Vasculitis associated with immune checkpoint inhibitors—a systematic review

Recent experimental and genetic studies have implicated the role of programmed cell death protein 1 (PD-1), programmed cell death protein-ligand 1 (PDL-1), and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) in the pathogenesis of medium and large vessel vasculitis. This study sought to evaluate the occurrence and nature of vasculitis associated with cancer treatment using immune checkpoint inhibition (anti-PD-1, anti-PDL-1, and anti-CTLA4). A systematic review of the medical literature was conducted by searching all available clinical data up to February 2018 in several databases and search engines including Cochrane Library, Embase, Google Scholar, Medline, Scopus, Web of Science, and Clinicaltrials.gov. Searches included the following FDA-approved anti-PD1 (nivolumab and pembrolizumab), anti-PDL1 (atezolizumab, avelumab, and durvalumab), and anti-CTLA4 (ipilimumab). The vasculitis cases were compiled and classified based on the 2012 revised Chapel Hill Consensus Conference nomenclature. The clinical feature of the vasculitis cases and their relationship to immune checkpoint inhibition was assessed. There were 53 cases of vasculitis of which 20 were confirmed. The main reported type of vasculitis was large vessel vasculitis and vasculitis of the central and peripheral nervous system. All cases resolved with either holding the immune checkpoint inhibitors and/or administering glucocorticoids. No death related to vasculitis was reported. Vasculitis, namely large vessel and vasculitis of the nervous system, is associated with immune checkpoint inhibition. Results of this study add to the growing evidence regarding the relationship between immune checkpoints and vasculitis and suggest that the pathway may be a therapeutic target.