Beta-cell, thyroid, gastric, adrenal and coeliac autoimmunity and HLA-DQ types in type 1 diabetes

The autoimmune attack in type 1 diabetes is not only targeted to β cells. We assessed the prevalence of thyroid peroxidase (aTPO), parietal cell (PCA), antiadrenal (AAA) and endomysial antibodies (EmA-IgA), and of overt autoimmune disease in type 1 diabetes, in relation to gender, age, duration of disease, age at onset, β-cell antibody status (ICA, GADA, IA2A) and HLA-DQ type. Sera from 399 type 1 diabetic patients (M/F: 188/211; mean age: 26 ± 16 years; duration: 9 ± 8 years) were tested for ICA, PCA, AAA and EmA-IgA by indirect immunofluorescence, and for IA2A (tyrosine phosphatase antibodies), GADA (glutamic acid decarboxylase-65 antibodies) and aTPO by radiobinding assays. The prevalence rates were: GADA 70%; IA2A, 44%; ICA, 39%; aTPO, 22%; PCA, 18%; EmA-IgA, 2%; and AAA, 1%. aTPO status was determined by female gender (β = − 1·15, P = 0·002), age (β = 0·02, P = 0·01) and GADA + (β = 1·06, P = 0·02), but not by HLA-DQ type or IA2A status. Dysthyroidism (P < 0·0001) was more frequent in aTPO + subjects. PCA status was determined by age (β = 0·03, P = 0·002). We also observed an association between PCA + and GADA + (OR = 1·9, P = 0·049), aTPO + (OR = 1·9, P = 0·04) and HLA DQA1*0501-DQB1*0301 status (OR = 2·4, P = 0·045). Iron deficiency anaemia (OR = 3·0, P = 0·003) and pernicious anaemia (OR = 40, P < 0·0001) were more frequent in PCA + subjects. EmA-IgA + was linked to HLA DQA1*0501-DQB1*0201 + (OR = 7·5, P = 0·039), and coeliac disease was found in three patients. No patient had Addison's disease. In conclusion, GADA but not IA2A indicate the presence of thyrogastric autoimmunity in type 1 diabetes. aTPO have a female preponderance, PCA are weakly associated with HLA DQA1*0501-DQB1*0301 and EmA-IgA + with HLA DQA1*0501-DQB1*0201.