Prevalence of coeliac disease in the adult population of central Greece.

OBJECTIVES: Recent studies from several countries have shown that coeliac disease (CD) is increasingly being diagnosed in adults, as the availability of new, accurate serologic tests has made screening in the general population possible. No data exist regarding the prevalence of CD in Greece. The aim of this study was the implementation of a serologic screening procedure for CD in the adult general population of Thessaly, an area of central Greece, using a novel diagnostic algorithm. METHODS: The study included 2230 participants (1226 women, 1004 men, median age 46 years, range 18-80 years), selected by systematic random sampling, from the adult general population of Thessaly. All the serum samples were tested for total immunoglobulin A (IgA)-serum levels, to exclude IgA deficiency. Samples with total IgA within the normal range were tested for IgA antibodies against native human-tissue transglutaminase (anti-tTG); samples that were anti-tTG positive were tested for IgA antiendomysial antibodies (EmA). Samples from participants with selective IgA deficiency were examined for IgG antigliadin antibodies. Participants who were EmA-positive or antigliadin antibody-positive were referred for intestinal biopsy and human leucocyte antigen (HLA) typing. RESULTS: No participant with selective IgA deficiency was detected. Four individuals tested positive for EmA, all of whom were biopsy-proven coeliacs. Therefore, the CD prevalence in this general population sample is 1 : 558 or 1.8 per 1000 (SE 0.13). The four new patients with abnormal histology (two men, two women) were aged between 18 and 35 years. Two of them were considered to be asymptomatic and two presented with a subclinical course. All four had the heterodimer HLA-DQ2. CONCLUSIONS: This first serological screening study for CD in Greece has demonstrated that CD prevalence in Thessaly is among the lowest reported in Europe.

Prevalence and clinical significance of immunoglobulin A antibodies against tissue transglutaminase in patients with diverse chronic liver diseases.

The prevalence of celiac disease (CD) and the prevalence and clinical significance of anti-tissue transglutaminase (tTG) antibodies (tTGAbs) in a large series of patients with chronic liver diseases were assessed. We studied 738 patients (462 with chronic viral hepatitis, 117 with autoimmune liver diseases, 113 with alcoholic or nonalcoholic fatty liver disease, and 46 with other liver disorders) and 1,350 healthy controls (HC). Immunoglobulin A (IgA) tTGAbs were measured by enzyme-linked immunosorbent assay and a microsphere-based flow cytometric assay. Positive sera were investigated for IgA antiendomysial antibodies (EmA). IgA tTGAb-positive subjects were invited to undergo a small-intestinal biopsy and HLA-DQ allele typing. Four of 1,350 HC (0.3%) tested tTGAb(+) EmA(+) and underwent a biopsy (CD confirmation in all). Four of 738 liver disease patients tested tTGAbs(+) EmA(+) (0.54%; not statistically significant). Two were HCV infected (1.24%; not statistically significant), and two had transaminasemia of unknown origin. Forty-three patients tested tTGAbs(+) EmA(-) (5.8%; P<0.001 compared to HC). Inhibition experiments verified the existence of specific IgA anti-tTG reactivity. Twenty-six of 43 patients underwent a biopsy (all negative for CD). Binary logistic regression analysis revealed age (P=0.008), cirrhosis (P=0.004), alkaline phosphatase (P=0.026), and antinuclear antibodies (P=0.012) as independent risk factors for tTGAb reactivity among the patients. It was concluded that CD prevalence is the same in HC and patients with chronic liver diseases. The prevalence of tTGAbs is higher in hepatic patients compared to HC, but their specificity for CD diagnosis in this group of patients is low. tTGAbs in patients appear to be associated with the presence of autoimmunity, cirrhosis, and cholestasis, irrespective of the origin of the liver disease.

Evaluation of a microsphere-based flow cytometric assay for diagnosis of celiac disease.

The multiplexed particle-based flow cytometric technology proposes a new approach for the diagnosis of autoimmune diseases combining the advantages of conventional methods with the ability to quantitatively determine multiple autoantibodies in the same sample, simultaneously and rapidly. Recently, a commercial kit (FIDIS Celiac, Biomedical Diagnostics, Mane la Vallé, France) was introduced for the simultaneous detection of IgA anti-tissue transglutaminase (anti-tTG), IgG, and IgA anti-gliadin antibodies (AGA). This study was undertaken to evaluate and compare the FIDIS Celiac kit with standardized commercial ELISAs (QUANTA Lite, INOVA Diagnostics Inc., San Diego, CA). A disease group consisted of 21 samples from untreated patients with biopsy confirmed celiac disease (CD), and two control groups of historical sera (207 from regular blood donors and 181 from chronically infected hepatitis patients) were studied. All control sera were negative for IgA anti-endomysial antibodies (EmA) and had an IgA concentration above the lower normal limit. Concerning the reproducibility, intra- and inter-assay coefficients of variation (CVs) ranging between 2% and 12%, and between 3% and 21%, respectively, were observed. Regarding the diagnostic quality, each assay was compared to the disease diagnosis using the McNemar test and the kappa (K) parameter, while ROC analysis was applied. Generally, the performance of FIDIS assay was proved almost equally adequate to that of ELISA in the detection of IgA anti-tTG antibodies, IgA and IgG AGA. However, the performance of FIDIS assay was found surmounting that of ELISA among hepatitis patients, possibly due to the avoidance of debris and unbound cross contaminants and, hence, the "noise" of such materials in samples under analysis. Taking our results together with the simplicity and the high throughput of FIDIS assay, its overall performance in the diagnosis of CD seems better than that of ELISA.