Erythema multiforme major in a patient with metastatic melanoma treated with nivolumab.

Nivolumab, a relatively novel immune checkpoint inhibitor with FDA approval in 2014, is gaining greater utilization due to its efficacy in treating metastatic melanoma. Many of the cutaneous immune-related adverse events (irAEs) being catalogued do not necessitate discontinuation of immunotherapy and are managed with supportive therapy. We present a case of erythema multiforme major secondary to nivolumab requiring hospitalization and discontinuation of treatment. This is only the second reported case of nivolumab-induced erythema multiforme in the literature we are aware of, and emphasizes the importance of oncologists working in conjunction with dermatologists for prompt diagnosis and management.

Emerging role of human basophil biology in health and disease.

Basophils have emerged in recent years as a small but potent subpopulation of leukocytes capable of bridging innate and adaptive immunity. They can be activated through IgE-dependent and IgE-independent mechanisms to release preformed mediators and to produce Th2 cytokines. In addition to their role in protective immunity to helminths, basophils are major participants in allergic reactions as diverse as anaphylaxis and immediate hypersensitivity reactions, late-phase hypersensitivity reactions, and delayed hypersensitivity reactions. Additionally, basophils have been implicated in the pathophysiology of autoimmune diseases such as lupus nephritis and rheumatoid arthritis, and the modulation of immune responses to bacterial infections, as well as being a feature of myelogenous leukemias. Distinct signals for activation, degranulation, transendothelial migration, and immune regulation are being defined, and demonstrate the important role of basophils in promoting a Th2 microenvironment. These mechanistic insights are driving innovative approaches for diagnostic testing and therapeutic targeting of basophils.