Autoantibodies to multiple islet autoantigens in patients with abrupt onset type 1 diabetes and diabetes diagnosed with urinary glucose screening

It has been reported that there is a heterogeneity in the clinical course o f Japanese patients with type 1 diabetes. To elucidate the associations of expression of autoantibodies to multiple islet antigens with age of onset a nd mode of diagnosis of diabetes in Japanese patients with type 1 diabetes, autoantibodies against the protein tyrosine phosphatase-like molecules ICA 512 (IA-2) and phogrin (IA-2 beta) (ICA512/phogrin-A), GAD (GADA), insulin (IAA), and islet cell cytoplasm (ICA) were determined in sera from 73 Japan ese patients with type 1 diabetes obtained within 14 days of diagnosis. Pat ients were divided into groups based on the age of onset (less than or equa l to 10 years, n = 24 and >10 years, n = 49) or the mode of onset (abrupt o nset, n = 59 and urinary screening identified, n = 14)1 Of 73 new-onset pat ients with type 1 diabetes, 43 (59%) and 32 (44%) had ICA512A and phogrin-A levels exceeding the 99th percentile of 184 normal control subjects, respe ctively. Forty-five patients (62%) were positive for either ICA512A or phog rin-A. The frequencies for other autoantibodies were 71% for GADA, 48% for IAA, and 62% for ICA. The frequency of ICA512/phogrin-A was significantly h igher in patients with an age of onset less than 10 years (83%) than in pat ients aged >10 years (51%, P<0.01). The positivity of ICA512/phogrin-A was less in patients whose diabetes was diagnosed by the urine glucose screenin g test (21%, P<0.001) than in abrupt onset patients (71%). Combined analysi s (greater than or equal to 1 antibody) of GADA, IAA, and ICA512/phogrin-A detected 88% of abrupt onset and 93% of screening-positive patients vs. 70% and 29%, respectively, for ICA (P<0.0005). These results indicate that the expression of ICA512/phogrin-A and cytoplasmic ICA is less in patients ide ntified by urinary glucose testing but indicate that with combined autoanti body testing 90% of patients can be identified independent of the mode of d iagnosis. (C) 1999 Academic Press.