Natural killer (NK) cells have emerged as one of the most promising components of cellular immunotherapy, thanks to their unique ability to identify and eliminate tumour cells independently of classical antigen presentation. However, the transition from preclinical to clinical research requires a rigorous and standardised approach to ensure that these therapies are safe, reproducible and effective.
Currently, the standardisation of NK cell-based therapies involves optimising each stage of the process, from obtaining the cell population to its administration to the patient, ensuring maximum control over the quality and functionality of the cells.
The clinical production of NK cells is a highly regulated process that combines advanced biotechnology with certified clinical protocols. The pipeline generally includes five critical stages: isolation, expansion, modification (when applicable), quality control, and clinical use.
The first step is to obtain high-purity NK cells from peripheral blood, bone marrow, or induced pluripotent stem cells (iPSCs). This isolation requires the removal of other cell populations, such as T or B lymphocytes, which could cause adverse reactions or interfere with therapeutic activity. Careful selection of the cell source is key to determining the availability and therapeutic potential of the therapy.
Once isolated, NK cells undergo expansion processes in controlled systems, using cytokines such as IL-2, IL-15 or IL-21 and, in some cases, support cells. This stage not only increases the number of cells but also optimises their functional activation, ensuring that each batch achieves the cytotoxicity necessary for clinical efficacy.
Genetic engineering can enhance the effectiveness of NK cells, especially in targeted therapies. Modifications include the insertion of chimeric receptors (CAR-NK) that guide the cells towards specific tumour antigens or the elimination of cytotoxicity-inhibiting genes. This step is critical in the creation of standardised and highly reproducible ‘off-the-shelf’ therapies.
Before administration to the patient, each batch of NK cells undergoes rigorous quality controls. The viability, purity, cytotoxic activity and immunophenotypic profile of the cells are evaluated, as well as sterility and absence of endotoxins. Compliance with GMP (Good Manufacturing Practice) standards is essential to ensure the safety and efficacy of the therapy.
Finally, NK cells are administered to the patient under strict clinical monitoring. The dose and therapeutic regimen are adjusted according to the type of cancer, patient characteristics, and cell origin, with close monitoring of adverse effects and therapeutic response.
A visual resource can improve understanding of this complex process. A horizontal flowchart representing each stage with clear icons is recommended:
This infographic can be inserted directly into the website to improve the user experience and encourage reading retention.
Autologous vs allogeneic vs iPSC-derived: which approach to choose?
The type of NK cells selected has a direct impact on availability, standardisation and therapeutic potential. Each approach has advantages and challenges:
The choice depends on multiple factors: tumour type, therapeutic urgency, donor availability, and the need for standardised and safe therapies.
The future of NK cell therapies points to robust and reproducible protocols capable of routinely delivering safe and effective treatments. The combination of selected donor banks, iPSC-derived cells, and genetic engineering strategies promises to make NK cells a reliable therapeutic resource, integrated into precision oncology medicine.
However, significant challenges remain. One of the main challenges is ensuring that NK cells persist and maintain their efficacy within the body after infusion, a critical factor for long-lasting therapeutic responses. Current research focuses on improving expansion, functional activation, and resistance to tumour immunosuppression, as well as developing genetic engineering strategies that prolong their half-life and effectiveness in vivo.
To learn more about these challenges and the most innovative strategies being explored, we invite you to watch this video, which analyses in detail the current challenges of NK cell immunotherapy:
VIDEO: The challenges of NK cell persistence and efficacy in vivo
This resource perfectly complements the clinical perspective presented in this article and demonstrates how translational research seeks to overcome the obstacles that still limit the effectiveness of these advanced therapies.