It has long been known that antibodies (antibodies) directed against the body’s own protein GAD65 can often be found in the blood of people with type 1 diabetes during the early phase of the disease. Testing for antibodies against GAD65 therefore plays an important role in making a diagnosis. GAD65 is mainly found in nerve cells, where it provides signal transfer between the nerve cells, but it is also found in the insulin-producing beta cells of the pancreas. However, it is not known what the role of GAD65 is there.

Earlier research in mice has shown that the administration of external GAD65 ensures that beta cells are less attacked by the immune system. A possible explanation for this is that exposure to GAD65 causes the immune system to “get used” to this protein – just like with a vaccine – so that the immune cells respond less strongly to beta cells and more functioning beta cells remain to produce insulin. In a Swedish study led by Johnny Ludvigsson, administration of “artificial” GAD65 (GAD65 + aluminum hydroxide: GAD-alum) also worked in children with type 1 diabetes, but these results could not be reproduced by others. There appeared to be many factors that influence how GAD alum works, such as how long after diagnosis the treatment is started, gender, certain risk genes, infections, and even time of year.

In order to find out for whom the GAD alum could work well, the DIAGNODE 1 and -2 studies were set up in 2018. The first results of the DIAGNODE-1 study in 12 participants show a positive course of the disease and also that GAD alum is well tolerated by participants after being injected directly into the lymph node in combination with treatment with vitamin D. The DIAGNODE-2 study, a randomized controlled trial, started early 2019, including 109 participants. Diabeter has also participated in this study. Results of this study have been published in July 2021 and June 2022, showing  slower decrease in C-peptide (i.e. insulin) production for people with type 1 diabetes carrying the HLA DR3-DQ2 haplotype. 

Currently people are being recruited for the Diagnode 3 study, including people with type diabetes who have the HLA DR3-DQ2 haplotype.