Islet cell-associated autoantibodies in Ethiopians with diabetes mellitus

Background & aims Our understanding of the role of autoimmunity in the pathogenesis of diabetes in African populations is limited. This study aims to evaluate the prevalence of 4 different islet cell-associated antibodies in Ethiopian patients with diabetes and non-diabetic controls. Methods A total of 187 subjects from a diabetic clinic at an Ethiopian hospital were evaluated in a cross-sectional study. Fifty-five patients had type 1 diabetes mellitus (T1DM), 86 had type 2 diabetes mellitus (T2DM) and 46 were non-diabetic controls. Islet cell-associated antibodies were measured using 4 different assays for antibodies against islet cells (ICA), glutamic acid decarboxylase (GADA), insulin (IAA) and the protein tyrosine phosphatase-like IA-2 (IA-2A). Results Comparing the antibody positivity in subjects with T1DM versus T2DM, the results were as follows: 29% versus 3.5% for GADA; 21% versus 2.7% for ICA; 27% versus 16% for IAA. In the control group, the only positive result was for IAA at 2%. IA-2A was absent in all groups. The combi-assay for GADA and IA-2A detected all GADA-positive subjects. T2DM patients who were GADA positive had lower BMI, lower C-peptide levels and all of them were on insulin therapy. Conclusions Compared to Caucasians, Ethiopians with T1DM have less prevalence of islet cell-associated antibodies, but the rates are higher than in T2DM. GADA is present in Ethiopians, whereas IA-2A seems to be absent. GADA positivity in T2DM correlates with clinical features of T1DM, indicating the existence in Ethiopia of the subgroup, latent autoimmune diabetes in adults.