CAR T therapy from haematological malignancies to aging-related diseases: An ever-expanding universe

Background: Short but impactful, the two-decade story of gene editing allowed a significant breakthrough in the treatment of haematological malignancies. However, despite different generations of chimeric antigen receptor T (CAR T), such a successful therapy has not yet been replicated in solid tumours and non-oncological diseases. Methods: This narrative review discusses how CAR T therapy still faces challenges in overcoming the complexity of the solid tumour microenvironment and the concerns that its long-term activity raises about potential unknown and unpredictable consequences in non-oncological diseases. Results: In the most recent studies, the senolytic potential of CAR T is becoming an exciting field of research. Still, experimental but promising results indeed indicate the clearance of senescent cells as an effective strategy to improve exercise capacity and metabolic dysfunction in physiological ageing, with long-term therapeutic and preventive effects. However, an effective expansion of a CAR T population requires a lympho-depleting chemotherapy prior to infusion. While this procedure sounds reasonable for rescue therapy of oncological diseases, it poses genotoxic risks that may not be justified for non-malignant diseases. Those represent the leading gaps for applying CAR T therapy in non-oncological diseases. Conclusion: More is expected from current studies on the other classes of CAR cells now under investigation. Engineering NK cells and macrophages are candidates to improve cytotoxic and immunomodulating properties, potentially able to broaden application in solid tumours and non-oncological diseases. Finally, engineering autologous T cells in old individuals may generate biologically deteriorated CAR T clones with impaired function and unpredictable effects on cytokine release.