[Value of serological markers in the diagnosis of celiac disease. A proposed protocol].
AIM: In recent years, the high frequency of atypical cases of celiac disease (CD) and of forms of this disease with minor symptoms has prompted the search for analytical markers that may support indications for intestinal biopsy. The commonest tests are those for serum class IgG and IgA antigliadin antibodies (IgG-AGA, IgA-AGA) and IgA antiendomysial antibodies (IgA-EmA). METHODS: We report our 10 year experience of studying AGA in 1,075 serum samples from patients with CD and IgA-EmA in 534 samples. The serological markers were compared with 152 intestinal biopsies performed simultaneously with the other tests. RESULTS: In patients with severe intestinal atrophy the sensitivity of IgA-AGA (91%) and IgA-EmA (94%) was high. IgA-EmA and the latter showed the highest positive (88%) and negative (97%) predictive values. In all patients, IgA-EmA positivity coincided with alterations in the biopsy. Determination of IgA-EmA was also the most efficient marker for monitoring the gluten free diet phase. However, in patients in whom minimal histological changes were found in the intestinal mucosa, none of the markers was sufficiently accurate. RESULTS: IgA- EmA antibodies are the most accurate serological marker of CD. In view of these results and the estimated prevalence of the disease, protocols for the use of serological markers are proposed for the differential diagnosis of malabsorption symptoms, for use in patients at low and high risk of CD and for the followup of those with a diagnosis of CD.