MEASURING CELL VIABILITY with EZ4U

Our EZ4U Cell Proliferation and Cytotoxicity Assay was successfully applied in a recent study investigating novel therapeutic options for Cutaneous T-cell lymphoma (CTCL), a type of skin cancer that can also affect the blood (1). Extracorporeal photopheresis (ECP) is an immunomodulating photochemotherapy that has been linked to improved overall survival in the treatment of CTCL (2, 3).

MEASURING CELL VIABILITY with EZ4U Cell Proliferation and Cytotoxicity Assay

EZ4U Cell Proliferation & Cytotoxicity Assay (cat. no. BI-5000) – Assay Highlights

• Non-Radioactive & Non-Toxic
• Reliable & Sensitive
• Convenient single-step incubation for use on living cells
• Widely cited in over 290 publications !

 

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Evidence of immunogenic cell death (ICD) and ICD-dependent dendritic cell activation induced by extracorporeal photopheresis in patients with leukaemic forms of cutaneous T-cell lymphoma. Lackner Aet al., Br J Dermatol. 2025.  

Abstract

Background: Despite novel therapeutic options, the long-term management of cutaneous T-cell lymphoma (CTCL) remains challenging. Extracorporeal photopheresis (ECP) is an immunomodulating photochemotherapy associated with higher overall survival when used for the treatment of leukaemic forms of CTCL. Its exact mode of action has not been fully elucidated. Immunogenic cell death (ICD) is pivotal in cancer immunotherapy, marked by the release of damage-associated molecular patterns that enhance dendritic cell (DC) maturation and cytotoxic T-lymphocyte responses.

Objectives: To explore ICD in patients with leukaemic forms of CTCL during ECP and its effect on DC activation.

Methods: We conducted in vitro studies with peripheral blood mononuclear cells (PBMCs) from healthy donors and ex vivo experiments with white blood cells (WBCs) from patients with leukaemic forms of CTCL undergoing ECP. We assessed cell viability, apoptosis and ICD markers [ATP, high mobility group box 1 protein (HMGB1), calreticulin] using flow cytometry, enzyme-linked immunosorbent assay and quantitative polymerase chain reaction. Engulfment assays evaluated DC activation by ECP-treated CD4+ T cells.

Results: ECP-treated healthy PBMCs and WBCs from patients with leukaemic forms of CTCL showed a significant induction of ICD hallmarks, including ATP release, HMGB1 secretion and calreticulin surface exposure. In patients with leukaemic forms of CTCL, calreticulin exposure was mainly present in CD4+CD26- T cells, indicating greater ICD susceptibility of malignant T cells. ECP-treated CD4+ T cells were phagocytosed by DCs, a process that was found to be dependent on ICD signals.

Conclusions: ECP induces ICD in malignant T cells and, to a lesser extent, in healthy T cells, facilitates DC activation. These findings suggest that ECP enhances targeted immune responses against malignant T cells in leukaemic forms of CTCL, offering new insights into its therapeutic mechanisms and potential applications in cancer immunotherapy.

 

Literature

1. Evidence of immunogenic cell death (ICD) and ICD-dependent dendritic cell activation induced by extracorporeal photopheresis in patients with leukaemic forms of cutaneous T-cell lymphoma. Lackner A, Burner T, Huber M, Dey S, Aigner S, Buxhofer-Ausch V, Geroldinger-Simic M, Iselin C, Chang YT, Tsai YC, Altrichter S, Wolf P, Kimeswenger S, Guenova E, Hoetzenecker W. Br J Dermatol. 2025 Jul 17;193(2):276-286. doi: 10.1093/bjd/ljaf102. PMID: 40112181.
2. Early intervention of extracorporeal photopheresis for advancing/progressing cutaneous T-cell lymphoma. Aires D, Abhyankar S.Hematol Oncol. 2023 Dec;41(5):809-816. doi: 10.1002/hon.3229. Epub 2023 Nov 16. PMID: 37974524.
3. Extracorporeal Photopheresis-An Overview. Front Med (Lausanne). Cho A, Jantschitsch C, Knobler R. 2018 Aug 27;5:236. doi: 10.3389/fmed.2018.00236. PMID: 30211164; PMCID: PMC6119964.