Some forms of blood cancer, such as multiple myeloma and lymphoma, are malignant diseases that originate from immune cells, specifically lymphocytes. In recent years, CAR-T cell therapies have become an essential part of the treatment of patients whose lymphoma or multiple myeloma has relapsed. This involves genetically modifying the patient’s own T lymphocytes (T cells) in order to specifically recognise and eliminate the cancer cells using a chimeric antigen receptor (CAR).

A special case is the subject of the current scientific publication. A 63-year-old patient with multiple myeloma developed T cell lymphoma in the blood, skin and intestine nine months after undergoing CAR-T cell therapy at the University Hospital of Cologne. The tumour developed from the genetically modified T cells that were used in the treatment.