Soluble Immune Checkpoint Research Articles

1150P Transforming growth factor-beta-1 and soluble co-inhibitory immune checkpoints as putative drivers of immune suppression in advanced basal cell carcinoma

1150P Transforming growth factor-beta-1 and soluble co-inhibitory immune checkpoints as putative drivers of immune suppression in advanced basal cell carcinoma

Analysis of SARS-CoV-2 isolates, namely the Wuhan strain, Delta variant, and Omicron variant, identifies differential immune profiles.

There is an urgent need to better understand the impact of different severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants on immune response and disease dynamics to facilitate better intervention strategies. Here, we show that SARS-CoV-2 variants differentially affect host immune responses. The magnitude and quantity of cytokines and chemokines were comparable in those infected with the Wuhan strain and the Delta variant. However, individuals infected with the Omicron variant had significantly lower levels of these mediators. We also found an elevation of plasma galectins (Gal-3, Gal-8, and Gal-9) in infected individuals, in particular, in those with the original strain. Soluble galectins exert a proinflammatory role in COVID-19 pathogenesis. This was illustrated by their correlation with the plasma levels of sCD14, sCD163, enhanced TNF-α/IL-6 secretion, and increased SARS-CoV-2 infectivity in vitro. Moreover, we observed enhanced CD4+ and CD8+ T cell activation in Wuhan strain-infected individuals. Surprisingly, there was a more pronounced T cell activation in those infected with the Omicron in comparison to the Delta variant. In line with T cell activation status, we observed a more pronounced expansion of T cells expressing different co-inhibitory receptors in patients infected with the Wuhan strain, followed by the Omicron and Delta variants. Individuals infected with the Wuhan strain or the Omicron variant had a similar pattern of plasma soluble immune checkpoints. Our results imply that a milder innate immune response might be beneficial and protective in those infected with the Omicron variant. Our results provide a novel insight into the differential impact of SARS-CoV-2 variants on host immunity. IMPORTANCE There is a need to better understand how different SARS-CoV-2 variants influence the immune system and disease dynamics to facilitate the development of better vaccines and therapies. We compared immune responses in 140 SARS-CoV-2-infected individuals with the Wuhan strain, the Delta variant, or the Omicron variant. All these patients were admitted to the intensive care unit and were SARS-CoV-2 vaccination naïve. We found that SARS-CoV-2 variants differentially affect the host immune response. This was done by measuring soluble biomarkers in their plasma and examining different immune cells. Overall, we found that the magnitude of cytokine storm in individuals infected with the Wuhan strain or the Delta variant was greater than in those infected with the Omicron variant. In light of enhanced cytokine release syndrome in individuals infected with the Wuhan strain or the Delta variant, we believe that a milder innate immune response might be beneficial and protective in those infected with the Omicron variant.

Serum soluble immune checkpoint levels predict cervical lymph node metastasis of differentiated thyroid carcinoma patients.

Cervical lymph node metastasis (CLNM) is common in patients with differentiated thyroid carcinoma (DTC); however, the efficiency to distinguish CLNM before surgery is limited. T cell exhaustion, characterized by the overexpression of immune checkpoints, plays a critical role in the immune evasion of tumors. The aim of this study is to analyze the association between serum levels of soluble immune checkpoints (sICs) and CLNM in DTC patients. Levels of sICs in serum of 71 DTC patients and 56 healthy volunteers were analyzed by ELISA. Peripheral blood mononuclear cells and cervical lymph nodes of DTC patients were isolated and their expression of sICs were analyzed. Lymphocytes in cervical lymph nodes were analyzed for immune checkpoints expression and transcription of exhaustion-associated factors. 30 out of 71 DTC patients were followed up from 3 to 9 months after the operation, and postoperative sTIM-3 were analyzed. Four sICs, including LAG-3, PD-1, PD-L1, and TIM-3, were increased in DTC patients. All four sICs exhibited higher sensitivity at discriminating CLNM than cervical ultrasound. In the patient-matched comparison, higher sTIM-3 levels were observed in tumor-involved lymph nodes (TILNs) than in normal lymph nodes (nLNs). T lymphocytes in TILNs had higher TIM-3 surface expression and increased secretion of sTIM-3 than those in patient-matched nLNs. Finally, postoperative serum sTIM-3 levels were decreased in DTC patients with CLNM compared to their preoperative levels. Serum levels of sICs, especially sTIM-3, could help to predict CLNM and provide evidence for surgical decision-making in DTC.

Retroviral b-Zip protein (HBZ) contributes to the release of soluble and exosomal immune checkpoint molecules in the context of neuroinflammation.

HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic, progressive, neuroinflammatory demyelinating condition of the spinal cord. We have previously shown that aberrant expression and activity of immune checkpoint (ICP) molecules such as PD-1 and PD-L1/PD-L2, negatively associates with the cytolytic potential of T cells in individuals with HAM/TSP. Interestingly, ICPs can exist in a soluble cell-free form and can be carried on extracellular vesicles (EVs) and exosomes (small EVs, <300nm) while maintaining their immunomodulatory activity. Therefore, we investigated the role of soluble and exosomal ICPs in HTLV-1 associated neuroinflammation. For the very first time, we demonstrate a unique elevated presence of several stimulatory (CD27, CD28, 4-1BB) and inhibitory (BTLA, CTLA-4, LAG-3, PD-1, PD-L2) ICP receptors in HAM/TSP sera, and in purified exosomes from a HAM/TSP-derived HTLV-1-producing (OSP2) cells. These ICPs were found to be co-localized with the endosomal sorting complex required for transport (ESCRT) pathway proteins and exhibited functional binding with their respective ligands. Viral proteins and cytokines (primarily IFNγ) were found to be present in purified exosomes. IFNγ exposure enhanced the release of ICP molecules while antiretroviral drugs (Azidothymidine and Lopinavir) significantly inhibited this process. HTLV-1 b-Zip protein (HBZ) has been linked to factors that enhance EV release and concurrent knockdown here led to the reduced expression of ESCRT associated genes (eg. Hrs, Vsp4, Alix, Tsg101) as well as abrogated the release of ICP molecules, suggesting HBZ involvement in this process. Moreso, exosomes from OSP2 cells adversely affected CD8 T-cell functions by dimishing levels of cytokines and cytotoxic factors. Collectively, these findings highlight exosome-mediated immunmodulation of T-cell functions with HBZ and ESCRT pathways as an underlying mechanism in the context of HTLV-1-induced neuroinflammation.

Transforming growth factor-b1 and soluble co-inhibitory immune checkpoints as putative drivers of immune suppression in advanced basal cell carcinoma.

9567 Background: BCC rarely metastasizes and the mortality rate is low; however, the disease is associated with substantial morbidity. Transforming growth factor-b1 (TGF-b1) is a key player in cell proliferation, differentiation, apoptosis, and immune regulation. TGF-b1 is associated with immunosuppression and resistance to immunotherapeutic drugs. Immune checkpoint proteins (ICMs) maintain self-tolerance and modulate the immune responses of effector cells. The current study compared the levels and possible associations between systemic soluble ICMs (sICMs) and a group of humoral modulators of immune suppressor cells in a cohort of patients with advanced basal cell carcinoma (BCC, n = 40) and a group of healthy control subjects (n = 20). Methods: We measured sICMs and immunosuppressive humoral modulators by using multiplex bead array or ELISA procedures, with plasma as the matrix. The sICMs comprised seven co-inhibitory (CTLA-4, BTLA, LAG-3, PD-1, PDL-1, PDL-2, and TIM-3) and eight co-stimulatory (CD27, CD28, CD40, CD80, CD86, GITR, GITRL, and ICOS) proteins, as well as the two dual-active sICPs, HVEM and TLR2. The seven humoral modulators of immunosuppressor cells included arginase 1, fibroblast activation protein (FAP), RANTES (Regulated upon Activation Normal T Cell Expressed and Presumably Secreted) also known as CCL5, interleukin-10 (IL-10), TGF-b1, and the M2-type macrophage biomarkers, soluble CD163 (sCD163) and sCD206. Ethics approval was granted by The Research Ethics Committee, Faculty of Health Sciences, University of Pretoria (Ethics Committee Approval Numbers 356/2020. Results: The plasma levels of six co-inhibitory sICPs, sCTLA-4, sLAG-3, sPD-1, sPD-L1, and sTIM-3 and sPD-L2 were significantly elevated in the cohort of BCC patients ( p&lt; 0.001- p&lt; 0.00001), while that of sBTLA was significantly decreased ( p&lt; 0.006). Of the co-stimulatory sICPs, sCD27 was significantly increased ( p &lt;0.0002) in the cohort of BCC patients, with the levels of the others essentially comparable with those of the control patients; of the dual active sICPs, sHVEM, sTLR2 was significantly elevated ( p&lt; 0.00001) and TLR2 comparable with the control group. Although the plasma levels of the seven modulators of immune suppressor function were not significantly different between the BCC and control groups, correlation heat maps revealed selective, strong associations of TGF-b1 with seven co-stimulatory (z = 0.618468-0.768131) and 4 co-inhibitory (z = 0.674040-0.808365) sICPs, as well as with sTLR2 (z = 0.696431). Conclusions: Notwithstanding the association of BCC with selective elevations in the levels of a large group of co-inhibitory sICPs, our novel findings also imply the probable involvement of TGF-b1 in driving immunosuppression in this malignancy, possibly via activation of regulatory T cells.

Dysregulation of immune checkpoint proteins in patients with newly diagnosed early breast cancer undergoing neoadjuvant chemotherapy: A comparison between patients with triple negative breast cancer (TNBC) and non-TNBC.

e14546 Background: Checkpoint proteins regulate the immune system. Breast cancer is associated with up-regulation or down-regulation of these proteins to evade anti-tumor immune responses. Soluble forms of immune checkpoint molecules (sICMs) can be measured in human plasma. The study aimed to measure the systemic levels of a series of co-stimulatory and co-inhibitory ICMs at diagnosis, post-neo-adjuvant chemotherapy (NAC) and post-surgery in newly- diagnosed BC patients (pts) and compare the biological behaviour of these sICMs between TNBC and non-TNBC patients. Methods: Soluble ICMs were measured using multiplex bead array technology in plasma from 72 BC pts and 45 healthy controls. Data were prospectively obtained and levels were compared between pre-treatment, post-NAC, and post-surgery using non-parametric tests (Mann-Whitney &amp; Kruskal-Wallis). Results: Following NAC, the plasma levels of six soluble co-stimulatory checkpoints (CD28, CD40, ICOS, CD27, CD80, GITR), all involved in the activation of CD8+ cytotoxic T cells, were significantly increased (p &lt; 0.04-p &lt; 0.00001). Four of the soluble co-inhibitory checkpoints (LAG-3, PDL1, TIM-3 and HVEM) increased significantly post-NAC, reaching levels significantly greater than those of the control group. PD-1 remained unchanged, while BTLA and CTLA-4 decreased significantly (p &lt; 0.03 and p &lt; 0.00001, respectively). Normalization of soluble co-stimulatory immune checkpoints seemingly indicates a reversal of systemic immune dysregulation following the administration of NAC in early BC. In contrast, recovery of immune homeostasis may explain the increased levels of several negative checkpoint proteins, albeit with the exceptions of CTLA-4 and PD-1. No significant differences were detected between the changes of 16 sICMs levels at pre-NAC, post-NAC and post-surgery when comparing the TNBC and non-TNBC patients. Conclusions: This study demonstrates low levels of co-stimulatory and co-inhibitory sICMs in newly-diagnosed, non-metastatic BC pts. Following treatment with NAC, the sICMs levels increase substantially, except CTLA-4. In the case of co-stimulatory sICMs, these novel findings are indicative of an immune-restorative mechanism. The pattern of co-inhibitory sICMs (elevated levels of PD-L1, LAG-3, TIM-3 and HVEM), might be indicative of immune-therapeutic resistance, underscoring the augmentative immune-therapeutic promise of targeting these molecules, either individually or in combination, to improve the outcome of pts with early BC. These differences were not significant between TNBC and non-TNBC patients.

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

Introduction: Immune checkpoints expressed in the tumor microenvironment (TME) play a key role in the immune evasion of cancer in general and in classical Hodgkin lymphoma (cHL) in particular. While few studies reported elevated PD-L1 serum levels in cHL compared to healthy individuals, the distribution and prognostic significance of soluble immune checkpoints (sCP) in the serum of cHL patients remains unclear. We therefore analyze the prognostic value of 14 different baseline sCP levels in prospectively treated patients with primary cHL. Methods: We measured serum levels of soluble BTLA, CD27, CD80, CTLA-4, GITR, GITR-L, HVEM, MICA, MICB, PD-L1, TIM-3, ULBP-1, ULBP-3, ULBP-4 with multiplex cytokine arrays in patients treated in the German Hodgkin Study Group (GHSG) trials HD7, HD8 and HD9. We designed a PFS-event-enriched study cohort from these patients. sCP levels were analyzed descriptively. In absence of validated thresholds, associations of sCP serum levels with PFS and OS were first tested using weighted cox-regression stratified for stage, age and sex, modeling sCP levels as continuous variables before performing secondary analyses separating levels into three groups: low, medium and high. All analyses of PFS and OS were weighted with respect to the proportion of progressions and relapses in the total study population to correct for event-enrichment. Results: Of 308 patients with measured sCP levels, 176 (57.1%) had advanced stage disease and median follow-up was 144 months. Weak correlations were noted among sCPs (median r = 0.12, IQR 0.24). Only TIM-3 and HVEM were significantly associated with PFS and OS by cox-regression modeling sCP levels as continuous variables. Interestingly, no associations of soluble PD-L1 with outcome was observed (PFS: p = 0.22, OS: p = 0.54). PFS and OS differed significantly when the cohort was split by TIM-3 sCP levels (p = 0.014 and 0.003, respectively for PFS and OS) but not when split by HVEM sCP levels (p = 0.051 and 0.2). In detail, Patients with TIM-3 serum levels in the upper third of levels had a higher risk of progression (HR 2.3, CI95: 1.3–4.0) or death (HR: 2.5 CI95: 1.2–5.4) compared to those in the lower third. High HVEM was associated with significantly shorter PFS (HR 1.8, CI95: 1.1–3.2) but not shorter OS (HR 1.6, CI95: 0.6–3.2). Exploratory separation by median rendered similar results. Keywords: Diagnostic and Prognostic Biomarkers, Hodgkin lymphoma No conflicts of interests pertinent to the abstract.

Prediction of risk and overall survival of pancreatic cancer from blood soluble immune checkpoint-related proteins.

Immune checkpoint inhibition holds promise as a novel treatment for pancreatic ductal adenocarcinoma (PDAC). The clinical significance of soluble immune checkpoint (ICK) related proteins have not yet fully explored in PDAC. We comprehensively profiled 14 soluble ICK-related proteins in plasma in 70 PDAC patients and 70 matched healthy controls. Epidemiological data of all subjects were obtained through structured interviews, and patients' clinical data were retrieved from electronical health records. We evaluated the associations between the biomarkers with the risk of PDAC using unconditional multivariate logistic regression. Consensus clustering (k-means algorithm) with significant biomarkers was performed to identify immune subtypes in PDAC patients. Prediction models for overall survival (OS) in PDAC patients were developed using multivariate Cox proportional hazards regression. Harrell's concordance index (C-index), time-dependent receiver operating characteristic (ROC) curve and calibration curve were utilized to evaluate performance of prediction models. Gene expressions of the identified ICK-related proteins in tumors from TCGA were analyzed to provide insight into underlying mechanisms. Soluble BTLA, CD28, CD137, GITR and LAG-3 were significantly upregulated in PDAC patients (all q < 0.05), and elevation of each of them was correlated with PDAC increased risk (all p < 0.05). PDAC patients were classified into soluble immune-high and soluble immune-low subtypes, using these 5 biomarkers. Patients in soluble immune-high subtype had significantly poorer OS than those in soluble immune-low subtype (log-rank p = 9.7E-03). The model with clinical variables and soluble immune subtypes had excellent predictive power (C-index = 0.809) for the OS of PDAC patients. Furthermore, the immune subtypes identified with corresponding genes' expression in PDAC tumor samples in TCGA showed an opposite correlation with OS to that of immune subtypes based on blood soluble ICK-related proteins (log-rank p =0.02). The immune-high subtype tumors displayed higher cytolytic activity (CYT) score than immune-low subtype tumors (p < 2E-16). Five soluble ICK-related proteins were identified to be significantly associated with the risk and prognosis of PDAC. Patients who were classified as soluble immune-low subtype based on these biomarkers had better overall survival than those of the soluble immune-high subtype.

23P Prognostic value of tumor-infiltrating lymphocytes (TILs) and soluble immune checkpoints in early triple-negative breast cancer (TNBC)

23P Prognostic value of tumor-infiltrating lymphocytes (TILs) and soluble immune checkpoints in early triple-negative breast cancer (TNBC)

Immune signatures in variant syndromes of primary biliary cholangitis and autoimmune hepatitis.

Variant syndromes of autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) share diagnostic features of both entities, but their immunological underpinnings remain largely unexplored. We performed blood profiling of 23 soluble immune markers and immunogenetics in a cohort of 88 patients with autoimmune liver diseases (29 typical AIH, 31 typical PBC and 28 with clinically PBC/AIH variant syndromes). The association with demographical, serological and clinical features was analyzed. While T and B cell receptor repertoires were highly skewed in variant syndromes compared to healthy controls, these biases were not sufficiently discriminated within the spectrum of autoimmune liver diseases. High circulating checkpoint molecules sCD25, sLAG-3, sCD86 and sTim-3 discriminated AIH from PBC on top of classical parameters such as transaminases and immunoglobulin levels. In addition, a second cluster of correlated soluble immune factors encompassing essentially TNF, IFNγ, IL12p70, sCTLA-4, sPD-1 and sPD-L1 appeared characteristic of AIH. Cases with complete biochemical responses to treatment generally showed a lower level of dysregulation. Unsupervised hierarchical clustering of classical and variant syndromes identified two pathological immunotypes consisting predominantly of either AIH or PBC cases. Variant syndromes did not form a separate group, but clustered together with either classical AIH or PBC. Clinically, patient with AIH-like variant syndromes were less likely to be able discontinue immunosuppressive treatment. Our analyses suggest that variants of immune mediated liver diseases may represent an immunological spectrum from PBC to AIH-like disease reflected by their pattern of soluble immune checkpoint molecules rather than separate entities.

Abstract 6381: Quantitative multiplex analysis of soluble and cellular immune checkpoint proteins in response to interferon gamma across multiple murine tumor models

Abstract Immune checkpoint proteins are key regulators of the immune system and drug targets of cancer immunotherapy. Immune checkpoint molecules have been found on the cell surface of various tumor cells and immune cells as immune activating or inhibitory receptors and ligands. Recent studies have shown these immune checkpoint proteins can undergo alternative splicing or proteolytic cleavage leading to soluble isoforms. IFNγ is a pleiotropic and multifunctional cytokine commonly released by cytotoxic immune cells. IFNγ production can be enhanced in response to immunotherapy and further modulates the expression of immune checkpoints in the tumor microenvironment. To better understand the immune checkpoint signatures in tumors, we developed a 28-plex mouse checkpoint protein multiplex immunoassay for quantitative analysis of soluble (secreted) and cellular immune checkpoint proteins. Using this immunoassay, we tested 16 mouse cell lines of tumor (n=13) and normal tissues as control (n=3): 2 melanomas (B16F10, YUMM1.7), 3 mammary carcinoma (4T1, NT5, AT-3), 1 lung carcinoma (LLC), 1 prostate cancer (MycCaP), 1 fibrosarcoma (MCA205), 1 ovarian cancer (ID8), 1 bladder cancer (MB49), 1 glioma (CT-2A), 2 blood cancer (RAW, EL4), 1 dendritic cells (DC2.4), 1 myoblast cells (C2C12), and 1 endothelial cells (bEnd.3). We analyzed changes in immune checkpoint protein expression and secretion in these cell lines cultured in normal conditions or upon exposure to IFNγ to reflect an immune inflamed microenvironment. Cells were cultured in 96-well plate, 100 mm, or 150 mm Petri dishes, and treated with either 10 ng/ml or 100 ng/mL mouse IFNγ. Cell culture supernatants and cell lysates were harvested after 6h, 12h, or 24h incubation with IFNγ and processed for multiplex Luminex bead-based immunoassay. The soluble and cellular checkpoint proteins most substantially modulated by IFNγ treatment in these cell lines included: CD137, BTLA, HVEM, PD-L1. The tumor-specific signature of cellular and soluble checkpoint proteins and its response to IFNγ may have implications in the tumor microenvironment and in the outcome to immunotherapy. Citation Format: Wen-Rong Lie, Ryan Bucktrout, Sanjukta Chakraborty, Andrea Orlando, Inna Serganova, Christine Kornmeier, James Hoberg, Roberta Zappasodi. Quantitative multiplex analysis of soluble and cellular immune checkpoint proteins in response to interferon gamma across multiple murine tumor models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6381.

Abstract 6380: Ultrasensitive detection of circulating human PD-1 and PD-L1 using Single Molecule Counting (SMC) technology

Abstract Immune checkpoint proteins are key regulators of the immune system and potential drug targets for cancer immunotherapy. Cancer immunotherapy targeting immune checkpoint, like programmed cell death protein-1 (PD-1) and programmed cell death ligand 1 (PD-L1) inhibitors has shown treatment efficacy for a broad spectrum of human cancers. Immune checkpoint molecules PD-1 and PD-L1 are expressed on the cell surface of immune cells and tumor cells. Recent studies have also reported these immune checkpoint proteins may undergo alternative splicing or proteolytic cleavage to produce soluble checkpoint proteins. Multiple molecular forms of soluble PD-1 (sPD-1) and PD-L1 (sPD-L1) are detectable in patient sera of multiple types of cancer, and these soluble checkpoint proteins have been reported as putative liquid biopsy biomarkers in the diagnosis and prognosis of oncological disease. Though the clinical significance of circulating soluble immune checkpoint protein profiles as predictive biomarkers has yet to be fully explored and validated, we have committed to develop better and more reliable bioassays to further this research. With that, we have developed 2 Luminex-based multiplex immunoassays for simultaneous quantitation of 48 immune checkpoint proteins, including PD-1 and PD-L1, for patient sera and tumor lysate samples. Here we report the development of 2 novel Single Molecule Counting (SMC) technology-based ultrasensitive single-plex immune checkpoint immunoassays for the detection of sPD-L1 and sPD-1 in human serum and plasma samples. Comparative studies demonstrate these SMC ultrasensitive assays possesses at least 10-100-fold higher sensitivity as compared with the Luminex-based immunoassays. Using these novel ultrasensitive assays, we have validated the detection of significant increases in sPD-L1 and sPD-1 in cancer serum samples as compared with the levels in healthy controls. We have also applied these high sensitivity assays to measure human PD-L1 and PD-1 biomarkers in other sample types including urine, tumor lysates and exosomes. In conclusion, we envision that these PD-1 and PD-L1 SMC assays may overcome a major limitation in biomarker utility and enable the ultrasensitive detection of sPD-1 and sPD-L1 in liquid biopsy and blood biomarker research. Citation Format: Laila Faramarzi, Wen-Rong Lie, Rick Wiese, Jared Fiske. Ultrasensitive detection of circulating human PD-1 and PD-L1 using Single Molecule Counting (SMC) technology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6380.

Dysregulation of systemic soluble immune checkpoints in early breast cancer is attenuated following administration of neoadjuvant chemotherapy and is associated with recovery of CD27, CD28, CD40, CD80, ICOS and GITR and substantially increased levels of PD-L1, LAG-3 and TIM-3.

Neoadjuvant chemotherapy (NAC) may alter the immune landscape of patients with early breast cancer (BC), potentially setting the scene for more effective implementation of checkpoint-targeted immunotherapy. This issue has been investigated in the current study in which alterations in the plasma concentrations of 16 soluble co-stimulatory and co-inhibitory, immune checkpoints were measured sequentially in a cohort of newly diagnosed, early BC patients (n=72), pre-treatment, post-NAC and post-surgery using a Multiplex® bead array platform. Relative to a group of healthy control subjects (n=45), the median pre-treatment levels of five co-stimulatory (CD27, CD40, GITRL, ICOS, GITR) and three co-inhibitory (TIM-3, CTLA-4, PD-L1) soluble checkpoints were significantly lower in the BC patients vs. controls (p<0.021-p<0.0001; and p<0.008-p<0.00001, respectively). Following NAC, the plasma levels of six soluble co-stimulatory checkpoints (CD28, CD40, ICOS, CD27, CD80, GITR), all involved in activation of CD8+ cytotoxic T cells, were significantly increased (p<0.04-p<0.00001), comparable with control values and remained at these levels post-surgery. Of the soluble co-inhibitory checkpoints, three (LAG-3, PD-L1, TIM-3) increased significantly post-NAC, reaching levels significantly greater than those of the control group. PD-1 remained unchanged, while BTLA and CTLA-4 decreased significantly (p<0.03 and p<0.00001, respectively). Normalization of soluble co-stimulatory immune checkpoints is seemingly indicative of reversal of systemic immune dysregulation following administration of NAC in early BC, while recovery of immune homeostasis may explain the increased levels of several negative checkpoint proteins, albeit with the exceptions of CTLA-4 and PD-1. Although a pathological complete response (pCR) was documented in 61% of patients (mostly triple-negative BC), surprisingly, none of the soluble immune checkpoints correlated with the pCR, either pre-treatment or post-NAC. Nevertheless, in the case of the co-stimulatory ICMs, these novel findings are indicative of the immune-restorative potential of NAC in early BC, while in the case of the co-inhibitory ICMs, elevated levels of soluble PD-L1, LAG-3 and TIM-3 post-NAC underscore the augmentative immunotherapeutic promise of targeting these molecules, either individually or in combination, as a strategy, which may contribute to the improved management of early BC.

Soluble immune checkpoints as correlates for HIV persistence and T cell function in people with HIV on antiretroviral therapy.

In people with HIV (PWH) both off and on antiretroviral therapy (ART), the expression of immune checkpoint (IC) proteins is elevated on the surface of total and HIV-specific T-cells, indicating T-cell exhaustion. Soluble IC proteins and their ligands can also be detected in plasma, but have not been systematically examined in PWH. Since T-cell exhaustion is associated with HIV persistence on ART, we aimed to determine if soluble IC proteins and their ligands also correlated with the size of the HIV reservoir and HIV-specific T-cell function. We used multiplex bead-based immunoassay to quantify soluble programmed cell death protein 1 (PD-1), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), lymphocyte activation gene-3 (LAG-3), T cell immunoglobulin domain and mucin domain 3 (TIM-3), PD-1 Ligand 1 (PD-L1) and PD-1 Ligand 2 (PD-L2) in plasma from PWH off ART (n=20), on suppressive ART (n=75) and uninfected controls (n=20). We also quantified expression of membrane-bound IC and frequencies of functional T-cells to Gag and Nef peptide stimulation on CD4+ and CD8+ T-cells using flow cytometry. The HIV reservoir was quantified in circulating CD4+ T-cells using qPCR for total and integrated HIV DNA, cell-associated unspliced HIV RNA and 2LTR circles. Soluble (s) PD-L2 level was higher in PWH off and on ART compared to uninfected controls. Higher levels of sPD-L2 correlated with lower levels of HIV total DNA and higher frequencies of gag-specific CD8+ T-cells expressing CD107a, IFNγ or TNFα. In contrast, the concentration of sLAG-3 was similar in uninfected individuals and PWH on ART, but was significantly elevated in PWH off ART. Higher levels of sLAG-3 correlated with higher levels of HIV total and integrated DNA, and lower frequency of gag-specific CD4+ T cells expressing CD107a. Similar to sLAG-3, levels of sPD-1 were elevated in PWH off ART and normalized in PWH on ART. sPD-1 was positively correlated with the frequency of gag-specific CD4+ T cells expressing TNF-a and the expression of membrane-bound PD-1 on total CD8+ T-cells in PWH on ART. Plasma soluble IC proteins and their ligands correlate with markers of the HIV reservoir and HIV-specific T-cell function and should be investigated further in in large population-based studies of the HIV reservoir or cure interventions in PWH on ART.

Immune-related toxicity and soluble profile in patients affected by solid tumors: a network approach

BackgroundImmune checkpoint inhibitors (ICIs) have particular, immune-related adverse events (irAEs), as a consequence of interfering with self-tolerance mechanisms. The incidence of irAEs varies depending on ICI class, administered dose and treatment schedule. The aim of this study was to define a baseline (T0) immune profile (IP) predictive of irAE development.MethodsA prospective, multicenter study evaluating the immune profile (IP) of 79 patients with advanced cancer and treated with anti-programmed cell death protein 1 (anti-PD-1) drugs as a first- or second-line setting was performed. The results were then correlated with irAEs onset. The IP was studied by means of multiplex assay, evaluating circulating concentration of 12 cytokines, 5 chemokines, 13 soluble immune checkpoints and 3 adhesion molecules. Indoleamine 2, 3-dioxygenase (IDO) activity was measured through a modified liquid chromatography–tandem mass spectrometry using the high-performance liquid chromatography-mass spectrometry (HPLC–MS/MS) method. A connectivity heatmap was obtained by calculating Spearman correlation coefficients. Two different networks of connectivity were constructed, based on the toxicity profile.ResultsToxicity was predominantly of low/moderate grade. High-grade irAEs were relatively rare, while cumulative toxicity was high (35%). Positive and statistically significant correlations between the cumulative toxicity and IP10 and IL8, sLAG3, sPD-L2, sHVEM, sCD137, sCD27 and sICAM-1 serum concentration were found. Moreover, patients who experienced irAEs had a markedly different connectivity pattern, characterized by disruption of most of the paired connections between cytokines, chemokines and connections of sCD137, sCD27 and sCD28, while sPDL-2 pair-wise connectivity values seemed to be intensified. Network connectivity analysis identified a total of 187 statistically significant interactions in patients without toxicity and a total of 126 statistically significant interactions in patients with toxicity. Ninety-eight interactions were common to both networks, while 29 were specifically observed in patients who experienced toxicity.ConclusionsA particular, common pattern of immune dysregulation was defined in patients developing irAEs. This immune serological profile, if confirmed in a larger patient population, could lead to the design of a personalized therapeutic strategy in order to prevent, monitor and treat irAEs at an early stage.

Biomarker Profiles and Immunologic Predictors of Neurodevelopment in Children who are HIV Exposed Uninfected

Background: Children who are HIV-exposed uninfected (HEU) have higher morbidity and mortality rates than their unexposed uninfected counterparts (HU). HEU also exhibit lower neurodevelopmental outcomes. Previous studies show that HIV-induced immune dysregulation can be linked to decreased neurodevelopment in HIV+ children. However, the role of inflammation on neurodevelopment in HEU remains unclear. &#x0D; Methods: This study investigated the plasma levels of 81 biomarkers in 82 Kenyan children between the ages of 18 and 36 months. Neurodevelopment was measured using the Bayley Scales of Infant and Toddler Development, 3rd edition. Bayesian model averaging was used to identify significant biomarkers. &#x0D; Results: HEU showed lower levels of 12 different proinflammatorycytokines/chemokines/growth factors: IL-12, leukemia inhibitory factor (LIF), macrophage migration inhibitory factor (MIF), TNF-related weak inducer of apoptosis (TWEAK), and A proliferation inducing ligand (APRIL); BLC, eoxtaxin-2, I-TAC, monokine induced by gamma interferon (MIG), and MIP-3a; fibroblast growth factor-2 (FGF-2) and granulocyte colony-stimulating factor (G-CSF). HEU showed higher levels of 2 inhibitory soluble immune checkpoints: T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) and CD40. Bayesian model averaging identified the biomarkers to best predict HEU vs. HU status were IL-12, IL-13, and CD40. In HU children, hepatocyte growth factor (HGF) and IL-5 predicted cognitive scores, BLC and IL-7 predicted motor outcomes, and IL-1a, IL-2R, IL-5, and maternal education predicted language scores. In HEU, FGF-2 predicted language scores, and IL-22 predicted motor development. Statistical analysis identified IL-2R and IL-22 as the strongest predictors of neurodevelopmental outcomes in HU and HEU, respectively.&#x0D; Conclusion/Potential Impact: This study shows that HEU exhibit an immune suppressive biomarker profile, rather than an inflammatory profile as indicated in previous studies. The significant biomarkers we found may be used to determine children at risk of decreased poor neurodevelopmental outcomes, allowing more time for intervention.

Rapid disease progression on immune checkpoint inhibitors in young patients with stage IV melanoma.

Immune checkpoint inhibitors (ICIs) are the standard of care for metastatic cutaneous melanoma (mCM) patients, but their efficacy in young adults aged less than 40 years remains unclear. We retrospectively analyzed 303 stage IV melanoma patients of different ages treated with nivolumab, pembrolizumab, or ipilimumab plus nivolumab combination therapy. Clinical data and blood values such as LDH, CRP, and absolute immune cell counts were retrieved from the medical records. Pre-treatment serum concentrations of soluble immune checkpoint proteins were measured using ELISA. In addition, information on frequencies of various T cell subsets in the peripheral blood was collected from a previously reported study (ELEKTRA). Patient characteristics and clinical information was correlated with PFS and OS using univariate and multivariate cox regression analysis. Of 303 patients, 33 (11%) were ≤ 40 years old. The older patients had a median age of 64 (95% CI: 61-66). Concerning prognostic parameters, there was no difference between the age groups, e.g., in gender, LDH, or the existence of brain or liver metastases. Patients aged ≤ 40 years [p = 0.014; HR: 1.6 (95% CI: 1.1-2.4)], presence of liver metastases [p = 0.016; HR: 1.4 (95% CI: 1.0-1.9)], line of ICI treatment [p = 0.009; HR: 1.4 (1.0-1.9)], elevated LDH [p = 0.076; HR: 1.3 (95% CI: 0.97-1.8)], and brain metastasis [p = 0.080; HR: 1.3 (95% CI: 0.97-1.7)], were associated with shorter PFS in univariate analysis. Multivariate analysis revealed that the patient's age (≤ 40 years) remains a high-risk factor upon adjusting for all potential confounders [p = 0.067; HR: 1.5 (95% CI: 0.97-2.3)]. Blood parameters revealed that patients ≤ 40 years have relatively higher frequencies of activated CD4 T cells (CD4 + Ki67 + CD4 + ICOS +) in the blood, and significantly lower number of basophils and CD45RA- memory T cells, compared to patients above 40 years (p < 0.05). In addition, patients ≤ 40 years experiencing disease progression within 6 months of ICI treatment had increased concentrations of sPDL1 (p = 0.05) and sTIM3 (p = 0.054) at baseline. Young patients with stage IV melanoma may experience shorter progression-free survival upon ICI treatment compared to patients above 40 years and are characterized by fewer basophils and memory T cells in the blood.

Study of the clinicopathological features of soluble PD-L1 in lung cancer patients

Objective: In recent years, an association between serum soluble immune checkpoint molecules (sICMs) and malignant tumors has been reported, which may become important biomarkers in the future. Although several reports have suggested a correlation between sICMs and prognosis, their origin is unclear. In this study, changes in serum soluble PD-L1 (sPD-L1) during the perioperative period and its origin were analyzed in patients with lung cancer. Patients and Methods: Patients with lung tumors (n=39) were included. Samples for sPD-L1 measurements were collected at five time points before and after surgery, and their changes over time were analyzed. ELISA was used to measure sPD-L1 levels. Results: Thirty-nine patients with lung tumors (31, males; 8, females; age, 74 (years) ± 7.7 (range: 51-89) years; malignancy/benign, 33/6) were enrolled. Eight cases of driver gene mutation-positive tumors were included. Twenty-eight (72%) patients were smokers, and their performance status was 0-1 in all 39 patients. PD-L1 TPS was ≥50%/1-49%/<1% in 8/10/14 patients. Stage I/II/III/IV/postoperative recurrence of lung cancer was observed in 21/0/6/5/1 patients, respectively. There were no significant correlations between sPD-L1 levels and clinicopathological features and no correlation with PD-L1 TPS. Comparing localized lesions (stages I-III) with advanced lesions (stage IV and postoperative recurrence), the distribution of sPD-L1 was slightly higher in advanced lesions, although the difference was not significant. No obvious changes in sPD-L1 expression were observed before and after surgery. Conclusion: sPD-L1 levels tended to be high in stage III and above lung cancer. There was no change in sPD-L1 levels before and after surgery. sPD-L1 levels did not correlate with the PD-L1 TPS.

Soluble immune checkpoint molecules in patients with antineutrophil cytoplasmic antibody-associated vasculitis

Immune checkpoint molecules balance immune effector responses with regulatory reactions. We speculated that soluble immune checkpoint molecules are involved in dysregulation of the immune response and autoimmunity. We evaluated the association between soluble immune checkpoint molecules and antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).A total of 56 patients with AAV from a prospective observational cohort and 40 healthy controls (HCs) were analyzed. Soluble PD-1, PD-L1, PD-L2, CTLA-4, CD28, CD80, CD86, ICOS, TIM-3, BTLA, CD40, LAG-3, TLR-2, and CD27 were measured in stored sera using the Milliplex MAP assay. Paired analyses were performed before and after the treatment. AAV-specific indices, including Birmingham vasculitis activity score, five factor score , vasculitis damage index, and blood samples, were collected.Patients with AAV had higher levels of sPD-L1, sCD28, sCD80, sCD86, sICOS, sTIM-3, sLAG-3, sTLR-2, and sCD27 and lower level of sCTLA-4 than HCs (p < 0.05). Patients with AAV had higher serum sCD28, sCD80, sTIM-3, and sCD27 levels than HCs at baseline and decreased after treatment. Furthermore, the serum levels of sCD28 and sTIM-3 were significantly correlated with disease activity.This study demonstrated altered concentrations of serum soluble immune checkpoint molecules in patients with AAV. In particular, sCD28 and sTIM-3 may act as surrogate markers of AAV disease activity.

The role of immune profile in predicting outcomes in cancer patients treated with immunotherapy.

Despite the efficacy of immunotherapy, only a small percentage of patients achieves a long-term benefit in terms of overall survival. The aim of this study was to define an immune profile predicting the response to immune checkpoint inhibitors (ICIs). Patients with advanced solid tumors, who underwent ICI treatment were enrolled in this prospective study. Blood samples were collected at the baseline. Thirteen soluble immune checkpoints, 3 soluble adhesion molecules, 5 chemokines and 11 cytokines were analyzed. The results were associated with oncological outcomes. Regardless of tumor type, patients with values of sTIM3, IFNα, IFNγ, IL1β, IL1α, IL12p70, MIP1β, IL13, sCD28, sGITR, sPDL1, IL10 and TNFα below the median had longer overall survival (p<0.05). By using cluster analysis and grouping the patients according to the trend of the molecules, two clusters were found. Cluster A had a significantly higher mean progression free survival (Cluster A=11.9 months vs Cluster B=3.5 months, p<0.01), a higher percentage of disease stability (Cluster A=34.5% vs. Cluster B=0%, p<0.05) and a lower percentage of disease progression (Cluster A=55.2% vs. Cluster B = 94.4%, p=0.04). The combined evaluation of soluble molecules, rather than a single circulating factor, may be more suitable to represent the fitness of the immune system status in each patient and could allow to identify two different prognostic and predictive outcome profiles.