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Lichenoid dermatitis in three patients with metastatic melanoma treated with anti-PD-1 therapy
Richard W Joseph1, Mark Cappel2, Brent Goedjen2
1Division of Medical Oncology, Mayo Clinic, Jacksonville, Florida. joseph.richard@mayo.edu.
Abstract:
Therapies that activate the immune system through blocking the binding of programmed death ligand 1 (PD-L1) present on tumors and PD-1 (programmed death 1) present on activated immune cells are revolutionizing the care for patients with cancer. These therapies work by inhibiting negative regulators of the immune system, thereby decreasing a tumor's ability to evade the immune system. The side effects of anti-PD-1/PD-L1 therapies are generally mild and as expected are related to autoimmune reactions. Two of the most common side effects of anti-PD-1/PD-L1 therapies are rash and pruritus occurring in approximately 20% of patients. Although the rash is generally recognized to be immune mediated, the exact mechanisms of the rash remain unclear. Herein, we report three cases of lichenoid dermatitis in three patients treated with MK-3475 (anti-PD-1) that were characterized with marked T-cell infiltrates with few PD-1-positive cells. The rashes in all three patients were relatively mild, allowing treatment to continue despite the rashes.
Insights
Immune checkpoint inhibitors targeting programmed death 1 (PD-1) and programmed death ligand 1 (PD-L1) can cause skin reactions. This study details three cases of lichenoid dermatitis in patients receiving anti-PD-1 therapy.
Area of Science:
- Oncology
- Immunology
- Dermatology
Background:
- Cancer immunotherapies, specifically anti-PD-1/PD-L1 therapies, harness the immune system to fight tumors by blocking immune evasion.
- Common side effects include rash and pruritus in about 20% of patients, suggesting an immune-mediated mechanism.
- The precise mechanisms underlying these immune-related dermatologic adverse events remain incompletely understood.
Purpose of the Study:
- To investigate the specific dermatopathological findings in patients experiencing rash during anti-PD-1 therapy.
- To characterize the immune infiltrates in biopsy specimens from patients with anti-PD-1-associated dermatitis.
Main Methods:
- Case series reporting three patients treated with MK-3475 (an anti-PD-1 therapy).
- Histopathological examination of skin biopsy specimens.
- Immunohistochemical analysis to identify T-cell infiltrates and PD-1 expression.
Main Results:
- Three patients developed lichenoid dermatitis while on anti-PD-1 therapy.
- Biopsies revealed significant T-cell infiltrates.
- A low number of PD-1-positive cells were observed within the lesional skin.
Conclusions:
- Lichenoid dermatitis associated with anti-PD-1 therapy exhibits prominent T-cell infiltrates.
- The findings suggest a specific immune response pattern in the skin during this treatment.
- The observed rashes were generally mild, permitting continued anti-PD-1 therapy.
