Successful Use of Immunotherapy in a Patient with Metastatic Squamous Cell Lung Cancer and Underlying Autoimmune Disease

The immune system removes abnormal and cancerous cells by way of T-cell detection at immune checkpoints. Cancerous cells, due to their expression of proteins such as T-cell inactivating programmed death-ligand 1 (PD-L1), may evade the immune system resulting in replication and ultimately metastases. Immunotherapy in the form of checkpoint blockade, such as anti-programmed cell death 1 (PD-1) monoclonal antibody pembrolizumab, targets and interferes with this interaction, thereby restoring T-cell ability to remove cancer cells. Immunotherapy has revolutionized cancer treatment and has improved survival in several malignancies. However, the presence of autoimmune disease is an exclusion criterion for most immunotherapy trials due to fear of potentially life-threatening immune system activation. Therefore, its safety and efficacy in patients with autoimmune disease are not well studied. We describe the successful use of pembrolizumab in a patient with systemic lupus erythematosus (SLE) and review available literature, demonstrating that there is a subset of patients with underlying autoimmune disease who can safely be treated with immunotherapy. Furthermore, that administration of traditional cytotoxic chemotherapy prior to immunotherapy may lead to autoimmune disease control by eliminating autoantibodies.