Expression of Inhibitory Receptors on T and NK Cells Defines Immunological Phenotypes of HCV Patients with Advanced Liver Fibrosis

Plasma levels of soluble PD-1, TIM-3, LAG-3 and galectin-3 and the degree of liver fibrosis in CHC and the impact of successful antiviral treatment on their levels

Chronic hepatitis C (CHC), caused by the hepatitis C virus, commonly leads to liver fibrosis. CHC is also related to T-cell exhaustion, phenotypically manifesting as overexpression of inhibitory receptors (iRs), e.g., programmed death receptor-1 (PD-1), T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3) and lymphocyte activation gene 3 (LAG-3), which have corresponding plasma-soluble analogs. Galectin-3 (Gal-3) is a pro-fibrotic and pro-inflammatory molecule, but its role in CHC is controversial. The study aimed to assess the relationship between plasma levels of soluble PD-1 (sPD-1), sTIM-3, sLAG-3 and Gal-3 and the degree of fibrosis in CHC and successful CHC treatment effect on these markers. The study comprised 98 CHC patients, qualified for treatment with direct-acting antivirals. Plasma samples were collected prior to and six months post-treatment. iRs were determined by ELISA. sPD-1 levels were significantly higher in more advanced fibrosis (F2 + F3 vs. F0/1). Regardless of the degree of fibrosis, sPD-1 and sLAG-3 levels significantly decreased after therapy. sTIM-3 levels also decreased, however, mostly in patients with no or mild (i.e., F0/1) fibrosis. Furthermore, Gal-3 increased in patients with more advanced fibrosis (F2 + F3). sPD-1 is associated with liver disease stage in CHC and effective treatment is related to the iRs levels reduction.

Cytokines in Focus: IL-2 and IL-15 in NK Adoptive Cell Cancer Immunotherapy

NK cell adoptive cell therapy (ACT) has emerged as a promising strategy for cancer immunotherapy, offering advantages in scalability, accessibility, efficacy, and safety. Ex vivo activation and expansion protocols, incorporating feeder cells and cytokine cocktails, have enabled the production of highly functional NK cells in clinically relevant quantities. Advances in NK cell engineering, including CRISPR-mediated gene editing and chimeric Ag receptor technologies, have further enhanced cytotoxicity, persistence, and tumor targeting. Cytokine support post-adoptive transfer, particularly with IL-2 and IL-15, remains critical for promoting NK cell survival, proliferation, and anti-tumor activity despite persistent challenges such as regulatory T cell expansion and cytokine-related toxicities. This review explores the evolving roles of IL-2 and IL-15 in NK cell-based ACT, evaluating their potential and limitations, and highlights strategies to optimize these cytokines for effective cancer immunotherapy.

Serum Galectin-9 mirrors immune-evasive microenvironment and predicts early recurrence in hepatocellular carcinoma

BACKGROUND

The precise role of Galectin-9, an immune checkpoint protein involved in immune responses, in hepatocellular carcinoma (HCC) remains elusive. Importantly, the prognostic value of serum Galectin-9 has not been clarified, and its association with infiltrating immune characteristics was unclear.

METHODS

The association between serum Galectin-9 concentration and HCC recurrence was analyzed in two cohorts of HCC patients (training 133; validation 97) who received curative resection during 2018 and 2019. Bioinformatic analyses, including WGCNA, GSEA, GO, KEGG, Hallmark, CIBERSORT, QUANTISEQ, ssGSEA and TISIDB, were performed to systematically demonstrate the expression pattern, immunomodulation role, and prognostic value of Galectin-9 in HCC. These findings were further validated by immunohistochemistry staining.

RESULTS

Patients with high serum Galectin-9 levels had significantly shorter time to tumor recurrence (TTR; P < 0.001) in both cohorts, and serum Galectin-9 was identified as an independent predictor of HCC recurrence, even in patients with low-AFP or early-stage. Bioinformatic analyzes revealed high Galectin-9 expression is involved in immune-evasive and inflammatory signaling pathways. It correlated with increased infiltration of exhausted CD8 + T cells, Tregs, TAMs and MDSCs. Interestingly, we found Galectin-9 was predominantly expressed on macrophages rather than malignant cells, and showed positively association with serum Galectin-9 concentration according to IHC results. Concordantly, high serum Galectin-9 levels also reflected an immune-evasive microenvironment composed by extensive CD163 + and FOXP3 + cell infiltrates.

CONCLUSIONS

Elevated serum Galectin-9 was a novel indicator for worse prognosis in HCC. The high expression of Galectin-9 may reflect the immunosuppressive environment by increasing CD163 + and FOXP3 + cell infiltrates.

CD7 activation regulates cytotoxicity-driven pathology in systemic sclerosis, yielding a target for selective cell depletion

OBJECTIVES

Cytotoxic T cells and natural killer (NK) cells are central effector cells in cancer and infections. Their effector response is regulated by activating and inhibitory receptors. The regulation of these cells in systemic autoimmune diseases such as systemic sclerosis (SSc) is less defined.

METHODS

We conducted ex vivo analysis of affected skin and blood samples from 4 SSc patient cohorts (a total of 165 SSc vs 80 healthy individuals) using single-cell transcriptomics, flow cytometry and multiplex immunofluorescence staining. We further analysed the effects of costimulatory modulation in functional assays, and in a severely affected SSc patient who was treated on compassionate use with a novel anti-CD3/CD7 immunotoxin treatment.

RESULTS

Here, we show that SSc-affected skin contains elevated numbers of proliferating T cells, cytotoxic T cells and NK cells. These cells selectively express the costimulatory molecule CD7 in association with cytotoxic, proinflammatory and profibrotic genes, especially in recent-onset and severe disease. We demonstrate that CD7 regulates the cytolytic activity of T cells and NK cells and that selective depletion of CD7+ cells prevents cytotoxic cell-induced fibroblast contraction and inhibits their profibrotic phenotype. Finally, anti-CD3/CD7 directed depletive treatment eliminated CD7+ skin cells and stabilised disease manifestations in a severely affected SSc patient.

CONCLUSION

Together, the findings imply costimulatory molecules as key regulators of cytotoxicity-driven pathology in systemic autoimmune disease, yielding CD7 as a novel target for selective depletion of pathogenic cells.

Galectin-9 in cancer therapy: from immune checkpoint ligand to promising therapeutic target

Galectin-9 (Gal-9) is a vital member of the galectin family, functioning as a multi-subtype galactose lectin with diverse biological roles. Recent research has revealed that Gal-9's interaction with tumors is an independent factor that influences tumor progression. Furthermore, Gal-9 in the immune microenvironment cross-talks with tumor-associated immune cells, informing the clarification of Gal-9's identity as an immune checkpoint. A thorough investigation into Gal-9's role in various cancer types and its interaction with the immune microenvironment could yield novel strategies for subsequent targeted immunotherapy. This review focuses on the latest advances in understanding the direct and indirect cross-talk between Gal-9 and hematologic malignancies, in addition to solid tumors. In addition, we discuss the prospects of Gal-9 in tumor immunotherapy, including its cross-talk with the ligand TIM-3 and its potential in immune-combination therapy.

Markers of Natural Killer Cell Exhaustion in HIV/HCV Coinfection and Their Dynamics After HCV Clearance Mediated by Direct-Acting Antivirals

Background

Liver fibrosis is a leading cause of morbimortality in people with HIV/hepatitis C virus (HCV). Natural killer (NK) cells are linked with amelioration of liver fibrosis; however, NK cells from individuals coinfected with HIV/HCV with cirrhosis display impaired functionality and high PD-1 expression. Here, we aimed to study PD-1, TIGIT, and Tim3 as potential exhaustion markers in NK cells from persons coinfected with HIV/HCV with mild and advanced liver fibrosis. We also evaluated the role of PD-1 expression on NK cells after HCV clearance by direct-acting antivirals (DAAs).

Methods

Peripheral blood mononuclear cells were isolated from individuals coinfected with HIV/HCV (N = 54; METAVIR F0/F1, n = 27; F4, evaluated by transient elastography, n = 27). In 26 participants, samples were collected before, at the end of, and 12 months after successful DAA treatment. The frequency, immunophenotype (PD-1, TIGIT, and Tim3 expression), and degranulation capacity (CD107a assay) of NK cells were determined by flow cytometry.

Results

Unlike PD-1, Tim3 and TIGIT were comparably expressed between persons with mild and advanced fibrosis. Degranulation capacity was diminished in NK/TIGIT+ cells in both fibrosis stages, while NK/PD-1+ cells showed a lower CD107a expression in cirrhotic cases. Twelve months after DAA treatment, those with advanced fibrosis showed an improved NK cell frequency and reduced NK/PD-1+ cell frequency but no changes in CD107a expression. In individuals with mild fibrosis, neither PD-1 nor NK cell frequency was modified, although the percentage of NK/CD107a+ cells was improved at 12 months posttreatment.

Conclusions

Although DAA improved exhaustion and frequency of NK cells in cirrhotic cases, functionality was reverted only in mild liver fibrosis, remarking the importance of an early DAA treatment.

The Important Roles of Natural Killer Cells in Liver Fibrosis

Liver fibrosis accompanies the development of various chronic liver diseases and promotes their progression. It is characterized by the abnormal accumulation of extracellular matrix proteins (ECM) and impaired ECM degradation. Activated hepatic stellate cells (HSCs) are the major cellular source of ECM-producing myofibroblasts. If liver fibrosis is uncontrolled, it may lead to cirrhosis and even liver cancer, primarily hepatocellular carcinoma (HCC). Natural killer (NK) cells are a key component of innate immunity and have miscellaneous roles in liver health and disease. Accumulating evidence shows that NK cells play dual roles in the development and progression of liver fibrosis, including profibrotic and anti-fibrotic functions. Regulating NK cells can suppress the activation of HSCs and improve their cytotoxicity against activated HSCs or myofibroblasts to reverse liver fibrosis. Cells such as regulatory T cells (Tregs) and molecules such as prostaglandin E receptor 3 (EP3) can regulate the cytotoxic function of NK cells. In addition, treatments such as alcohol dehydrogenase 3 (ADH3) inhibitors, microRNAs, natural killer group 2, member D (NKG2D) activators, and natural products can enhance NK cell function to inhibit liver fibrosis. In this review, we summarized the cellular and molecular factors that affect the interaction of NK cells with HSCs, as well as the treatments that regulate NK cell function against liver fibrosis. Despite a lot of information about NK cells and their interaction with HSCs, our current knowledge is still insufficient to explain the complex crosstalk between these cells and hepatocytes, liver sinusoidal endothelial cells, Kupffer cells, B cells, and T cells, as well as thrombocytes, regarding the development and progression of liver fibrosis.

Etiology of end-stage liver cirrhosis impacts hepatic natural killer cell heterogenicity

The natural killer (NK) cell population is a critical component of the innate immune compartment of the liver, and its functions are deeply affected by the surrounding environment. In the late stage of fibrosis, NK cells become dysfunctional, but the influence of disease etiology on NK cell behavior during cirrhosis remains unclear. Using single-cell RNA sequencing (scRNA-seq), we characterized the hepatic NK cells from end-stage cirrhotic livers from subjects with non-alcoholic steatohepatitis (NASH), chronic hepatitis C infection (HCV) and primary sclerosing cholangitis (PSC). Here, we show that although NK cells shared similar dysfunctions, the disease etiology impacts hepatic NK cell heterogeneity. Therapeutical strategies targeting NK cells for the prevention or treatment of fibrosis should consider liver disease etiology in their design.

Natural Killer Cells Induce CD8+ T Cell Dysfunction via Galectin-9/TIM-3 in Chronic Hepatitis B Virus Infection

The antiviral response of natural killer (NK) cells and CD8⁺ T cells is weak in patients with chronic hepatitis B (CHB) infection. However, the specific characteristics of these cells and the association between NK cells and CD8⁺ T cell dysfunction is not well known. In this study, higher galectin-9 (Gal-9) expression was observed in circulating NK cells from CHB patients than from healthy controls and was found to contribute to NK cell dysfunction. In addition, circulating CD8⁺ T cells showed obvious dysfunction and overexpressed TIM-3, the natural receptor of Gal-9, during active CHB infection. Gal-9⁺ and Gal-9^- NK cells from active CHB patients were sorted and cocultured with autologous CD8⁺ T cells. The proportion of tetramer⁺CD8⁺ T cells and the cytokines production of CD8⁺ T cells were lower after cocultivation with Gal-9⁺ than with Gal-9^- NK cells. We showed that in vitro depletion of NK cells increased circulating hepatitis B virus (HBV)-specific CD8⁺ T cell responses in patients with active CHB infection. Because Gal-9 is increased in the serum of CHB patients, CD8⁺ T cells were sorted and cultured with exogenous Gal-9, resulting in lower IFN-γ, TNF-α, CD107a, and granzyme B levels, decreased expression of the activation receptor CD69, increased expression of TIM-3, and a high percentage of early apoptotic CD8⁺ T cells. Blocking Gal-9 or TIM-3 in vitro in a culture of peripheral blood mononuclear cells (PBMCs) stimulated with HBV peptide from active CHB patients restored CD8⁺ T cell function. However, blocking Gal-9 in vitro after removal of NK cells from PBMCs did not rescue CD8⁺ T cells exhaustion. Furthermore, NK and CD8⁺ T cells from active CHB patients were sorted and cocultured in vitro, and the exhaustion of CD8⁺ T cells were alleviated after blocking Gal-9 or TIM-3. In summary, overexpression of Gal-9 on NK cells, which interacts with TIM-3⁺CD8⁺ T cells and likely contributes to antiviral CD8⁺ T cell dysfunction, may be a potential target for the treatment of CHB patients.

The role of natural killer cells in liver inflammation

The liver is an important immunological site that can promote immune tolerance or activation. Natural killer (NK) cells are a major immune subset within the liver, and therefore understanding their role in liver homeostasis and inflammation is crucial. Due to their cytotoxic function, NK cells are important in the immune response against hepatotropic viral infections but are also involved in the inflammatory processes of autoimmune liver diseases and fatty liver disease. Whether NK cells primarily promote pro-inflammatory or tolerogenic responses is not known for many liver diseases. Understanding the involvement of NK cells in liver inflammation will be crucial in effective treatment and future immunotherapeutic targeting of NK cells in these disease settings. Here, we explore the role that NK cells play in inflammation of the liver in the context of viral infection, autoimmunity and fatty liver disease.

Immunmodulatory Treatment Strategies of Hepatocellular Carcinoma: From Checkpoint Inhibitors Now to an Integrated Approach in the Future

BACKGROUND

Hepatocellular carcinoma (HCC) still represents a human tumor entity with very limited therapeutic options, especially for advanced stages. Here, immune checkpoint modulating drugs alone or in combination with local ablative techniques could open a new and attractive therapeutic "door" to improve outcome and response rate for patients with HCC.

METHODS

Published data on HCC experimental to pre-(clinical) treatment strategies from standard of care to novel immunomodulatory concepts were summarized and discussed in detail.

RESULTS

Overall, our knowledge of the role of immune checkpoints in HCC is dramatically increased in the last years. Experimental and pre-clinical findings could be translated to phase 1 and 2 clinical trials and became standard of care. Local ablative techniques of HCC could improve the effectivity of immune checkpoint inhibitors in situ.

CONCLUSIONS

This review demonstrates the importance of immunomodulatory treatment strategies of HCC, whereby the "best treatment code" of immune checkpoint drugs, combination with ablative techniques and of timing must be evaluated in coming clinical trials.

Splenic CD4+ and CD8+ T-cells highly expressed PD-1 and Tim-3 in cirrhotic patients with HCV infection and portal hypertension

Introduction: The spleen plays an important role in regulating the immune response to infectious pathogens. T-cells dysfunction and exhaustion have been reported in patients with hepatitis B/C virus (HBV/HCV) infection, which contributes to persistent virus infection. The aims of this study were to investigate spleen-related evidence of immunosuppression and immune tolerance in HCV cirrhotic patients with portal hypertension (PH). Methods: The expression of programmed cell death 1 (PD-1), T-cell immunoglobulin domain and mucin domain-containing molecule-3 (Tim-3) and its ligand PD-L1/2, and Galectin-9 in the spleens and livers of HCV cirrhotic patients (n = 15) was analyzed using real-time PCR and immunohistochemistry. Flow cytometry was used to evaluate the expression of PD-1 and Tim-3 on splenic T-cells and the peripheral blood T-cells before and after splenectomy (n = 8). Results: Spleens from patients with PH showed significantly increased mRNA levels of PD-L2, Tim-3, Galectin-9, CD80, and CD86, and decreased levels of CD28 compared to control spleens (spleens removed due to traumatic injury) (all p < 0.05). Additionally, protein expression of inhibitory signaling molecules was significantly increased in both the spleens and livers of cirrhotic patients compared with controls (all p < 0.05). Peripheral blood and splenic CD4+ and CD8+ T-cells also expressed higher protein levels of PD-1, Tim-3, and CTLA-4 in cirrhotic patients as compared with healthy controls (all p < 0.05). The proportion of PD-1+CD4+T lymphocytes (26.2% ± 7.12% vs. 21.0% ± 9.14%, p = 0.0293) and Tim-3+CD8+ T lymphocytes (9.4% ± 3.04% vs. 6.0% ± 2.24%, p = 0.0175) in peripheral blood decreased followed splenectomy. Conclusion: The CD4+ and CD8+ T-cells in spleen and peripheral blood highly expressed PD-1 and Tim-3 in HCV-infected and cirrhotic patients with portal hypertension. Highly expressed PD-1 and Tim-3 in peripheral blood T-lymphocytes can be partly reversed following splenectomy.