Immunologic and genetic markers in insulin-dependent diabetes mellitus (Type 1) in a argentine population

RESUMEN

The objective was to evaluate the prevalence and association of several markers (islet cell antibodies: ICA, ainsulin autoantibodies: IAA, glutamic acid decarboxylase antibodies: GADA and ICA512 antibodies: ICA512A) along with HLA DQB1 genotype in type 1 diabetes mellitus of recent onset, including siblings and individuals without any history of this disease, in an Argentine population. A total of 79 children with type 1 diabetes mellitus of recent onset were studied, as well as 79 control children, and 68 healthy siblings of type 1 diabetic cases. IAA, ICA, GADA, ICA512A and HLA DQB1 alleles were determined. Sensitivity was 67.1 por ciento for ICA, 36.7 percent for IAA, 74.6 por ciento for GADA and 63.4 por ciento ICA512A. None of the control subjects was positive for the immunological markers. Combined sensitivity of ICA-IAA-GADA was 89.8 por ciento, similar to the ICA512A- GADA (87.3 percent) or ICA512A-GADA-IAA combination (91.1 por ciento ). GADA correlated positively with ICA, but no such correlation was found between IAA, ICA512A and ICA. IAA correlated negatively and GADA positively with age. IAA was associated to DQB1*0201, whereas ICA and ICA512A associated to DQB1*0302. Among siblings, 3/68 (4.4 percent) were positive for IAA and a single case (1.5 percent) was positive for GADA and one for ICA512A. Our findings show that the combination of multiple tests increases the sensitivity for prediction, with the ICA512A-GADA combination proving highly sensitive and equivalent to other proposed combinations, such as ICA-IAA-GADA.