Adenosine is a potent modulator that has a tremendous effect on the immune system.Adenosine affects T cell activity, and is necessary in maintaining the T helper/regulatory T cell (T reg ) ratio. Adenosine signalling is also involved in activating neutrophils and the formation of neutrophil extracellular traps (NETs), which has been linked to autoimmune disorders. Therefore, adenosine, through its receptors, is extremely important in maintaining homeostasis and involved in the development of autoimmune diseases. In this study, we aim to evaluate the role of adenosine A 1 and A 2A receptors in involvement of autoimmune diseases. We studied adenosine regulation by NETosis in vitro, and used two murine models of autoimmune diseases: type I diabetes mellitus (T1DM) induced by low-dose streptozotocin and pristane-induced systemic lupus erythematosus (SLE). We have found that A 1 R enhances and A 2A R suppresses NETosis. In addition, in both models, A 1 R-knock-out (KO) mice were predisposed to the development of autoimmunity.In the SLE model in wild-type (WT) mice we observed a decline of A 1 R mRNA levels 6 h after pristane injection that was parallel to lymphocyte reduction. Following pristane,