Skin Manifestation Induced by Immune Checkpoint Inhibitors

Immunological Mechanisms in Cutaneous Adverse Drug Reactions

Adverse drug reactions (ADRs) are an inherent aspect of drug use. While approximately 80% of ADRs are predictable, immune system-mediated ADRs, often unpredictable, are a noteworthy subset. Skin-related ADRs, in particular, are frequently unpredictable. However, the wide spectrum of skin manifestations poses a formidable diagnostic challenge. Comprehending the pathomechanisms underlying ADRs is essential for accurate diagnosis and effective management. The skin, being an active immune organ, plays a pivotal role in ADRs, although the precise cutaneous immunological mechanisms remain elusive. Fortunately, clinical manifestations of skin-related ADRs, irrespective of their severity, are frequently rooted in immunological processes. A comprehensive grasp of ADR morphology can aid in diagnosis. With the continuous development of new pharmaceuticals, it is noteworthy that certain drugs including immune checkpoint inhibitors have gained notoriety for their association with ADRs. This paper offers an overview of immunological mechanisms involved in cutaneous ADRs with a focus on clinical features and frequently implicated drugs.

Skin Infiltrate Composition as a Telling Measure of Responses to Checkpoint Inhibitors

Checkpoint inhibitors treat a variety of tumor types with significant benefits. Unfortunately, these therapies come with diverse adverse events. Skin rash is observed early into treatment and might serve as an indicator of downstream responses to therapy. We studied the cellular composition of cutaneous eruptions and whether their contribution varies with the treatment applied. Skin samples from 18 patients with cancer and 11 controls were evaluated by mono- and multiplex imaging, quantification, and statistical analysis. T cells were the prime contributors to skin rash, with T cells and macrophages interacting and proliferating on site. Among T cell subsets examined, type 1 and 17 T cells were relatively increased among inflammatory skin infiltrates. A combination of increased cytotoxic T cell content and decreased macrophage abundance was associated with dual checkpoint inhibition over PD1 inhibition alone. Importantly, responders significantly separated from nonresponders by greater CD68+ macrophage and either CD11c+ antigen-presenting cell or CD4+ T cell abundance in skin rash. The microenvironment promoted epidermal proliferation and thickening as well. The combination of checkpoint inhibitors used affects the development and composition of skin infiltrates, whereas the combined abundance of two cell types in cutaneous eruptions aligns with responses to checkpoint inhibitor therapy.

Cytokine release syndrome complicated with severe rashes induced by nivolumab plus ipilimumab therapy in a patient with non-small cell lung cancer: A case report

Cytokine release syndrome (CRS) is a severe and life-threatening toxicity typically reported in chimeric antigen receptor T cell therapy and is rarely reported in immune checkpoint inhibitor (ICI) therapy. This study reports the case of a 75-year-old Japanese woman who received nivolumab plus ipilimumab therapy for the postoperative recurrence of non-small cell lung cancer. She was admitted to our hospital with fever, hypotension, hepatic disorder, and thrombocytopenia. We observed slight skin rashes on her neck on admission, which spread rapidly across her body within a few days. We diagnosed CRS complicated by severe rashes. CRS symptoms were resolved with corticosteroid therapy, and did not recur thereafter. CRS is a rare, but important, immune-related adverse event associated with ICI therapy.

Molecular Mechanisms of Cutaneous Immune-Related Adverse Events (irAEs) Induced by Immune Checkpoint Inhibitors

Over the past few decades, immune checkpoint inhibitors (ICIs) have emerged as promising therapeutic options for the treatment of various cancers. These novel treatments effectively target key mediators of immune checkpoint pathways. Currently, ICIs primarily consist of monoclonal antibodies that specifically block cytotoxic T-lymphocyte antigen 4 (CTLA-4), programmed cell death 1 (PD-1), programmed cell death-ligand 1 (PD-L1), and lymphocyte activation gene 3 protein (LAG-3). Despite the notable efficacy of ICIs in cancer treatment, they can also trigger immune-related adverse events (irAEs), which present as autoimmune-like or inflammatory conditions. IrAEs have the potential to affect multiple organ systems, with cutaneous toxicities being the most commonly observed. Although cutaneous irAEs are typically of low-grade severity and can usually be managed effectively, there are cases where severe irAEs can become life-threatening. Therefore, early recognition and a comprehensive understanding of the mechanisms underlying cutaneous irAEs are crucial for improving clinical outcomes in cancer patients. However, the precise pathogenesis of cutaneous irAEs remains unclear. This review focuses on the skin manifestations induced by ICIs, the prognosis related to cutaneous irAEs, and the exploration of potential mechanisms involved in cutaneous irAEs.

Cutaneous manifestations associated with immune checkpoint inhibitors

Immune checkpoint inhibitors (ICIs) are monoclonal antibodies that block key mediators of tumor-mediated immune evasion. The frequency of its use has increased rapidly and has extended to numerous cancers. ICIs target immune checkpoint molecules, such as programmed cell death protein 1 (PD-1), PD ligand 1 (PD-L1), and T cell activation, including cytotoxic T-lymphocyte-associated protein-4 (CTLA-4). However, ICI-driven alterations in the immune system can induce various immune-related adverse events (irAEs) that affect multiple organs. Among these, cutaneous irAEs are the most common and often the first to develop. Skin manifestations are characterized by a wide range of phenotypes, including maculopapular rash, psoriasiform eruption, lichen planus-like eruption, pruritus, vitiligo-like depigmentation, bullous diseases, alopecia, and Stevens-Johnson syndrome/toxic epidermal necrolysis. In terms of pathogenesis, the mechanism of cutaneous irAEs remains unclear. Still, several hypotheses have been proposed, including activation of T cells against common antigens in normal tissues and tumor cells, increased release of proinflammatory cytokines associated with immune-related effects in specific tissues/organs, association with specific human leukocyte antigen variants and organ-specific irAEs, and acceleration of concurrent medication-induced drug eruptions. Based on recent literature, this review provides an overview of each ICI-induced skin manifestation and epidemiology and focuses on the mechanisms underlying cutaneous irAEs.

A Rare Case Presentation of Vitiligo Associated With Atezolizumab

Immune checkpoint inhibitors (ICIs) are monoclonal antibodies used in the treatment of solid and hematologic malignancies. Immune checkpoint inhibitors target the T-cell deactivation system via the cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) receptor, programmed cell death protein 1 (PD-1) receptor, and programmed cell death ligand 1 (PD-L1). As a result, the activated T-cell enhances the host tumor response. However, even with their essential clinical benefits, ICIs are associated with a broad spectrum of adverse effects that can be generalized or tissue-specific inflammatory responses known as immune-related adverse events (irAEs). The most common dermatologic toxicity manifests mainly as maculopapular rash and pruritus. Understanding the complexity of immune-mediated response and the importance of clinical histopathologic correlation in recognizing irAEs allows for appropriate intervention and patient care due. We present the case of a 71-year-old African American male diagnosed with a large-cell poorly differentiated neuroendocrine tumor in the gastroesophageal junction of the stomach with mediastinal lymphadenopathy. He was treated with carboplatin, etoposide, and atezolizumab for 4 cycles. However, he developed vitiligo while on maintenance atezolizumab, which is rarely seen with atezolizumab use. Despite the improving clinical outcomes in oncology with ICIs, their adverse effects should not be ignored. When promptly recognized and treated, patients on ICI monotherapy may not need treatment interruption or discontinuation.