The effect of age on ICA and thyrogastric antibodies at diagnosis of IDDM was evaluated in 633 consecutively diagnosed Swedish diabetic patients aged 15–34 yr and in 282 volunteers of the same age. These diseases appear when our own immune system, which normally protects us from foreign pathogens (viruses, bacteria,…), attacks our own cells. In Study I, groups of eight male and eight female non-diabetic rats of the BB/E/H line were killed at 15 day intervals from 30-105 days and plasma samples were obtained by cardiac puncture. Thirty-six patients (29%) were positive for at least 1 antibody. Genetic factors were also implicated in susceptibility to occurrence of LCAs. During recent years, promising results of a few clinical trials have been published with the administration of anti-CD3 mAbs targeting T lymphocytes at the time of diagnosis of type 1 diabetes.