Immunoglobulin G insulin autoantibodies in BABYDIAB offspring appear postnatally: Sensitive early detection using a protein A/G-based radiobinding assay
He. Naserke et al., Immunoglobulin G insulin autoantibodies in BABYDIAB offspring appear postnatally: Sensitive early detection using a protein A/G-based radiobinding assay, J CLIN END, 84(4), 1999, pp. 1239-1243
Insulin autoantibodies (IAA) are early sensitive markers of prediabetes in
the young. The aim of this study was to assess whether, using IgG-specific
measurement with a protein A/G assay, IAA are already present at birth, and
whether this assay is suitable for early autoantibody screening. Cord bloo
d and follow-up samples from offspring of parents with type 1 diabetes incl
uded in the BABYDIAB study were analyzed. Although insulin antibodies in co
rd blood from children of mothers with type I diabetes were readily detecte
d and correlated well with levels in the maternal circulation, no insulin b
inding was detected in 247 cord blood samples from children of father proba
nds. IgG EAA were detected at 2 yr in all 21 children who had multiple isle
t autoantibodies or who later developed type 1 diabetes, but were confirmed
in only 6 of 58 with IAA by the conventional IAA assay in the absence of o
ther islet autoantibadies. False positive IAAs in the conventional assay we
re often attributable to hemolysis. Hemolysis did not affect protein A/G IA
A measurement, and results in whole capillary blood samples were comparable
to those in corresponding serum samples (r(2) = 0.99). These data show tha
t IgG IAA appear early and after birth, and that the protein A/G IAA assay
is sufficiently sensitive for early screening. The specificity of this assa
y requires further evaluation.