Bilbao J R, Calvo B, Urrutia I, Linares A, Castaño L
Department of Pediatrics, Hospital de Cruces, Barakaldo-Basque Country, Bizkaia, Spain.
Diabetes. 1997 Apr;46(4):713-6. doi: 10.2337/diab.46.4.713.
Insulin autoantibodies (IAAs) are present in approximately 60% of type I diabetes patients at onset and are used as predictors for the disease. Although the prevalence of IAAs in the general population has been reported to be <1%, preliminary data have pointed out a higher proportion of IAA positivity in newborn cord-blood serum, and some authors have suggested that they are immunoglobulin G antibodies, resulting from a hypothetical gestational insulitis. To characterize this insulin-binding activity, we analyzed cord-blood sera from 100 healthy newborns, as well as serum from 21 of their mothers at delivery, 179 new-onset type I diabetic patients, and 200 healthy control subjects. IAAs were present in 0.5% of the control subjects and 54% of new-onset type I diabetic patients. On the other hand, 96% of the newborn cord-blood sera showed anti-insulin activity, while it was detected in only 14% of their mothers. No significant differences were observed between cord sera and the general population for islet-cell or anti-GAD autoantibodies. Anti-insulin activity in cord serum was not bound by protein A or protein G, in contrast with type I diabetes-related IAA activity. We conclude that this insulin-binding activity, present in most newborn cord sera and specific to the child, is not IgG mediated. These data, together with the absence of other pancreatic autoimmunity markers in this population, suggest that it is an isolated phenomenon not related to type I diabetes or other pancreatic autoimmune processes and is due to the presence of a cross-reacting molecule in cord blood that has yet to be identified.
胰岛素自身抗体（IAA）在约60%的I型糖尿病患者发病时即存在，并用作该疾病的预测指标。尽管据报道普通人群中IAA的患病率<1%，但初步数据指出新生儿脐带血血清中IAA阳性的比例更高，一些作者认为它们是免疫球蛋白G抗体，由假设的妊娠期胰岛炎产生。为了表征这种胰岛素结合活性，我们分析了100名健康新生儿的脐带血血清，以及他们21名母亲分娩时的血清、179名新诊断的I型糖尿病患者的血清和200名健康对照者的血清。IAA存在于0.5%的对照者和54%的新诊断I型糖尿病患者中。另一方面，96%的新生儿脐带血血清显示出抗胰岛素活性，而其母亲中只有14%检测到这种活性。在脐带血清与普通人群之间，未观察到胰岛细胞或抗谷氨酸脱羧酶自身抗体有显著差异。与I型糖尿病相关的IAA活性不同，脐带血清中的抗胰岛素活性不与蛋白A或蛋白G结合。我们得出结论，这种存在于大多数新生儿脐带血清中且特定于婴儿的胰岛素结合活性不是由IgG介导的。这些数据，连同该人群中不存在其他胰腺自身免疫标志物，表明这是一种与I型糖尿病或其他胰腺自身免疫过程无关的孤立现象，是由于脐带血中存在一种尚未鉴定的交叉反应分子所致。
