IgA Anti-transglutaminase Autoantibodies at Type1 Diabetes Onset Are Less Frequent in Adult Patients and Are Associated With a General Celiac-Specific Lower Immune Response in Comparison With Nondiabetic Celiac Patients at Diagnosis.

OBJECTIVE To evaluate the celiac-associated humoral autoimmunity in child, adolescent, and adult patients at type 1 diabetes (DM1) onset and to determine whether DM1 celiac-specific humoral immunoreactivity occurs similarly to that in nondiabetic patients at celiac disease (CD) diagnosis. RESEARCH DESIGN ANDMETHODS IgA anti-transglutaminase autoantibody (IgA-tTGAb) was detected in 654 new-onset DM1 sera. IgA-tTGAb+ DM1 sera were subsequently analyzed for IgG-tTG, deamidated gliadin (DGP), and actin antibodies, and results were com- pared with those found in 83 screen-detected nondiabetic patients at CD diagnosis. RESULTS A total of 12.8% DM1 serawere IgA-tTGAb+,with a lower autoantibody frequency in adult patients aged >18 years (6.8 vs. 15.1%, aged ≤18 years; P = 0.005). IgA-tTGAb titers, IgG- tTGAb, and DGPAb frequency/titers and mean number of celiac-autoantibody positivities per patient were signi cantly lower in IgA-tTGAb+ DM1 compared with nondiabetic CD patients. CONCLUSIONS Age of diabetes onset is negatively associated with risk of CD. The celiac-specific humoral immunoreactivity at DM1 onset is significantly lower compared with that found in nondiabetic patients at CD diagnosis. [ABSTRACT FROM AUTHOR]