Thirty-six coeliac children on gluten-containing diet were studied for AGA IgA and IgG levels. Patients were typed for HLA-A, -B, -C, -DR, -DQ antigens and data were analysed for any correlation between HLA-DR phenotype and AGA levels. AGA IgA and/or IgG were present in all these children. Subjects negative for DR3 or DR7 showed lower AGA levels than those DR3 + and/or DR7 positive. The data suggest that these patients could escape diagnosis if screening for those requiring intestinal biopsy is based only on AGA assay. The observation that coeliac children negative for DR3 and DR7 showed lower AGA levels is consistent with clinical and genetic heterogeneity of coeliac disease.