SCREENING FOR CELIAC-DISEASE - THE MEANING OF LOW TITERS OF ANTIGLIADIN ANTIBODIES (AGA) IN NON-CELIAC CHILDREN

Coeliac disease is diagnosed by means of jejunal biopsy, an invasive p rocedure. Anti-gliadin antibodies (AGA) have therefore been used in th e first screening of the disease. On the other hand, low titers of AGA are widely detected also in normal subjects. In order to investigate if low levels of AGA could be correlated with laboratory and clinical data, we performed a study on 167 subjects with various illnesses, suc h as recurrent abdominal pain, failure to thrive, short stature, diarr hoea or constipation, cow-milk protein intolerance and/or food allergy , recurrent vomiting or previous gastroenteritis, all non coeliac cond itions which have been associated with AGA presence. Seventy coeliac c hildren, all biopsied, were selected as a control group. Among the 167 cases we found 60 subjects positive for AGA (35.9%), a high proportio n as compared with the general population. Only 33/167 patients, all I gG and IgA AGA positive, fulfil our laboratory and clinical criteria t o perform a 'confirming' biopsy. For the 134 residual cases (14 IgA, 1 3 only IgG AGA positive, 107 AGA negative) a diagnosis of coeliac dise ase has been excluded by clinical criteria (scoring). As a whole, the patients with coeliac disease had significantly higher levels of AGA o f both IgG and IgA classes (p < 0.01). On the other hand, no significa nt difference emerged for all the anamnestic and laboratory parameters considered between AGA+ and AGA- non-coeliac subjects. However, labor atory parameters of IgG-AGA and/or IgA-AGA positive patients were simi lar to those of coeliac children for iron, Xylose, total IgA count. As no biopsied case showed mucosal atrophy, it is suggested that the pre sence of even low AGA levels in non-coeliac children may represent a h ighly sensitive index of intestinal alteration causing an increased pe rmeability to macromolecules, but it is very unlikely that one could d etect coeliac children by means of Ig-AGA among such illnesses and nor mal subjects. Strong clinical diagnosis and laboratory parameters are required to justify intestinal biopsies. In fact, the production of AG A seems to be a merely immunological phenomenon linked to an increased and probably transient permeability to macromolecules of the intestin al mucosa.