Regulatory T cells in HBV and HCV liver diseases: implication of regulatory T lymphocytes in the control of immune response

Nanosuspensions in ophthalmology: Overcoming challenges and enhancing drug delivery for eye diseases

This review article provides a comprehensive overview of the advancements in using nanosuspensions for controlled drug delivery in ophthalmology. It highlights the significance of ophthalmic drug delivery due to the prevalence of eye diseases and delves into various aspects of this field. The article explores molecular mechanisms, drugs used, and physiological factors affecting drug absorption. It also addresses challenges in treating both anterior and posterior eye segments and investigates the role of mucus in obstructing micro- and nanosuspensions. Nanosuspensions are presented as a promising approach to enhance drug solubility and absorption, covering formulation, stability, properties, and functionalization. The review discusses the pros and cons of using nanosuspensions for ocular drug delivery and covers their structure, preparation, characterization, and applications. Several graphical representations illustrate their role in treating various eye conditions. Specific drug categories like anti-inflammatory drugs, antihistamines, glucocorticoids, and more are discussed in detail, with relevant studies. The article also addresses current challenges and future directions, emphasizing the need for improved nanosuspension stability and exploring potential technologies. Nanosuspensions have shown substantial potential in advancing ophthalmic drug delivery by enhancing solubility and absorption. This article is a valuable resource for researchers, clinicians, and pharmaceutical professionals in this field, offering insights into recent developments, challenges, and future prospects in nanosuspension use for ocular drug delivery.

Immunological pathways in viral hepatitis-induced hepato-cellular carcinoma

Hepatocellular carcinoma (HCC) is a serious neoplastic disease with increasing incidence and mortality, accounting for 90% of all liver cancers. Hepatitis viruses are the major causative agents in the development of HCC. Hepatitis A virus (HAV) primarily causes acute infections, which is associated with HCC to a certain extent, as shown by clinicopathological studies. Chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infections lead to persistent liver inflammation and cirrhosis, disrupt multiple pathways associated with cellular apoptosis and proliferation, and are the most common viral precursors of HCC. Mutations in the HBV X protein (HBx) gene are closely associated with the incidence of HCC, while the expression of HCV core proteins contributes to hepatocellular lipid accumulation, thereby promoting tumorigenesis. In the clinical setting, hepatitis D virus (HDV) frequently co-infects with HBV, increasing the risk of chronic hepatitis. Hepatitis E virus (HEV) usually causes acute infections. However, chronic infections of HEV have been increasing recently, particularly in immuno-compromised patients and organ transplant recipients, which may increase the risk of progression to cirrhosis and the occurrence of HCC. Early detection, effective intervention and vaccination against these viruses may significantly reduce the incidence of liver cancer, while mechanistic insights into the interplay between hepatitis viruses and HCC may facilitate the development of more effective intervention strategies. This article provides a comprehensive overview of hepatitis viruses and reviews recent advances in research on aberrant hepatic immune responses and the pathogenesis of HCC due to viral infection.

The positive feedback loop of furin and TGFβ1 enhances the immune responses of Tregs to hepatocellular carcinoma cells and hepatitis B virus in vitro

Regulatory T cells (Tregs) can exert immunosuppressive activity. Furin can regulate Treg functions, hepatitis B virus (HBV) persistent infection, and hepatocellular carcinoma (HCC) development. However, it remains unknown whether furin can regulate the immune responses of Tregs to HBV and HCC cells. Here, coculture systems of HBV1.3P-HepG2.3P-HepG2 cells and Tregs transduced with or without lentiviral particles that could overexpress furin or knockdown furin/transforming growth factor β1 (TGFβ1) were established to investigate the regulatory relationship between furin and TGFβ1 and the effect of furin/TGFβ1 on Treg activity. Also, the effects of furin overexpression or furin/TGFβ1 knockdown in Tregs on the immunological activity of effector T cells (Teffs)/cytotoxic T lymphocytes (CTLs) and HBV replication/expression were explored in the coculture system of Teff/CTL, Treg, and HBV1.3P-HepG2 cells. Our results showed that furin expression and TGFβ1 secretion were notably increased in Tregs, and Furin and TGFβ1 formed a positive feedback loop to activate Tregs in the coculture system of Tregs and HBV1.3P-HepG2 cells. Furin or TGFβ1 knockdown in Tregs promoted Teff cell proliferation, stimulated interleukin-2 and interferon-γ secretion, and inhibited HBV replication/gene expression in the coculture system of Teff, Treg, and HBV1.3P-HepG2 cells. Moreover, furin or TGFβ1 depletion in Tregs enhanced the killing activity of CTLs against HBV1.3P-HepG2 cells and curbed HBV replication/gene expression in the coculture system of Tregs, CTLs, and HBV1.3P-HepG2 cells. In conclusion, the positive feedback loop of furin and TGFβ1 enhanced the immune responses of Tregs to HCC cells and HBV in vitro.

Immunotherapy of hepatocellular carcinoma: Unique challenges and clinical opportunities

Current therapies for advanced hepatocellular carcinoma (HCC) are marginally effective and exacerbate underlying liver disease. The ability of immunotherapy to elicit nontoxic, systemic, long-lived anti-tumor activity makes it particularly well-suited for use in the setting of HCC. While therapeutic benefit has been achieved in early clinical trials, the efficacy of immune-based therapies is limited by several unique properties of HCC, most notably the inherently tolerogenic character of the liver in both healthy and diseased (chronically-infected or tumor-bearing) states. Therapeutic regimens that both counteract these immunosuppressive mechanisms and amplify tumor-specific immunity are expected to profoundly improve clinical outcomes for HCC patients.

Immunotherapy of hepatocellular carcinoma: Unique challenges and clinical opportunities

Current therapies for advanced hepatocellular carcinoma (HCC) are marginally effective and exacerbate underlying liver disease. The ability of immunotherapy to elicit nontoxic, systemic, long-lived anti-tumor activity makes it particularly well-suited for use in the setting of HCC. While therapeutic benefit has been achieved in early clinical trials, the efficacy of immune-based therapies is limited by several unique properties of HCC, most notably the inherently tolerogenic character of the liver in both healthy and diseased (chronically-infected or tumor-bearing) states. Therapeutic regimens that both counteract these immunosuppressive mechanisms and amplify tumor-specific immunity are expected to profoundly improve clinical outcomes for HCC patients.

Comprehensive analysis of the relationship between competitive endogenous RNA (ceRNA) networks and tumor infiltrating-cells in hepatocellular carcinoma

Background

The innovation of immune checkpoint blockade (ICB) represents a promising shift in the treatment of advanced hepatocellular carcinoma (HCC). However, response to ICB has varied largely due to the high tumor heterogeneity and complex tumor microenvironment (TME). The competitive endogenous RNA (ceRNA) network also plays an important role in tumor occurrence and progression, but its relation with tumor-infiltrating immune cells (TICs) remains largely unexplored in HCC. The overriding objective of our study was thus to construct a prognosis-related risk model and to further evaluate the relationship between ceRNA networks and TICs.

Methods

Differentially expressed gene (DEG) analysis was performed to identify the differentially expressed RNAs. Lasso and multivariable Cox regression analyses were used to construct risk models, which were assessed by the area under the receiver operating characteristic curve (AUC of ROC) and Kaplan-Meier (K-M) curves. Then, a single-sample gene set enrichment analysis (ssGSEA) algorithm was adopted to dissect the TICs in HCC samples. Nomograms were constructed and calibration curves were used to verify the discrimination and accuracy of the nomograms. Finally, integration analysis was performed to validate the correlation of ceRNA and TICs.

Results

In the study, 7 differentially expressed RNAs [5 messenger RNA s (mRNAs) and 2 micro RNAs (miRNAs)] were incorporated to construct a ceRNA risk model. The AUC of the 1-, 3-, and 5-year overall survival (OS) were 0.784, 0.685, and 0.691 respectively. Likewise, 7 types TICs were in the TICs signature model and the AUC of the 1-, 3-, and 5-year OS were 0.706, 0.731, and 0.721 respectively. The integration analysis showed that 7 pairs of mRNA-TICs and 1 pair of miRNA-TICs had a close relation (all correlation coefficients >0.2, P<0.001).

Conclusions

Through constructing two risk models based on ceRNA network and TICs, we identified the hub RNAs and key TICs in the progression and prognosis of HCC, and further explored the relationship between ceRNA and TME. Importantly, targeting these hub RNAs may facilitate the remodeling of the TME and be a potential therapeutic alternative to enhancing the response to ICB, thus improving the prognosis of HCC patients.

Salmonella Persistence and Host Immunity Are Dictated by the Anatomical Microenvironment

The intracellular bacterial pathogen Salmonella is able to evade the immune system and persist within the host. In some cases, these persistent infections are asymptomatic for long periods and represent a significant public health hazard because the hosts are potential chronic carriers, yet the mechanisms that control persistence are incompletely understood. Using a mouse model of chronic typhoid fever combined with major histocompatibility complex (MHC) class II tetramers to interrogate endogenous, Salmonella-specific CD4⁺ helper T cells, we show that certain host microenvironments may favorably contribute to a pathogen's ability to persist in vivo We demonstrate that the environment in the hepatobiliary system may contribute to the persistence of Salmonella enterica subsp. enterica serovar Typhimurium through liver-resident immunoregulatory CD4⁺ helper T cells, alternatively activated macrophages, and impaired bactericidal activity. This contrasts with lymphoid organs, such as the spleen and mesenteric lymph nodes, where these same cells appear to have a greater capacity for bacterial killing, which may contribute to control of bacteria in these organs. We also found that, following an extended period of infection of more than 2 years, the liver appeared to be the only site that harbored Salmonella bacteria. This work establishes a potential role for nonlymphoid organ immunity in regulating chronic bacterial infections and provides further evidence for the hepatobiliary system as the site of chronic Salmonella infection.

Circulating CTLA-4 levels and CTLA4 polymorphisms associate with disease condition and progression and hepatocellular carcinoma patients' survival in chronic hepatitis B virus infection

BACKGROUND

CTLA-4 is involved in the immune dysfunction of hepatitis B virus (HBV) infection and hepatocellular carcinoma (HCC). This study analyzed the association of circulating CTLA-4 levels and CTLA4 polymorphisms with disease condition and progression in chronic HBV infection.

METHODS

Serum CTLA-4 levels and CTLA4 rs231775 and rs5742909 polymorphisms were determined in patients with various HBV-related diseases [53 asymptomatic HBV carrier status (ASC), 147 chronic hepatitis, 130 cirrhosis and 102 HCC] and nearly a 10-year follow-up.

RESULTS

Serum CTLA-4 levels were stepwisely increased from ASC, chronic hepatitis, cirrhosis to HCC and independently associated with HCC (OR 2.628, P < 0.001). HCC patients had lower frequencies of rs231775 genotype GA, genotype AA and allele A than ASC, chronic hepatitis and cirrhosis patients. Rs231775 genotype GG was independently associated with HCC (OR 2.324, P = 0.010) and higher CTLA-4 levels in patients with HBV infection. In the follow-up, higher baseline CTLA-4 levels and CTLA4 rs231775 genotype GG significantly associated with disease progression from chronic hepatitis to cirrhosis (OR 2.561, P = 0.011 and OR 2.799, P = 0.015, respectively) or from cirrhosis to HCC (OR 2.673, P = 0.008 and OR 2.097, P = 0.023, respectively) and with a shorter overall survival in HCC patients (HR 0.317, P = 0.018 and HR 0.682, P = 0.026, respectively). Rs5742909 had no significant association with CTLA-4 levels and disease progression.

CONCLUSION

CTLA-4 levels and CTLA4 rs231775 polymorphism associate with the disease condition and progression and HCC development in chronic HBV infection and their determination may be used for monitoring disease progression and predicting patient prognosis.

Differential alternative splicing regulation among hepatocellular carcinoma with different risk factors

Background

Hepatitis B virus (HBV), hepatitis C virus (HCV), and alcohol consumption are predominant causes of hepatocellular carcinoma (HCC). However, the molecular mechanisms underlying how differently these causes are implicated in HCC development are not fully understood. Therefore, we investigated differential alternative splicing (AS) regulation among HCC patients with these risk factors.

Methods

We conducted a genome-wide survey of AS events associated with HCCs among HBV (n = 95), HCV (n = 47), or alcohol (n = 76) using RNA-sequencing data obtained from The Cancer Genome Atlas.

Results

In three group comparisons of HBV vs. HCV, HBV vs. alcohol, and HCV vs. alcohol for RNA seq (ΔPSI> 0.05, FDR < 0.05), 133, 93, and 29 differential AS events (143 genes) were identified, respectively. Of 143 AS genes, eight and one gene were alternatively spliced specific to HBV and HCV, respectively. Through functional analysis over the canonical pathways and gene ontologies, we identified significantly enriched pathways in 143 AS genes including immune system, mRNA splicing-major pathway, and nonsense-mediated decay, which may be important to carcinogenesis in HCC risk factors. Among eight genes with HBV-specific splicing events, HLA-A, HLA-C, and IP6K2 exhibited more differential expression of AS events (ΔPSI> 0.1). Intron retention of HLA-A was observed more frequently in HBV-associated HCC than HCV- or alcohol-associated HCC, and intron retention of HLA-C showed vice versa. Exon 3 (based on ENST00000432678) of IP6K2 was less skipped in HBV-associated in HCC compared to HCV- or alcohol-associated HCC.

Conclusion

AS may play an important role in regulating transcription differences implicated in HBV-, HCV-, and alcohol-related HCC development.

Hepatitis C Virus Improves Human Tregs Suppressive Function and Promotes Their Recruitment to the Liver

Background: The role of regulatory T cells (Tregs) is now well established in the progression of hepatocellular carcinoma (HCC) linked to Hepatitis C virus (HCV) infection. However, nothing is known about the potential interplay between Tregs and HCV. In this pilot study, we have investigated the ability of Tregs to hang HCV on and the subsequent effect on their suppressive function and phenotype. Moreover, we have evaluated how HCV could promote the recruitment of Tregs by infected primary human hepatocytes. Methods: Tregs of healthy donors were incubated with JFH-1/HCVcc. Viral inoculation was assessed using adapted assays (RT-qPCR, Flow Citometry (FACS) and Western Blot (WB). Expression of Tregs phenotypic (CD4, CD25, CD127 and Foxp3) and functional (IL-10, GZMB, TGF-β1 and IL-2) markers was monitored by RT-qPCR, FACS and ELISA. Suppressive activity was validated by suppressive assays. Tregs recruitment by infected primary hepatic cells was evaluated using Boyden Chamber. Results: Tregs express the classical HCV receptors (CD81, CLDN1 and LDLR) and some co-receptors (CD5). HCV inoculation significantly increases the suppressive phenotype and activity of Tregs, and raises their anergy by inducing an unexpected IL-2 production. Moreover, HCV infection induces the expression of chemokines (CCL17, CXCL16, and CCL20) by primary hepatic human hepatocytes and chemokine receptors (CCR4, CXCR6 and CCR6) by Tregs. Finally, infected hepatocytes have a significantly higher potential to recruit Tregs in a seemingly CCL20-dependent manner. Conclusions: Direct interaction between HCV and Tregs represents a newly defined mechanism that could potentiate HCV immune evasion and favor intratumoral recruitment contributing to HCC progression.

Chronic Hepatitis C: Conspectus of immunological events in the course of fibrosis evolution

In chronically infected HCV patients emergence and evolution of fibrosis, as a consequence of virus persistence, can be considered as an indicator of disease advancement. Therefore the aim of this study was to correlate alterations of immune response in chronic HCV patients with liver histopathology. Sera cytokine levels and frequency of circulating and liver infiltrating cells were evaluated using 13plex Kit Flow Cytomix, flow cytometry and immunohistochemistry. We found that the number of circulating T lymphocytes (including CD4+, CD8+ and Treg) and B lymphocytes, as well as DCs, was higher in patients with no fibrosis than in healthy subjects. In patients with fibrosis frequency of these cells decreased, and contrarily, in the liver, number of T and B lymphocytes gradually increased with fibrosis. Importantly, in patients with advanced fibrosis, liver infiltrating regulatory T cells and DC-SIGN+ mononuclear cells with immunosuppressive and wound-healing effector functions were abundantly present. Cytokine profiling showed predominance of proinflammatory cytokines in patients with no fibrosis and a tendency of decline in level of all cytokines with severity of liver injury. Lower but sustained IL-4 production refers to Th2 predominance in higher stages of fibrosis. Altogether, our results reveal graduall alterations of immunological parameters during fibrosis evolution and illustrate the course of immunological events through disease progression.

Early high levels of regulatory T cells and T helper 1 may predict the progression of recurrent hepatitis C after liver transplantation

BACKGROUND

Immune response failure against hepatitis C virus (HCV) has been associated with an increased regulatory T cell (Treg) activity. After liver transplantation (LT), 80% of patients experience an accelerated progression of hepatitis C recurrence. The aim of this work was to assess the involvement of Tregs, T helper (Th) 1, 2 and 17 cells in recurrent hepatitis C.

METHODS

Peripheral blood cells obtained before and one month after LT from 22 recipients were analysed. Forty-four key molecules related to Treg, Th1, 2 and 17 responses, were evaluated using qRT-PCR. Liver recipients were classified in two groups according to graft fibrosis evaluated by the METAVIR score on the biopsy performed one year after LT (mild: F ≤ 1, n = 13; severe: F > 1, n = 9). Patients developing a severe recurrence were compared with patients with a mild recurrence.

RESULTS

mRNA levels of Treg markers obtained one month after LT were significantly increased in patients with a severe disease course when compared to patients with a mild recurrence. Markers of the Th1 response were elevated in the same group. No differences in the markers determined before LT were observed.

CONCLUSION

These findings suggest that Treg, induced by a multifactorial process, which could include a strong Th1 response itself, may play a role in suppressing the early antiviral response, leading to a severe recurrence of hepatitis C.

Immunotherapy with interferon-α-induced dendritic cells for chronic HCV infection (the results of pilot clinical trial)

The key role of T cells in hepatitis C virus (HCV) elimination and the ability of dendritic cells (DCs) to induce antiviral T cell responses suggest that DC vaccines could be a promising approach in the treatment of chronic HCV infection. The aim of our study was to evaluate, whether immunotherapy with DCs is safe and elicits anti-HCV T cell responses. Ten patients with HCV (genotype 1) were vaccinated with monocyte-derived DCs, generated in the presence of IFN-α (IFN-DCs) and pulsed with recombinant HCV Core and NS3 proteins. Treatment schedule included four subcutaneous vaccinations with 1 week interval and six vaccinations with month interval. No serious adverse events or an increase in hepatitis C biochemical activity were registered after vaccination. Using ex vivo assays for the detection of proliferative responses, IFN-γ production and CD8⁺ degranulation have shown that immunotherapy elicited antigen-specific responses in all patients although individual heterogeneity existed within their types, magnitude, and timing. Core/NS3-specific proliferative response and CD8⁺ T cell degranulation have already been registered after the first course of vaccination. Of note, Core-specific responses had higher magnitude. The appearance of antigen-specific IFN-γ responses was registered after the second vaccination course. Vaccination did not cause Th2 response and expansion of the CD4⁺CD25⁺CD127^- regulatory T cells. Generated immune responses failed to provide virus elimination. Nevertheless, there were inverse correlations between viral load and NS3-specific proliferation (R _S = 0.62; p = 0.05) and IFN-γ secretion (R _S = - 0.82; p = 0.001) at 6-month post-treatment period. Immunotherapy with IFN-DCs was safe and elicited HCV-specific T cell responses which were insufficient to eliminate viruses but could be implicated in the restriction of viral replication.

Immunotherapy for hepatocellular carcinoma patients: is it ready for prime time?

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy and the second most common cause of cancer death worldwide. Current treatment options for patients with intermediate and advanced HCC are limited, and there is an unmet need for novel therapeutic approaches. HCC is an attractive target for immunomodulation therapy, since it arises in an inflammatory milieu due to hepatitis B and C infections and cirrhosis. However, a major barrier to the development and success of immunotherapy in patients with HCC is the liver's inherent immunosuppressive function. Recent advances in the field of cancer immunology allowed further characterization of immune cell subsets and function, and created new opportunities for therapeutic modulation of the immune system. In this review, we present the different immune cell subsets involved in potential immune modulation of HCC, discuss their function and clinical relevance, review the variety of immune therapeutic agents currently under investigation in clinical trials, and outline future research directions.

Genetic Polymorphisms of Fas/FasL Promoter Associated with Hepatitis C cirrhosis and HCC

Aim:

The present study was performed to determine any associations of genetic polymorphisms of Fas/FasL promoter regions, at Fas670 and Fas1377 and FasL844, with hepatitis C cirrhosis and HCC, with a focus on severity of disease.

Methods:

Totals of 120 patients with cirrhosis and 101 with hepatocellular carcinoma (HCC) were enrolled. All had chronic HCV infection as indicated by positive anti-HCV antibodies and positive HCV RNA on real time PCR. One hundred healthy control subjects were also included in the study. Patients were subjected to full clinical, radiological and histopathological examinations. In addition to routine laboratory tests for liver function tests, Fas670 and Fas1377 and FasL844 genetic polymorphisms of Fas/FasL promoter regions were assessed by RFLP-PCR (restriction fragment length polymorphism with polymerase chain reaction).

Results:

Significant higher levels of the AG genotype in Fas670 and Fas1773 were observed in patients with cirrhosis and HCC (P=0.0001) as compared to control subjects. In addition, the CC genotype in FASL844 was also more common in patients (P=0.01). Furtehrmore, there was a significant association of substitution of A by G alleles in Fas670 and Fas1773 with advanced BCA staging (P=0.02, P=0.0001 respectively) and larger tumor size >5cm (P=0.01, P=0.0001 respectively) and in Fas670 with advanced pathological grading (P=0.0001). Moreover the CC genotype of FASL844 was significantly linked with advanced BCA, large tumor size >5cm and advanced pathological grading (P=0.0001).

Conclusion:

The findings of the present study highlight associations of genetic polymorphisms of promoter regions in Fas and Fas L with cirrhosis and HCC associated with chronic HCV. Support was also obtained for the conclusion that single nucleotide polymorphisms of the Fas/ FasL system impact on clinical and histopathological grading of HCCs. Further large scale studies are recommended for confirmation.

Tissue-specific control of latent CMV reactivation by regulatory T cells

Cytomegalovirus (CMV) causes a persistent, lifelong infection. CMV persists in a latent state and undergoes intermittent subclinical viral reactivation that is quelled by ongoing T cell responses. While T cells are critical to maintain control of infection, the immunological factors that promote CMV persistence remain unclear. Here, we investigated the role of regulatory T cells (Treg) in a mouse model of latent CMV infection using Foxp3-diphtheria toxin receptor (Foxp3-DTR) mice. Eight months after infection, MCMV had established latency in the spleen, salivary gland, lung, and pancreas, which was accompanied by an increased frequency of Treg. Administration of diphtheria toxin (DT) after establishment of latency efficiently depleted Treg and drove a significant increase in the numbers of functional MCMV-specific CD4+ and CD8+ T cells. Strikingly, Treg depletion decreased the number of animals with reactivatable latent MCMV in the spleen. Unexpectedly, in the same animals, ablation of Treg drove a significant increase in viral reactivation in the salivary gland that was accompanied with augmented local IL-10 production by Foxp3-CD4+T cells. Further, neutralization of IL-10 after Treg depletion significantly decreased viral load in the salivary gland. Combined, these data show that Treg have divergent control of MCMV infection depending upon the tissue. In the spleen, Treg antagonize CD8+ effector function and promote viral persistence while in the salivary gland Treg prevent IL-10 production and limit viral reactivation and replication. These data provide new insights into the organ-specific roles of Treg in controlling the reactivation of latent MCMV infection.

Cytomegalovirus (CMV) infection in both mice and humans is normally initially contained by a vigorous adaptive immune response that drives the virus into latency in multiple tissues. However, the immunologic mechanisms that control latency are not well understood. In this report, we have examined the role of regulatory T cells (Treg) in a mouse model of CMV infection. Interestingly, depletion of regulatory T cells had profound consequences on MCMV latent infection, depending upon the tissue. In the spleen, Treg depletion enhanced CD8+ T cell responses and reduced reactivatable latent infection from the spleen. In striking contrast, in the salivary gland, Treg depletion enhanced the production of IL-10 from CD4+ T cells as well as viral reactivation. Thus, Treg play divergent and tissue specific roles in controlling MCMV reactivation from latency.

Regulatory T cell frequencies and phenotypes following anti-viral vaccination

Regulatory T cells (Treg) function in the prevention of excessive inflammation and maintenance of immunological homeostasis. However, these cells may also interfere with resolution of infections or with immune reactions following vaccination. Effects of Treg on vaccine responses are nowadays investigated, but the impact of vaccination on Treg homeostasis is still largely unknown. This may be a relevant safety aspect, since loss of tolerance through reduced Treg may trigger autoimmunity. In exploratory clinical trials, healthy adults were vaccinated with an influenza subunit vaccine plus or minus the adjuvant MF59®, an adjuvanted hepatitis B subunit vaccine or a live attenuated yellow fever vaccine. Frequencies and phenotypes of resting (rTreg) and activated (aTreg) subpopulations of circulating CD4+ Treg were determined and compared to placebo immunization. Vaccination with influenza vaccines did not result in significant changes in Treg frequencies and phenotypes. Vaccination with the hepatitis B vaccine led to slightly increased frequencies of both rTreg and aTreg subpopulations and a decrease in expression of functionality marker CD39 on aTreg. The live attenuated vaccine resulted in a decrease in rTreg frequency, and an increase in expression of activation marker CD25 on both subpopulations, possibly indicating a conversion from resting to migratory aTreg due to vaccine virus replication. To study the more local effects of vaccination on Treg in lymphoid organs, we immunized mice and analyzed the CD4+ Treg frequency and phenotype in draining lymph nodes and spleen. Vaccination resulted in a transient local decrease in Treg frequency in lymph nodes, followed by a systemic Treg increase in the spleen. Taken together, we showed that vaccination with vaccines with an already established safe profile have only minimal impact on frequencies and characteristics of Treg over time. These findings may serve as a bench-mark of inter-individual variation of Treg frequencies and phenotypes following vaccination.

Regulatory T-cells promote hepatitis B virus infection and hepatocellular carcinoma progression

Regulatory T-cells (Tregs), known for their immune suppressive function, have been reported in higher numbers, with activated phenotypes and greater potency, in hepatitis B virus (HBV)-related liver diseases than in normal conditions. The numbers, phenotypes, and function of intrahepatic and/or tumor-infiltrating Tregs in HBV-related liver diseases also differ from those of Tregs in the peripheral blood. By inhibiting the function of effector T-cells (Teffs), Tregs play a substantial role in the formation and maintenance of the liver's suppressive microenvironment, which might account for the progression of HBV-related hepatitis and hepatocellular carcinoma (HCC). In acute hepatitis B virus infection, Tregs can safeguard the liver from damage at the cost of prolonged antiviral processes, which results in chronic HBV infection in the liver. Furthermore, Tregs play a role in the development of cirrhosis, the transformation of cirrhosis to HCC, and the progression and metastasis of HCC. Higher levels of Tregs in the peripheral blood and/or tumor sites signify a poorer prognosis in HBV-related liver conditions, and observational data from mouse models and human patients support the theory that depleting Tregs may be therapeutic in HBV-related liver diseases by inducing antiviral and antitumor immunity.

Risk factors for deep sternal wound infection after cardiac surgery: Influence of red blood cell transfusions and chronic infection

BACKGROUND

Deep sternal wound infection (DSWI) following cardiac surgery is a serious complication, but risk factors associated with DSWI have not been fully elucidated.

METHODS

We analyzed all DSWI cases at our institution from 2010-2013 in adult cardiac median sternotomy cases, based on Society of Thoracic Surgeons or National Healthcare Safety Network definitions, but with 1-year surveillance postsurgery. Controls were matched 3:1 per case for procedure, age, and year of surgery. Demographic and operative data were pulled from Society of Thoracic Surgeons database and chart review. Potential variables were evaluated using univariate and multivariate conditional logistic regression.

RESULTS

Out of 1,894 surgeries performed, 39 DSWI cases (2%) and 117 controls were identified. In univariate analyses, patients with red blood cell (RBC) transfusion ≥ 4 units, any platelet transfusion, previous infections, and chronic infections were associated with higher DSWI. RBC transfusion ≥ 4 units (P = .037) and chronic infections (P = .029) remained significant risk factors for DSWI in multivariate analysis. Preoperative anemia alone was not associated with more DSWI, but its interaction with RBC transfusion ≥ 4 units was significant.

CONCLUSIONS

High-volume RBC transfusions and chronic infections were strongly associated with DSWI in our population and represent potentially modifiable areas for improvement.

Hepatic expansion of virus-specific CD8+BTLA+ T cells with regulatory properties in chronic hepatitis B virus infection

Similar to programmed death-1 (PD-1), B and T lymphocyte attenuator (BTLA) is a co-inhibitory molecule of the CD28 family. PD-1 is involved in T cell exhaustion during chronic viral infection. However, the role of BTLA in virus-specific T cells is poorly defined. Here we investigated the expression and function of BTLA in T cells from patients with chronic hepatitis B virus (HBV) infection. The phenotype of peripheral and intrahepatic HBV-specific T cells from 43 patients with chronic HBV infection was assessed by flow cytometry. Functional evaluation was analyzed by T cell expansion and cytokine secretion after different treatments. In chronic HBV patients, a subset of inefficient interferon-γ producing antigen-specific CD8⁺ T cells recruited to the liver expressed high BTLA levels. The BTLA⁺ HBV-specific CD8⁺ T cell suppressive function was antigen-specific, at least in the induction phase, because they were only activated by a pool of HBV peptides but not with a pool of unrelated peptides. Suppression of T cell responses was restored by a BTLA signaling blockade and neutralizing IL-10, indicating that BTLA signaling-mediated IL-10 secretion plays a key role in suppression. This study provides important evidence that there is a subset of liver infiltrated virus-specific CD8⁺BTLA⁺ regulatory T cells in patients with chronic HBV infection. This subset of cells plays a pivotal role in controlling hepatic effector CD8⁺ T cell responses through BTLA signaling mediated regulatory factor IL-10 production.

Adaptive immunity in the liver

The anatomical architecture of the human liver and the diversity of its immune components endow the liver with its physiological function of immune competence. Adaptive immunity is a major arm of the immune system that is organized in a highly specialized and systematic manner, thus providing long-lasting protection with immunological memory. Adaptive immunity consists of humoral immunity and cellular immunity. Cellular immunity is known to have a crucial role in controlling infection, cancer and autoimmune disorders in the liver. In this article, we will focus on hepatic virus infections, hepatocellular carcinoma and autoimmune disorders as examples to illustrate the current understanding of the contribution of T cells to cellular immunity in these maladies. Cellular immune suppression is primarily responsible for chronic viral infections and cancer. However, an uncontrolled auto-reactive immune response accounts for autoimmunity. Consequently, these immune abnormalities are ascribed to the quantitative and functional changes in adaptive immune cells and their subsets, innate immunocytes, chemokines, cytokines and various surface receptors on immune cells. A greater understanding of the complex orchestration of the hepatic adaptive immune regulators during homeostasis and immune competence are much needed to identify relevant targets for clinical intervention to treat immunological disorders in the liver.

The immune system in hepatocellular carcinoma and potential new immunotherapeutic strategies

BACKGROUND

Hepatocellular carcinoma is a major health problem worldwide and the third most common cause of cancer-related death. HCC treatment decisions are complex and dependent upon tumor staging. Several molecular targeted agents have been evaluated in clinical trials in advanced HCC. Despite of only modest objective response rates according to the Response Evaluation Criteria in Solid Tumors, several studies showed encouraging results in terms of prolongation of the time to progression, disease stabilization, and survival. Cellular immunotherapy would improve the immune state and has potential in enhancing the therapeutic outcome for HCC patients.

MATERIALS AND METHODS

A search of the literature was made using cancer literature, the PubMed, Scopus, and Web of Science (WOS) database for the following keywords: "hepatocellular carcinoma," "molecular hepatocarcinogenesis," "targeted therapy," "molecular immunological targets," "tumour-associated antigens," "Tregs," "MDSCs," "immunotherapy."

DISCUSSION AND CONCLUSION

Treatment strategies combining blockade of immunoregulatory cell types such as Tregs and MDSCs and of inhibitory receptors, with vaccine-induced activation of TAA-specific T cells, may be necessary to achieve the most effective therapeutic antitumour activity in HCC. In the future, new therapeutic options will be represented by a blend of immunotherapy-like vaccines and T-cell modulators, supplemented by molecularly targeted inhibitors of tumor signaling pathways.

Amphiregulin promotes the immunosuppressive activity of intrahepatic CD4+ regulatory T cells to impair CD8+ T-cell immunity against hepatitis B virus infection

Hepatitis B virus (HBV) infection causes liver diseases and hepatocellular carcinoma. Immunotolerance in HBV-infected patients is one of the factors that incur failure of HBV clearance and persistent HBV amplification. However, the mechanisms underlying immunotolerance after HBV infection are yet to be thoroughly understood. Using a novel HBV mouse model, we found for the first time that epidermal growth factor receptor (EGFR) is up-regulated on intrahepatic regulatory T (Treg) cells in HBV-infected mouse livers. The EGFR-positive Treg cells are more immunosuppressive than EGFR-negative Treg cells, demonstrated by higher expression of immunosuppressive cytokines and robust inhibition of CD8⁺ T-cell proliferation in vitro. Furthermore, EGFR-positive Treg cells potently restrain CD8⁺ T-cell-mediated anti-viral activity, leading to higher HBV burden in hepatocytes. Amphiregulin, a cytokine of the EGF family, is significantly up-regulated in HBV-infected livers, but the cellular sources of amphiregulin are still elusive. Amphiregulin promotes the immunosuppressive activity of EGFR-positive Treg cells in vitro, so as to profoundly inhibit production of anti-viral components in CD8⁺ T cells. Taken together, our discovery elucidated a novel mechanism contributing to immunotolerance and viral amplification after HBV infection. Our study may provide new clues for developing therapeutic strategies against HBV infection.

Contradictory immune response in post liver transplantation hepatitis B and C

Hepatitis B and C often progress to decompensated liver cirrhosis requiring orthotopic liver transplantation (OLT). After OLT, hepatitis B recurrence is clinically controlled with a combination of hepatitis B immunoglobulin (HBIG) and nucleos(t)ide analogues. Another approach is to induce self-producing anti-hepatitis B virus (HBV) antibodies using a HBV envelope antigen vaccine. Patients who had not been HBV carriers such as acutely infected liver failure or who received liver from HBV self-limited donor are good candidate. For chronic HBV carrier patients, a successful response can only be achieved in selected patients such as those treated with experimentally reduced immunosuppression protocols or received an anti-HBV adaptive memory carrying donor liver. Hepatitis C virus (HCV) reinfects transplanted livers at a rate of >90%. HCV reinfected patients show different severities of hepatitis, from mild and slowly progressing to severe and rapidly progressing, possibly resulting from different adaptive immune responses. More than half the patients require interferon treatment, although the success rate is low and carries risks for leukocytopenia and rejection. Managing the immune response has an important role in controlling recurrent hepatitis C. This study aimed to review the adaptive immune response in post-OLT hepatitis B and C.

The effect of citrus peel extracts on cytokines levels and T regulatory cells in acute liver injury

Background. T cell-mediated immune responses contribute to the hepatocellular injury during autoimmune hepatitis, viral infection, and hepatotoxins. Pharmacological compounds regulating immune responses are suitable candidates for prevention/treatment of this pathology. Therefore, the main aim of this study was to define the effects of antioxidant, anti-inflammatory mixture of citrus peel extract (CPE) on the immune-mediated liver injury. Methods. The influence of CPE on liver injury was determined by the activity of transaminases in plasma and the histological changes. Anti-inflammatory and antioxidant effects were studied by measuring frequency of T regulatory cells (Tregs), cytokines (TNF-α, IL-10, and IFN-γ), and nitric oxide levels. Results. The CPE application notably prevents development of liver injury through decreasing levels of both cytokines (TNF-alpha, INF) and regulatory T cells and increasing levels of IL-10. CPE injection also diminished the serum NO, which in turn resulted in evident reduction of the liver damage. Conclusion. Our findings represent the primary preclinical data indicating that the CPE in vivo could ameliorate Con A induced hepatitis. The low dose of CPE most likely can be used for the treatment of the T cell-mediated liver injury as in autoimmune hepatitis, alcoholic hepatitis, and chronic viral hepatitis.

Hepatocellular carcinoma: novel molecular targets in carcinogenesis for future therapies

BACKGROUND

Hepatocellular carcinoma is one of the most common and lethal malignant tumors worldwide. Over the past 15 years, the incidence of HCC has more than doubled. Due to late diagnosis and/or advanced underlying liver cirrhosis, only limited treatment options with marginal clinical benefit are available in up to 70% of patients. During the last decades, no effective conventional cytotoxic systemic therapy was available contributing to the dismal prognosis in patients with HCC. A better knowledge of molecular hepatocarcinogenesis provides today the opportunity for targeted therapy.

MATERIALS AND METHODS

A search of the literature was made using cancer literature, the PubMed, Scopus, and Web of Science (WOS) database for the following keywords: "hepatocellular carcinoma," "molecular hepatocarcinogenesis," "targeted therapy," and "immunotherapy."

DISCUSSION AND CONCLUSION

Treatment decisions are complex and dependent upon tumor staging, presence of portal hypertension, and the underlying degree of liver dysfunction. The knowledge of molecular hepatocarcinogenesis broadened the horizon for patients with advanced HCC. During the last years, several molecular targeted agents have been evaluated in clinical trials in advanced HCC. In the future, new therapeutic options will be represented by a blend of immunotherapy-like vaccines and T-cell modulators, supplemented by molecularly targeted inhibitors of tumor signaling pathways.

Frequency of regulatory T-cell and hepatitis C viral antigen-specific immune response in recurrent hepatitis C after liver transplantation

INTRODUCTION

Regulatory T (Treg) and type 1 regulatory T (Tr1) cells facilitate hepatitis C virus (HCV) recurrence after orthotopic liver transplantation (OLT). However, their frequencies and effects on HCV-specific immune responses have not been well investigated.

METHODS

We determined Treg and Tr1 frequencies in OLT patients with hepatitis C and assessed their associations with HCV-specific T cell responses. These patients comprised the following groups: an early post-transplantation group (n=14); an OLT-chronic active hepatitis C group (n=14) with active hepatitis C (alanine aminotransferase of>upper limit of normal/positive for HCV-RNA); an OLT-persistently normal alanine aminotransferase group (n=12) without active hepatitis C (not interferon/positive for HCV-RNA); and an OLT-sustained viral response group (n=6) with sustained viral responses using interferon treatment (negative for HCV-RNA). The frequencies of HCV-specific CD4+ T cells that secreted interferon-γ were determined by enzyme-linked immunosorbent spot assay (except for the OLT early group).

RESULTS

Treg and Tr1 frequencies were low during the early post-transplantation period. OLT patients with sustained viral responses had lower Treg frequencies than those with chronic hepatitis C, whereas Tr1 frequencies were significantly reduced in OLT patients with persistently normal alanine aminotransferase levels compared to those with chronic hepatitis C (p<0.05). Treg frequencies positively correlated with HCV NS3 antigen-specific interferon-γ responses, which corresponded to HCV clearance.

CONCLUSIONS

Increased Treg frequencies and reduced HCV-NS3 antigen-specific responses recovered after viral eradication in post-OLT chronic hepatitis C patients. Reduced Tr1 frequencies were associated with hepatitis activity control, which may facilitate controlling chronic hepatitis C in patients after OLT.

Systemic therapies in hepatocellular carcinoma: present and future

Hepatocellular carcinoma (HCC) is now the third leading cause of cancer deathsworldwide and is generally presented at an advanced stage, limiting patients' quality of life. The conventional cytotoxic systemic therapy has proved to be ineffective in HCC, since its induction several decades ago. Today it is possible to use our knowledge of molecular hepatocarcinogenesis to provide a targeted therapy. Sorafenib has demonstrated large improvements in overall survival in HCC. This review describes the molecular mechanisms and potential therapeutic targets, focusing on sorafenib, sunitinib, tivantinib, antiangiogenic agents, and current and future immunotherapies. Thus, it will be necessary in the future to classify HCCs into subgroups according to their genomic and proteomic profiling. The identification of key molecules/receptors/signaling pathways and the assessment of their relevance as potential targets will be the main future challenge potentially influencing response to therapy. Defining molecular targeted agents that are effective for a specific HCC subgroup will hopefully lead to personalized therapy.

Quantification of hepatic FOXP3+ T-lymphocytes in HIV/hepatitis C coinfection

Coinfection with HIV adversely impacts every stage of hepatitis C (HCV) infection. Liver damage in HCV infection results from host antiviral responses rather than direct viral pathogenesis. Despite depressed cellular immunity, coinfected patients show accelerated hepatic fibrosis compared with HCV monoinfected patients. This paradox is poorly understood. T-regulatory (Treg) cells (CD4+ and FOXP3+) are hypothesized to limit hepatic damage in HCV. Our hypothesis was that reduced frequency of hepatic Treg in HIV/HCV coinfection compared with HCV monoinfection may explain poorer outcomes. We quantified FOXP3+, CD4+, CD8+ and CD20+ cells in liver biopsies of 35 male subjects matched by age and ISHAK fibrosis score, 12 HIV monoinfected, 11 HCV monoinfected and 12 HIV/HCV coinfected. Cell counts were performed using indirect immunohistochemical staining and light microscopy. HIV/HCV coinfected subjects had fewer hepatic FOXP3+ (P = 0.031) and CD4+ cells (P = 0.001) than HCV monoinfected subjects. Coinfected subjects had more hepatic CD8+ cells compared with HCV monoinfected (P = 0.023), and a lower ratio of FOXP3+ to CD8+ cells (0.08 vs 0.27, P < 0.001). Multivariate analysis showed number of CD4+ cells controlled for differences in number of FOXP3+ cells. Fewer hepatic FOXP3+ and CD4+ cells in HIV/HCV coinfection compared with HCV monoinfection suggests lower Treg activity, driven by an overall loss of CD4+ cells. Higher number of CD8+ cells in HIV/HCV coinfection suggests higher cytotoxic activity. This may explain poorer outcomes in HIV/HCV coinfected patients and suggests a potential mechanism by which highly active antiretroviral therapy may benefit these patients.

Assembly of human organs from stem cells to study liver disease

Recently, significant developments in the field of liver tissue engineering have raised new possibilities for the study of complex physiological and pathophysiological processes in vitro, as well as the potential to assemble entire organs for transplantation. Human-induced pluripotent stem cells have been differentiated into relatively functional populations of hepatic cells, and novel techniques to generate whole organ acellular three-dimensional scaffolds have been developed. In this review, we highlight the most recent advances in organ assembly regarding the development of liver tissue in vitro. We emphasize applications that involve multiple types of cells with a biomimetic spatial organization for which three-dimensional configurations could be used for drug development or to explain mechanisms of disease. We also discuss applications of liver organotypic surrogates and the challenges of translating the highly promising new field of tissue engineering into a proven platform for predicting drug metabolism and toxicity.

CD4 T cell responses in latent and chronic viral infections

The spectrum of tasks which is fulfilled by CD4 T cells in the setting of viral infections is large, ranging from support of CD8 T cells and humoral immunity to exertion of direct antiviral effector functions. While our knowledge about the differentiation pathways, plasticity, and memory of CD4 T cell responses upon acute infections or immunizations has significantly increased during the past years, much less is still known about CD4 T cell differentiation and their beneficial or pathological functions during persistent viral infections. In this review we summarize current knowledge about the differentiation, direct or indirect antiviral effector functions, and the regulation of virus-specific CD4 T cells in the setting of persistent latent or active chronic viral infections with a particular emphasis on herpes virus infections for the former and chronic lymphocytic choriomeningitis virus infection for the latter.

T-cell responses in hepatitis B and C virus infection: similarities and differences

Chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infection are global health problems affecting 600 million people worldwide. Indeed, HBV and HCV are hepatotropic viruses that can cause acute and chronic liver disease progressing to liver cirrhosis and even hepatocellular carcinoma. Furthermore, co-infections of HBV and HCV with HIV are emerging worldwide. These co-infections are even more likely to develop persistent infection and are difficult to treat. There is growing evidence that virus-specific CD4⁺ and CD8⁺ T-cell responses play a central role in the outcome and pathogenesis of HBV and HCV infection. While virus-specific T-cell responses are able to successfully clear the virus in a subpopulation of patients, failure of these T-cell responses is associated with the development of viral persistence. In this review article, we will discuss similarities and differences in HBV- and HCV-specific T-cell responses that are central in determining viral clearance, persistence and liver disease.

Hepatitis B surface antigen could contribute to the immunopathogenesis of hepatitis B virus infection

Various findings concerning the clinical significance of quantitative changes in hepatitis B surface antigen (HBsAg) during the acute and chronic phase of hepatitis B virus (HBV) infection have been reported. In addition to being a biomarker of HBV-replication activity, it has been reported that HBsAg could contribute to the immunopathogenesis of HBV persistent infection. Moreover, HBsAg could become an attractive target for immune therapy, since the cellular and humeral immune response against HBsAg might be able to control the HBV replication and life cycle. However, several reports have described the immune suppressive function of HBsAg. HBsAg might suppress monocytes, dendritic cells (DCs), natural killer (NK), and natural killer T (NK-T) cells by direct interaction. On the other hand, cytotoxic T lymphocytes (CTLs) and helper T (Th) cells were exhausted by high amounts of HBsAg. In this paper, we focused on the immunological aspects of HBsAg, since better understanding of the interaction between HBsAg and immune cells could contribute to the development of an immune therapy as well as a biomarker of the state of HBV persistent infection.

Major challenges limiting liver transplantation in the United States

Liver transplantation is the gold standard of care in patients with end-stage liver disease and those with tumors of hepatic origin in the setting of liver dysfunction. From 1988 to 2009, liver transplantation in the United States grew 3.7-fold from 1713 to 6320 transplants annually. The expansion of liver transplantation is chiefly driven by scientific breakthroughs that have extended patient and graft survival well beyond those expected 50 years ago. The success of liver transplantation is now its primary obstacle, as the pool of donor livers fails to keep pace with the growing number of patients added to the national liver transplant waiting list. This review focuses on three major challenges facing liver transplantation in the United States and discusses new areas of investigation that address each issue: (1) the need for an expanded number of useable donor organs, (2) the need for improved therapies to treat recurrent hepatitis C after transplantation and (3) the need for improved detection, risk stratification based upon tumor biology and molecular inhibitors to combat hepatocellular carcinoma.

Cumulative Epigenetic Abnormalities in Host Genes with Viral and Microbial Infection during Initiation and Progression of Malignant Lymphoma/Leukemia

Although cancers have been thought to be predominantly driven by acquired genetic changes, it is becoming clear that microenvironment-mediated epigenetic alterations play important roles. Aberrant promoter hypermethylation is a prevalent phenomenon in human cancers as well as malignant lymphoma/leukemia. Tumor suppressor genes become frequent targets of aberrant hypermethylation in the course of gene-silencing due to the increased and deregulated DNA methyltransferases (DNMTs). The purpose of this article is to review the current status of knowledge about the contribution of cumulative epigenetic abnormalities of the host genes after microbial and virus infection to the crisis and progression of malignant lymphoma/leukemia. In addition, the relevance of this knowledge to malignant lymphoma/leukemia assessment, prevention and early detection will be discussed.