Biomedical subjects
C Ribes-Koninckx
Publications and source records attributed to C Ribes-Koninckx.
A beta-turn rich oats peptide as an antigen in an ELISA method for the screening of coeliac disease in a paediatric population.
BACKGROUND: ELISA methods for the measurement of IgA antigliadin antibodies (AGA), both home-made and commercial systems, routinely employ wheat gliadin fractions as coating antigens. We investigate the sensitivity and specificity for CD diagnosis of a new ELISA method using a highly immunoreactive beta-turn rich gamma3-avenin peptide as an alternative coating antigen. METHODS: The assay was standardized with antihuman IgA peroxidase-conjugated as the second antibody. Alternatively, an ELISA based on the use of protein A-peroxidase was assayed to measure both IgG plus IgA antibodies. Sixty-three sera from healthy controls were analyzed to establish the system's cut-off point. Sera from 103 coeliac and from 65 noncoeliac children were tested; for diagnosis purposes, a small intestinal biopsy had been performed in all of them. RESULTS: For the IgA class antibodies assay a high sensitivity and specificity of 90.3% and 98.5%, respectively, was obtained, comparable to those achieved for IgA antiendomysium antibodies (EmA) with the same sera. CONCLUSIONS: In view of the high sensitivity and specificity obtained together with water solubility of the peptide and easiness for large-scale reproducible synthesis, the new AGA IgA avenin peptide ELISA represents a significant improvement in CD diagnosis in comparison with conventional established AGA IgA ELISA using crude gliadins as coating antigens.
A novel visual immunoassay for coeliac disease screening.
BACKGROUND: To date, the most commonly accepted techniques for the screening of coeliac disease are indirect immunofluorescence and enzyme-linked immunosorbent assay (ELISA), which reveal antiendomysium and antigliadin antibodies respectively. We report the use of a simple visual system for coeliac disease screening based on the use of Staphylococcus aureus protein A, which binds to both IgG and IgA, thus avoiding the need for two parallel immunoassays. MATERIALS AND METHODS: Opaque polystyrene microwell strips coated with a wheat gliadin extract were incubated with sera followed by incubation with protein A-colloidal gold conjugate. The resulting colour was compared with that of positive and negative control sera. The procedure took less than an hour. RESULTS: One hundred and forty-five biopsy-proven sera, 94 from active coeliac patients and 51 from non-coeliac patients with diverse gastrointestinal pathologies or diabetes mellitus, were assayed. Ninety of the 94 sera from the active coeliac patients were positive, whereas only 3 of the 51 non-coeliac control subjects were positive. The technique has a sensitivity of 95.7% and a specificity of 94.1%. CONCLUSIONS: The sensitivity and specificity of the visual system are greater than those of most ELISA systems and are similar to those observed with IgA antiendomysium antibodies when tested in the same population. Moreover, it is inexpensive, quick, simple to perform and easy to interpret, i.e. it requires no qualified personnel. It is for these features, together with the outstanding sensitivity and specificity, that we propose this immunoassay as a new test for reliable coeliac disease screening.
IgA antigliadin antibodies as a screening method for nonovert celiac disease in children with insulin-dependent diabetes mellitus.
One hundred forty-one children with insulin-dependent diabetes mellitus were screened for serum immunoglobulin A (IgA) antigliadin antibodies by means of an enzyme-linked immunosorbent assay (ELISA) method. None of them had gastrointestinal symptoms, and no major nutritional disturbances were detected except for a girl with moderate growth delay. Twelve patients with positive IgA antigliadin antibodies on two or more consecutive measurements underwent a small intestinal biopsy; four of them had a subtotal villous atrophy, and celiac disease was diagnosed; in another patient, a partial villous atrophy was observed. Children suffering from both diabetes and celiac disease showed an onset of diabetes at a younger age than did nonceliac patients. Prevalence of celiac disease in the screened population is 2.85%, which is higher than in the general population of the Comunidad Valenciana (one in 2,500 live births).
Serological screening (antigliadin and antiendomysium antibodies) for non-overt coeliac disease in children of short stature.
This study aimed to assess the value of IgA-antigliadin and antiendomysium antibodies for coeliac disease screening in children with short stature. In 118 children with height less than the 3rd percentile for age preliminary work-up included absorption, hormonal and genetic studies, sweat test, X-ray for bone age, serum immunoglobulin levels and antigliadin antibodies. In 65 patients antiendomysium antibody and a small-intestinal biopsy were performed. Forty-three children had a normal mucosa and 22 a subtotal villous atrophy. Three coeliac children were negative for both antigliadin and antiendomysium antibodies; one further 11-year-old boy was negative only for antiendomysium antibodies. Sensitivity and specificity for antigliadin antibodies were 94.75% and 93%, respectively, and for antiendomysium antibodies 88.3% and 90.5%. Our results show that the use of antiendomysium antibodies as a confirmatory test to select patients for biopsy could result in coeliac disease going undiagnosed in adolescents.