T Cells Take Aim at Merkel Cell Carcinoma


A recent study offers a beacon of hope for patients battling Merkel cell carcinoma (MCC), a rare but aggressive form of skin cancer (Figure 1). The study has identified a novel approach to harness the power of the immune system to combat this deadly disease.

Figure 1: Graphical abstract.

The crux of the research lies in pinpointing specific viral components, called epitopes, within the Merkel cell polyomavirus (MCPyV) – the primary culprit behind MCC development. These epitopes serve as flags for the immune system’s T cells, allowing them to recognize and eliminate virus-infected cells. However, in elderly or immunocompromised individuals, this natural defense mechanism often weakens, leaving them susceptible to MCC.

Building upon previous clinical trials, the researchers employed a two-pronged strategy. First, they leveraged a well-established technique known as immune checkpoint blockade, a Nobel Prize-winning approach that reinvigorates exhausted T cells by blocking the PD-1 receptor. This essentially removes the “brakes” on the immune system, allowing T cells to unleash a more potent attack.

Secondly, the researchers developed a unique method to cultivate a large number of MCC-specific T cells directly from patients. This innovative approach utilizes technology involving nanostructures designed to stimulate T cells against MCPyV epitopes. This personalized approach ensures the generated T cells are highly targeted towards eradicating cancer cells.

The study demonstrates the successful expansion of T cells capable of targeting MCC in a significant portion (90%) of patient samples.

The potential impact of this research is significant. If successful, it could lead to the development of a new immunotherapy specifically tailored to combat MCC. This targeted approach offers a potentially more effective and personalized treatment option for patients battling this aggressive form of skin cancer.

Journal article: Hansen, U.K. et al., 2024. T antigen–specific CD8+ T cells associate with PD-1 blockade response in virus-positive Merkel cell carcinoma, Journal of Clinical Investigation.

Summary by Stefan Botha


International Union of Immunological SocietiesUniversity of South AfricaInstitute of Infectious Disease and Molecular MedicineElizabeth Glazer Pediatric Aids Foundation