CD70-induced differentiation of proinflammatory Th1/17/22/GM lymphocytes associated with disease progression and immune reconstitution during HIV infection.

Immune overactivation is a hallmark of chronic HIV infection, which is critical to HIV pathogenesis and disease progression. The imbalance of helper T cell (Th) differentiation and subsequent cytokine dysregulation are generally considered to be the major drivers of excessive activation and inflammatory disorders in HIV infection. However, the accurate factors driving HIV-associated Th changes remained to be established. CD70, which was a costimulatory molecule, was found to increase on CD4+ T cells during HIV infection. Overexpression of CD70 on CD4+ T cells was recently reported to associate with highly pathogenic proinflammatory Th1/Th17 polarization in multiple sclerosis. Thus, the role of CD70 in the imbalance of Th polarization and immune overactivation during HIV infection needs to be investigated. Here, we found that the elevated frequency of CD70 + CD4+ T cells was negatively correlated with CD4 count and positively associated with immune activation in treatment-naïve people living with HIV (PLWH). More importantly, CD70 expression defined a population of proinflammatory Th1/17/22/GM subsets in PLWH. Blocking CD70 decreased the mRNA expression of subset-specific markers during Th1/17/22/GM polarization. Furthermore, we demonstrated that CD70 influenced the differentiation of these Th cells through STAT pathway. Finally, it was revealed that patients with a high baseline level of CD70 on CD4+ T cells exhibited a greater risk of poor immune reconstitution after antiretroviral therapy (ART) than those with low CD70. In general, our data highlighted the role of CD70 in Th1/17/22/GM differentiation during HIV infection and provided evidence for CD70 as a potential biomarker for predicting immune recovery.

A Nomogram Prognostic Model for Advanced Hepatocellular Carcinoma Based on the Interaction Between CD8+T Cell Counts and Age.

Objective: CD8+T cells are essential components of the adaptive immune system and are crucial in the body's immune system. This study aimed to investigate how the prognosis of patients with advanced hepatocellular carcinoma (HCC) was affected by their CD8+ T cell counts and age and established an effective nomogram model to predict the overall survival (OS). Methods: A total of 427 patients with advanced HCC from Beijing Ditan Hospital, Capital Medical University, were enrolled in this study and randomly divided into training and validation groups, with 300 and 127 individuals in each group, respectively. Cox regression analysis was used to screen for independent risk factors for advanced HCC, and the interactive relationship between CD8+T cells and patient age was examined to establish a nomogram prediction model. Results: Cox multivariate regression and interaction analyses indicated that tumor number, tumor size, aspartate aminotransferase (AST), C-reactive protein (CRP), relationship of CD8+T cell counts and age were independent predictors of 6-month OS in patients with advanced HCC, and the nomogram model was established based on these factors. The area under the receiver operating characteristic curve (AUC) of the nomogram model for predicting the 3-month, 6-month, and 12-month OS rates were 0.821, 0.802, and 0.756, respectively. Moreover, in clinical practice, patients with true-positive survival benefit more than true-positive death, therefore, we selected 25% as the clinical decision threshold probability based on probability density functions (PDFs) and clinical utility curves (CUCs), which can distinguish approximately 92% of patients who died and 37% of patients who survived. Conclusion: The nomogram model based on CD8+T cell counts and age accurately assessed the prognosis of patients with advanced HCC and suggested that high CD8+T cell levels are beneficial to the survival of patients with advanced HCC.

Sepsis induces non-classic innate immune memory in granulocytes.

Secondary infection in patients with sepsis triggers a new wave of inflammatory response, which aggravates organ injury and increases mortality. Trained immunity boosts a potent and nonspecific response to the secondary challenge and has been considered beneficial for the host. Here, using a murine model of polymicrobial infection, we find that the primary infection reprograms granulocytes to boost enhanced inflammatory responses to the secondary infection, including the excessive production of inflammatory cytokines, respiratory burst, and augmented phagocytosis capacity. However, these reprogramed granulocytes exhibit "non-classic" characteristics of innate immune memory. Two mechanisms are independently involved in the innate immune memory of granulocytes: a metabolic shift in favor of glycolysis and fatty acid synthesis and chromatin remodeling leading to the transcriptional inactivity of genes encoding inhibitors of TLR4-initiated signaling pathways. Counteracting the deleterious effects of stressed granulocytes on anti-infection immunity might provide a strategy to fight secondary infections during sepsis.

HTE- and AI-assisted development of DHP-catalyzed decarboxylative selenation.

1,4-Dihydropyridine (DHP) derivatives play key roles in biology, but are rarely used as catalysts in synthesis. Here, we developed a DHP derivative-catalyzed decarboxylative selenation reaction that showed a broad substrate scope, with the assistance of high-throughput experimentation (HTE) and artificial intelligence (AI). The AI-based model could identify the key structural features and give accurate prediction of unseen reactions (R2 = 0.89, RMSE = 9.0%, and MAE = 6.3%). Our work not only developed the catalytic applications of DHP derivatives, but also demonstrated the power of the combination of HTE and AI to advance chemical synthesis.

Phenotypic and functional alterations of monocyte subsets with aging.

BACKGROUND: It has been widely accepted that monocytes are one of the central mediators contributing to inflammaging. However, it remains unclear whether aged monocytes, similar to aged T cells, have characteristics of hyperactivation and increased expression of co-inhibitory molecules. METHODS: Peripheral blood mononuclear cells (PBMCs) were isolated from young (21-40 years old), middle-aged (41-60 years old), and older human subjects (> 60 years old). Flow cytometry was used to monitor changes in the expression of surface molecules of monocyte subsets and cytokine-producing capacity. RESULTS: We observed increased tumor necrosis factor-α: TNF-α and decreased interleukin-6 (IL-6) production in monocytes from older adults compared with young and middle-aged adults. Older adults had a greater percentage of intermediate and non-classical monocyte subsets, along with increased levels of the immune activation markers human leukocyte antigen-DR (HLA-DR), and adhesion molecules cluster of differentiation molecule 11b (CD11b) and L-selectin (CD62L). Furthermore, we observed increased C-C motif chemokine receptor 2 (CCR2) expression on classical monocytes and decreased C-X3-C motif chemokine receptor 1 (CX3CR1) expression on non-classical monocytes in older adult subjects. The expression of co-inhibitory receptors was reduced on monocyte subsets in older adults. CONCLUSIONS: Circulating monocytes in older adults exhibit increased expression of activation, adhesion, and migration markers, but decreased expression of co-inhibitory molecules.

Elevated Foxp3+ double-negative T cells are associated with disease progression during HIV infection.

Persistent immune activation, which occurs during the whole course of HIV infection, plays a pivotal role in CD4+ T cells depletion and AIDS progression. Furthermore, immune activation is a key factor that leads to impaired immune reconstitution after long-term effective antiretroviral therapy (ART), and is even responsible for the increased risk of developing non-AIDS co-morbidities. Therefore, it's imperative to identify an effective intervention targeting HIV-associated immune activation to improve disease management. Double negative T cells (DNT) were reported to provide immunosuppression during HIV infection, but the related mechanisms remained puzzled. Foxp3 endows Tregs with potent suppressive function to maintain immune homeostasis. However, whether DNT cells expressed Foxp3 and the accurate function of these cells urgently needed to be investigated. Here, we found that Foxp3+ DNT cells accumulated in untreated people living with HIV (PLWH) with CD4+ T cell count less than 200 cells/µl. Moreover, the frequency of Foxp3+ DNT cells was negatively correlated with CD4+ T cell count and CD4/CD8 ratio, and positively correlated with immune activation and systemic inflammation in PLWH. Of note, Foxp3+ DNT cells might exert suppressive regulation by increased expression of CD39, CD25, or vigorous proliferation (high levels of GITR and ki67) in ART-naive PLWH. Our study underlined the importance of Foxp3+ DNT cells in the HIV disease progression, and suggest that Foxp3+ DNT may be a potential target for clinical intervention for the control of immune activation during HIV infection.

Decreased CD73+ Double-Negative T Cells and Elevated Level of Soluble CD73 Correlated With and Predicted Poor Immune Reconstitution in HIV-Infected Patients After Antiretroviral Therapy.

Although extensive use of antiretroviral therapy (ART) has made great progress in controlling HIV replication and improving CD4+ T cell recovery, the immune reconstitution remained insufficient in some patients, who were defined as poor immunological responders (PIRs). These PIRs were at a high risk of AIDS-related and non-AIDS complications, resulting in higher morbidity and mortality rate. Thus, it is a major challenge and urgently needed to distinguish PIRs early and improve their immune function in time. Immune activation is a key factor that leads to impaired immune reconstitution in people living with HIV (PLWH) who are receiving effective ART. Double negative T cells (DNT) were reported to associate with the control of immune activation during HIV infection. However, the precise mechanisms by which DNT cells exerted their suppressive capacity during HIV infection remained puzzled. CD73, both a soluble and a membrane-bound form, display immunosuppressive effects through producing adenosine (ADO). Thus, whether DNT cells expressed CD73 and mediated immune suppression through CD73-ADO pathway needs to be investigated. Here, we found a significant downregulation of CD73 expression on DNT cells in treatment-naïve PLWH (TNs) compared to healthy controls, accompanied with increased concentration of sCD73 in plasma. Both the frequency of CD73+ DNT cells and the level of plasma sCD73 recovered after ART treatment. However, PIRs showed decreased percentage of CD73+ DNT cells compared to immunological responders (IRs). The frequency of CD73+ DNT cells was positively correlated with CD4+ T cell count and CD4/CD8 ratio, and negatively correlated with immune activation in PLWH. The level of sCD73 also showed a negative correlation to CD4+ T cell count and CD4/CD8 ratio. More importantly, in the present cohort, a higher level of sCD73 at the time of initiating ART could predict poor immune reconstitution in PLWH after long-term ART. Our findings highlighted the importance of CD73+ DNT cells and sCD73 in the disease progression and immune reconstitution of PLWH, and provided evidences for sCD73 as a potential biomarker of predicting immune recovery.

High Levels of CD244 Rather Than CD160 Associate With CD8+ T-Cell Aging.

Aging leads to functional dysregulation of the immune system, especially T cell defects. Previous studies have shown that the accumulation of co-inhibitory molecules plays an essential role in both T cell exhaustion and aging. In the present study, we showed that CD244 and CD160 were both up-regulated on CD8+ T cells of elderly individuals. CD244+CD160- CD8+ T cells displayed the increased activity of ß-GAL, higher production of cytokines, and severe metabolic disorders, which were characteristics of immune aging. Notably, the functional dysregulation associated with aging was reversed by blocking CD244 instead of CD160. Meanwhile, CD244+CD160+ CD8+ T cells exhibited features of exhaustion, including lower levels of cytokine, impaired proliferation, and intrinsic transcriptional regulation, compared to CD244+CD160- population. Collectively, our findings demonstrated that CD244 rather than CD160 acts as a prominent regulator involved in T cell aging, providing a solid therapeutic target to improve disorders and comorbidities correlated to immune system aging.

A novel prediction model to evaluate the probability of CD4+/CD8+ cell ratio restoration in HIV-infected individuals.

BACKGROUND: Our study aimed to develop a clinical prediction model to evaluate the possibility of CD4+/CD8+ ratio restoration in HIV-positive individuals. METHODS: About 1980, HIV/AIDS patients initiated with antiretroviral treatment from 1 January 2013, to 30 December 2016, at Beijing Ditan Hospital and achieved persistent virological suppression during the 4 years follow-up were included in this study. Multivariate Cox proportional regression analysis was used to identify the independent risk factors and establish a predictive model. The model's performance was assessed using the area under the receiver operating characteristic and calibration plots. RESULTS: Overall, after 4 years of treatment, a total of 455 individuals (22.98%) restored their CD4+/CD8+ ratio (≥1). The area under the receiver operating characteristic was 0.782 and 0.743 in the deriving and validation cohort, respectively. The ultimate model included five indexes: age at AIDS diagnosis, albumin, and syphilis status, and baseline CD4+ and CD8+ values. A nomogram further visualized the model, and the calibration plots indicated high agreement of predicted and observed outcomes. CONCLUSION: Our prediction model might be practical and easily applied to recognize HIV/AIDS individuals most likely to benefit from modern antiretroviral therapy.

CD200R Combined Neutrophil-Lymphocyte Ratio Predict 90-Day Mortality in HBV-Related Acute-On-Chronic Liver Failure.

Background: Survival of acute-on-chronic liver failure (ACLF) cannot be properly predicted based on clinical characteristics. Aims: This study aimed to develop a predictive model to evaluating the prognosis for hepatitis B virus-related ACLF (HBV-ACLF) based on specific laboratory and immune indicators. Methods: Baseline laboratory results were obtained and immune indicators were detected by flow cytometry. A predictive model, which estimates the prognosis at 90-day follow-up, was developed using data from a prospective study on 45 patients hospitalized of HBV-ACLF from June 2016 to April 2018 at the Beijing Ditan Hospital, Capital Medical University. The prognostic values of the predictive factors were determined by the area under the receiver operating characteristic (AUROC) curves. Results: Six factors exhibited statistical differences between the survival and non-survival groups: proportions of CD4+TN, CD4+TEM, CD8+TN, CD8+TEM, CD200R+CD4+T cells and neutrophil-lymphocyte ratio (NLR). CD200R combined with the NLR had an AUROC of 0.916, which was significantly higher than the AUROC values of CD200R+CD4+T cells (0.868), NLR (0.761), model for end-stage liver disease (MELD) (0.840), MELD-Na (0.870), Child-Turcotte-Pugh (CTP) (0.580), or chronic liver failure-consortium ACLF (CLIF-C ACLF) score(0.840). At the cut-off point of-3.87, matching the maximum Youden index determined by ROC analysis, the positive predictive and negative predictive values for the mortality were 0.86 and 0.97, respectively. Conclusions: The 90-day prediction model based on baseline levels of CD200R+CD4+T cells and NLR offers potential predictive value for the mortality of HBV-ACLF.

Manifestations and Related Risk Factors of Thrombocyte Abnormalities in HIV-Positive Patients Before and After the Initiation of ART.

BACKGROUND: At present, the thrombocyte abnormality is not well described before and after the initiation of antiretroviral therapy (ART). The purpose of this research is to investigate the dynamic changes and related risk factors of thrombocytopenia and thrombocytosis in HIV-infected individuals. METHODS: We performed a real-world observational study among 6637 HIV patients who started ART from January, 2013 to August, 2020 at the Beijing Ditan Hospital. Hazard indicators linked with thrombocytopenia and thrombocytosis were analyzed by logistic/Cox regression. RESULTS: The prevalence of thrombocytopenia and thrombocytosis was 2.65% and 5.85% among ART-naïve patients, respectively. Correlated risk factors: (thrombocytopenia) older age, coinfection with HBV, leucopenia, anemia, and CD4 count <350 cells/uL; (thrombocytosis) WBC level ≥4.0 x 109/L, anemia, NLR ≥2.0, and CD4 count ≥350 cells/uL. As for the recovery rate, it was 86.6/54.2, 83.4/46.3, 66.0/35.1, and 65.3/ 33.9 per 100 PYFU in thrombocytopenia/thrombocytosis at different treatment period (12m, 24m, 36m, and 48m). While the new-onset incidence of thrombocytopenia/thrombocytosis at different ART period (12m, 24m, 36m, 48m, 60m, 72m, and 84m) was 0.25/7.2, 0.19/6.31, 0.16/4.74, 0.16/4.55, 0.16/4.48, 0.15/4.41, and 0.15/4.39. And the driving forces of thrombocytosis were antiretroviral treatment, female, overweight, and WBC level ≥ 4.0 x 109/L. CONCLUSION: In the medical practice, while paying attention to thrombocytopenia, clinicians should be highly vigilant about the thrombocytosis of HIV/AIDS patients, and related treatment strategies need to be further studied.

Altered T-Cell Subsets are Associated with Dysregulated Cytokine Secretion of CD4+ T Cells During HIV Infection.

BACKGROUND: CD4+ T cells play a critical role in the regulation of immunopathogenesis in HIV infection. Previous studies have shown contradictory results of the CD4+ T-cell responses in people living with HIV (PLHIV). METHODS: A cross-sectional study was performed on 40 healthy controls, 134 ART-naïve PLHIV, and 34 individuals who experienced 3-year ART with low baseline CD4 count from 4 August 2016 to 23 January 2019. We determined the frequencies of CD4+ T-cell subsets and described the cytokine secretion pattern of total and subsets of CD4+ T cells in these individuals. RESULTS: We found that CD4+ T cells in PLHIV displayed enhanced secretion of pro-inflammation cytokines and polyfunctionality due to HIV disease progression (r = -0.282, P = 0.0035 for IFN-γ; r = -0.412, P = 0.0002 for TNF-α; r = -0.243, P < 0.0001 for GM-CSF; r = -0.252, P = 0.0093 for IFN-γ+ TNF-α+ cells). However, the altered T-cell subsets, as presented by the loss of naïve cells and expansion of memory/effector population in PLHIV, were associated with discordant results in total and subsets of CD4+ T cells. As major cytokine-producing T subsets, effector/memory CD4 subsets showed impaired cytokine production (P < 0.05). We further demonstrated that 3-year ART treatment could improve CD4 counts by increasing the pool of naïve T cells but could not restore cytokine secretion in CD4+ T-cell subsets (P < 0.05). CONCLUSION: These data identified the impaired capacity of cytokine secretion in CD4+ T-cell subsets due to HIV disease progression, and the altered T-cell subsets were associated with pseudo-elevation of cytokine production in total CD4+ T cells. This study collectively suggested the importance of therapies that can preserve and/or enhance the function of CD4+ T cells in strategies of HIV remission.

Persistent High Percentage of HLA-DR+CD38high CD8+ T Cells Associated With Immune Disorder and Disease Severity of COVID-19.

Background: The global outbreak of coronavirus disease 2019 (COVID-19) has turned into a worldwide public health crisis and caused more than 100,000,000 severe cases. Progressive lymphopenia, especially in T cells, was a prominent clinical feature of severe COVID-19. Activated HLA-DR+CD38+ CD8+ T cells were enriched over a prolonged period from the lymphopenia patients who died from Ebola and influenza infection and in severe patients infected with SARS-CoV-2. However, the CD38+HLA-DR+ CD8+ T population was reported to play contradictory roles in SARS-CoV-2 infection. Methods: A total of 42 COVID-19 patients, including 32 mild or moderate and 10 severe or critical cases, who received care at Beijing Ditan Hospital were recruited into this retrospective study. Blood samples were first collected within 3 days of the hospital admission and once every 3-7 days during hospitalization. The longitudinal flow cytometric data were examined during hospitalization. Moreover, we evaluated serum levels of 45 cytokines/chemokines/growth factors and 14 soluble checkpoints using Luminex multiplex assay longitudinally. Results: We revealed that the HLA-DR+CD38+ CD8+ T population was heterogeneous, and could be divided into two subsets with distinct characteristics: HLA-DR+CD38dim and HLA-DR+CD38hi. We observed a persistent accumulation of HLA-DR+CD38hi CD8+ T cells in severe COVID-19 patients. These HLA-DR+CD38hi CD8+ T cells were in a state of overactivation and consequent dysregulation manifested by expression of multiple inhibitory and stimulatory checkpoints, higher apoptotic sensitivity, impaired killing potential, and more exhausted transcriptional regulation compared to HLA-DR+CD38dim CD8+ T cells. Moreover, the clinical and laboratory data supported that only HLA-DR+CD38hi CD8+ T cells were associated with systemic inflammation, tissue injury, and immune disorders of severe COVID-19 patients. Conclusions: Our findings indicated that HLA-DR+CD38hi CD8+ T cells were correlated with disease severity of COVID-19 rather than HLA-DR+CD38dim population.

PDK1/mTOR Signaling in Myeloid Cells Differentially Regulates the Early and Late Stages of Sepsis.

The cecal ligation and perforation (CLP) model is the gold standard for the polymicrobial sepsis. In the CLP mice, the myeloid cells play an important role in septic shock. The phenotypes and the activation state of the macrophage and neutrophil correlate with their metabolism. In the present study, we generated the specific myeloid deletion of PDK1 and mTOR mice, which was the important regulator of metabolic signaling. We found that the deletion of PDK1 in the myeloid cells could aggravate the early septic shock in the CLP mice, as well as the deletion of mTORC1 and mTORC2. Moreover, PDK1 deletion attenuated the inflammation induced by LPS in the late stage on CLP mice, which was exacerbated in mTORC1 and mTORC2 knockout mice. Both PDK1 and mTORC1/2 could not only regulate the cellular metabolism but also play important roles on the myeloid cells in the secondary stimulation of sepsis. The present study will provide a theoretical prospect for the therapy of the septic shock in different stages.

CD70 contributes to age-associated T cell defects and overwhelming inflammatory responses.

Aging is associated with immune dysregulation, especially T cell disorders, which result in increased susceptibility to various diseases. Previous studies have shown that loss of co-stimulatory receptors or accumulation of co-inhibitory molecules play important roles in T cell aging. In the present study, CD70, which was generally regarded as a costimulatory molecule, was found to be upregulated on CD4+ and CD8+ T cells of elderly individuals. Aged CD70+ T cells displayed a phenotype of over-activation, and expressed enhanced levels of numerous inhibitory receptors including PD-1, 2B4 and LAG-3. CD70+ T cells from elderly individuals exhibited increased susceptibility to apoptosis and high levels of inflammatory cytokines. Importantly, the functional dysregulation of CD70+ T cells associated with aging was reversed by blocking CD70. Collectively, this study demonstrated CD70 as a prominent regulator involved in immunosenescence, which led to defects and overwhelming inflammatory responses of T cells during aging. These findings provide a strong rationale for targeting CD70 to prevent dysregulation related to immunosenescence.

PD-1+ TIGIT+ CD8+ T cells are associated with pathogenesis and progression of patients with hepatitis B virus-related hepatocellular carcinoma.

Hepatitis B virus-associated hepatocellular carcinoma (HBV-HCC) is usually considered an inflammation-related cancer associated with chronic inflammation triggered by exposure to HBV and tumor antigens. T-cell exhaustion is implicated in immunosuppression of chronic infections and tumors. Although immunotherapies that enhance immune responses by targeting programmed cell death-1(PD-1)/PD-L1 are being applied to malignancies, these treatments have shown limited response rates, suggesting that additional inhibitory receptors are also involved in T-cell exhaustion and tumor outcome. Here, we analyzed peripheral blood samples and found that coexpression of PD-1 and T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT) was significantly upregulated on CD4+ and CD8+ T cells from patients with HBV-HCC compared with those from patients with chronic HBV or HBV-liver cirrhosis. Additionally, PD-1+ TIGIT+ CD8+ T-cell populations were elevated in patients with advanced stage and progressed HBV-HCC. Importantly, PD-1+ TIGIT+ CD8+ T-cell populations were negatively correlated with overall survival rate and progression-free survival rates. Moreover, we showed that PD-1+ TIGIT+ CD8+ T cells exhibit features of exhausted T cells, as manifested by excessive activation, high expression of other inhibitory receptors, high susceptibility to apoptosis, decreased capacity for cytokine secretion, and patterns of transcription factor expression consistent with exhaustion. In conclusion, PD-1+ TIGIT+ CD8+ T-cell populations are associated with accelerated disease progression and poor outcomes in HBV-HCC, which might not only have important clinical implications for prognosis but also provide a rationale for new targets in immunotherapy.

Two types of poor immunological responder showing distinct responses to long-term HAART.

OBJECTIVES: Most previous studies on poor immunological responders (PIRs) have been performed on one cohort at one time-point following highly active antiretroviral therapy (HAART). The aim of this study was to investigate whether there are different subtypes of PIR and whether a certain population might achieve better immune reconstitution following longer HAART. METHODS: This study was designed as an ambispective cohort study, including a 4-5-year retrospective study and a 2-year prospective follow-up investigation. Thymic output, activated T cell and regulatory T cell (Treg) subset frequencies, expression levels of interferon-stimulated genes, and plasma concentrations of neopterin were determined at 4-5 years and 6-7 years following HAART initiation. RESULTS: PIRs were subdivided into two populations after 4-5 years of HAART, according to the kinetics of T cell recovery. Type II PIRs exhibited a significantly lower percentage of naïve CD4+ T cells and CD31+ naïve CD4+ T cells compared with type I PIRs. After an additional 2 years of HAART treatment, type I PIRs showed a better outcome than type II PIRs. Furthermore, it was found that 2 years of additional HAART could persistently improve thymic output. CONCLUSIONS: The two PIR subgroups are different in terms of immune characteristics and the response to prolonged HAART.