T cell compositional changes over the course of treatment
heterogenous, PD, tumor, CM
TUMOR
Given the increased frequency of T cells from pre-treatment to C2D1, we next set to dissect features of T cell subsets in greater detail over the course of therapy and in context of tumor response. Within CD8 + and CD4 + T cell populations, we found no significant differences in frequencies of canonical naïve, central memory (CM), effector memory (EM), or effector memory CD45RA + (EMRA) populations at baseline (Supplemental Fig. 2). However, the patient with PD had the lowest frequency of naïve CD8 + T cells (5.7% vs. 22.6% mean in CR/PR/SD) and second lowest frequency of naïve CD4 + T cells (20.1% vs. 39.7% mean in CR/PR/SD) among all patients.Unbiased clustering was performed and identified 20 unique clusters of T cell subsets that were then manually annotated based on marker expression (Fig. T cell subset in association with response to doxorubicin and pembrolizumab. Circulating T cells were assessed by flow cytometry for complex phenotyping. Dimensionality reduction by the FlowSOM algorithm was performed to identify T cell metaclusters in an unbiased manner. Baseline frequencies of T cell subsets were heterogeneous across different response groups (Fig. We next asked how T cell composition was altered over the course of therapy. Interpatient variability in frequency changes was high across all T cell subsets, with no significant differences between pre-treatment frequencies and frequencies at C2D1 or Post Cycle 3 (Supplemental Fig. 3A and B). Similarly, fold changes in T cell populations were heterogenous across patient response status (Supplemental Fig. 3C and 3D). Surprisingly, the cell populations that showed the greatest change over the course of therapy were an increase in naïve CD8 + and naïve CD4 + T cells from pre-treatment to C2D1 (Dynamics of a proliferating CD8 + T cell population in patients treated with doxorubicin and pembrolizumab. Ki-67 + proliferating T cells were identified as shown in representative dot plots from pre-treatment and C2D1 (