Today, improvements in diagnostic and therapeutic options allow patients with autoimmune diseases (ADs) to live longer and have more active lives compared with patients receiving conventional anti-inflammatory therapy just two decades ago. Current therapies for ADs aim to inhibit immune cell activation and effector immune pathways, including those activated by cytokines and cytokine receptors. Understandably, such goals become more complicated in patients with long-term established ADs who develop parallel chronic or comorbid conditions, including life-threatening diseases, such as cancer. Compared with the general population, patients with ADs have an increased risk of developing hematological, lymphoproliferative disorders, and solid tumors. However, the aim of current cancer therapies is to activate the immune system to create autoimmune-like conditions and eliminate tumors. As such, their comorbid presentation creates a paradox on how malignancies must be addressed therapeutically in the context of autoimmunity. Because the physiopathology of malignancies is less understood in the context of autoimmunity than it is in the general population, we undertook this review to highlight the peculiarities and mechanisms governing immune cells in established ADs. Moreover, we examined the role of the autoimmune cytokine milieu in the development of immune-related adverse events during the implementation of conventional or immune-based therapy.
Keywords: autoimmune diseases; cancer; check point inhibitors; immune-related adverse events; immunotherapy.