Do adults with high gliadin antibody concentrations have subclinical gluten intolerance?
Gliadin antibodies of the IgG and IgA isotypes and IgG subclasses were measured in 200 adults who were randomly selected from the Icelandic National Register. Those with the highest gliadin antibody concentrations were invited with negative controls to participate in a clinical evaluation. Neither the study subjects nor the physicians who recorded and evaluated the clinical findings were aware of the antibody levels. Significantly higher proportion of the gliadin antibody positive individuals reported unexplained attacks of diarrhoea (p = 0.03), and IgA gliadin antibodies were associated with increased prevalence of chronic fatigue (p = 0.0037). The gliadin antibody positive group also showed significantly decreased transferrin saturation, mean corpuscular volume and mean corpuscular haemoglobin compared with the gliadin antibody negative controls. Serum folic acid concentrations were significantly lower in the IgA gliadin antibody positive individuals. On blind global assessment 15 of the 48 participants were thought to have clinical and laboratory features that are compatible with gluten sensitive enteropathy, and 14 of these were in the gliadin antibody positive group (p = 0.013). Complaints that have not been associated with gluten intolerance had similar prevalence in both groups with the exception of persistent or recurrent headaches that were more common in the gliadin antibody positive group. These findings raise the possibility that a subclinical form of gluten intolerance may be relatively common.