Objective: Use radio binding assay (RBA) to quantify the frequency of autoantibodies to glutamic acid decarboxylase in Mexican children with type 1 diabetes mellitus (DM 1).
Research design and methods: GAD antibodies were measured in 140 mestizo children with DM 1, 66 female (47.14%) and 74 male (52.8%); age 11.7 +/- 3.55 years, and range 1.10 to 18.5 years. Most patients were treated with intermediate acting insulin, and some with the former combined with regular insulin. Mean disease duration was 3.11 +/- 2.94 years, and range 1 month to 14.5 years. Once the signed written consent was obtained, a 5.0-mL blood sample was drawn, immediately centrifuged, and the serum was kept frozen to -20 degrees C until RBA evaluation was performed with a commercial kit.
Results: The anti-GAD was positive in 76 DM 1 patients (54.28%) with values from 1.11 to 156.73 U/mL, and negative in 64 (45.71%). In 19 positive anti-GAD patients, the test was repeated and levels were found between 1.38 and 156.62 U/mL. An initial control group consisting of 25 healthy non-related volunteers matched by sex and age, showed negative anti-GAD for all.
Conclusions: The frequency of anti-GAD in these patients was lower than that of the DM 1 European patients, but similar to that of Asians. This supports the heterogeneity of the etiopathogenic factors of DM 1 in different ethnic groups.