay for the screening of celiac disease in saliva samples.

A highly sensitive electrochemical immunoassay for the initial diagnosis of celiac disease (CD) in saliva samples that overcomes the problems related to its high viscosity and to the low concentration of anti-transglutaminase antigen (tTG) IgA in this medium has been developed for the first time. The system uses magnetic beads (MBs) covered with tTG, which reacts with the anti-tTG IgA antibodies present in positive saliva samples. An anti-human IgA, conjugated with alkaline phosphate (AP) enzyme, was used as the label and a strip of eight magnetized screen-printed electrodes as the electrochemical transducer. In particular, two different immunoassay approaches were optimized and blindly compared to analyze a large number of saliva samples, whose anti-tTG IgA levels were independently determined by the radioimmunoassay (RIA) method. The obtained results, expressed as Ab index, were used to perform a diagnostic test evaluation through the construction of receiver operating characteristic (ROC) curves. The approach, involving a pre-incubation between the anti-human IgA-AP and saliva samples prior to the addition of MBs-tTG, showed a cutoff of 0.022 with 95% clinical sensitivity and 96% clinical specificity. The area under the ROC curve is equal to 1, a result that classifies our test as "perfect." This study demonstrates that it is possible to perform the screening of CD with a rapid, simple, inexpensive, and sensitive method able to detect anti-tTG antibodies in saliva samples, which are easily obtained by non-invasive techniques. This aspect is of fundamental importance to screen a large number of subjects, especially in the pediatric age.

Coeliac disease screening among a large cohort of overweight/obese children.

Coeliac disease (CD) is a chronic, gluten-dependent enteropathy with a prevalence of approximately 1% in Western countries. Up to now, CD has been described only in sporadic cases of obesity. Our study aimed to evaluate retrospectively CD prevalence in a large series of overweight/obese children and adolescents. Among the 1527 overweight/obese children and adolescents consecutively evaluated, 17 (7 boys, 1.11%) were positive for serology and showed villous atrophy. In all of the patients with CD a well-balanced gluten-free diet was started, and a loss of weight rapidly obtained. Our study demonstrates that CD prevalence in overweight/obese children is similar to the general paediatric population in Italy.

Anti-transglutaminase immunoreactivity and histological lesions of the duodenum in coeliac patients.

Coeliac disease (CD) is characterized by several markers, including anti-transglutaminase auto-antibodies (tTGAb) directed against multiple epitopes of the gliadin protein. We aimed to investigate the correlation among CD duodenal lesions, tTGAb titres and the immunoreactivity against tTG constructs. A total of 345 CD patients (209 females, 136 males, overall median age: 7.3 years) were tested for full-length (fl) tTGAb with a fluid-phase radioimmunoassay. Out of the total, 231 patients were also tested for immunoreactivity against tTG fragments (F1: a.a. 227-687 and F2: a.a. 473-687). Patients were classified according to diffuse (D), patchy (P) or bulb (B) histological lesions. All sera were found fltTGAb positive. Patients with D, P and B lesions had a mean Ab index of 0.84±0.39, 0.57±0.39 and 0.45±0.24, respectively. Mean tTGAb titre varied between D and localized (P+B) patients (0.84±0.39 versus 0.52±0.34, P < 0.0001). Overall, 86.1% of patients were F1 auto-antibody (F1Ab) positive (D: 89%, P: 75%, B: 40%; D versus P+B: P = 0.004) and 49% of patients were F2 auto-antibody (F2Ab) positive (D: 53%, P: 19%, B: 10%; D versus P+B: P = 0.0006). Of the D patients 50.7% showed combined F1Ab-F2Ab (D versus P+B: P = 0.001), whereas 60% of B patients were negative for both F1Ab and F2Ab (B versus D: P < 0.0001). Coeliac-specific tTGAb immunoreactivity correlates with the grading and extension of histological duodenal lesions in CD patients at diagnosis. The immunoreactivity against single and combined tTG fragments is significantly higher in patients with D lesions. This is the first evidence of a distinct coeliac-specific immunoreactivity in patients with different duodenal involvement.

Subclinical synovitis detected by ultrasound in children affected by coeliac disease: a frequent manifestation improved by a gluten-free diet.

OBJECTIVES: Coeliac disease (CD) is a chronic autoimmune disease of the small intestine caused by the ingestion of gluten, in which musculoskeletal manifestations may occur. Aim of this study was to evaluate the prevalence and severity of joint involvement in paediatric patients with CD using musculoskeletal ultrasound (US). METHODS: Consecutive paediatric CD patients were enrolled and underwent US evaluations at level of knees, hips and ankles. The presence of joint effusion (JE), synovial hypertrophy, power Doppler signal and structural damage lesions (bone irregularities and erosions) was registered. Inflammatory abnormalities were scored on a semi-quantitative scale (0-3), and structural damage lesions on a dichotomous scale (0-1). RESULTS: Seventy-four CD children (mean age: 7.6 years; range: 1-14.2; M/F 24/50) were enrolled. Thirty-eight were on a gluten-containing diet (GCD) and 36 on a gluten-free diet (GFD). US showed the presence of abnormalities in 23 patients overall (31.1%); JE was the most frequently observed change (23/23). US abnormalities were observed in 19 patients (50.0%) of GCD group and in 4 of GFD group (11.1%, p=0.007). Interestingly, 12/23 (52.2%) patients with US-detected changes were asymptomatic. CONCLUSIONS: This is the first US study demonstrating joint involvement in children with CD. JE, the most frequent manifestation, was present also in asymptomatic patients and was reduced in those on GFD. These findings may indicate that, also at joint level, an inflammatory response represented by the appearance of JE may be induced by exposure to gluten.

The celiac iceberg: characterization of the disease in primary schoolchildren.

OBJECTIVE: Celiac disease (CD) has a prevalence of 0.55% to 1% in Italy. Identifying CD in schoolchildren to characterize CD iceberg and evaluate the effect of diagnosis in screening-detected children. METHODS: A total of 7377 5- to 8-year-old children were invited to participate. A total of 5733 salivary samples were collected and tested for anti-transglutaminase antibodies (tTGAb), using a fluid-phase radioimmunoassay. Salivary tTGAb-positive children were analyzed for serum antibodies (anti-endomysium antibodies, radioimmunoassay, and enzyme-linked immunosorbent assay tTGAb). Positive children underwent endoscopy and then started gluten-free diet (GFD) and periodical follow-up. RESULTS: Forty-six subjects were found salivary tTGAb-positive and 16 border-line. Forty-five of 46 and 5 of 15 of them were also serum antibody-positive. Forty-two children showed duodenal villous atrophy and 1 had only type 1 lesions. Three children started GFD without performing endoscopy. CD prevalence (including 23 previously diagnosed children with CD) was 1.2%. Considering all 65 celiacs in our sample, a silent CD was found in 64%, typical in 28%, atypical in 7%, and potential in 1%. All patients showed strict adherence to GFD, weight and stature increase, and well-being improvement. Eighty-five percent and all but 2 screening-detected children with CD had Italian parents. CONCLUSIONS: Our sample size, representative of primary schoolchildren of our region, demonstrated that CD prevalence is growing in Italy, with a modified clinical spectrum and iceberg deepness.

Investigating the Relationship Between COVID-19 and Celiac Disease. A Dual Research Approach.

Background: Most evidence on the coronavirus disease 2019 (COVID-19) pandemic, has been obtained from web- or telephone-based surveys. In particular, few laboratory data, often incomplete, have been reported on the frequency of COVID-19-related serology at celiac disease (CD) diagnosis or on the effects of COVID-19 on the development of CD-specific autoimmunity. Objectives: The objective of this retrospective cross-sectional case/control study was to: (1) evaluate the frequency of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in 78 children and adolescents at CD diagnosis (CD, 44 females, median age 7.4 years); (2) evaluate the frequency of IgA-anti-transglutaminase antibodies (IgA-tTGAbs) in 97 nonceliac patients (50 females, median age 9.0 years) who contracted SARS-CoV-2 infection during the pandemic (February-April 2021). As a control (CTRL) group, we analyzed 141 healthy subjects (79 females, median age 9.8 years) enrolled during the pandemic. Methods: SARS-CoV-2 IgM- and IgG-antibodies were detected by chemiluminescent microparticle immunoassays. IgA-tTGAbs were detected by a fluid-phase radioimmunoassay. Results: Six out of 78 (7.7%) CD patients tested positive for SARS-CoV-2Abs, with a frequency not significantly different from CTRL subjects (9.2%). None of the 97 nonceliac COVID-19 patients tested positive for IgA-tTG antibodies. Conclusion: These 2 distinct research approaches showed (1) similar frequencies of SARS-CoV-2 immunoreactivities in CD patients and CTRL subjects and, (2) no ability of SARS-CoV-2 to induce a CD-specific immune response, at least in the 3-4 months following SARS-CoV-2 infection.

Duodenal bulb in celiac adults: the "whether biopsying" dilemma.

BACKGROUND: Celiac disease (CD)-related lesions were described in duodenal bulb of celiac patients. GOAL: Our aim was to evaluate the morphology of bulb mucosa in adult celiac patients and in controls to evaluate its usefulness for CD diagnosis. STUDY: We studied 43 celiac patients (10 male, median age: 35.2 y) at diagnosis and 43 gastroenterological controls (10 male, median age: 37.8 y), submitted to upper endoscopy for gastroenterological complaints. Histologic lesions were assayed by an experienced pathologist according to the Marsh modified classification. Antiendomysium antibodies and antitransglutaminase antibodies-tTGAb (ELISA and/or RIA) have been tested. In selected patients, DNA was typed for DRB1, DQA1, and DQB1 genes by sequence-specific primer polymerase chain reaction. RESULTS: In all celiac patients lesions were present in the bulb mucosa. One female with thyroiditis, who had a CD daughter, showed lesions only in the duodenal bulb. Patchy villous atrophy was found in another patient. All celiacs were antiendomysium and/or tTGAb positive. DQ2 heterodimer was present in 5 CD patients. The gastroenterological controls showed normal mucosa in the duodenum. CONCLUSIONS: This study demonstrates that CD-related histologic lesions are present in duodenal bulb of adult patients. Moreover, the normal aspect of this mucosa in gastroenterological controls implies the high negative predictive value of this finding. Therefore, we suggest taking at least 1 biopsy on the bulb area and 1 from the distal duodenum for CD diagnosis, in all the patients submitted to upper endoscopy, to avoid missed or delayed diagnosis.

Endoscopic and histological gastric lesions in children with celiac disease: mucosal involvement is not only confined to the duodenum.

OBJECTIVES: Lymphocytic gastritis (LG) has been reported in patients with celiac disease (CD). The aim of the present study was to evaluate gastric mucosa involvement in celiac children and gastroenterological controls (GC). METHODS: In a retrospective study on 226 patients with CD (82  M; median age: 5.7 years) at diagnosis and 154 GC (66  M; median age: 7.4 years), the evaluation of gastric and duodenal mucosa was performed. CD was diagnosed according to the North America Society for Pediatric Gastroenterology, Hepatology, and Nutrition criteria. Gastric lesions were classified according to Updated Sydney System. Anti-gastric parietal cell antibodies (GPCA) were assayed by enzyme-linked immunosorbent assay. RESULTS: A total of 21.2% and 7% of patients with CD showed chronic superficial gastritis (CSG) and LG, respectively. Helicobacter pylori (Hp) infection was found in 6 (2.7%) children with CD (66.7% had CSG, 16.7% LG, and 16.7% interstitial gastritis). CSG was present in 21.4% of controls. No control subject showed LG. Hp infection was found in 24 (15.6%) children with GC (91.7% had CSG). Among patients with CSG, Hp infection was more frequent in controls than in celiac children (P < 0.0001). Ten of 90 patients with CD and 1 of 29 controls were positive for GPCA. CONCLUSIONS: Gastritis is a common finding in children with CD and adolescents. In celiac subjects, CSG is the most frequently detected. Our data suggest the hypothesis that LG may be related to a longer exposure to gluten. The presence of GPCA may suggest the presence of an underlying autoimmune process.

First salivary screening of celiac disease by detection of anti-transglutaminase autoantibody radioimmunoassay in 5000 Italian primary schoolchildren.

OBJECTIVE: The high prevalence of celiac disease (CD) prompted us to evaluate a new, noninvasive disease screening strategy. The aim was to identify CD in 6- to 8-year-old children for a timely diagnosis, start gluten-free diet (GFD) in compliant subjects, achieve the growth target, and prevent CD complications. METHODS: Five thousand subjects were invited to participate in the study. Four thousand forty-eight saliva samples were tested for anti-tissue transglutaminase (tTG) immunoglobulin (Ig)A using a fluid-phase radioimmunoprecipitation method. Positive children were tested for serum radioimmunoassay tTG IgA, enzyme-linked immunosorbent assay tTG IgA, and anti-endomysium IgA. Children confirmed as positive by serum assays underwent endoscopy with duodenal biopsies and, at the diagnosis of CD, were suggested to start GFD. RESULTS: Consent was obtained from 4242 parents (84.8%) for the screening to be performed, and adequate saliva samples were collected from 4048 children (95.4%). Thirty-two children were found to be salivary tTG IgA positive and 9 with borderline autoantibody levels. Thirty-one of the 32 and 3 of the 9 subjects were also serum positive. Twenty-eight children showed villous atrophy when undergoing intestinal biopsy, whereas 1 had Marsh 1 lesions; 3 children were suggested to start GFD without performing endoscopy. CD prevalence in the population investigated (including 19 CD known cases) was 1.16%. The ratio between screening-detected patients and those diagnosed before the screening was 3:2. The ratio between symptomatic and asymptomatic patients was 1:1.6. CONCLUSIONS: We demonstrated that it is possible to perform a powerful, simple, well-accepted, and sensitive CD screening using saliva. Until now, the compliance with GFD in children with CD has been optimal.

A report on the International Transglutaminase Autoantibody Workshop for Celiac Disease.

OBJECTIVES: Measurement of transglutaminase autoantibodies (TGAA) is considered to be the most efficient single serologic test for celiac disease (CD) by the American Gastroenterological Association Institute. We hypothesized that a large international collaborative effort toward improving and standardizing TGAA measurement is both feasible and necessary. The primary aim of this workshop is to compare TGAA assays among various research and clinical laboratories to examine assay concordance and improve (and eventually standardize) the TGAA assay. METHODS: A total of 20 laboratories (5 commercial laboratories, 15 research and clinical laboratories) participated that included enzyme-linked immunosorbent assay (ELISA) and radiobinding assays. A total of 150 serum samples were distributed to each laboratory, with each laboratory receiving an equal aliquot that was coded and blinded, composed of 100 healthy control sera and 50 CD sera. RESULTS: Laboratory sensitivity ranged from 69% to 93% and specificity ranged from 96% to 100%. By receiver operator characteristic analysis, the area under the curve (C index) ranged from 0.9488 to 0.9904. When analyzing for linear correlation, r-squared was as high as 0.8882 but as low as 0.4244 for the celiac samples between different laboratories performing ELISA. CONCLUSIONS: This transglutaminase autoantibody workshop allows for larger-scale international participation for the purposes of improving and eventually standardizing the TGAA assay with subsequent workshops.

HLA-DQ and risk gradient for celiac disease.

Celiac disease (CD) is a rare example of multifactorial disorder in which a genetic test is of great clinical relevance, as the disease rarely develops in the absence of specific HLA alleles. We typed DR-DQ genes in 437 Italian children with celiac disease, 834 first-degree relatives, and 551 controls. Of patients, 91% carried DQ2 and/or DQ8 heterodimers, 6% only had beta2 chain, 2% was alpha5 positive, and four were DQ2/DQ8/beta2/alpha5 negative. Only the presence of alpha5 resulted negatively associated to disease (p = 2 x 10(-4)), whereas we confirmed the effect of the beta half of DQ2 dimer on CD predisposition (p = 4 x 10(-12)). Considering 1:100 disease prevalence, we obtained a risk gradient ranging from 1:7 for DQ2 and DQ8 individuals down to 1:2518 for subjects lacking all predisposing factors. The DQB1*02 and DQB1*0302 concurrence (p = 9 x 10(-4)), besides the DQB1*02/*02 homozygosity, had an additional role in disease genetic determination. The CD prevalence rose to 17.6% in sisters, 10.8% in brothers, and 3.4% in parents. In the three groups, the subjects carrying high-risk HLA molecules were 57%, 71%, and 58%; among them, 29%, 15%, and 6% respectively had CD. Those siblings and parents with no susceptible factors were not affected. These findings indicate the impact of the HLA test for CD in clinical practice.

HLA-DQ and susceptibility to celiac disease: evidence for gender differences and parent-of-origin effects.

BACKGROUND AND AIMS: Celiac disease (CD) is twice as frequent among female than male. Despite the large number of reports on the DQ2/DQ8 association, no systematic studies have investigated a possible different role of the HLA genes in the two genders. We performed case-control and family-based analyses of DR-DQ variants in a pediatric CD cohort with the aim of comparing female to male associations and to investigate the paternal/maternal inheritance of the disease-predisposing haplotypes. METHODS: A total of 281 female and 156 male pediatric celiac patients, 292 nuclear families, and 551 controls were genotyped for HLA-DRB1, DQA1, and DQB1 loci. Odds ratio, parental origin of the disease-associated haplotypes, and transmission ratio distortion were evaluated in-between male and female cases. RESULTS: DQ2/DQ8 were more frequent in female than in male patients (94% F, 85% M; P = 1.6 x 10(-3)) with a 99.1% and 90.5% calculated negative predictive value of the HLA test, respectively. Surprisingly, the majority of the 39 DQ2/DQ8 negative cases were male. The analysis of the DQ2 haplotype origin showed that 61% of female patients and 42% of male patients carried a paternal combination (P = 0.02). The transmission disequilibrium test (TDT) proved the major distortion in the DR3-DQ2 transmission from fathers to daughters. CONCLUSIONS: CD is confirmed to be more prevalent in female than in male (F:M = 1.8) but, in DQ2/DQ8 negative patients, we found an unexpected male excess (F:M = 0.7). Moreover, only the inheritance of a paternal DQ2 haplotype led to a daughters predominance. These data show a role of HLA genes on the disease sex bias and suggest a possible different effect of parent-specific epigenetic modifications in the two genders.

HLA-DQB1*02 dose effect on RIA anti-tissue transglutaminase autoantibody levels and clinicopathological expressivity of celiac disease.

OBJECTIVES: Celiac disease is an autoimmune enteropathy caused by gluten ingestion in genetically susceptible individuals. Anti-transglutaminase autoantibody (tTGAb) assay is useful to detect candidates undergoing intestinal biopsy. Our aim was to investigate whether the DQB1*02 allele could influence tTGAb titers and the clinicopathological expressivity of the disease. METHODS: A total of 124 patients with celiac disease, tested for RIA tTGAb at diagnosis, were typed for HLA-DRB1, -DQA1, and -DQB1 genes and divided according to the number of DQB1*02 alleles: group 1, homozygous; group 2, heterozygous; group 3, negative. RESULTS: The mean of tTGAb indexes was significantly higher in group 1 patients than in group 2 (P < 0.02) and group 3 patients (P < 0.01). Patients with at least 1 DQB1*02 allele showed more often a typical CD and diffuse histological lesions than did patients in the other groups. CONCLUSIONS: The study demonstrates that tTGAb titers are HLA-DQB1*02 dose dependent, with significantly higher levels in homozygous individuals. Moreover, individuals with at least 1 HLA-DQB1*02 allele tend to have a more expressed clinical and histological form of celiac disease.

Duodenal bulb biopsies in celiac disease: a multicenter study.

OBJECTIVES: Celiac disease (CD)-related lesions have been reported in duodenal bulb biopsies, sometimes the bulb mucosa being the only one affected. The aim was to verify in a significant series whether histological lesions are always present in the bulb of celiac patients, what is the prevalence of lesions when isolated to the bulb, and if similar lesions are present in nonceliac subjects. METHODS: We studied 665 children with CD (241 males, range 9 months-15 years, 8 months), at diagnosis on a gluten-containing diet, and 348 age- and sex-matched gastroenterological controls submitted to upper endoscopy for gastroenterological complaints. During endoscopy, multiple biopsies (1 bulb and 4 distal duodenum samples) were taken. Anti-endomysium antibodies were evaluated by immunofluorescence method, anti-human tissue-transglutaminase antibodies by an enzyme-linked immunosorbent assay or radioimmunoassay. Human leukocyte antigen-DRB1, -DQA1, and -DQB1 genes were typed by polymerase chain reaction sequence-specific primers repeat method. RESULTS: In all of the patients with CD, histological lesions were present in the bulb sample; in 16 of them, the lesions were present only in the bulb. Patchy villous atrophy was found in 20 children. All of the patients with CD were anti-endomysium and/or antitransglutaminase positive. The controls showed neither autoantibody positivity nor mucosal changes compatible with CD. CONCLUSIONS: This study demonstrated that CD-related histological lesions are always present in the bulb; sometimes this specific site is the only one affected. Therefore, we suggest taking 2 biopsies from the bulb and 2 from the distal duodenum for CD diagnosis.

Analysis of candidate genes on chromosomes 5q and 19p in celiac disease.

BACKGROUND AND AIM: Celiac disease (CD) is a multifactorial disease with involvement of both environmental and genetic susceptibility factors. The HLA-DQ loci account for <40% of CD heritability, but linkage studies have delineated other loci at the 5q31-33 (CELIAC2), and 19p13 regions (CELIAC4), similarly as in inflammatory bowel diseases. However, data in association studies are contradictory. To evaluate whether single nucleotide polymorphisms (SNPs) tagging the MYO9B susceptibility haplotype and the IBD5 locus (5q31-33) are involved in CD predisposition, we performed case-control and family-based analyses. Additionally, any possible correlation with the HLA-DQ status was investigated. Finally, our data were pooled with the results of other studies by a meta-analysis. PATIENTS AND METHODS: In all, 337 unrelated patients with CD, 424 parents (212 sets), and 452 healthy individuals were genotyped for the IGR2198a_1, rs12521868, rs1050152, and rs2631367 SNPs (IBD5 locus) and the rs962917, rs2305764, and rs1545620 SNPs of the MYO9B gene by the restriction enzyme method and the TaqMan system ABI PRISM 7700, respectively. RESULTS: In comparison with healthy control individuals, the allele, genotype, and haplotype frequencies of all investigated SNPs were not different in the CD patients, nor was any correlation observed with the HLA-DQ status or clinical presentation. The transmission disequilibrium test did not show a transmission distortion. Five other studies were available for meta-analysis on MYO9B variants; by pooling of data, no significant association was demonstrated by the random effect model. A significant heterogeneity (P < 0.002) among the studies was present, mainly explained by a single study in the Dutch population. CONCLUSIONS: Our results and those of the meta-analysis (>2000 CD patients and 4000 control individuals) question the role of MYO9B at the CELIAC4 locus as a disease-causing gene. Moreover, none of the investigated SNPs explain the linkage at the CELIAC2 locus.

Celiac disease in a large cohort of children and adolescents with recurrent headache: A retrospective study.

BACKGROUND: The clinical picture of celiac disease is changing with the emergence of subclinical forms and growing evidence reporting associated neurological disorders. AIMS: To establish the prevalence of celiac disease in children suffering from recurrent headache. METHODS: In our retrospective study we collected charts from 1131 children attending our tertiary care Centre for Paediatric Headache over the period 2001-2012. They were screened for celiac disease and positive patients were referred to our Operative Unit for Coeliac disease and confirmed positive children underwent upper endoscopy with multiple duodenal biopsies. Celiac children started a gluten-free diet. RESULTS: 883 children (481 females; median age, 9.8 years, range 3-19) performed celiac disease screening, and among them, 11 children (7 females; median age, 8.2 years, range: 4.8-13.9) were diagnosed with celiac disease. Seven children (5 females, median age, 11.9 years, range: 10.3-13.9) had been diagnosed as celiac prior to the neurological evaluation. The prevalence of celiac disease in our sample is 2.04% vs. 1.2% of the general population (p=0.034). CONCLUSIONS: Our study demonstrates, on a large series, that celiac disease prevalence is doubled in patients with chronic headache. Screening for celiac disease could be advised as part of the diagnostic work-up in these paediatric patients, particularly among pharmacological non-responders.