Hepatitis C virus-mediated modulation of cellular immunity

Central Nervous System Histoplasma-Associated Post-infectious Inflammatory Response Syndrome (Histo-PIIRS)

We present a case of central nervous system (CNS) histoplasmosis in a previously healthy adult with hepatitis C (HCV) presenting with neurological symptoms refractory to antifungal therapy and ventriculoperitoneal (VP) shunting 4 months after initial diagnosis. Persistent symptoms were thought to be inflammatory rather than infectious given negative cerebrospinal fluid (CSF) and serum fungal antigens. The patient promptly improved after initiation of corticosteroid therapy. Elevated CSF cytokines and regional enhancement on brain MRI resolved with corticosteroid treatment. This is the first case of Histoplasma-associated post-infectious inflammatory response syndrome (Histo-PIIRS) documented by CSF cytokine reduction in response to corticosteroid therapy.

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.

Sustained viral response and treatment-induced cytopenia correlate with SLCs and KLF12 genotypes in interferon/ribavirin-treated Chinese chronic hepatitis C patients

BACKGROUND AND AIM

Genetic variations in solute carrier (SLC) genes are associated with liver diseases, and Kruppel-like factor 12 (KLF12) affects the b chain of hemoglobin. We investigated possible correlations of SLC and KLF12 polymorphisms with viral clearance (spontaneous and treatment-induced) and adverse effects in Chinese chronic hepatitis C (CHC) patients.

METHODS

We genotyped the single nucleotide polymorphisms in 525 CHC patients, 137 patients with spontaneous clearance, and 207 healthy controls. Three hundred fifty-seven CHC patients received recombinant interferon-alpha2b/ribavirin (IFN-α2b/RBV) treatment, and 175 patients were chosen for analysis of drug-induced cytopenia. All raw P-values were corrected by the Bonferroni method.

RESULTS

A higher rate of sustained viral response was detected in patients with SLC4A11 rs3810560 CC variant versus TT/TC variant (76.9% vs 59.2%; OR, 2.42; 95% CI, 1.06-5.56, P = 0.037 after adjustment), but there was no significant difference among different hepatitis C virus genotypes. RBV-induced anemia was independently correlated with SLC29A1 rs760370 AA genotype (OR, 2.90; 95% CI, 1.29-6.54, P = 0.010), and the severity of IFN-induced thrombocytopenia was related to GG genotype (OR, 4.98; 95% CI, 1.27-19.61; P = 0.021); the detected effects held true for HCV-2a patients but weakened in HCV-1b patients. A reactive increase in platelet count was closely associated with KLF12 rs9543524 TT variant.

CONCLUSION

SLC4A11 rs3810560 polymorphism independently affected the sustained viral response rates in CHC patients, whereas SLC29A1 rs760370 and KLF12 rs9543524 single nucleotide polymorphisms correlated with treatment-induced adverse events. Clearly, the predictive power varied with HCV genotypes and the reason for genotype-dependent discrepancy was not fully understood.

Ocular surface and tear parameters in patients with chronic hepatitis C at initial stages of hepatic fibrosis

PURPOSE

The aim of this study was to evaluate changes in ocular surface and tear function parameters in chronic hepatitis C at initial stages of hepatic fibrosis.

METHODS

Thirty-one patients with biopsy-proven chronic hepatitis C and 31 age- and sex-matched healthy control subjects without systemic hepatitis C infection were examined with the Ocular Surface Disease Index (OSDI) questionnaire, Schirmer I, tear film break-up time, and scoring of ocular surface fluorescein and Rose Bengal staining using modified Oxford and van Bijsterveld scoring systems, respectively.

RESULTS

All ocular surface parameters, except OSDI and corneal staining scores, were significantly worse in hepatitis C group. The control group had greater OSDI scores than the hepatitis C group, but there was no statistically important difference. In subgroup analysis, progression of hepatic fibrosis was found to be correlated strongly with decreased Schirmer test I, increased OSDI, lid parallel conjunctival folds, conjunctival, and corneal staining scores.

CONCLUSION

Patients with chronic hepatitis C were more likely to exhibit severe ocular surface damage and signs of dry eye.

Oral anti-CD3 immunotherapy for HCV-nonresponders is safe, promotes regulatory T cells and decreases viral load and liver enzyme levels: results of a phase-2a placebo-controlled trial

Orally administered anti-CD3 antibodies are biologically active in the gut through induction of regulatory T cells, exert an immune-modulatory effect, and alleviate insulin resistance and liver damage in patients with NASH.

AIMS

To determine the safety of oral anti-CD3 monoclonal antibody (MAb) immunotherapy in chronic HCV patients with associated immune dysfunction.

METHODS

Four groups (n = 9) of chronic HCV patients who were nonresponders to interferon plus ribavirin therapy received oral placebo (group A) or anti-CD3 MAb at one of three dosage levels for 30 days. Patients were followed for safety parameters and serum levels of liver enzymes, virus, cytokines and regulatory T cells.

RESULTS

Oral anti-CD3 immunotherapy was safe and well tolerated; no treatment-related adverse events were noted. The following improvements were noted relative to pretreatment levels: HCV viral load and AST and ALT levels decreased in the low- and high-dose groups following 30 days of therapy. In two of the treated groups, an increase in regulatory T cells (CD4(+) CD25(+) ) was noted. The positive effects were somewhat more apparent in subjects with initially elevated liver enzyme levels.

CONCLUSIONS

Oral anti-CD3 MAb immunotherapy for nonresponder HCV patients was safe and well tolerated. Trends and statistically significant improvements were observed as reductions in viral load and liver enzyme levels, along with an increase in regulatory T-cell levels. These data support a role for the immune system in the pathogenesis of HCV infection and suggest that this immunotherapy is worthy of evaluation in combination with HCV antiviral drugs.

Genetic (KIR, HLA-C) and Some Clinical Parameters Influencing the Level of Liver Enzymes and Early Virologic Response in Patients with Chronic Hepatitis C

Natural killer cells play an important role as effectors of innate immunity and regulators of adaptive immunity. They are important elements of the innate response to viral infections, which they detect using human leukocyte antigen (HLA) class I-binding receptors. Most polymorphic of these are killer cell immunoglobulin-like receptors (KIRs) which exist as two basic isotypes, activating or inhibitory receptors and are encoded by genes distributed differently in unrelated individuals. We searched for links between selected clinical data (including HCV viremia, liver enzymes level and liver histology parameters) and the presence of genes encoding these receptors and their ligands in hepatitis C virus-infected individuals subjected to pegylated interferon-α and ribavirin therapy. Genomic DNA samples from two hundred and ninety-two chronically infected patients were typed by polymerase chain reaction for the presence or absence of genes for KIRs and their ligands, class I HLA molecules, and clinical data of the patients were collected. Our results suggest an importance of clinical parameters and the contribution of KIR and HLA genes to the course of hepatitis C virus infection and the response to therapy. The study revealed that levels of liver enzymes before therapy were about 30 % higher in patients who possessed a variant KIR2DS4 gene with 22-base pair deletion. Decrease of ALT activity after treatment was higher in HLA-C C2-positive than negative individuals. Beside it, patients demonstrated early virologic response to the therapy if the time lag before treatment was short, particularly in women.

CD24 Ala57Val polymorphism is associated with spontaneous viral clearance in the HCV-infected Chinese population

BACKGROUND & AIMS

Host immune response to hepatitis C virus (HCV) is a vital factor involved in both viral clearance and liver disease pathogenesis. CD24 plays an important role in inflammation and immune response and CD24 polymorphisms are associated with risk and progression of chronic hepatitis B virus infection. Our study evaluated whether CD24 polymorphisms affect HCV clearance.

METHODS

We genotyped 544 chronic hepatitis C (CHC) patients, 78 spontaneous hepatitis C clearance (SHC) patients and 215 healthy controls for CD24 gene variants at positions -P534, P170, P1527 and IFNL3 rs12979860 by pyrosequencing. In CHC patients, 362 individuals were treated with a recombinant IFN-α2b/ribavirin combination for 48 weeks and were followed up for an additional 24 weeks. Lymphocyte CD24 expression was analysed by flow cytometry.

RESULTS

We show that P170 CT and CT/TT genotypes were over-represented in the SHC group compared to CHC patients (62.8% vs. 47.2% and 75.6% vs. 60.3%, for respective polymorphisms). In multivariate logistic analysis, P170 (CD24 Ala57Val) polymorphism was an independent predictor of SHC (adjusted OR = 2.11, 95%CI = 1.19-3.73, P = 0.010 for CT genotype; OR = 2.01, 95%CI = 1.15-3.49, P = 0.014 for CT/TT genotype). No significant associations were found between the CD24 polymorphisms and treatment-induced viral clearance in log-rank analysis and Cox regression analysis. Patients with the CT/TT genotype had greater T-cell CD24 expression than patients with the CC genotype.

CONCLUSIONS

Our findings suggest that CD24 Ala57Val polymorphism and associated variations in CD24 expression may be an important predictor for SHC, but have no effect on antiviral drug treatment response in Chinese CHC patients.

Long-term follow-up of successful hepatitis C virus therapy: waning immune responses and disappearance of liver disease are consistent with cure

BACKGROUND

A sustained viral response (SVR) after interferon-based therapy of chronic hepatitis C virus (HCV) infection is regarded to represent a cure. Previous studies have used different markers to clarify whether an SVR truly represents a cure, but no study has combined a clinical work-up with highly sensitive HCV RNA detection, and the determination of immune responses.

AIM

To determine clinical, histological, virological and immunological markers 5-20 years after SVR.

METHODS

In 54 patients, liver biochemistry, histology and elastography were evaluated. Liver biopsies, plasma and peripheral blood mononuclear cells (PBMCs) were tested for minute amounts of HCV RNA. HCV-specific T-cell responses were monitored by ELISpot and pentamer staining, and humoral responses by measuring HCV nonstructural (NS)3-specific antibodies and virus neutralisation.

RESULTS

Liver disease regressed significantly in all patients, and 51 were HCV RNA-negative in all tissues tested. There was an inverse association between liver disease, HCV-specific T-cell responses and HCV antibody levels with time from SVR, supporting that the virus had been cleared. The three patients, who all lacked signs of liver disease, had HCV RNA in PBMCs 5-9 years after SVR. All three had HCV-specific T cells and NS3 antibodies, but no cross-neutralising antibodies.

CONCLUSIONS

Our combined data confirm that a SVR corresponds to a long-term clinical cure. The waning immune responses support the disappearance of the antigenic stimulus. Transient HCV RNA traces may be detected in some patients up to 9 years after SVR, but no marker associates this with an increased risk for liver disease.

Contribution of genes for killer cell immunoglobulin-like receptors (KIR) to the susceptibility to chronic hepatitis C virus infection and to viremia

BACKGROUND

Natural killer (NK) cells are an important element of innate immunity against viruses, although their numbers decrease in the liver during chronic HCV infection. NK cells express a large panel of inhibitory and activating receptors. The most polymorphic of these are killer cell immunoglobulin-like receptors (KIRs) which are encoded by multiple genes that may be present or absent in given individuals depending on their genotype. This variability results in differential susceptibility to viral infections and diseases, including HCV infection and its consequences.

AIMS AND METHODS

The aim of this study was to test whether chronical infection with HCV and the viremia levels are associated with any KIR gene in the Polish population. We typed 301 chronically HCV-infected patients and 425 non-infected healthy individuals for the presence or absence of KIR genes and their ligands, HLA-C C1 and C2 groups as well as HLA-B and HLA-A Bw4-positive alleles.

RESULTS

We found that males, but not females, possessing KIR2DS2 and KIR2DL2 genes had a 1.7 higher probability to become chronically HCV-infected than males negative for these genes (p=0.0213). In accord with this, centromeric B region, containing KIR2DS2 and KIR2DL2 genes, was also associated with chronic HCV infection in males. In addition, patients of both genders possessing KIR2DS3 but not KIR2DS5 gene exhibited, on average, 2.6 lower level of viremia than HCV-infected individuals with other genotypes (p=0.00282). This was evident in those infected at a young age. KIR2DS3-positive patients also had lower mean levels of bilirubin than KIR2DS3-negative ones (p=0.02862).

CONCLUSION

Our results suggest a contribution of the KIR2DS2 and KIR2DL2 genes (cenB haplotype) to the susceptibility to chronic HCV infection, and an association of the KIR2DS3 gene in the absence of KIR2DS5 with low viremia levels.

Detection and significance of cytotoxic cell subsets in biopsies of HCV-infected human livers

Chronic viral hepatitis C still remains the clinical challenge. Attempts of the immune system to cope with this infection are unsatisfactory. There is a conviction that the main site of interaction between virus (Hepatitis C virus, HCV) and immune system is in situ, i.e., in liver. Natural killer (NK) cells appeared relevant in the acute hepatitis. Less is known about the immune response in the chronic HCV infection. The aim of this study was to evaluate the prevalence of various cytotoxic cell subsets in chronic HCV⁺ liver tissue and to seek links between them and laboratory data of patients. Sections from paraffin blocks of liver biopsy tissues of HCV⁺ untreated patients were subjected to the reaction with antibodies vs. cytotoxic cell subsets and immunohistochemistry. Positive cells were searched in cellular infiltrates in portal areas and in liver parenchyma. They were classified on the “Yes” or “No” basis. Majority of liver biopsies exhibited cellular infiltrates in portal spaces and as single cells in liver parenchyma. Infiltrates consisted of CD8⁺ T cells, CD56⁺ NK ones, including CD158i⁺ and CD158b⁺. The latter were rarely seen. There were also granzyme B⁺ cells. The most abundant were NKG2D⁺ cells, much more common than NK CD56⁺ ones. It implied that NKG2D was also expressed on T cells. Prevalence of NKG2D⁺ cells correlated with high activity of liver enzymes such as alanine aminotransferase, aspartate aminotransferase and a greater histological severity of liver injury. NKG2D⁺ cells form the bulk of cells infiltrating HCV-infected human liver. Correlation of NKG2D⁺ cells with some laboratory parameters of patients suggests their role in hepatitis C pathogenesis.

Innate immune cell networking in hepatitis C virus infection

Persistent viral infection, such as HCV infection, is the result of the inability of the host immune system to mount a successful antiviral response, as well as the escape strategies devised by the virus. Although each individual component of the host immune system plays important roles in antiviral immunity, the interactive network of immune cells as a whole acts against the virus. The innate immune system forms the first line of host defense against viral infection, and thus, virus elimination or chronic HCV infection is linked to the direct outcome of the interactions between the various innate immune cells and HCV. By understanding how the distinct components of the innate immune system function both individually and collectively during HCV infection, potential therapeutic targets can be identified to overcome immune dysfunction and control chronic viral infection.

The role of chemokines in hepatitis C virus-mediated liver disease

The hepatitis C virus (HCV) is a global health problem affecting more than 170 million people. A chronic HCV infection is associated with liver fibrosis, liver cirrhosis and hepatocellular carcinoma. To enable viral persistence, HCV has developed mechanisms to modulate both innate and adaptive immunity. The recruitment of antiviral immune cells in the liver is mainly dependent on the release of specific chemokines. Thus, the modulation of their expression could represent an efficient viral escape mechanism to hamper specific immune cell migration to the liver during the acute phase of the infection. HCV-mediated changes in hepatic immune cell chemotaxis during the chronic phase of the infection are significantly affecting antiviral immunity and tissue damage and thus influence survival of both the host and the virus. This review summarizes our current understanding of the HCV-mediated modulation of chemokine expression and of its impact on the development of liver disease. A profound knowledge of the strategies used by HCV to interfere with the host's immune response and the pro-fibrotic and pro-carcinogenic activities of HCV is essential to be able to design effective immunotherapies against HCV and HCV-mediated liver diseases.

Cleavage of the T cell protein tyrosine phosphatase by the hepatitis C virus nonstructural 3/4A protease induces a Th1 to Th2 shift reversible by ribavirin therapy

Ribavirin has proven to be a key component of hepatitis C therapies both involving IFNs and new direct-acting antivirals. The hepatitis C virus-mediated interference with intrahepatic immunity by cleavage of mitochondrial antiviral signaling protein (MAVS) and T cell protein tyrosine phosphatase (TCPTP) suggests an avenue for compounds that may counteract these effects. We therefore studied the effects of ribavirin, with or without inhibition of the nonstructural (NS)3/4A protease, on intrahepatic immunity. The intrahepatic immunity of wild-type and NS3/4A-transgenic mice was determined by Western blot, ELISA, flow cytometry, and survival analysis. Various MAVS or TCPTP constructs were injected hydrodynamically to study their relevance. Ribavirin pretreatment was performed in mice expressing a functional or inhibited NS3/4A protease to analyze its effect on NS3/4A-mediated changes. Intrahepatic NS3/4A expression made mice resistant to TNF-α-induced liver damage and caused an alteration of the intrahepatic cytokine (IFN-γ and IL-10) and chemokine (CCL3, CCL17, CCL22, CXCL9, and CXCL11) profiles toward an anti-inflammatory state. Consistent with this, the number of intrahepatic Th1 cells and IFN-γ(+) T cells in NS3/4A-transgenic mice decreased, whereas the amount of Th2 cells increased. These effects could be reversed by injection of uncleavable TCPTP but not uncleavable MAVS and were absent in a mouse expressing a nonfunctional NS3/4A protease. Importantly, the NS3/4A-mediated effects were reversed by ribavirin treatment. Thus, cleavage of TCPTP by NS3/4A induces a shift of the intrahepatic immune response toward a nonantiviral Th2-dominated immunity. These effects are reversed by ribavirin, supporting that ribavirin complements the effects of direct-acting antivirals as an immunomodulatory compound.

Containing "The Great Houdini" of viruses: combining direct acting antivirals with the host immune response for the treatment of chronic hepatitis C

Presently the development of new therapies for hepatitis C virus (HCV) is rapidly moving forward. Almost every week new data appear on how direct acting antivirals (DAAs) succeed or fail in clinical trials. Despite the potency of many of the DAA combinations, the effect exerted by ribavirin (RBV) is still needed for an effective therapy in many new DAA combinations. Due to the strong antiviral effect of DAAs, it is likely that a major complementary therapeutic effect exerted by RBV is immune modulation resulting in an increased barrier to development of resistance. For HCV genotype 1a infections elimination of pegylated interferon, is not possible in many DAA combinations without jeopardizing the results. The host immune response is thus likely to play a key role even during DAA-based therapies. Hence, T cells may recognize and eliminate viral variants with resistance to the DAAs. We herein show several examples where this may be the case, supporting the rationale of including the host response also in the new therapeutic regimens. This review will describe the potential benefits of combining various DAAs with means to activate the specific immune response against HCV.

Gastrointestinal histoplasmosis in a hepatitis C-infected individual

Gastrointestinal histoplasmosis is a rare manifestation of this fungal infection, typically identified in immunocompromised patients, such as those with HIV/AIDS. Here, we report a case of disseminated histoplasmosis with gastrointestinal involvement in a Hepatitis C-infected patient. The fungal agent was confirmed to be Histoplasma capsulatum by a DNA probe assay performed on a bone marrow sample. We propose that this fungal disease should be kept on the differential of patients infected with the Hepatitis C virus, as it has been reported to have numerous damaging effects on the adaptive immune system.

Non-structural 3 protein expression is associated with T cell protein tyrosine phosphatase and viral RNA levels in chronic hepatitis C patients

The hepatitis C virus (HCV) non-structural 3 (NS3) protein plays key roles in both the viral life cycle and in the modulation of intrahepatic signaling and immunity. We recently showed that NS3 cleaves the T cell protein tyrosine phosphatase (TCPTP). To better understand the inactivation of TCPTP in HCV-infected humans, we investigated whether there is an association between TCPTP cleavage, NS3 protein levels and clinical parameters in hepatitis C patients. Liver biopsies were obtained from 69 HCV RNA positive patients with confirmed chronic HCV infection and 16 control patients. Hepatic NS3 and TCPTP protein levels were determined and correlated to viral load or clinical parameters for the severity of liver disease. We found a positive correlation between the viral load and the intrahepatic NS3 protein levels in patients infected with HCV. HCV-infected patients had significantly lower intrahepatic TCPTP levels than non-infected control patients. In HCV-infected patients both intrahepatic NS3 expression and the viral load were inversely correlated with the intrahepatic TCPTP protein levels. Detection of NS3 did not associate with any other clinical parameters such as liver damage, the grade of liver inflammation or fibrosis stage. This is the first study reporting a detailed analysis of HCV NS3 and TCPTP protein levels in the liver. It demonstrates a clear link between HCV viral load, NS3 expression in the liver and intrahepatic TCPTP levels. Thus, the association between TCPTP cleavage and viral replication may have important consequences for the HCV life cycle and HCV-induced liver diseases.

Killer cell immunoglobulin-like receptor gene associations with autoimmune and allergic diseases, recurrent spontaneous abortion, and neoplasms

Killer cell immunoglobulin-like receptors (KIRs) are a family of cell surface inhibitory or activating receptors expressed on natural killer cells and some subpopulations of T lymphocytes. KIR genes are clustered in the 19q13.4 region and are characterized by both allelic (high numbers of variants) and haplotypic (different numbers of genes for inhibitory and activating receptors on individual chromosomes) polymorphism. This contributes to diverse susceptibility to diseases and other clinical situations. Associations of KIR genes, as well as of genes for their ligands, with selected diseases such as psoriasis vulgaris and atopic dermatitis, rheumatoid arthritis, recurrent spontaneous abortion, and non-small cell lung cancer are discussed in the context of NK and T cell functions.