The
glutamic acid decarboxylase 65 antibody (GAD65-Ab) is an autoimmune marker in some diseases such as diabetes or autoimmune disorders of the central nervous system such as
stiff-man syndrome. It can appear with other pancreatic
autoantibodies, such as
insulin autoantibodies (IAA), presenting as early signs of pancreatic islet β-cells impairing, and play roles in the pathogenesis of type1 diabetes (T1D) and
latent autoimmune diabetes in adults (LADA). Positive GAD65-Ab is rarely observed in
insulin-dependent diabetic patients with other acquired
autoimmune diseases, such as
Sjogren's syndrome (SS). Besides, LADA revealed by islet
autoantibodies such as GAD65-Ab can also be complicated with Hashimoto's
thyroiditis (HT), another autoimmune
thyroid disease. To date, whether GAD65-Ab positive in patients with
autoimmune diseases predicts the onset or progression to T1D or LADA remains unknown. Herein, two unique cases of middle-aged Chinese Han women free from diabetes for three years are described despite their blood tests persistently testing positive for GAD65-Ab or IAA. Both patients suffered from HT and SS. Follow-up OGTTs (oral
glucose tolerance test) for three years revealed that the patients had a well-controlled glycemic level and normal pancreatic function. However, one of the patients had a temporary increase of postprandial
glucose after a short-term loss of diet control. The presence of auto-immune
antibodies in these patients had little impact on
glucose tolerance or insulin secretion in 3 years. The study postulate that both the primary immune injury caused by serum GAD65-Ab positive, an autoimmune marker, and increased
body weight contribute to the progression of LADA.