CD28-CD57+ T cells from head and neck cancer patients produce high levels of cytotoxic granules and type II interferon but are not senescent.

T lymphocytes expressing CD57 and lacking costimulatory receptors CD27/CD28 have been reported to accumulate with aging, chronic infection, and cancer. These cells are described as senescent, with inability to proliferate but enhanced cytolytic and cytokine-producing capacity. However, robust functional studies on these cells taken directly from cancer patients are lacking. We isolated these T cells and their CD27/28+ counterparts from blood and tumor samples of 50 patients with previously untreated head and neck cancer. Functional studies confirmed that these cells have enhanced ability to degranulate and produce IFN-γ. They also retain the ability to proliferate, thus are not senescent. These data suggest that CD27/28-CD57+ CD8+ T cells are a subset of highly differentiated, CD45RA+ effector memory (TEMRA) cells with retained proliferative capacity. Patients with > 34% of these cells among CD8+ T cells in the blood had a higher rate of locoregional disease relapse, suggesting these cells may have prognostic significance.

Distinct SIV-specific CD8+ T cells in the lymph node exhibit simultaneous effector and stem-like profiles and are associated with limited SIV persistence.

Human immunodeficiency virus (HIV) cure efforts are increasingly focused on harnessing CD8+ T cell functions, which requires a deeper understanding of CD8+ T cells promoting HIV control. Here we identifiy an antigen-responsive TOXhiTCF1+CD39+CD8+ T cell population with high expression of inhibitory receptors and low expression of canonical cytolytic molecules. Transcriptional analysis of simian immunodeficiency virus (SIV)-specific CD8+ T cells and proteomic analysis of purified CD8+ T cell subsets identified TOXhiTCF1+CD39+CD8+ T cells as intermediate effectors that retained stem-like features with a lineage relationship with terminal effector T cells. TOXhiTCF1+CD39+CD8+ T cells were found at higher frequency than TCF1-CD39+CD8+ T cells in follicular microenvironments and were preferentially located in proximity of SIV-RNA+ cells. Their frequency was associated with reduced plasma viremia and lower SIV reservoir size. Highly similar TOXhiTCF1+CD39+CD8+ T cells were detected in lymph nodes from antiretroviral therapy-naive and antiretroviral therapy-suppressed people living with HIV, suggesting this population of CD8+ T cells contributes to limiting SIV and HIV persistence.

Localized high-risk prostate cancer harbors an androgen receptor low subpopulation susceptible to HER2 inhibition.

Patients diagnosed with localized high-risk prostate cancer have higher rates of recurrence, and the introduction of neoadjuvant intensive hormonal therapies seeks to treat occult micrometastatic disease by their addition to definitive treatment. Sufficient profiling of baseline disease has remained a challenge in enabling the in-depth assessment of phenotypes associated with exceptional vs. poor pathologic responses after treatment. In this study, we report comprehensive and integrative gene expression profiling of 37 locally advanced prostate tumors prior to six months of androgen deprivation therapy (ADT) plus the androgen receptor (AR) inhibitor enzalutamide prior to radical prostatectomy. A robust transcriptional program associated with HER2 activity was positively associated with poor outcome and opposed AR activity, even after adjusting for common genomic alterations in prostate cancer including PTEN loss and expression of the TMPRSS2:ERG fusion. Patients experiencing exceptional pathologic responses demonstrated lower levels of HER2 and phospho-HER2 by immunohistochemistry of biopsy tissues. The inverse correlation of AR and HER2 activity was found to be a universal feature of all aggressive prostate tumors, validated by transcriptional profiling an external cohort of 121 patients and immunostaining of tumors from 84 additional patients. Importantly, the AR activity-low, HER2 activity-high cells that resist ADT are a pre-existing subset of cells that can be targeted by HER2 inhibition alone or in combination with enzalutamide. In summary, we show that prostate tumors adopt an AR activity-low prior to antiandrogen exposure that can be exploited by treatment with HER2 inhibitors.

Early generation of a precursor CD8 T cell that can adapt to acute or chronic viral infection.

Virus specific PD-1+ TCF-1+ TOX+ stem-like CD8+ T cells are essential for maintaining T cell responses during chronic infection and are also critical for PD-1 directed immunotherapy. In this study we have used the mouse model of chronic LCMV infection to examine when these virus specific stem-like CD8+ T cells are generated during the course of chronic infection and what is the role of antigen in maintaining the stem-like program. We found that these stem-like CD8+ T cells are generated early (day 5) during chronic infection and that antigen is essential for maintaining their stem-like program. This early generation of stem-like CD8+ T cells suggested that the fate commitment to this cell population was agnostic to the eventual outcome of infection and the immune system prepares a priori for a potential chronic infection. Indeed, we found that an identical virus specific stem-cell like CD8+ T cell population was also generated during acute LCMV infection but these cells were lost once the virus was cleared. To determine the fate of these early PD-1+TCF-1+TOX+ stem-like CD8+ T cells that are generated during both acute and chronic LCMV infection we set up two reciprocal adoptive transfer experiments. In the first experiment we transferred day 5 stem-like CD8+ T cells from chronically infected into acutely infected mice and examined their differentiation after viral clearance. We found that these early stem-like CD8+ T cells downregulated canonical markers of the chronic stem-like CD8+ T cells and expressed markers (CD127 and CD62L) associated with central memory CD8+ T cells. In the second experiment, we transferred day 5 stem-like cells from acutely infected mice into chronically infected mice and found that these CD8+ T cells could function like resource cells after transfer into a chronic environment by generating effector CD8+ T cells in both lymphoid and non-lymphoid tissues while also maintaining the number of stem-like CD8+ T cells. These findings provide insight into the generation and maintenance of virus specific stem-like CD8+ T cells that play a critical role in chronic viral infection. In particular, our study highlights the early generation of stem-like CD8+ T cells and their ability to adapt to either an acute or chronic infection. These findings are of broad significance since these novel stem-like CD8+ T cells play an important role in not only viral infections but also in cancer and autoimmunity.

Characteristics and anatomic location of PD-1+TCF1+ stem-like CD8 T cells in chronic viral infection and cancer.

CD8 T cells play an essential role in antitumor immunity and chronic viral infections. Recent findings have delineated the differentiation pathway of CD8 T cells in accordance with the progenitor-progeny relationship of TCF1+ stem-like and Tim-3+TCF1- more differentiated T cells. Here, we investigated the characteristics of stem-like and differentiated CD8 T cells isolated from several murine tumor models and human lung cancer samples in terms of phenotypic and transcriptional features as well as their location compared to virus-specific CD8 T cells in the chronically lymphocytic choriomeningitis virus (LCMV)-infected mice. We found that CD8 tumor-infiltrating lymphocytes (TILs) in both murine and human tumors exhibited overall similar phenotypic and transcriptional characteristics compared to corresponding subsets in the spleen of chronically infected mice. Moreover, stem-like CD8 TILs exclusively responded and produced effector-like progeny CD8 T cells in vivo after antigenic restimulation, confirming their lineage relationship and the proliferative potential of stem-like CD8 TILs. Most importantly, similar to the preferential localization of PD-1+ stem-like CD8 T cells in T cell zones of the spleen during chronic LCMV infection, we found that the PD-1+ stem-like CD8 TILs in lung cancer samples are preferentially located not in the tumor parenchyma but in tertiary lymphoid structures (TLSs). The stem-like CD8 T cells are present in TLSs located within and at the periphery of the tumor, as well as in TLSs closely adjacent to the tumor parenchyma. These findings suggest that TLSs provide a protective niche to support the quiescence and maintenance of stem-like CD8 T cells in the tumor.

Longitudinal Analysis of the Phenotype, Transcriptional Profile, and Anatomic Location of Memory CD8 T Cell Subsets after Acute Viral Infection.

Increased demand for novel, highly effective vaccination strategies necessitates a better understanding of long-lived memory CD8 T cell differentiation. To achieve this understanding, we used the mouse model of acute lymphocytic choriomeningitis virus (LCMV) infection. We reexamined classical memory CD8 T cell subsets and performed in-depth, longitudinal analysis of their phenotype, transcriptional programming, and anatomic location within the spleen. All analyses were performed at multiple time points from 8 days to 1 year postinfection. Memory subsets are conventionally defined by their expression of KLRG1 and IL-7Rα, as follows: KLRG1+IL-7Rα- terminal effectors (TEs) and KLRG1-IL-7Rα+ memory precursors (MPs). But we also characterized a third KLRG1+IL-7Rα+ subset which we refer to as KLRG1+ MPs. In these analyses, we defined a comprehensive memory phenotype that is associated with higher levels of CD28 expression. We also demonstrated that MPs, KLRG1+ MPs, and TEs have distinct localization programs within the spleen. We found that MPs became preferentially enriched in the white pulp as early as 1 to 2 weeks postinfection, and their predominance in the white pulp was maintained throughout the course of a year. On the other hand, KLRG1+ MPs and TEs localized to the red pulp just as early, and they consistently localized to the red pulp thereafter. These findings indicate that location may be crucial for memory formation and that white pulp-derived signals may contribute to long-term memory survival. Achieving robust memory responses following vaccination may require more deliberate consideration of which memory phenotypes are induced, as well as where they traffic, as these factors could impact their longevity. IMPORTANCE CD8 T cells play a critical role in viral immunity and it is important to understand how memory cells are formed and what processes lead to their long-term maintenance. Here, we use a mouse model of acute infection to perform an in-depth, longitudinal analysis of memory CD8 T cell differentiation, examining the phenotype and location of memory cells out to 1 year postinfection.

PD-1-cis IL-2R agonism yields better effectors from stem-like CD8+ T cells.

Expansion and differentiation of antigen-experienced PD-1+TCF-1+ stem-like CD8+ T cells into effector cells is critical for the success of immunotherapies based on PD-1 blockade1-4. Hashimoto et al. have shown that, in chronic infections, administration of the cytokine interleukin (IL)-2 triggers an alternative differentiation path of stem-like T cells towards a distinct population of 'better effector' CD8+ T cells similar to those generated in an acute infection5. IL-2 binding to the IL-2 receptor α-chain (CD25) was essential in triggering this alternative differentiation path and expanding better effectors with distinct transcriptional and epigenetic profiles. However, constitutive expression of CD25 on regulatory T cells and some endothelial cells also contributes to unwanted systemic effects from IL-2 therapy. Therefore, engineered IL-2 receptor ß- and γ-chain (IL-2Rßγ)-biased agonists are currently being developed6-10. Here we show that IL-2Rßγ-biased agonists are unable to preferentially expand better effector T cells in cancer models and describe PD1-IL2v, a new immunocytokine that overcomes the need for CD25 binding by docking in cis to PD-1. Cis binding of PD1-IL2v to PD-1 and IL-2Rßγ on the same cell recovers the ability to differentiate stem-like CD8+ T cells into better effectors in the absence of CD25 binding in both chronic infection and cancer models and provides superior efficacy. By contrast, PD-1- or PD-L1-blocking antibodies alone, or their combination with clinically relevant doses of non-PD-1-targeted IL2v, cannot expand this unique subset of better effector T cells and instead lead to the accumulation of terminally differentiated, exhausted T cells. These findings provide the basis for the development of a new generation of PD-1 cis-targeted IL-2R agonists with enhanced therapeutic potential for the treatment of cancer and chronic infections.

PD-1 combination therapy with IL-2 modifies CD8+ T cell exhaustion program.

Combination therapy with PD-1 blockade and IL-2 is highly effective during chronic lymphocytic choriomeningitis virus infection1. Here we examine the underlying basis for this synergy. We show that PD-1 + IL-2 combination therapy, in contrast to PD-1 monotherapy, substantially changes the differentiation program of the PD-1+TCF1+ stem-like CD8+ T cells and results in the generation of transcriptionally and epigenetically distinct effector CD8+ T cells that resemble highly functional effector CD8+ T cells seen after an acute viral infection. The generation of these qualitatively superior CD8+ T cells that mediate viral control underlies the synergy between PD-1 and IL-2. Our results show that the PD-1+TCF1+ stem-like CD8+ T cells, also referred to as precursors of exhausted CD8+ T cells, are not fate-locked into the exhaustion program and their differentiation trajectory can be changed by IL-2 signals. These virus-specific effector CD8+ T cells emerging from the stem-like CD8+ T cells after combination therapy expressed increased levels of the high-affinity IL-2 trimeric (CD25-CD122-CD132) receptor. This was not seen after PD-1 blockade alone. Finally, we show that CD25 engagement with IL-2 has an important role in the observed synergy between IL-2 cytokine and PD-1 blockade. Either blocking CD25 with an antibody or using a mutated version of IL-2 that does not bind to CD25 but still binds to CD122 and CD132 almost completely abrogated the synergistic effects observed after PD-1 + IL-2 combination therapy. There is considerable interest in PD-1 + IL-2 combination therapy for patients with cancer2,3, and our fundamental studies defining the underlying mechanisms of how IL-2 synergizes with PD-1 blockade should inform these human translational studies.

TGF-ß regulates the stem-like state of PD-1+ TCF-1+ virus-specific CD8 T cells during chronic infection.

Recent studies have defined a novel population of PD-1+ TCF-1+ stem-like CD8 T cells in chronic infections and cancer. These quiescent cells reside in lymphoid tissues, are critical for maintaining the CD8 T cell response under conditions of persistent antigen, and provide the proliferative burst after PD-1 blockade. Here we examined the role of TGF-ß in regulating the differentiation of virus-specific CD8 T cells during chronic LCMV infection of mice. We found that TGF-ß signaling was not essential for the generation of the stem-like CD8 T cells but was critical for maintaining the stem-like state and quiescence of these cells. TGF-ß regulated the unique transcriptional program of the stem-like subset, including upregulation of inhibitory receptors specifically expressed on these cells. TGF-ß also promoted the terminal differentiation of exhausted CD8 T cells by suppressing the effector-associated program. Together, the absence of TGF-ß signaling resulted in significantly increased accumulation of effector-like CD8 T cells. These findings have implications for immunotherapies in general and especially for T cell therapy against chronic infections and cancer.

Invariant NKT cell-augmented GM-CSF-secreting tumor vaccine is effective in advanced prostate cancer model.

Invariant natural killer T cells (iNKT cells) express a semi-invariant T cell receptor that recognizes certain glycolipids (including α-galactosylceramide, αGC) bound to CD1d, and can induce potent antitumor responses. Here, we assessed whether αGC could enhance the efficacy of a GM-CSF-producing tumor cell vaccine in the transgenic SV40 T antigen-driven TRAMP prostate cancer model. In healthy mice, we initially found that optimal T cell responses were obtained with αGC-pulsed TRAMP-C2 cells secreting GM-CSF and milk fat globule epidermal growth factor protein-8 (MFG-E8) with an RGD to RGE mutation (GM-CSF/RGE TRAMP-C2), combined with systemic low dose IL-12. In a therapeutic model, transgenic TRAMP mice were then castrated at ~ 20 weeks, followed by treatment with the combination vaccine. Untreated mice succumbed to tumor by ~ 40 weeks, but survival was markedly prolonged by vaccine treatment, with most mice surviving past 80 weeks. Prostates in the treated mice were heavily infiltrated with T cells and iNKT cells, which both secreted IFNγ in response to tumor cells. The vaccine was not effective if the αGC, IL-12, or GM-CSF secretion was eliminated. Finally, immunized mice were fully resistant to challenge with TRAMP-C2 cells. Together these findings support further development of therapeutic vaccines that exploit iNKT cell activation.

Sarcopenia and systemic inflammation are associated with decreased survival after cytoreductive nephrectomy for metastatic renal cell carcinoma.

BACKGROUND: This study was aimed at assessing the associations of sarcopenia, muscle density, adiposity, and inflammation with overall survival (OS) after cytoreductive nephrectomy (CN) for metastatic renal cell carcinoma. METHODS: In all, 158 patients undergoing CN from 2001 to 2014 had digitized preoperative imaging for tissue segmentation via Slice-O-Matic software (version 5.0) at the mid-L3 level. The skeletal muscle index was calculated with the skeletal muscle area (cm2 ) normalized for height (m2 ), and the skeletal muscle density (SMD) was calculated with average Hounsfield units. Adiposity was measured with the cross-sectional area (cm2 ) of visceral, subcutaneous, and intramuscular adiposity compartments and was similarly normalized for height. The average fat density was obtained in Hounsfield units. OS was estimated with the Kaplan-Meier method. Associations between body composition, inflammation metrics, and relevant clinicopathology and OS were assessed with univariable and multivariate Cox analyses. RESULTS: Seventy-six of the 158 patients (48%) were sarcopenic. Sarcopenia was associated with elevated neutrophil to lymphocyte ratios (NLRs; P = .02), increased age (P = .001), lower body mass indices (P = .009), greater modified Motzer scores (P = .019), and lower SMD (P = .006). The median OS was 15.0 and 29.4 months for sarcopenic and nonsarcopenic patients, respectively (P = .04). Elevated inflammation (NLR or C-reactive protein), in addition to sarcopenia, was independently associated with OS, with an elevated NLR ≥ 3.5 and sarcopenia associated with the poorest OS at 10.2 months. No associations were observed between measurements of muscle density or adiposity and OS. CONCLUSIONS: Sarcopenia and measures of high systemic inflammation are additively associated with inferior OS after CN and may be of use in preoperative risk stratification. LAY SUMMARY: Body composition and sarcopenia (a deficiency in skeletal musculature) have been shown to affect outcomes in cancer. We found that sarcopenic patients had poor survival in comparison with nonsarcopenic patients in the setting of metastatic renal cell carcinoma (mRCC). Patients with both elevated inflammation and sarcopenia had the poorest survival. Sarcopenia is an objective measure of nutrition that can assist in therapeutic counseling and decision-making for individualized treatment in mRCC.

Defining the Molecular Hallmarks of T-Cell Memory.

The pool of memory CD8 T cells is comprised of highly specialized subpopulations of cells with both shared and distinct functions. The ongoing study of T-cell memory is focused on how these different subpopulations arise, how the cells are maintained over the life of the host, and how the cells protect a host against reinfection. As a field we have used the convenience of a narrow range of surface markers to define and study these memory T-cell subsets. However, as we learn more about these cells, it is becoming clear that these broad definitions are insufficient to capture the complexity of the CD8 memory T-cell pool, and an updated definition of these cellular states are needed. Here, we discuss data that have recently arisen that highlight the difficulty in using surface markers to functionally characterize CD8 T-cell populations, and the possibility of using the epigenetic state of cells to more clearly define the functional capacity of CD8 memory T-cell subsets.

Functional HPV-specific PD-1+ stem-like CD8 T cells in head and neck cancer.

T cells are important in tumour immunity but a better understanding is needed of the differentiation of antigen-specific T cells in human cancer1,2. Here we studied CD8 T cells in patients with human papillomavirus (HPV)-positive head and neck cancer and identified several epitopes derived from HPV E2, E5 and E6 proteins that allowed us to analyse virus-specific CD8 T cells using major histocompatibility complex (MHC) class I tetramers. HPV-specific CD8 T cells expressed PD-1 and were detectable in the tumour at levels that ranged from 0.1% to 10% of tumour-infiltrating CD8 T lymphocytes (TILs) for a given epitope. Single-cell RNA-sequencing analyses of tetramer-sorted HPV-specific PD-1+ CD8 TILs revealed three transcriptionally distinct subsets. One subset expressed TCF7 and other genes associated with PD-1+ stem-like CD8 T cells that are critical for maintaining T cell responses in conditions of antigen persistence. The second subset expressed more effector molecules, representing a transitory cell population, and the third subset was characterized by a terminally differentiated gene signature. T cell receptor clonotypes were shared between the three subsets and pseudotime analysis suggested a hypothetical differentiation trajectory from stem-like to transitory to terminally differentiated cells. More notably, HPV-specific PD-1+TCF-1+ stem-like TILs proliferated and differentiated into more effector-like cells after in vitro stimulation with the cognate HPV peptide, whereas the more terminally differentiated cells did not proliferate. The presence of functional HPV-specific PD-1+TCF-1+CD45RO+ stem-like CD8 T cells with proliferative capacity shows that the cellular machinery to respond to PD-1 blockade exists in HPV-positive head and neck cancer, supporting the further investigation of PD-1 targeted therapies in this malignancy. Furthermore, HPV therapeutic vaccination efforts have focused on E6 and E7 proteins; our results suggest that E2 and E5 should also be considered for inclusion as vaccine antigens to elicit tumour-reactive CD8 T cell responses of maximal breadth.

Body Composition as an Independent Predictive and Prognostic Biomarker in Advanced Urothelial Carcinoma Patients Treated with Immune Checkpoint Inhibitors.

BACKGROUND: Several immune checkpoint inhibitors (ICIs) are approved for the treatment of advanced urothelial carcinoma (UC). There are limited biomarkers for ICI-treated patients with UC. We investigated the association between body composition and clinical outcomes in ICI-treated UC patients. MATERIALS AND METHODS: We conducted a retrospective analysis of 70 ICI-treated patients with advanced UC at Winship Cancer Institute from 2015 to 2020. Baseline computed tomography images within 2 months of ICI initiation were collected at mid-L3 and muscle and fat compartments (subcutaneous, intermuscular, and visceral) were segmented using SliceOMatic v5.0 (TomoVision, Magog, Canada). A prognostic body composition risk score (high: 0-1, intermediate: 2-3, or low-risk: 4) was created based on the ß coefficient from the multivariate Cox model (MVA) following best-subset variable selection. Our body composition risk score was skeletal muscle index (SMI) + 2 × attenuated skeletal muscle (SM) mean + visceral fat index (VFI). Concordance statistics (C-statistics) were used to quantify the discriminatory magnitude of the predictive model. RESULTS: Most patients (70%) were men and the majority received ICIs in the second- (46%) or third-line (21%) setting. High-risk patients had significantly shorter overall survival (OS; hazard ratio [HR], 6.72; p < .001), progression-free survival (HR, 5.82; p < .001), and lower chance of clinical benefit (odds ratio [OR], 0.02; p = .003) compared with the low-risk group in MVA. The C-statistics for our body composition risk group and myosteatosis analyses were higher than body mass index for all clinical outcomes. CONCLUSION: Body composition variables such as SMI, SM mean, and VFI may be prognostic and predictive of clinical outcomes in ICI-treated patients with UC. Larger, prospective studies are warranted to validate this hypothesis-generating data. IMPLICATIONS FOR PRACTICE: This study developed a prognostic body composition risk scoring system using radiographic biomarkers for patients with bladder cancer treated with immunotherapy. The study found that the high-risk patients had significantly worse clinical outcomes. Notably, the study's model was better at predicting outcomes than body mass index. Importantly, these results suggest that radiographic measures of body composition should be considered for inclusion in updated prognostic models for patients with urothelial carcinoma treated with immunotherapy. These findings are useful for practicing oncologists in the academic or community setting, particularly given that baseline imaging is routine for patients starting on treatment with immunotherapy.

Body Composition Variables as Radiographic Biomarkers of Clinical Outcomes in Metastatic Renal Cell Carcinoma Patients Receiving Immune Checkpoint Inhibitors.

BACKGROUND: Immune checkpoint inhibitors (ICI) have revolutionized the treatment of metastatic renal cell carcinoma (mRCC). Biomarkers for mRCC patients treated with ICI are limited, and body composition is underutilized in mRCC. We investigated the association between body composition and clinical outcomes in ICI-treated mRCC patients. METHODS: We performed a retrospective analysis of 79 ICI-treated mRCC patients at Winship Cancer Institute from 2015-2020. Baseline CT images were collected at mid-L3 and segmented using SliceOMatic v5.0 (TomoVision). Density of skeletal muscle (SM), subcutaneous fat, inter-muscular fat, and visceral fat were measured and converted to indices by dividing by height(m)2 (SMI, SFI, IFI, and VFI, respectively). Total fat index (TFI) was defined as the sum of SFI, IFI, and VFI. Patients were characterized as high versus low for each variable at gender-specific optimal cuts using overall survival (OS) as the primary outcome. A prognostic risk score was created based on the beta coefficient from the multivariable Cox model after best subset variable selection. Body composition risk score was calculated as IFI + 2*SM mean + SFI and patients were classified as poor (0-1), intermediate (2), or favorable risk (3-4). Kaplan-Meier method and Log-rank test were used to estimate OS and PFS and compare the risk groups. Concordance statistics (C-statistics) were used to measure the discriminatory magnitude of the model. RESULTS: Most patients were male (73%) and most received ICI as first (35%) or second-line (51%) therapy. The body composition poor-risk patients had significantly shorter OS (HR: 6.37, p<0.001), PFS (HR: 4.19, p<0.001), and lower chance of CB (OR: 0.23, p=0.044) compared to favorable risk patients in multivariable analysis. Patients with low TFI had significantly shorter OS (HR: 2.72, p=0.002), PFS (HR: 1.91, p=0.025), and lower chance of CB (OR: 0.25, p=0.008) compared to high TFI patients in multivariable analysis. The C-statistics were higher for body composition risk groups and TFI (all C-statistics ≥ 0.598) compared to IMDC and BMI. CONCLUSIONS: Risk stratification using the body composition variables IFI, SM mean, SFI, and TFI may be prognostic and predictive of clinical outcomes in mRCC patients treated with ICI. Larger, prospective studies are warranted to validate this hypothesis-generating data.

Immune-Related Adverse Events as Clinical Biomarkers in Patients with Metastatic Renal Cell Carcinoma Treated with Immune Checkpoint Inhibitors.

BACKGROUND: Immune checkpoint inhibitors (ICIs) are an important treatment for metastatic renal cell carcinoma (mRCC). These agents may cause immune-related adverse events (irAEs), and the relationship between irAEs and outcomes is poorly understood. We investigated the association between irAEs and clinical outcomes in patients with mRCC treated with ICIs. METHODS: We performed a retrospective study of 200 patients with mRCC treated with ICIs at Winship Cancer Institute from 2015 to 2020. Data on irAEs were collected from clinic notes and laboratory values and grades were determined using Common Terminology Criteria in Adverse Events version 5.0. The association with overall survival (OS) and progression-free survival (PFS) was modeled by Cox proportional hazards model. Logistic regression models were used to define odds ratios (ORs) for clinical benefit (CB). Landmark analysis and extended Cox models were used to mitigate lead-time bias by treating irAEs as a time-varying covariate. RESULTS: Most patients (71.0%) were male, and one-third of patients (33.0%) experienced at least one irAE, most commonly involving the endocrine glands (13.0%), gastrointestinal tract (10.5%), or skin (10.0%). Patients who experienced irAEs had significantly longer OS (hazard ratio [HR], 0.52; p = .013), higher chance of CB (OR, 2.10; p = .023) and showed a trend toward longer PFS (HR, 0.71; p = .065) in multivariate analysis. Patients who had endocrine irAEs, particularly thyroid irAEs, had significantly longer OS and PFS and higher chance of CB. In a 14-week landmark analysis, irAEs were significantly associated with prolonged OS (p = .045). Patients who experienced irAEs had significantly longer median OS (44.5 vs. 18.2 months, p = .005) and PFS (7.5 vs. 3.6 months, p = .003) without landmark compared with patients who did not. CONCLUSION: We found that patients with mRCC treated with ICIs who experienced irAEs, particularly thyroid irAEs, had significantly improved clinical outcomes compared with patients who did not have irAEs. This suggests that irAEs may be effective clinical biomarkers in patients with mRCC treated with ICIs. Future prospective studies are warranted to validate these findings. IMPLICATIONS FOR PRACTICE: This study found that early onset immune-related adverse events (irAEs) are associated with significantly improved clinical outcomes in patients with metastatic renal cell carcinoma (mRCC) treated with immune checkpoint inhibitors (ICIs). In this site-specific irAE analysis, endocrine irAEs, particularly thyroid irAEs, were significantly associated with improved clinical outcomes. These results have implications for practicing medical oncologists given the increasing use of ICIs for the treatment of mRCC. Importantly, these results suggest that early irAEs and thyroid irAEs at any time on treatment with ICIs may be clinical biomarkers of clinical outcomes in patients with mRCC treated with ICIs.

CMV Status Drives Distinct Trajectories of CD4+ T Cell Differentiation.

Cytomegalovirus (CMV) is one of the most commonly recognized opportunistic pathogens and remains the most influential known parameter in shaping an individual's immune system. As such, T cells induced by CMV infection could have a long-term impact on subsequent immune responses. Accumulating evidence indicates that memory T cells developed during past bacterial and viral infection can cross-react with unrelated pathogens, including transplant antigens, and can alter responses to de novo infections, vaccines, cancers, or rejection. Therefore, careful examination of T cell responses elicited by CMV is warranted to understand their potentially beneficial or harmful roles in future major immune events. Our detailed exploration of the distribution, phenotype, TCR repertoire and transcriptome of CD4+ T cells within CMV seropositive healthy individuals using high-dimensional flow cytometry and single cell multi-omics sequencing reveals that CMV seropositivity has highly significant age-independent effects, leading to a reduction in CD4+ naïve T cells and an expansion of CD4+ effector memory T cells and CD45RA+ effector memory T cells. These induced CD4+ effector memory T cells undergo a specific differentiation trajectory resulting in a subpopulation of CD57+CD27-CD28-CD244+ CD4+ T cells with cytotoxic function and TCR oligoclonality for optimal controlled coexistence with cytomegalovirus. Through gene set enrichment analysis, we found that this subpopulation is similar to virus-specific CD8+ T cells and T cells that mediate acute rejection in patients using tacrolimus and belatacept, a selective costimulation blocker. Together, these data suggest that memory CD4+ T cells induced by cytomegalovirus are formed via a distinct differentiation program to acquire cytotoxic function and can be potentially detrimental to transplant patients adopting costimulation blockade immunosuppressive regimen.

Organized immune cell interactions within tumors sustain a productive T-cell response.

Tumor-infiltrating CD8 T cells are associated with improved patient survival and response to immunotherapy in various cancers. Persistent antigen leads to CD8 T-cell exhaustion, where proliferation/self-renewal and killing are divided within distinct subsets of CD8 T cells in the tumor. CD8 T-cell responses in chronic antigen settings must be maintained for long periods of time, suggesting that mechanisms that regulate chronic CD8 T-cell responses may differ from those in acute settings. Currently, factors that regulate the maintenance of stem-like CD8 T cells in the tumor or their differentiation into terminally differentiated cells are unknown. In this review, we discuss the role of dendritic cells in the activation and differentiation of CD8 T-cell subsets within secondary lymphoid tissue and tumors. In addition, we examine changes in CD4 T-cell differentiation in response to chronic antigens and consider how subset-specific mechanisms could assist the stem-like and terminally differentiated CD8 T-cell subsets. Finally, we highlight how tumor-infiltrating CD4 T cells and dendritic cells interact with CD8 T cells within organized lymphoid-like areas in the tumor and propose a CD8 T-cell differentiation model that requires the collaboration of CD4 T cells and dendritic cells. These organized interactions coordinate the anti-tumor response and control disease progression by mechanisms that regulate CD8 T-cell differentiation, which permit the maintenance of an effective balance of stem-like and terminally differentiated CD8 T cells.

Case Report: Exceptional Response to Nivolumab Plus Ipilimumab in a Young Woman With TFE3-SFPQ Fusion Translocation-Associated Renal Cell Carcinoma.

Translocation-associated renal cell carcinoma (tRCC) is a rare, aggressive malignancy that primarily affects children and young adults. There is no clear consensus on the most effective treatment for tRCC and there are no biomarkers of response to treatments in these patients. We present a case of a 23 year-old female with metastatic tRCC to the lungs who was started on treatment with nivolumab and ipilimumab. She had a complete radiographic response to treatment and has been progression-free for over 18 months. Immunofluorescence imaging performed on the baseline primary tumor sample showed significant intratumoral immune infiltration. Importantly, these cells are present in niches characterized by TCF1+ CD8+ T cells. Histopathologic investigation showed the presence of lymphocytes in the fibrovascular septae and foci of lymphovascular invasion. Furthermore, lymphovascular invasion and intratumor niches with TCF1+ CD8+ T cells may predict a favorable response to treatment with nivolumab and ipilimumab. These findings have significant clinical relevance given that immune checkpoint inhibitors are approved for several malignancies and predictive biomarkers for response to treatment are lacking. Importantly, the identification of these TCF1+ CD8+ T cells may guide treatment for patients with tRCC, which is a rare malignancy without a consensus first-line treatment option.

Defining HPV-specific B cell responses in patients with head and neck cancer.

Tumours often contain B cells and plasma cells but the antigen specificity of these intratumoral B cells is not well understood1-8. Here we show that human papillomavirus (HPV)-specific B cell responses are detectable in samples from patients with HPV-positive head and neck cancers, with active production of HPV-specific IgG antibodies in situ. HPV-specific antibody secreting cells (ASCs) were present in the tumour microenvironment, with minimal bystander recruitment of influenza-specific cells, suggesting a localized and antigen-specific ASC response. HPV-specific ASC responses correlated with titres of plasma IgG and were directed against the HPV proteins E2, E6 and E7, with the most dominant response against E2. Using intratumoral B cells and plasma cells, we generated several HPV-specific human monoclonal antibodies, which exhibited a high degree of somatic hypermutation, consistent with chronic antigen exposure. Single-cell RNA sequencing analyses detected activated B cells, germinal centre B cells and ASCs within the tumour microenvironment. Compared with the tumour parenchyma, B cells and ASCs were preferentially localized in the tumour stroma, with well-formed clusters of activated B cells indicating ongoing germinal centre reactions. Overall, we show that antigen-specific activated and germinal centre B cells as well as plasma cells can be found in the tumour microenvironment. Our findings provide a better understanding of humoral immune responses in human cancer and suggest that tumour-infiltrating B cells could be harnessed for the development of therapeutic agents.