Diabetes, Vol 38, Issue 3 358-363, Copyright © 1989 by American Diabetes Association
Radioassay determination of insulin autoantibodies in NOD mice. Correlation with increased risk of progression to overt diabetes
AG Ziegler, P Vardi, AT Ricker, M Hattori, JS Soeldner and GS Eisenbarth
Joslin Diabetes Center, Boston, MA 02215.
In an initial cross-sectional study, 29 female and 25 male nondiabetic
weaned nonobese diabetic (NOD) mice of various ages (age range 30-300 days,
mean 108 +/- 10 days) and 11 unweaned NOD pups were evaluated for
competitive insulin autoantibodies (CIAAs) with a fluid-phase radioassay.
Eleven of 54 (20%) weaned NOD mice had CIAA levels above the range (greater
than 39 nU/ml) of 81 control mice. The group of NOD mice that progressed to
diabetes had a significantly higher level of CIAAs than NOD mice that did
not progress to diabetes (NOD mice progressing to diabetes: CIAA 63 +/- 12
nU/ml; NOD mice not progressing to diabetes: CIAA 8 +/- 4 nU/ml; P less
than .02). Seven of 11 (64%) NOD mice having CIAA concentrations exceeding
the normal range progressed to diabetes, whereas only 4 of 43 (9%) NOD mice
progressed to diabetes without detection of elevated CIAAs (Fisher's exact
test, P less than .0005). The relative risk of progressing to overt
diabetes with CIAA levels greater than 39 nU/ml was therefore 17 (P less
than .005), giving a positive predictive value of 64%, a negative
predictive value of 91%, and an overall accuracy of 85%. None of 11
unweaned NOD pups had CIAA levels above the normal range (mean -9.4 +/- 4.9
nU/ml). At 6 wk of age, 37% of female NOD mice were CIAA+, whereas none of
the male animals exceeded the normal range at this age (38 +/- 13 vs. 5 +/-
6 nU/ml, P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)