Detection of insulin antibodies in newly-diagnosed type 1 diabetic children after "acid-stripping" of sera.
A sensitive microassay using sera from which endogenous bound insulin was removed by acid-stripping was employed to screen for insulin antibodies in 48 newly-diagnosed Type 1 diabetic children and 20 age-matched controls. Using intact diabetic sera, the binding of 125I-insulin exceeded the upper control range in 16/48 (33%); when the sera were acid-stripped at pH 4.2 for 30 minutes at 4 degrees C, binding to the 16 positive sera increased further and in another five sera became significant, making a total of 21/48 positive (44%). Children 5 years of age or less had a higher prevalence of insulin antibodies. Islet cell antibodies, assayed by indirect immunofluorescence, were detected in equal fractions of insulin antibody-positive and -negative sera (76% versus 77%). Assay of insulin antibodies using acid-stripped sera under the conditions described significantly increases the sensitivity of insulin antibody detection. Insulin antibodies appear to be a specific marker of islet autoimmunity, but compared to islet cell antibodies are relatively insensitive, and may be a marker for a particular subgroup of diabetics.
Rayner
M L
ML
Department of Diabetes and Endocrinology, Royal Melbourne Hospital, Parkville, Victoria, Australia.
Harrison
L C
LC
Campbell
I L
IL
Heyma
P
P
Cook
J J
JJ
D000293:Adolescent; D001323:Autoantibodies / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000175:diagnosis*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007223:Infant; D007330:Insulin Antibodies / Q000032:analysis*; D007457:Iodine Radioisotopes; D007515:Islets of Langerhans / Q000276:immunology*
D001323:Autoantibodies; D007330:Insulin Antibodies; D007457:Iodine Radioisotopes