Auroinirnunity, 1992, Vol. 13, pp. 187-196 Reprints available directly from the publisher Photocopying permitted by license only

0 1992 Harwood Academic Publishers GmbH Printed in the United Kingdom

QUANTITATIVE ANALYSIS OF ISLET GLUTAMIC ACID DECARBOXYLASE p64 AUTOANTIBODIES IN INSULIN-DEPENDENT DIABETES MELLITUS HEIKE BARMEIER', JARL AHLMEN', MONA LANDIN-OLSSON3, RAY V. RAJOTTE4, GORAN SUNDKVIST?, GARTH WARNOCK4 and AKE LERNMARK'

Autoimmunity Downloaded from informahealthcare.com by Chinese University of Hong Kong on 12/26/14 For personal use only.

'Dept. of Medicine, University of Washington. Seattle, W A ; 'Karnsjukhuset, SkBvde. Sweden; 'Dept. of Medicine. General Hospital. Unit, University qf Alberta, Edmonton, Canada Mulmii, Swreden; 4Surgicul-Medic~ul-Research

(ReceivedJanuary 7,1992; in f i n a l f o r m May 6 , 1 9 9 2 ) Autoantibodies against the b-cell Mr 64,000 protein ( ~ 6 4 )recently . identified as an isoform of glutamic acid decarboxylase (GAD), are prevalent in patients with insulin-dependent diabetes mellitus (IDDM). Dog islets were found to represent an abundant source of native p64 allowing the study of antigen-antibody interactions in IDDM. A quantitative, standardized assay for p64 antibodies based on dog islets was developed and evaluated. Utilizing dog and human islets the p64 antibodies were detected in 17/19 (89%) new onset 15-32-yearold patients, compared to 15/19 (79%) in a rat islet assay. ICA were detected in 15/19 (79%) patients and correlated with the presence of p64 antibodies (r,=0.59, P