Krieg, et al. – Summary
Krieg C, Nowicka M, Guglietta S, Schindler S, Hartmann FJ, Weber LM, Dummer R, Robinson MD, Levesque MP, Becher B. High-dimensional single-cell analysis predicts response to anti-PD-1 immunotherapy. Nat Med. 2018; 24(2):144-153. Available at: https://www.nature.com/articles/nm.4466. Erratum in: Nat Med. 2018; 24(11):1773-1775.
Anti-PD1 therapy has greatly improved metastatic melanoma patient’s survival, however, half of the patients still do not benefit from this therapy. Using cutting edge technology, we aimed to gain better understanding of the state of the patient’s immune system prior the drug is administered, and determine if this could explain why some patients are responding and some others are not. The technique used allows to assess the “identity” and “status” of individual cell in the sample allowing to depict a very precise picture of the immune status of the patient prior to treatment initiation.
By comparing blood samples from patients who eventually responded to samples of patients who did not respond, we detected interesting differences. The patients who are most likely to respond to the therapy showed a lower level of circulating T cells, which are presumably leaving the blood stream and heading towards the tumor site. Furthermore, a higher frequency of a specific cell type called “classical monocytes” was also observed in responding patients. Once the study has been validated in a larger set of patients, this could be used as a specific marker to predict which patient are more likely to benefit from anti-PD1 therapy.