Time clustering of high titre insulin autoantibodies (IAA) in the cord blood of infants born to non-diabetic mothers.
Insulin autoantibodies (IAA) are markers for autoimmune insulitis, and are reported in up to 100% of diabetic children before the age of five years, but in fewer than 1% of their controls. Their origins are unknown. In this report a cluster of high titre IAA in cord blood is reported, distinct from the low titre 'non-specific' binding previously described. The distributions of displaceable insulin binding measured in adults (Group A, n = 79), adolescents (Group B, n = 19), primary school children (Group C, n = 32) and third trimester pregnant women (Group D, n = 60) were all unimodal, normal and not different from each other (A = 0.57+/-0.64%, B = 0.87+/-0.45%, C = 0.81+/-0.87% and D = 0.35+/-0.48%). The distribution of insulin binding in the cord sera of consecutive newborns (n = 428) born between October and the following May, however, was bimodal. The first distribution, included 400 sera, was symmetrical and not different (0.79+/-0.45%) from groups A, B, C and D. The second distribution comprised the remaining 28 sera (7% of the total sample) with insulin-displaceable binding values in an IDW-validated radio assay ranging from 2.2% to 31.1%. The appearance of IAA was not HLA-restricted, but the frequency of IAA+ samples was seen to vary over five consecutive months. The timing is consistent with acute viral infection, but the implications for future insulin dependent diabetes will await long-term follow-up of the children and mothers involved.
Galloway
T S
TS
Deparment of Medicine, University of Plymouth, Devon, UK. tgalloway@plymouth.ac.uk
Fewster
D
D
Crocker
D
D
Noor
M
M
Wilkin
T J
TJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000918:Antibody Specificity; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology*; D001324:Autoantigens / Q000276:immunology; D001667:Binding, Competitive; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000276:immunology; D005260:Female; D005312:Fetal Blood / Q000276:immunology*; D005968:Glutamate Decarboxylase / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007132:Immunoglobulin Isotypes / Q000032:analysis; D007231:Infant, Newborn / Q000276:immunology*; D007330:Insulin Antibodies / Q000097:blood* / Q000276:immunology*; D007527:Isoenzymes / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011247:Pregnancy; D013997:Time Factors
D001323:Autoantibodies; D001324:Autoantigens; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D007330:Insulin Antibodies; D007527:Isoenzymes; D005968:Glutamate Decarboxylase; C401141:glutamate decarboxylase 2