OBJECTIVE We examined changes in GAD65 and islet cell autoantibody-512 autoantibodies (GADA and IA-2 antigen [IA-2A]) during progression to type 1 diabetes (T1D).
RESEARCH DESIGN AND METHODS Diabetes Prevention Trial–Type 1 participants were assessed for changes in positivity and titers of GADA and IA-2A during the progression to T1D.
RESULTS Among 99 progressors to T1D with GADA and IA-2A measurements at baseline and diagnosis (mean interval = 3.3 ± 1.5 years), GADA positivity changed little and GADA titers decreased (P < 0.01). In contrast, both IA-2A positivity and titers increased substantially (P < 0.001). Even among those positive at baseline, IA-2A titers increased from baseline to diagnosis (n = 57; P < 0.001), whereas GADA titers decreased (n = 80; P < 0.01). The same patterns of change were also evident among those positive for both autoantibodies (n = 48) at baseline.
CONCLUSIONS IA-2A titers increase during the years before the diagnosis of T1D, even among those positive for IA-2A. In contrast, GADA titers tend to decline during those years.
- Received May 25, 2011.
- Accepted August 2, 2011.
- © 2011 by the American Diabetes Association.
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