Role of Immune Cells and Non-immune Cells with Immune Functions in the Pathogenesis of ALI/ARDS

This review outlines the effects of different types of cells with immune function on acute lung injury(ALI)inflammation and the regulation of inflammatory responses between these cells via cell-cell interactions.It is expected to provide some possible strategies for the research and treatment of ALI and acute respiratory distress syndrome(ARDS).

Establishing prognostic models for intrahepatic cholangiocarcinoma based on immune cells

BACKGROUND Intrahepatic cholangiocarcinoma(ICC)is a malignant liver tumor that is challenging to treat and manage and current prognostic models for the disease are inefficient or ineffective.Tumor-associated immune cells are critical for tumor development and progression.The main goal of this study was to establish models based on tumor-associated immune cells for predicting the overall survival of patients undergoing surgery for ICC.AIM To establish 1-year and 3-year prognostic models for ICC after surgical resection.METHODS Immunohistochemical staining was performed for CD4,CD8,CD20,pan-cytokeratin(CK),and CD68 in tumors and paired adjacent tissues from 141 patients with ICC who underwent curative surgery.Selection of variables was based on regression diagnostic procedures and goodness-of-fit tests(PH assumption).Clinical parameters and pathological diagnoses,combined with the distribution of immune cells in tumors and paired adjacent tissues,were utilized to establish 1-and 3-year prognostic models.RESULTS This is an important application of immune cells in the tumor microenvironment.CD4,CD8,CD20,and CK were included in the establishment of our prognostic model by stepwise selection,whereas CD68 was not significantly associated with the prognosis of ICC.By integrating clinical data associated with ICC,distinct prognostic models were derived for 1-and 3-year survival outcomes using variable selection.The 1-year prediction model yielded a C-index of 0.7695%confidence interval(95%CI):0.65-0.87 and the 3-year prediction model produced a C-index of 0.69(95%CI:0.65-0.73).Internal validation yielded a C-index of 0.761(95%CI:0.669-0.853)for the 1-year model and 0.693(95%CI:0.642-0.744)for the 3-year model.CONCLUSION We developed Cox regression models for 1-year and 3-year survival predictions of patients with ICC who underwent resection,which has positive implications for establishing a more comprehensive prognostic model for ICC based on tumor immune microenvironment and immune cell changes in the future.

Transcriptome sequencing reveals novel biomarkers and immune cell infiltration in esophageal tumorigenesis

BACKGROUND Esophageal squamous cell carcinoma(ESCC)is one of the most common malignancies worldwide,and its development comprises a multistep process from intraepithelial neoplasia(IN)to carcinoma(CA).However,the critical regulators and underlying molecular mechanisms remain largely unknown.AIM To explore the genes and infiltrating immune cells in the microenvironment that are associated with the multistage progression of ESCC to facilitate diagnosis and early intervention.METHODS A mouse model mimicking the multistage development of ESCC was established by providing warter containing 4-nitroquinoline 1-oxide(4NQO)to C57BL/6 mice.Moreover,we established a control group without 4NQO treatment of mice.Then,transcriptome sequencing was performed for esophageal tissues from patients with different pathological statuses,including low-grade IN(LGIN),high-grade IN(HGIN),and CA,and controlled normal tissue(NOR)samples.Differentially expressed genes(DEGs)were identified in the LGIN,HGIN,and CA groups,and the biological functions of the DEGs were analyzed via Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses.The CIBERSORT algorithm was used to detect the pattern of immune cell infilt-ration.Immunohistochemistry(IHC)was also conducted to validate our results.Finally,the Luminex multiplex cytokine analysis was utilized to measure the serum cytokine levels in the mice.RESULTS Compared with those in the NOR group,a total of 681541,and 840 DEGs were obtained in the LGIN,HGIN,and CA groups,respectively.Using the intersection of the three sets of DEGs,we identified 86 genes as key genes involved in the development of ESCC.Enrichment analysis revealed that these genes were enriched mainly in the keratinization,epidermal cell differentiation,and interleukin(IL)-17 signaling pathways.CIBERSORT analysis revealed that,compared with those in the NOR group,M0 and M1 macrophages in the 4NQO group showed stronger infiltration,which was validated by IHC.Serum cytokine analysis revealed that,compared with those in the NOR group,IL-1βand IL-6 were upregulated,while IL-10 was downregulated in the LGIN,HGIN,and CA groups.Moreover,the expression of the representative key genes,such as S100a8 and Krt6b,was verified in external human samples,and the results of immunohistochemical staining were consistent with the findings in mice.CONCLUSION We identified a set of key genes represented by S100a8 and Krt6b and investigated their potential biological functions.In addition,we found that macrophage infiltration and abnormal alterations in the levels of inflam-mation-associated cytokines,such as IL-1β,IL-6,and IL-10,in the peripheral blood may be closely associated with the development of ESCC.

Clinical significance of peripheral blood immune cells in patients with gastric cancer after surgery

BACKGROUND Gastric cancer is one of the most common malignant tumors worldwide,and surgical resection is one of the main ways to treat gastric cancer.However,the immune status of postoperative patients is crucial for prognosis and survival,and immune cells play an important role in this process.Therefore,it is helpful to understand the immune status of postoperative patients by evaluating the levels of peripheral blood immune cells,especially total T cells(CD3+),helper T cells(CD3+CD4+),and suppressor T cells(CD3+CD8+),and its relationship to sur-vival.AIM To analyzed the immune cells in peripheral blood of patients with gastric cancer after surgery,detect the levels of total T cells,helper T cells and suppressor T cells.METHODS A total of 58 patients with gastric cancer who received surgical treatment were included in the retrospective study.Flow cytometry was used to detect the level of peripheral blood immune cells and analyze the correlation between total T cells,helper T cells and inhibitory T cells.To explore the relationship between these immune markers and patient survival.RESULTS The results showed that the levels of total T cells,helper T cells,and suppressor T cells changed in patients after gastric cancer surgery.There was a significant positive correlation between total T cells,helper T cells and suppressor T cells(r=0.35,P<0.01;r=0.56,P<0.01).However,there was a negative correlation between helper T cells and suppressor T cells(r=-0.63,P<0.01).Follow-up showed that the survival rate of patients in the high-level total T cell group was significantly higher than that in the low-level group(28.87±24.98 months vs 18.42±16.21 months).The survival curve shows that the curve of patients in the high-level group is shifted to the upper right,and that of the low-level group is shifted downward.There was no significant difference between the levels of helper T cells and suppressor T cells and patient survival time.CONCLUSION By detecting peripheral blood immune cells with flow cytometry,we can initially evaluate the immune status of patients after gastric cancer surgery and initially explore its relationship with patient survival.

Comprehensive assessment of the association between tumorinfiltrating immune cells and the prognosis of renal cell carcinoma

BACKGROUND According to current statistics,renal cancer accounts for 3%of all cancers world-wide.Renal cell carcinoma(RCC)is the most common solid lesion in the kidney and accounts for approximately 90%of all renal malignancies.Increasing evi-dence has shown an association between immune infiltration in RCC and clinical outcomes.To discover possible targets for the immune system,we investigated the link between tumor-infiltrating immune cells(TIICs)and the prognosis of RCC.AIM To investigate the effects of 22 TIICs on the prognosis of RCC patients and iden-tify potential therapeutic targets for RCC immunotherapy.METHODS The CIBERSORT algorithm partitioned the 22 TIICs from the Cancer Genome Atlas cohort into proportions.Cox regression analysis was employed to evaluate the impact of 22 TIICs on the probability of developing RCC.A predictive model for immunological risk was developed by analyzing the statistical relationship between the subpopulations of TIICs and survival outcomes.Furthermore,multi-variate Cox regression analysis was used to investigate independent factors for the prognostic prediction of RCC.A value of P<0.05 was regarded as statistically significant.RESULTS Compared to normal tissues,RCC tissues exhibited a distinct infiltration of im-mune cells.An immune risk score model was established and univariate Cox regression analysis revealed a significant association between four immune cell types and the survival risk connected to RCC.High-risk individuals were correlated to poorer outcomes according to the Kaplan-Meier survival curve(P=1E-05).The immunological risk score model was demonstrated to be a dependable predictor of survival risk(area under the curve=0.747)via the receiver operating characteristic curve.According to multivariate Cox regression analysis,the immune risk score model independently predicted RCC patients'prognosis(hazard ratio=1.550,95%CI:1.342–1.791;P<0.001).Finally,we established a nomogram that accurately and comprehensively forecast the survival of patients with RCC.CONCLUSION TIICs play various roles in RCC prognosis.The immunological risk score is an independent predictor of poor survival in kidney cancer cases.

Facing challenges with hope:universal immune cells for hematologic malignancies

Many patients have achieved a favorable overall survival rate since allogenic hematopoietic stem cell transplantation(allo-HSCT)has been widely implemented to treat hematologic malignancies.However,graft-versus-host disease(GVHD)and complications of immunosuppressive drugs after allo-HSCT are the main causes of non-relapse mortality and a poor quality of life.In addition,GVHD and infusion-induced toxicity still occur with donor lymphocyte infusions(DLIs)and chimeric antigen receptor(CAR)T-cell therapy.Because of the special immune tolerance characteristics and anti-tumor ability of universal immune cells,universal immune cell therapy may strongly reduce GVHD,while simultaneously reducing tumor burden.Nevertheless,widespread application of universal immune cell therapy is mainly restricted by poor expansion and persistence efficacy.Many strategies have been applied to improve universal immune cell proliferation and persistence efficacy,including the use of universal cell lines,signaling regulation and CAR technology.In this review we have summarized current advances in universal immune cell therapy for hematologic malignancies with a discussion of future perspectives.

Three-dimensional structure of liver vessels and spatial distribution of hepatic immune cells

As the largest internal organ of the human body,the liver has an extremely complex vascularnetwork and multiple types of immune cells.It plays an important role in blood circulation,material metabolism,and immune response.Optical imaging is an effective tool for studying finevascular structure and immunocyte distribution of the liver.Here,we provide an overview of thestructure and composition of liver vessels,the threedimensional(3D)imaging of the liver,andthe spatial distribution and immune function of various cell components of the liver.Especially,we emphasize the 3D imaging methods for visualizing fine structure in the liver.Finally,wesummarize and prospect the development of 3D imaging of liver vesels and immune cells.

Prognostic role of ring finger and WD repeat domain 3 and immune cell infiltration in hepatocellular carcinoma

We have found that the expression of ring finger and WD repeat domain 3(RFWD3)is significantly higher in unpaired and paired hepatocellular carcinoma(HCC)tissues than in normal tissues.Moreover,this expression has a significant correlation with the infiltration level of 14 immune cell types and when the detected RFWD3 expression levels were grouped as high and low,a prominent difference was revealed for overall survival,disease-specific survival,and progression-free interval.Through statistical analysis(univariate Cox),we were also able to identify RFWD3 as an independent prognostic element for HCC,with RFWD3 having an ability to accurately predict HCC prognosis(area under the curve of 0.863).Finally,we have generated prognostic nomograms for probabilities of 1-,3-and 5-year overall survival in HCC via integrating the factors of age,pathologic stage,alpha-fetoprotein level,and RFWD3 expression.

Diverse Roles of Immune Cells in Transplant Rejection and Immune Tolerance

Organ transplant rejection(OTR)is a complex immune reaction involving multiple cells,and it determines graft survival and patient prognosis.At present,most transplant recipients are administered a combination of immunosuppressive and biological agents to protect them from OTR.However,immunosuppressive agents negatively impact the immune system of the patients,causing them to suffer from serious complications,such as chronic infection and malignant tumors.Therefore,a thorough understanding of the mechanisms involved in immune tolerance and immune rejection with regard to organ transplant(OT)is essential for developing better treatment options and improving patient outcomes.This article reviews the role of immune cells in OTR and organ transplant tolerance(OTT),including the novel cell therapies that are currently under clinical trials for transplant recipients.

Roles of liver innate immune cells in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has become the most common liver disease in the United States and other developed countries and is expected to increase in the next few years. Emerging data suggest that some patients with NAFLD may progress to nonalcoholic steatohepatitis (NASH), cirrhosis and even hepatocellular carcinoma. NAFLD can also promote the development and progression of disease in other organ systems, such as the cardiovascular and endocrine (i.e. diabetes) systems. Thus, understanding the pathogenesis of NAFLD is of great clinical importance and is critical for the prevention and treatment of the disease. Although the "two-hit hypothesis" is generally accepted, the exact pathogenesis of NAFLD has not been clearly established. The liver is an important innate immune organ with large numbers of innate immune cells, including Kupffer cells (KCs), natural killer T (NKT) cells and natural killer (NK) cells. Recent data show that an imbalance in liver cytokines may be implicated in the development of fatty liver disease. For example, Th1 cytokine excess may be a common pathogenic mechanism for hepatic insulin resistance and NASH. Innate immune cells in the liver play important roles in the excessive production of hepatic Th1 cytokines in NAFLD. In addition, liver innate immune cells participate in the pathogenesis of NAFLD in other ways. For example, activated KCs can generate reactive oxygen species, which induce liver injury. This review will focus primarily on the possible effect and mechanism of KCs, NKT cells and NK cells in the development of NAFLD.

Atherosclerosis and the role of immune cells

Atherosclerosis is a chronic inflammatory disease arising from lipids, specifically low-density lipoproteins, and leukocytes. Following the activation of endothelium with the expression of adhesion molecules and monocytes, inflammatory cytokines from macrophages, and plasmacytoid dendritic cells, high levels of interferon(IFN)-α and β are generated upon the activation of tolllike receptor-9, and T-cells, especially the ones with Th1 profile, produce pro-inflammatory mediators such as IFN-γ and upregulate macrophages to adhere to the endothelium and migrate into the intima. This review presents an exhaustive account for the role of immunecells in the atherosclerosis.

Comprehensive insights into the effects and regulatory mechanisms of immune cells expressing programmed death-1/programmed death ligand 1 in solid tumors

The programmed cell death-1(PD-1)/programmed cell death ligand 1(PD-L1)signaling pathway is an important mechanism in tumor immune escape,and expression of PD-L1 on tumor cells has been reported more frequently.However,accumulating evidence suggests that PD-1/PD-L1 is also widely expressed on immune cells,and that regulation is also critical for tumor immune responses.In this review,we emphasized that under solid tumor conditions,the immunoregulatory effects of immune cells expressing PD-1 or PD-L1,affected the prognoses of cancer patients.Therefore,a better understanding of the mechanisms that regulate PD-1 or PD-L1 expression on immune cells would provide clear insights into the increased efficacy of anti-PD antibodies and the development of novel tumor immunotherapy strategies.

Liver infiltration of multiple immune cells during the process of acute liver injury and repair

BACKGROUND Immune cells,including neutrophils,natural killer(NK)cells,T cells,NKT cells and macrophages,participate in the progression of acute liver injury and hepatic recovery.To date,there has been no systematic study on the quantitative changes in these different immune cells from initial injury to subsequent recovery.AIM To investigate the infiltration changes of various immune cells in acute liver injury models over time,and to study the relationship between the changes in leukocyte cellderived chemotaxin 2(LECT2)and the infiltration of several immune cells.METHODS Carbon tetrachloride-and concanavalin A-induced acute liver injury models were employed to mimic toxin-induced and autoimmune-mediated liver injury respectively.The quantitative changes in various immune cells were monitored at different time points.Serum samples were collected,and liver tissues were harvested.Ly6G,CD161,CD4,CD8 and F4/80 staining were used to indicate neutrophils,NK/NKT cells,CD4^(+)T cells,CD8^(+)T cells and macrophages,respectively.Lect2-KO mice were used to detect the function of LECT2.RESULTS During the injury and repair process,different types of immune cells began to increase,reached their peaks and fell into decline at different time points.Furthermore,when the serum alanine transaminase(ALT)and aspartate transaminase(AST)indices reverted to normal levels 7 d after the injury,the infiltration of immune cells still existed even 14 d after the injury,showing an obvious lag effect.We found that the expression of LECT2 was upregulated in acute liver injury mouse models,and the liver injuries of Lect2-KO mice were less severe than those of wild-type mice.Compared with wild-type mice,Lect2-KO mice had different immune cell infiltration.CONCLUSION The recovery time of immune cells was far behind that of serum ALT and AST during the process of liver repair.LECT2 could regulate monocyte/macrophage chemotaxis and might be used as a therapeutic target for acute liver injury.

Tail regeneration reduction in lizards after repetitive amputation or cauterization reflects an increase of immune cells in blastemas

Lizards are key amniote models for studying organ regeneration. During tail regeneration in lizards, blastemas contain sparse granulocytes, macrophages, and lymphocytes among the prevalent mesenchymal cells. Using transmission electron microscopy to examine scarring blastemas after third and fourth sequential tail amputations, the number of granulocytes, macrophages, and lymphocytes increased at 3-4 weeks in comparison to the first regeneration. An increase in granulocytes and agranulocytes also occurred within a week after blastema cauterization during the process of scarring Blood at the third and fourth regeneration also showed a significant increase in white blood cells compared with that under normal conditions and at the first regeneration. The extracellular matrix of the scarring blastema, especially after cauterization, was denser than that in the normal blastema and numerous white blood cells and fibroblasts were surrounded by electron-pale, fine fibrinoid material mixed with variable collagen fibrils. In addition to previous studies, the present observations support the hypothesis that an increase in inflammation and immune reactions determine scarring rather than regeneration. These new findings verify that an immune reaction against mesenchymal and epidermal cells of the regenerative blastema is one of the main causes for the failure of organ regeneration in amniotes.

Hub genes associated with immune cell infiltration in breast cancer, identified through bioinformatic analyses of multiple datasets

Objective:The aim of this study was to identify hub genes associated with immune cell infiltration in breast cancer through bioinformatic analyses of multiple datasets.Methods:Nonparametric(NOISeq)and robust rank aggregation-ranked parametric(EdgeR)methods were used to assess robust differentially expressed genes across multiple datasets.Protein-protein interaction network,GO,KEGG enrichment,and subnetwork analyses were performed to identify immune-associated hub genes in breast cancer.Immune cell infiltration was evaluated with the CIBERSORT,XCELL,and TIMER methods.The association between the hub gene-based risk signature and survival was determined through Kaplan–Meier survival analysis,multivariate Cox analysis,and a nomogram with external verification.Results:We identified 163 robust differentially expressed genes in breast cancer through applying both nonparametric and parametric methods to multiple GEO(n=2,212)and TCGA(n=1,045)datasets.Integrated bioinformatic analyses further identified 10 hub genes:CXCL10,CXCL9,CXCL11,SPP1,POSTN,MMP9,DPT,COL1A1,ADAMDEC1,and RGS1.The 10 hub-gene-based risk signature significantly correlated with the prognosis of patients with breast cancer.Moreover,these hub genes were strongly associated with the extent of infiltration of CD4+T cells,CD8+T cells,neutrophils,macrophages,and myeloid dendritic cells into breast tumors.Conclusions:Integrated analyses of multiple databases led to the discovery of 10 robust hub genes that together may serve as a risk factor characteristic of the immune microenvironment in breast cancer.

The prognostic landscape of genes and infiltrating immune cells in cytokine induced killer cell treated-lung squamous cell carcinoma and adenocarcinoma

Objective:Patients with non–small cell lung cancer(NSCLC)respond differently to cytokine-induced killer cell(CIK)treatment.Therefore,potential prognostic markers to identify patients who would benefit from CIK treatment must be elucidated.The current research aimed at identifying predictive prognostic markers for efficient CIK treatment of patients with NSCLC.Methods:Patients histologically diagnosed with NSCLC were enrolled from the Tianjin Medical University Cancer Institute and Hospital.We performed whole-exome sequencing(WES)on the tumor tissues and paired adjacent benign tissues collected from 50 patients with NSCLC,and RNA-seq on tumor tissues of 17 patients with NSCLC before CIK immunotherapy treatment.Multivariate Cox proportional hazard regression analysis was used to analyze the association between clinical parameters and prognostic relevance.WES and RNA-seq data between lung squamous cell carcinoma(SCC)and adenocarcinoma(Aden)were analyzed and compared.Results:The pathology subtype of lung cancer was the most significantly relevant clinical parameter associated with DFS,as analyzed by multivariate Cox proportional hazard regression(P=0.031).The patients with lung SCC showed better CIK treatment efficacy and extended DFS after CIK treatment.Relatively low expression of HLA class II genes and checkpoint molecules,and less immunosuppressive immune cell infiltration were identified in the patients with lung SCC.Conclusions:Coordinated suppression of the expression of HLA class II genes and checkpoint molecules,as well as less immune suppressive cell infiltration together contributed to the better CIK treatment efficacy in lung SCC than lung Aden.

CD34^(+)CD38^(-)subpopulation without CD123 and CD44 is responsible for LSC and correlated with imbalance of immune cell subsets in AML

Acute myeloid leukemia(AML)is regarded as a stem cell disease.However,no one unique marker is expressed on leukemia stem cells(LSC)but not on leukemic blasts nor normal hematopoietic stem cells(HSC).CD34^(+)CD38^(-)with or without CD123 or CD44 subpopulations are immunophenotypically defined as putative LSC fractions in AML.Nevertheless,markers that can be effectively and simply held responsible for the intrinsical heterogeneity of LSC is still unclear.In the present study,we examined the frequency of three different LSC subtypes(CD34^(+)CD38^(-),CD34^(+)CD38^(-)CD123^(+),CD34^(+)CD38^(-)CD44^(+))in AML at diagnosis.We then validated their prognostic significance on the relevance of spectral features for diagnostic stratification,immune status,induction therapy response,treatment effect maintenance,and long^(-)term survival.In our findings,high proportions of the above three different LSC subtypes were all significantly characterized with low complete remission(CR)rate,high relapse/refractory rate,poor overall survival(OS),frequent FLT3^(-)ITD mutation,the high level of regulatory T cells(Treg)and monocytic myeloid^(-)derived suppressor cells(M^(-)MDSC).However,there was no significant statistical difference in all kinds of other clinical performance among the three different LSC groups.It was demonstrated that CD34^(+)CD38^(-)subpopulation without CD123 and CD44 might be held responsible for LSC and correlated with an imbalance of immune cell subsets in AML.

Inhibition of Rgs10 Expression Prevents Immune Cell Infiltration in Bacteria-induced Inflammatory Lesions and Osteoclast-mediated Bone Destruction

Regulator of G-protein Signaling 10 （Rgsl0） plays an important function in osteoclast differentiation. However, the role of Rgsl0 in immune cells and inflammatory responses, which activate osteoclasts in inflam- matory lesions, such as bacteria-induced periodontal disease lesions, remains largely unknown. In this study, we used an adeno-associated virus （AAV-） mediated RNAi （AAV-shRNA-Rgs10） knockdown approach to study Rgsl0＇s function in immune cells and osteoclasts in bacteria-induced inflammatory lesions in a mouse model of periodontal disease. We found that AAV-shRNA-Rgs10 mediated Rgs10 knockdown impaired osteoclastogenesis and osteoclast-mediated bone resorption, in vitro and in vivo. Interestingly, local injection of AAV-shRNA-Rgs10 into the periodontal tissues in the bacteria-induced inflammatory lesion greatly decreased the number of dendritic cells, T-cells and osteoclasts, and protected the periodontal tissues from local inflammatory damage and bone destruction. Importantly, AAV-mediated Rgs10 knockdown also reduced local expression of osteoclast markers and pro-inflammatory cytokines. Our results demonstrate that AAV- shRNA-Rgs10 knockdown in periodontal disease tissues can prevent bone resorption and inflammation simultaneously. Our data indicate that Rgsl0 may regulate dendritic cell proliferation and maturation, as well as the subsequent stimulation of T-cell proliferation and maturation, and osteoclast differentiation and acti- vation. Our study suggests that AAV-shRNA-Rgs10 can be useful as a therapeutic treatment of periodontal disease.

“Standby” EMT and “immune cell trapping” structure as novel mechanisms for limiting neuronal damage after CNS injury

The central nervous system （CNS） contains the two most important organs, the brain and spinal cord, for the orchestration of the mental and physical activities of life. Because of its importance, the human body has evolved barrier systems to protect CNS tissue from the external environment. This barrier is a membrane composed of tightly apposed cells and is selectively permeable to specific molecules by way of membrane transporters.

Overexpression of CD155 is associated with PD-1 and PD-L1 expression on immune cells,rather than tumor cells in the breast cancer microenvironment

BACKGROUND CD155 is an immune checkpoint protein in cancers and interacts with ligands to regulate the immune microenvironment.The expression of CD155 is correlated with the prognosis and pathological features of breast cancer.AIM To investigate the expression status of CD155 and the association with exhausted CD4+helper and CD8+cytotoxic tumor infiltrating lymphocytes(TILs)and PD-L1 in the breast cancer microenvironment.METHODS One hundred and twenty-six breast cancer patients with invasive ductal breast cancer were consecutively recruited into this study.Immunohistochemistry was used to detect the expression CD155,PD-L1 and PD-1 on tumor-infiltrating immune cells and tumor cells in the microenvironment.RESULTS The proportion of patients with CD155 expression was higher in triple negative breast cancer(72.7%)than in Luminal A patients(22.2%,P<0.05).Patients with positive CD155 expression had a higher percentage of CD4+/PD-1+helper TILs(30%)than patients with negative CD155 expression(21%,P<0.05).Patients with positive CD155 expression also had higher cell counts of exhausted CD4+TILs[47 vs 20/high-power fields(HPF)]and unexhausted CD8+TILs(30 vs 17/HPF)than patients with negative expression(P<0.05).CD155 expression was correlated with increased PD-L1 expression in immune cells,0.8%and 0.02%immune cells expressed PD-L1 in patients with positive and negative CD155 expression,respectively(P<0.05).CONCLUSION CD155 was related to an inhibitory immune breast cancer microenvironment.CD155 was associated with a high proportion of exhausted CD4+and unexhausted CD8+TILs and high PD-L1 expression in immune cells.