High Dimensional Longitudinal Single-Cell Peripheral Blood Immune Monitoring in Lymphoma Reveals Skewed Monocyte and T Cell Profiles at Baseline Followed By Differential T-Cell Recovery in Patients Treated with Bendamustine

Introduction: The combination of chemotherapy and immunotherapy, commonly referred to as chemo-immunotherapy (CIT), has long been a cornerstone in the treatment of lymphoma. Although this approach has resulted in successful treatments for many patients (pts), a significant number continue to experience unfavorable results, underscoring the urgency for improved treatments. There is still a significant gap in knowledge about the immune profile of lymphoma pts, specifically in terms of (1) how their immune phenotype compare to those of healthy individuals and (2) how treatment affects their immune system. This study aimed to compare the immune profiles of lymphoma pts (at baseline) to that of matched healthy controls, and track the changes in the immune system during and after lymphoma treatment.

Methods: Pts with newly diagnosed, untreated lymphoma, without prior history of cancer or autoimmunity were enrolled in the Dyna-RISC study. Whole blood samples were collected at baseline (BL), on day 1 of cycle 2 (C2D1), on day 1 of last cycle (CLD1), and 6 months after completion of therapy (6mo). Age- and gender-matched healthy individuals provided blood for baseline comparison. Samples were stained fresh with a pre-mixed lyophilized cocktail containing 30 metal-tagged monoclonal antibodies (Maxpar Direct Immune Profile Assay), fixed and cryopreserved. Samples were barcoded and acquired in batches on the Helios CyTOF (cytometry by time-of-flight) system. Cytometry data was analyzed using OMIQ. Differential abundance analysis was performed using relative frequencies of cell subsets (% of parent) using a false-discovery rate of 0.05 to account for multiple comparisons.

Results: Between 11/2020 and 06/2021, 15 lymphoma pts were enrolled. Median age was 62 years (range 43-86), 5 pts (33%) were female. Five pts had follicular lymphoma (FL), 3 had diffuse large B-cell lymphoma (DLBCL),1 had primary mediastinal B-cell lymphoma (PBML), 1 had classic Hodgking lymphoma (cHL), 1 had mantle cell lymphoma (MCL), 1 had plasmablastic lymphoma (PBL), 1 had splenic marginal zone lymphoma (SpMZL), 1 had ALK- anaplastic large cell lymphoma (ALCL), 1 had subcutaneous panniculitis-like T-cell lymphoma (SPTCL). Four pts received bendamustine plus rituximab (BR) and 7 pts received R-CHOP. In total, more than 30 million cellular events were acquired, resulting in over 18 million analyzable live single-cell events after expert manual gating. A total of 27 cell subsets were identified within 9 major immune cell compartments.

At baseline, lymphoma pts showed significant reduction (p<0.05) of CD4+ naïve T cells (median 1.37%, range 0.33%-9.01%) compared to controls (median 9.28%, range 3.44-21.3%). Concurrently, lymphoma patients at baseline had significant elevation (p<0.05) of intermediate monocytes (median 2.1%, range 0.64%-5.73%) compared to controls (median 0.8%, range 0.2%-2.73%). Naïve cytotoxic T cells were significantly increased (p<0.05) in lymphoma pts at the 6mo timepoint (median 2.08%, range 0.7%-7.46%) compared to baseline (median 0.23%, range 0.03%-4.79%). A sub-group analysis restricted to patients who received either BR or R-CHOP with 6mo timepoint samples available (n=10), showed a significant reduction (p<0.05) in the frequency of CD4+ central memory T cells in the BR group (median 0.76%, range 0.06%-1.02%) compared to the R-CHOP group (median 3.3%, range 2.19%-5.0%). Additional results describing the details of the immune profile dynamics at intermediate timepoints (C2D1, CLD1) will be presented at the conference.

Conclusion: Our results suggest that lymphoma patients have an unfavorable immune profile (high intermediate monocytes combined with low naïve CD4+ T cells) at the time of diagnosis, compared to matched healthy individuals. Their immune profile is reshaped after treatment with increase in naïve cytotoxic T cells 6 months after therapy. Bendamustine-based treatment seems to particularly affect T cell recovery post-therapy, leading to a reduction in CD4+ central memory T cells, compared to patients treated with R-CHOP. These findings highlight the importance of studying baseline and treatment-mediated immune changes in lymphoma pts. This characterization is of special interest in the context of therapies that rely on the fitness of immune cells to mediate an effect, such as chimeric antigen receptor (CAR) T cell therapy and bispecific T cell engagers (BiTEs).

Leon-Ferre:Gilead Sciences: Consultancy; Lyell Immunopharma: Consultancy; AstraZeneca: Consultancy; MJH Life Sciences: Honoraria. Soekojo:J&J: Honoraria; Sanofi: Honoraria; Smart immune: Honoraria; Antegene: Honoraria. Villasboas Bisneto:CRISPR: Research Funding; Regeneron: Research Funding; Genentech: Research Funding; Epizyme: Research Funding; Enterome: Research Funding; Aptose: Research Funding.