CD57+ EMRA CD8+ T cells in cancer patients over 70: associations with prior chemotherapy and response to anti-PD-1/PD-L1 therapy

Abstract

Background: Immune ageing complicates cancer treatment in older individuals. While immunotherapy targeting the PD-1/PD-L1 pathway can reinvigorate T cells, these cells tend to become senescent with age. This study investigates different CD8⁺ T cell subsets usually associated with senescence, in cancer patients over 70 years old who are undergoing anti-PD-1/PD-L1 immunotherapy, and examines the relationship between these senescent cells and prior chemotherapy exposure. We analyzed data from the Elderly Cancer Patient (ELCAPA) cohort, which included 35 patients enrolled between March 2018 and March 2021.

Results: Flow cytometry and unsupervised analysis were employed to characterize Effector Memory CD45RA⁺ (EMRA) and CD8⁺ T cell senescence at baseline, before initiating PD-1/PD-L1 therapy. EMRA cells were found to overexpress CD57 and KLRG1 compared to overall CD8⁺ T cells. Chemotherapy prior to anti-PD-1/PD-L1 was associated with an increased proportion of CD57⁺ EMRA CD8⁺ T cells (p = 0.009) and its granzyme B (GRZB) subset (p = 0.007). Using a 10% cut-off to define positivity, the six-month non-response tends to be associated with the CD57⁺ GRZB⁺ EMRA positivity (p = 0.097). Other CD8⁺ T cell subsets (EMRA, CD57⁺, or KLRG1⁺), usually associated with senescence, showed no significant association with previous chemotherapy or response to anti-PD-1/anti-PD-L1 therapy.

Conclusions: These findings underscore the impact of prior chemotherapy on expanding the pool of senescent T cells, particularly CD57⁺ EMRA CD8⁺ T and CD57⁺ GRZB⁺ EMRA CD8⁺ T cells, whose expansion could potentially affect the effectiveness of anti-PD-1/PD-L1 immunotherapy in elderly patients. This highlights the need for tailored approaches in this population.

Keywords: Ageing; CD57; CD8-positive T-lymphocytes; Cancer; EMRA; Geriatrics; Immune-ageing; Immunotherapy; PD-1; Senescence; Tumour.

Fig. 1

Optimized t-distributed stochastic neighbor embedding (opt-SNE) plots of CD8⁺ T cells from 25 cohort patients. Opt-SNE plots of CD8 + T cells from 25 eligible patients’ data were generated, with overlaid to illustrate the expression of selected markers. In the scatterplots, marker expressions is represented by a continuous color gradient, ranging from dark blue (indicating minimal expression) to dark red (indicating maximal expression). The central optSNE1/optSNE2 plot reveals 5 distinct clusters corresponding to the differentiation stages, identified through CD27, CD28, CD45RA expression levels as naïve, central memory (CM), effector memory (EM) and terminally differentiated effector memory (EMRA). The expression of NK receptors (CD57 KLRG1) and granzyme B functional marker expressions characterize mainly effector memory cells (EM and EMRA). DAP12 is highly expressed in CD57hi CD8 + T cells. Granzyme B + CD8 + T cells are mainly CD28-

Fig. 2

Mean fluorescence intensity of Sestrin-2, granzyme B, and Ki-67 across CD8⁺ T cells maturation stages. The mean fluorescence intensity (MFI) of Sestrin-2, granzyme B, and Ki-67 was measured across different stages of CD8 + T cell maturation, ranging from the least differentiated (naïve) to the most differentiated (CD57 + DAP12 + EMRA) cells (n = 35). CM: central memory; EM: effector memory. Differences between the two groups were tested using a two-sided unpaired t-test. The p-values are indicated by asterisks as follows: < 0.05*, < 0.01**, < 0.001***, < 0.0001****

Fig. 3

Association of CD8⁺ T cells senescence with prior chemotherapy and response to anti-PD-1/PD-L1 therapy: A The senescence of CD8⁺ T cells, indicated by EMRA, CD57, and granzyme B (GRZB) expression, is analyzed in relation to prior chemotherapy exposure. The data are presented as a proportion of the total CD8⁺ T cell population. B The frequency of CD57⁺ EMRA CD8⁺ T cells (cut-off 10%) is compared based on pre-exposure to chemotherapy. C The proportion of CD57⁺ EMRA and CD57⁺ GRZB⁺ EMRA CD8.⁺ T cells (cut-off 10%) is shown in relation to treatment response, categorized as progressive disease (PD), partial response (PR), or stable disease (SD)