Citations

The immune tumor microenvironment (iTME) plays a crucial role in disease biology of plasma cell (PC) dyscrasias, but remains poorly characterized in self-identified Black individuals, a population at increased risk. Mass cytometry and scRNA-seq of 128 bone marrow aspirates revealed significant changes in immune cell composition across the disease spectrum, including shifts from naïve to effector T cells with declines in B cells, MAIT, pDCs, and increases in monocytes with disease progression. Self-identified Black patients had higher relative proportions of terminally differentiated T cells and lower monocytes in newly diagnosed and treated multiple myeloma (MM). ScRNA-seq revealed genes overexpressed in self-identified Black individuals were enriched for E2F targets and G2-M checkpoints, while reduced genes were enriched for TNF-α/NF-kB, interferon and inflammatory responses pathways. These findings were supported by genetic ancestry and validated in an independent dataset of 286 patients with MM from the MMRF Immune Atlas. Self-identified race and African genetic similarity are significantly associated with remodeling the MM iTME, with potential implications for disease biology and treatment response.

Abstract Frailty influences treatment outcomes in older patients with multiple myeloma (MM), yet existing frailty tools capture limited geriatric domains and are incompletely studied in the context of contemporary therapies. We prospectively evaluated patient-reported comprehensive geriatric assessment (CGA) domains and their associations with treatment toxicity and patient-reported outcomes (PRO) in older adults with MM. Patients aged ≥60 years with newly diagnosed or relapsed/refractory MM initiating a new therapy completed electronic CGA and PRO questionnaires at baseline and 4 months. Outcomes included clinician- and patient-reported treatment toxicity, treatment adaptations, health care use, and health-related quality of life (HRQOL). A cumulative deficit frailty index (FI) was derived from CGA and HRQOL domains. Among 90 patients (mean age, 72 years), geriatric impairments were common, particularly physical function domains. High-grade nonhematologic toxicities were significantly associated with older age, comorbidities, patient-reported functional limitations, and anxiety. Toxicity rates on the PRO version of the Common Terminology Criteria for Adverse Events (CTCAE) were higher than on CTCAE, highlighting a discordance between physician- and patient-reported treatment toxicity. Frailty was present in 22% and associated with worse baseline HRQOL and increased high-grade nonhematologic toxicity but not treatment adaptations or health care use. Average CGA and HRQOL scores remained stable over 4 months, although individual trajectories varied. Patient-reported geriatric impairments are prevalent in older adults with MM and strongly associated with nonhematologic toxicities even in the contemporary treatment era. Physician-reported CTCAE may not fully reflect patients' symptom burden. Heterogeneity in individual geriatric trajectories during treatment emphasize the need for longitudinal assessment. This study was registered at www.clinicaltrials.gov as NCT05918185.

Abstract Immune checkpoint inhibitors (ICIs) which target immune checkpoint proteins like programmed cell death protein 1 (PD-1) and programmed cell death ligand 1 (PD-L1) have revolutionized cancer therapy. Skeletal toxicities are emerging immune-related adverse events for patients treated with ICIs, and PD-1 blockade in pre-clinical mouse models significantly reduces bone mass. However, the effect of PD-L1 inhibition on the bone throughout development is not well understood. We investigated the role of PD-L1 loss on bone microarchitecture with genetic PD-L1 knockout in myeloid cells using LysM-Cre;PD-L1Flox/Flox mice and pharmacologic inhibition with a PD-L1 neutralizing antibody in adult and aged mice. We report that neither PD-L1 deletion in myeloid cells nor inhibition with α-PD-L1 significantly impacts femoral trabecular bone microarchitecture; however, α-PD-L1 treatment increases vertebral trabecular bone volume. Additionally, PD-L1 blockade influences T cell expansion by decreasing naïve T cells and increasing effector memory T cells in the bone marrow, consistent with previous studies on the effects of PD-1 inhibition. The trabecular bone-sparing effect of PD-L1 inhibition is strikingly different from the bone loss observed with PD-1 blockade. Clinical studies are necessary and justified to determine if PD-L1 may be a less bone destructive alternative for cancer patients treated with ICIs who are at high risk of fracture.

Abstract Background: Patients (pts) with myeloma (MM) receiving CAR-T therapy have usually been exposed to many prior therapies. Melphalan (HDM) and other chemotherapies can induce cellular senescence. It has recently been shown that MM cells can also exhibit features of therapy-induced senescence (TIS). TIS tumor cells are associated with resistance to therapy and relapse. To investigate the presence of TIS MM cells prior to CAR-T and association with response, we examined the transcriptome and phenotype of MM prior to CAR-T. Method: We used scRNA-seq data from bone marrow (BM) MM cells: Boiarsky, et al. (GSE193531, dbGaP: phs001323.v3.p1) newly diagnosed MM (NDMM) pts; Dhodapkar, et al. (GSE210079), pre- and post CAR-T; pts who received CAR-T at Mayo Clinic, pre- (N=10) and post- (N=2). To evaluate TIS, single-cell gene set enrichment analysis (scGSEA) for several gene sets (PMID: 40164720): SenUp (Senescence Upregulated), SenGA (Senescence Growth Arrest), and SCAPs (Senescent Cell Anti-apoptosis Pathways); and a Plasma Cell Senescence (PCSen) gene set (GSE5900, GSE47552). To assess TIS and myeloid phenotype, BM MM cells (CD138+) were stained for CD14, CD16, KLRG1 and GPNMB and analyzed by CytoFlex and Kaluza. Results: In the integrated dataset, scGSEA showed significantly higher enrichment of PCSen, SenUp, SenGA, and SCAPs in late-stage MM cells (both pre- and post-CAR-T) compared to NDMM and healthy donors (p<0.05, Kruskal-Wallis with Dunn’s posttest). Conversely, the Normal gene set was significantly enriched in healthy plasma cells relative to MM (p<0.05). Expression of CDKN2A, which encodes the senescence marker p16, was also increased in late-stage MM relative to NDMM or healthy plasma cells. Notably, in our newly generated scRNA-seq samples collected within 6 months before CAR-T, a significant inverse correlation between senescence marker expression and progression free survival (PFS) post-CAR-T was seen, suggesting that MM cells exhibiting TIS may be more resistant to T cell mediated cytotoxicity. We found that 62.5% (25/40) of pts had >1% MM cells that were CD14+. Among them, the median CD14+ MM cells were 5.5% (1-71%); and median CD14+CD16+ MM cells were 2.14% (0.4-67%). Among 7 pts with available samples for KLRG1 and GPNMB assessment, 100% (7/7) had KLRG+ MM cells (median: 59% (24-99%)) and 57% (4/7) had GPNMB+ MM cells (median: 15% (3.9-30%)), and KLRG1+GPNMB+ MM cells (median: 9.6% (3.8-17%)). Conclusion: Our study shows that late-line MM cells exhibit transcriptional and phenotype profiles consistent with TIS. This senescent phenotype may contribute to resistance to immunotherapies, including CAR-T. Additional phenotype data is collected and will be presented. A phase II clinical trial is ongoing (NCT06940297) to assess for the combined treatment with senolytic drugs dasatinib and quercetin peri-CART to deepen clinical response. Citation Format: Sofia Arbelaez, Andre De Menezes Silva Corraes, Gabriel Alvares Borges, Chen Wu, Christoph Schaefers, Malvika Gupta, Zuoyi Shao, Kevin Regan, Rayaan Kamal, Angelo Jose Guilatco, Neal I. Sannuli, Ying Li, Taxiarchis Kourelis, Wilson Gonsalves, Moritz Binder, Melinda Tan, Nadine Abdallah, Megan Weivoda, Yi Lin. Myeloma cells with therapy-induced senescence-like phenotype are associated with resistance to CAR-T therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 6467.

Abstract Background: Therapy-induced senescence (TIS), a tumor cell state associated with distinct gene expression patterns and implicated in therapy resistance, may be activated in Multiple Myeloma (MM) patients (pt) by genotoxic chemotherapies, such as high-dose melphalan (HDM). We investigated whether TIS is activated in MM cells following chemotherapy and linked to resistance to T-cell directed therapies. Method: We integrated scRNA-seq data from healthy donors (CNTRL) and MM pts (newly-diagnosed (NDMM), pre/post-CAR-T) bone marrow plasma cells (PCs) using two public datasets (Boiarsky, et al.; Dhodapkar, et al.) and a newly generated pt dataset. Senescence was evaluated using scGSEA with published gene sets (SenUp, SenGA, and SCAPs). For in vitro MM cytotoxicity assay, human H929 MM cells were treated with vehicle (Veh) or HDM (3µM, IC90) for 6h and examined for TIS features. H929VEH or H929HDM were co-cultured with CNTRL T cells with or without teclistamab (Tec, 10 nM) or with day 14 PBMCs from MM pts post-CAR-T (E:T 5:1). CAR+ T cells were high among the day 14 PBMC (median±SD: 93.4±7.2% of CD3+ cells, n=6). Results: scGSEA revealed significantly higher enrichment of SenUp, SenGA, and SCAPs in late-stage MM cells compared to NDMM and CNTRL (p<0.05). Expression of CDKN2A, encoding the senescence marker p16, was also increased in late-stage MM relative to NDMM/CNTRL PCs. Of interest, cells enriched for senescence also exhibited enrichment for myeloid markers (TET2, CEBP family). Notably, in pre-CAR-T, increased baseline senescence or myeloid marker expression showed an inverse association with CAR-T progression-free survival (PFS), suggesting TIS confers resistance to T cell mediated cytotoxicity. This may be due to myeloid plasticity. TIS MM cells generated in vitro, H929HDM, exhibited a distinct morphology characterized by increased cell size and enhanced cytoplasmic granularity. Increased CD14 expression was seen in 4 of the 6 experiments (median, range % increase: 11.2%, 2.5%-21%), consistent with myeloid plasticity; Increased KLRG1 expression was seen in 5 of the 7 experiments (median MFI ratio, range: 3.7, 1.3-471). No significant change was seen in GPNMB expression. Compared to H929VEH, H929HDM had a reduction in killing by CAR-T cells (median±SD: 22.8±32.94% n=6, p=0.016, Wilcoxon paired test). Similarly, H929HDM had a 10.69% decrease in Tec-mediated T-cell killing compared to H929VEH (n=8, p=0.02, Wilcoxon paired test). Conclusions: Late-stage MM cells exhibit transcriptional signatures consistent with TIS, which can be associated with decreased PFS to CAR-T. We report an in vitro model of TIS MM cells for testing of resistance to T cell killing. Based on these findings, a phase II trial (NCT06940297) is underway to test the hypothesis that peri-CAR-T senolytic therapy with dasatinib and quercetin will deepen responses by targeting this resistant TIS MM population. Citation Format: Christoph Schaefers, Angelo Jose Guilatco, Sofia Arbelaez, Gabriel Alvares Borges, Chen Wu, Andre de Menezes Silva Corraes, Malvika Gupta, Zuoyi Shao, Kevin Regan, Rayaan Kamal, Neal I. Sannuli, Ying Li, Taxiarchis Kourelis, Wilson Gonsalves, Melinda Tan, Nadine Abdallah, Yi Lin, Megan Weivoda. Myeloma cells with therapy-induced senescence-like phenotype have increased resistance to killing by T cell directed therapies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 6475.

Abstract Frailty predicts adverse outcomes in multiple myeloma (MM), yet an objective frailty biomarker is lacking. Circulating senescence-associated secretory phenotype (SASP) factors correlate with frailty and adverse outcomes in chronic diseases, but their relevance in MM is unclear. In this study, we investigated the relationship between 36 plasma SASP factors, frailty, and clinical outcomes in: (1) a historical cohort using stored specimens from 59 patients with newly diagnosed MM, and (2) a prospective cohort of 36 patients initiating new MM treatment. Several SASP factors were significantly associated with frailty after adjusting for age, sex, and body mass index; GDF-15, TNF-RI, IL-6, and IL-8 showed positive correlations with both cumulative-deficit based and physical frailty indices. Additionally, significant age-adjusted associations were observed between SASP factors and treatment outcomes, including overall survival (OS), high-grade toxicity, and healthcare utilization. We developed a 5-factor SASP model that demonstrated superior predictive performance for OS compared to chronological age, R-ISS stage, and clinical frailty, and TNF-RI alone (5-year OS AUC: 0.90). These findings highlight the association between senescence biomarkers and frailty and OS, and support further investigation of SASP factors as objective frailty biomarkers in MM.

Abstract Introduction: Multiple myeloma (MM) predominantly affects older adults who vary widely in physiological status and treatment outcomes. Comprehensive Geriatric Assessment (CGA) is considered the gold standard for frailty assessment in older cancer patients (pts), but clinical useis limited. Current frailty tools for MM include only select GCA domains, rely on trial datasets, and do not incorporate pt-reported outcomes (PROs). Since their development, treatment strategies have evolved with the use of anti-CD38 MAbs and quadruplets in older pts. The impact of geriatric impairments on treatment tolerance in the era of modern therapy remains unclear and changes in geriatric domains during treatment are not well characterized. Aim: This prospective study evaluates the association between pt-reported CGA and treatment outcomes in older MM pts.Methods: We included MM pts ≥60 years initiating a new treatment at Mayo Clinic from March 2023-June 2024. Pts completed the CARG GCA (Hurria et al 2005) electronically prior to and after 4 treatment cycles. We collected data on toxicity using CTCAE and PRO-CTCAE and quality of life using the PROMIS10-GH SF.Results: Ninety pts were enrolled. Median age was 72 (range: 63-86), 42% female, and >90% non-Hispanic white. Over half (59%) were newly diagnosed with 41% and 56% receiving quadruplets and triplets, respectively. Among newly diagnosed pts, 34% had early stem cell transplant. Baseline median self- and physician- reported KPS were 80% and 90%, respectively, with high correlation (r=0.657). The median number of meds per pt was 9 (range:0-30), 39% had ≥3 comorbidities, 21% reported ≥1 fall in the past 6 months, and 40% reported ≥1 IADL limitation. On the Hospital Anxiety and Depression Scale, 3% and 7% had anxiety and depression, respectively. On the Blessed Orientation-Memory-Concentration test, 19% had mild cognitive impairment, and 1% had severe cognitive impairment. While only 19% had grade (G) ≥3 non-hematologic toxicity by CTCAE, 71% had ≥1 treatment delay, dose reduction, or discontinuation, and 39% had ≥1 ED visit or unplanned hospitalization within the first 4 cycles. This suggests physician grading of non-hem toxicities may inadequately capture toxicity burden from MM therapy. Notably, the rate of G≥3 toxicity by PRO-CTCAE was 49%, highlighting the discrepancy between physician- and pt-reported symptom burden. CGA domains significantly associated with G≥3 non-hem toxicity were: age (74 v 71.5, p=0.032), ≥3 comorbidities (65% v 33%, p=0.015), anxiety (18% v 0%, p=0.006), ≥1 IADL limitation (65% v 33%, p=0.018), physician KPS ≤80 (53% v 27%, p=0.042), limitations in vigorous activities (100% v 78%, p=0.023) and limitations in climbing several flights of stairs (88% v 56%, p<0.001). Predictors of PRO-CTCAE G≥3 toxicity were ≥1 falls (30% v 11%, p=0.030), ≥3 comorbidities (52% v 26%, p=0.011), polypharmacy (≥9 meds) (67% v 43%, p=0.023), and physician KPS ≤80 (43% v 22%, p=0.030). CGA domains associated with ≥1 treatment adjustments were polypharmacy (62% v 33%, p=0.017) and unintentional weight loss (35% v 12%, p=0.028). Polypharmacy was the only domain associated with healthcare utilization (68% v 45%, p = 0.040), which may reflect underlying multimorbidity and greater pain burden. On multivariable logistic regression, any level of limitation in climbing several flights of stairs (OR: 6.0, 95% CI 1.2-30.3; p= 0.030) and older age (OR: 1.1, 95% CI 1.0-1.1; p=0.032) were independently associated with G≥3 non-hem toxicity, reflecting impaired functional status and reduced physiologic reserve, while ≥3 comorbidities only trended toward significance (OR:1.9, 95% CI 1.1-3.9, p=0.051).Compared to baseline, there were no significant changes in CGA domains or PROMIS10 scores after 4 cycles. While there was no significant difference in the proportion of pts reporting limitations in IADLs or physical function, we observed heterogeneity among individual pts, with changes in all 3 directions (improvement, stability, and decline). Conclusions: Geriatric impairments are prevalent in older pts with MM; pt-reported impairments are significantly associated with G≥3 non-hem toxicities, need for treatment modifications, and increased healthcare utilization, even in the era of novel therapies. Physical functional trajectories during treatment are variable among individual pts, underscoring the need for personalized treatment strategies and reassessment of geriatric domains throughout treatment.

Abstract Introduction: Multiple myeloma (MM) is an incurable plasma cell (PC) malignancy, in which nearly all patients are expected to relapse and undergo multiple lines of treatment over the course of their disease. By the time patients receive CAR-T cell therapy, they have typically been exposed to numerous prior therapies, including high-dose melphalan (HDM). Chemotherapeutic agents that cause genotoxic stress, such as HDM, can induce cellular senescence in normal cells. More recently, it has been demonstrated that tumor cells can also exhibit features of therapy-induced senescence (TIS). TIS in tumor cells is associated with distinct gene expression patterns that have been implicated in resistance to therapy and relapse. To investigate whether TIS is activated in MM cells following exposure to chemotherapies, particularly in the context of late-stage disease, we performed an integrated analysis of single-cell RNA sequencing (scRNA-seq) datasets. Methods: We integrated scRNA-seq data from bone marrow plasma cells and MM cells using the following three sources: 1) Boiarsky, et al. (GSE193531, dbGaP: phs001323.v3.p1), which includes healthy donors, MGUS, SMM, and newly diagnosed MM (NDMM) patients; 2) Dhodapkar, et al. (GSE210079), which includes late-stage MM patients pre- and post-CAR-T cell therapy; and 3) newly generated scRNA-seq data from healthy donor (N=3) and late-stage MM patients pre- (N=10) and post- (N=2) CAR-T cell therapy. Non-plasma cells were excluded based on canonical plasma cell markers. We used Seurat v4.3 for data integration, employing canonical correlation analysis (CCA) to define anchors using the FindIntegrationAnchors and IntegrateData functions. Integration quality across datasets was validated by the consistent clustering of healthy plasma cells and expected expression patterns of chromosomal translocation markers CCND1 in t(11;14) cases and FGFR3 in t(4;14) cases, as previously described (PMID: 36396631). To evaluate senescence, we applied single-cell gene set enrichment analysis (scGSEA) using previously published gene sets (PMID: 40164720): SenUp (Senescence Upregulated), SenGA (Senescence Growth Arrest), and SCAPs (Senescent Cell Anti-apoptosis Pathways). We also curated a Plasma Cell Senescence (PCSen) gene set, composed of senescence-related genes that were differentially upregulated in pre-malignant plasma cells across two independent datasets (GSE5900, GSE47552).A normal plasma cell gene set was also generated, comprising genes differentially expressed between healthy and abnormal plasma cells in GSE193531. Results:In the integrated dataset, scGSEA revealed significantly higher enrichment of PCSen, SenUp, SenGA, and SCAPs in late-stage MM cells (both pre- and post-CAR-T cell therapy) compared to NDMM and healthy donors (p<0.05, Kruskal-Wallis with Dunn's posttest). Conversely, the Normal gene set was significantly enriched in healthy plasma cells relative to MM (p<0.05). Expression of CDKN2A, which encodes the senescence marker p16, was also increased in late-stage MM relative to NDMM or healthy plasma cells. Notably, in our newly generated scRNA-seq samples collected within 6 months before CAR-T therapy, we observed a significant inverse correlation between senescence marker expression and progression free survival (PFS) post-CAR-T, suggesting that MM cells exhibiting TIS may be more resistant to T cell mediated cytotoxicity. Supporting this, preliminary in vitro experiments showed that MM cells treated with HDM displayed reduced sensitivity to T cell-mediated cytotoxicity, consistent with a senescence-associated resistant phenotype. Conclusion: Our findings demonstrate that late-stage MM cells exhibit transcriptional signatures consistent with therapy-induced senescence, potentially driven by prior exposure to chemotherapy. This senescent phenotype may contribute to resistance to immunotherapies, including CAR-T cells. These data highlight senescence as a mechanism of resistance and a potential biomarker for predicting CAR-T outcomes. Further studies are needed to explore senescence-targeted strategies to enhance immunotherapeutic efficacy in MM.

Abstract Description A subset of follicular lymphoma patients has an early relapse with a poor outcome. We showed that this unfavorable group displays increased expression of IRF4, dysregulated immune signaling and an immunosuppressive microenvironment. However, little is known on the molecular mechanisms whereby IRF4 controls the crosstalk between B and T cells. To this aim, we leveraged Cγ1cre;irf4fl/fl mice that yield conditional deletion of irf4 (cKO) in germinal center B cells (GCB). After 10 days of immunization, cKO GCB showed significant increase of HLA-DR and CD40 expression, a skewed LZ:DZ ratio towards increased DZ, and suppression of plasma cells compared to WT. Upon irf4 deletion, we also found a significant increase of total CD4 and TFH cells and a decrease in Treg cells. To test if this effect was antigen-dependent, we cocultured sorted GCB from NP-OVA-immunized cKO and WT mice with CSFE-labeled OVA-specific OT-II CD4 T cells at a ratio of 2:1 for 5 days. We observed increased antigen specific proliferation of CD4 T cells with cKO GCB compared to WT. We then performed seahorse assay and mass spectrometry of the same GCB to define if IRF4-dependent B cell metabolic reprogramming influences immune responses. GCB cKO had lower glycolytic ECAR and increased intracellular glucose and non-essential amino acids than WT cells, suggesting a metabolic shift from glycolysis to the TCA cycle. Thus, IRF4 controls immune and metabolic signaling with functional effects on the B-T cell crosstalk. Funding Sources NCI K08CA279652, LRF Clinical Investigator Award (CDA 1020588), the Gerstner Family Career Development Award, the ASH Junior Faculty Scholar Award. Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

Abstract Multiple Myeloma (MM) is an incurable plasma cell malignancy that progresses from the precursor condition monoclonal gammopathy of undetermined significance (MGUS). African Americans (AA) have the highest incidence of MGUS and MM of any population group in the U.S., with ∼1.5-2-fold higher age-adjusted incidence than European Americans (EA) for reasons that remain unclear. Despite the increased incidence, MM tumors in AA patients show fewer TP53 deletions/mutations and high-risk cytogenetic features compared to EA patients. Studies also show that, with equal access to care, AA patients have better overall survival (OS) independent of age. Given recent studies demonstrating accelerated biological aging in AA individuals, we hypothesize that immunosenescence that occurs with aging reduces the immune pressure on MM cells, resulting in the increased emergence of less aggressive tumors. To test this, we utilized viably frozen bone marrow samples from the Mayo Clinic Myeloma Biobank. We profiled samples from 128 individuals (N= 53 and 75 AA vs. EA, respectively) with either newly diagnosed MM (NDMM) or treated MM (N= 27 and 38 AA vs. EA, respectively), MGUS (N=18 and 23 AA vs. EA, respectively), or healthy controls (N= 8 and 14 AA vs. EA, respectively) by mass cytometry (CyTOF) (N= 17 MGUS, 55 MM and 22 healthy controls) using the CyTOF Human Immune Profile Assay or by single cell RNA-sequencing (scRNA-seq, N= 24 MGUS/SMM and 10 MM). Profiling of the CD45+ non-tumor lymphocytes by scRNA-seq revealed AA patients exhibited increased T cell populations (odds ratio (OR)=2.3), including a reduction in CD8+ effector memory (OR=0.94) and an increase in CD8+ cytotoxic effector (OR=1.02) in a multivariate model adjusting for age and sex. Analysis by CyTOF confirmed an increase in overall CD3+ T cells (49.5% vs. 35.3%, p=0.0001) including increases in CD8+ terminal effector (9.5% vs. 5.2%, p=0.021) and CD4+ terminal effector T cells (5.5% vs. 2.7%, p=5.7x10^-6) among AA patients, and this difference remained after adjusting for age and sex. Within the CD8+ terminal effector T cells, we also noted increases in CD57+/CD28- senescent T cells, consistent with immune exhaustion that occurs with biological aging. We are currently working to assess whether AA patients with MGUS and MM exhibit accelerated biological aging as measured by frailty index, peripheral senescence associated secretory phenotypes, and PBMC epigenetic clock scores. We plan to extend our analysis of the immune microenvironment to assess patient T cell function ex vivo. Finally, we will evaluate whether MM cells from AA patients exhibit increased sensitivity to control cytotoxic T cell induced cell death in vitro compared to cells from EA patients. The results from this study will allow further understanding of components causing the increased risk for MM development seen in AA individuals. Citation Format: Alani Perkin, Megan Moore Weivoda, Linda Baughn. Immunosenescence driven T-cell remodeling may underlie increased risk of Multiple Myeloma in African Americans [abstract]. In: Proceedings of the 18th AACR Conference on the Science of Cancer Health Disparities; 2025 Sep 18-21; Baltimore, MD. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2025;34(9 Suppl):Abstract nr A051.