DO GLUTAMIC-ACID DECARBOXYLASE ANTIBODIES IMPROVE THE PREDICTION OF IDDM-I IN FIRST-DEGREE RELATIVES AT RISK FOR IDDM

Schmidli, RS; Colman, PG; Harrison, LC

Author(s): Schmidli, RS; Colman, PG; Harrison, LC;
Details: Publication Year 1994-12,Volume 7,Issue #6,Page 873-879
Journal Title: JOURNAL OF AUTOIMMUNITY
Publication Type: Journal Article
Abstract: To determine whether the predictive value of islet cell antibodies (ICA) and insulin autoantibodies (IAA) is increased by measurement of glutamic acid decarboxylase antibodies (GADAb) in first-degree relatives of patients with insulin-dependent diabetes mellitus (IDDM), we measured GADAb in those developing IDDM and in relatives found to be ICA- or IAA-positive in our family screening study. First-degree relatives (n=2904) were followed for 2.4 (median, range 0.04-5.8) years. Of the subjects developing IDDM, 11/14 (78%) had ICA greater than or equal to 20JDF units, 1/14 (7%) had IAA greater than or equal to 100 nU/ml and 6/14 (43%) had GADAb (greater than or equal to 460nU/ml, measured by precipitation of enzymatic activity). Of the four subjects with ICA<Z0 and IAA<100 nU/ml who developed IDDM, one had elevated GADAb. Significant inhibition of GAD enzymatic activity by serum immunoglobulins, a potential cause of false-negative results in our immunoprecipitation assay, was not detected in seven subjects who developed IDDM in the absence of GADAb. Sixty-nine of the 2904 subjects with ICA greater than or equal to 20 or IAA greater than or equal to 100 were followed for 3.1 (median range 0.1-5.4) years. Survival analysis showed that diabetes-free survival in this group was not influenced significantly by GADAb positivity. In conclusion, GADAb in the absence of ICA and IAA are uncommon in first-degree relatives who progress to IDDM and the presence of GADAb does not increase the risk for IDDM in ICA- or IAA-positive relatives.
Publisher: ACADEMIC PRESS LTD
Keywords: ISLET-CELL ANTIBODIES; DEPENDENT DIABETES-MELLITUS; INSULIN AUTOANTIBODIES; INDIVIDUALS; POPULATION
Publisher's Version: https://doi.org/10.1006/jaut.1994.1071
Terms of Use/Rights Notice: Refer to copyright notice on published article.

Creation Date: 1994-12-01 12:00:00