IL28B genetic variation and hepatitis C virus–specific CD4+ T‐cell responses in anti‐HCV‐positive blood donors

Summary. Epidemiological, viral and host factors are associated with the outcome of hepatitis C virus (HCV) infection, and strong host immune responses against HCV favour viral clearance. Recently, genome‐wide association studies have shown a strong correlation between single‐nucleotide polymorphisms (SNPs) near the interleukin‐28B (IL28B) gene and spontaneous or treatment‐induced HCV clearance. We have investigated whether protective IL28B genetic variants are associated with HCV‐specific T‐cell responses among Spanish blood donors. The rs12979860 IL28B haplotype was determined in 69 anti‐HCV‐positive blood donors (21 HCV RNA negative and 48 HCV RNA positive) and 30 seronegative donors. In all cases, HCV‐specific CD4⁺ T‐cell responses to HCV recombinant proteins (core, NS3 and NS3 helicase) were assessed by ex vivo interferon‐γ ELISpot assay. The rs12979860‐CC genotype was highly overrepresented in donors with spontaneous HCV clearance when compared to those with chronic infection (76.2%vs 29.2%, P < 0.001; odds ratio, 7.77; 95% confidence interval, 2.4–25.3, P < 0.001). HCV‐specific CD4⁺ T‐cell responses were detected in 16 (76.2%) spontaneous resolvers especially towards nonstructural proteins, but with no correlation with IL28B genotype. Chronic individuals had a significantly lower overall T‐cell response again irrespective of IL28B genotype. When spontaneous resolvers and chronic individuals were stratified according to their IL28B genotype, significantly stronger T‐cell responses were only observed among those with non‐CC haplotypes. Although the protective rs12979860 IL28B CC genotype is associated with spontaneous HCV clearance, stronger CD4⁺ T‐cell responses towards NS3 were only evident among those with non‐CC haplotypes.     

Impact of oral silymarin on virus‐ and non‐virus‐specific T‐cell responses in chronic hepatitis C infection

Silymarin displays anti‐inflammatory effects on T lymphocytes in vitro. The immunomodulatory properties of oral silymarin in vivo in humans with chronic hepatitis C have not previously been characterized. We hypothesized that silymarin would suppress T‐cell proliferation and pro‐inflammatory cytokine production of virus‐ and non‐virus‐specific T cells while increasing anti‐inflammatory IL‐10 production in vivo. Patients from one site of the SyNCH‐HCV double‐masked, placebo‐controlled study of oral silymarin in prior interferon nonresponders with chronic hepatitis C provided blood samples at baseline and treatment week 20. Mononuclear cells were stimulated with recombinant HCV proteins and controls in ³H‐thymidine proliferation assays, IFNγ ELISPOT and IL‐10 ELISPOT. The frequency of CD4⁺CD25^hi and CD4⁺foxp3⁺ regulatory T cells, serum cytokine levels, serum IP‐10 and lymphocyte interferon‐stimulated gene expression were also quantified at baseline and week 20. Thirty‐two patients were recruited (10; placebo, 11; 420 mg three times a day, 11; 700 mg three times a day). Serum ALT and HCV RNA titres did not change in any group. HCV‐specific CD4⁺ T‐cell proliferation and the frequency of IFNγ‐ and IL‐10‐producing T cells were not significantly changed in silymarin‐treated subjects. However, C. albicans‐induced T‐cell IFNγ and phytohaemagglutinin‐induced T‐cell proliferation were suppressed by silymarin therapy. A trend towards augmentation of interferon‐induced ISG15 expression was present in the high‐dose silymarin group. While no effect on HCV‐specific T cells was identified, these data confirm that high‐dose oral silymarin exerts modest nonspecific immunomodulatory effects in vivo. The impact of this anti‐inflammatory effect on long‐term liver health in chronic hepatitis C merits future clinical investigation.     

Differential virus‐specific CD8+ T‐cell epitope repertoire in hepatitis C virus genotype 1 versus 4

Virus‐specific CD8⁺ T‐cell responses play an important role in the outcome of hepatitis C virus (HCV) infection. To date, most HCV‐specific CD8⁺ T‐cell epitopes have been defined in HCV genotype 1 infection. In contrast, the HCV genotype 4‐specific CD8⁺ T‐cell response is poorly defined. Here, we analysed whether known HCV‐specific CD8⁺ T‐cell epitopes are also recognized in HCV genotype 4‐infected patients and set out to identify the first HCV genotype 4‐specific CD8⁺ T‐cell epitopes. We studied patients chronically infected with HCV genotype 1 (n = 20) or 4 (n = 21) using 91 well‐described HCV‐specific epitope peptides. In addition, we analysed 24 genotype 4‐infected patients using 40 epitope candidates predicted using an in silico approach. HCV‐specific CD8⁺ T‐cell responses targeting previously described epitopes were detectable in the majority of genotype 1‐infected patients (11 of 20). In contrast, patients infected with HCV genotype 4 rarely targeted these epitopes (4 of 21; P = .0247). Importantly, we were able to identify eight novel HCV genotype 4‐specific CD8⁺ T‐cell epitopes. Only one of these epitopes was shared between genotype 1 and genotype 4. These results indicate that there is little overlap between CD8⁺ T‐cell repertoires targeting HCV genotype 1 and 4. Prophylactic vaccination studies based on HCV genotype 1 are currently underway. However, in countries with the highest prevalence of HCV infection, such as Egypt, most patients are infected with HCV genotype 4. Thus, prophylactic vaccination strategies need to be adapted to HCV genotype 4 before their application to regions where HCV genotype 4 is endemic.     

Hepatitis C viraemia reversibly maintains subset of antigen‐specific T‐bet+ tissue‐like memory B cells

Background: Chronic antigen exposure and/or ageing increases the frequency of T‐box expressed in T cells (T‐bet)‐expressing B‐lymphocytes in mice. The frequency and significance of B‐cell T‐bet expression during chronic hepatitis C (HCV) infection in human subjects has never been described. Methods: Healthy controls, cirrhotic and noncirrhotic HCV‐infected patients, and non‐HCV patients with cirrhosis were recruited. Peripheral blood mononuclear cells were phenotyped for expression of T‐bet and related markers by flow cytometry. In a subset of patients who underwent antiviral therapy and were cured of HCV infection (sustained virological response), the dynamics of T‐bet expression in B cells was monitored. After cure, convalescent B cells were tested for T‐bet expression after re‐exposure to infected plasma or recombinant HCV proteins. Results: Forty‐nine patients including 11 healthy donors, 30 hepatitis C‐infected individuals (nine with liver cancer, 13 with cirrhosis, eight without cirrhosis) and eight patients with cirrhosis due to non‐HCV‐related cause were recruited. We found that B cells in patients with chronic HCV exhibited increased frequency of T‐bet+ B cells relative to noninfected individuals (median 11.5% v. 2.2%, P<.0001) but that there were no significant differences between noncirrhotic, cirrhotic and cancer‐bearing infected individuals. T‐Bet⁺ B cells expressed higher levels of CD95, CXCR3, CD11c, CD267 and FcRL5 compared to T‐bet^? B cells and predominantly exhibit a tissue‐like memory CD27^?CD21^? phenotype independent of HCV infection. T‐bet⁺ B cells in HCV‐infected patients were more frequently class‐switched IgD^?IgG⁺ (40.4% vs. 26.4%, P=.012). Resolution of HCV infection with direct‐acting antiviral (DAA) therapy leads to a marked reduction in the frequency of T‐bet⁺ B cells (median 14.1% pretreatment v. 6.7% end of treatment v. 6.1% SVR12, P≤.01). Re‐exposure of convalescent (cured) B cells to viremic plasma and recombinant HCV E2 protein led to re‐expression of T‐bet. Conclusion: Chronic antigenemia in chronic HCV infection induces and maintains an antigen‐specific T‐bet⁺ B cell. These B cells share markers with tissue‐like memory B cells. Antigen‐driven T‐bet expression may be a critical suppressor of B‐cell activation in chronic HCV infection.     

A prospective study of T‐ and B‐lymphocyte subpopulations,CD81 expression levels on B cells and regulatory CD4+CD25+CD127low/−FoxP3+ T cells in patients with chronic HCV infection during pegylated interferon‐alpha2a plus ribavirin treatment

Summary. Resolution of hepatitis C virus (HCV) infection requires a complex interplay between innate and adaptative immune responses. The role of lymphocyte subpopulations during combined antiviral treatment remains to be defined. This study was conducted to assess the effect of pegylated interferon‐alpha2a (pegIFN‐α2a) and ribavirin treatment on peripheral blood lymphocytes, mainly on CD81 expression on B cells and CD4⁺CD25⁺CD127^low/?FoxP3⁺ regulatory T cells (Tregs) in patients with chronic HCV infection. Thirty‐five patients with chronic HCV infection who started pegIFN‐α2a and ribavirin treatment were enrolled. Peripheral blood mononuclear cells (PBMC) were obtained at baseline before treatment (BT), mid‐treatment (MT), the end of treatment (ET) and 24 weeks post‐treatment (PT). During combined antiviral treatment, a significant decrease in the percentage of CD3⁺, CD8⁺, CD3⁺gamma/delta (γδ)⁺, CD19⁺ lymphocyte subpopulations and Tregs was observed. There was also a significant increase in the percentage of the CD4⁺ lymphocyte subpopulation and in CD81 expression levels on CD19⁺ B cells when BT was compared with ET (all P < 0.05). Seventeen patients were nonresponders (NR) and 18 had a sustained virological response (SVR). At baseline, NR patients had higher CD81 expression levels on CD19⁺ B cells (P = 0.017) and a higher Tregs percentage (P = 0.025) than SVR patients. Our results suggest that immunomodulation fluctuates during antiviral treatment and that percentage CD81 expression levels on B cells and Tregs might be useful as an immunological prognostic factor for pegIFN‐α2a and ribavirin treatment response in chronic HCV infection.     

Hepatic compartmentalization of exhausted and regulatory cells in HIV/HCV‐coinfected patients

Accelerated intrahepatic hepatitis C virus (HCV) pathogenesis is likely the result of dysregulation within both the innate and adaptive immune compartments, but the exact contribution of peripheral blood and liver lymphocyte subsets remains unclear. Prolonged activation and expansion of immunoregulatory cells have been thought to play a role. We determined immune cell subset frequency in contemporaneous liver and peripheral blood samples from chronic HCV‐infected and HIV/HCV‐coinfected individuals. Peripheral blood mononuclear cells (PBMC) and biopsy‐derived liver‐infiltrating lymphocytes from 26 HIV/HCV‐coinfected, 10 chronic HCV‐infected and 10 HIV‐infected individuals were assessed for various subsets of T and B lymphocytes, dendritic cell, natural killer (NK) cell and NK T‐cell frequency by flow cytometry. CD8⁺ T cells expressing the exhaustion marker PD‐1 were increased in HCV‐infected individuals compared with uninfected individuals (P = 0.02), and HIV coinfection enhanced this effect (P = 0.005). In the liver, regulatory CD4⁺CD25⁺Foxp3⁺ T cells, as well as CD4⁺CD25⁺PD1⁺ T cells, were more frequent in HIV/HCV‐coinfected than in HCV‐monoinfected samples (P < 0.001). HCV was associated with increased regulatory T cells, PD‐1⁺ T cells and decreased memory B cells, regardless of HIV infection (P ≤ 0.005 for all). Low CD8⁺ expression was observed only in PD‐1⁺CD8⁺ T cells from HCV‐infected individuals and healthy controls (P = 0.002) and was associated with enhanced expansion of exhausted CD8⁺ T cells when exposed in vitro to PHA or CMV peptides. In conclusion, in HIV/HCV coinfection, ongoing HCV replication is associated with increased regulatory and exhausted T cells in the periphery and liver that may impact control of HCV. Simultaneous characterization of liver and peripheral blood highlights the disproportionate intrahepatic compartmentalization of immunoregulatory T cells, which may contribute to establishment of chronicity and hepatic fibrogenesis in HIV coinfection.     

Expression of programmed cell death protein 1 and T‐cell immunoglobulin‐ and mucin‐domain‐containing molecule‐3 on peripheral blood CD4+CD8+ double positive T cells in patients with chronic hepatitis C virus infection and in subjects who spontaneously cleared the virus

Chronic hepatitis C virus (HCV) infection is characterized by increased proportion of CD4+CD8+ double positive (DP) T cells, but their role in this infection is unclear. In chronic hepatitis C, immune responses to HCV become functionally exhausted, which manifests itself by increased expression of programmed cell death protein 1 (PD‐1) and T‐cell immunoglobulin‐ and mucin‐domain‐containing molecule‐3 (Tim‐3) on T cells. The aim of our study was to determine PD‐1 and Tim‐3 phenotype of DP T cells in subjects with naturally resolved and chronic HCV infection. Peripheral blood mononuclear cells from 16 patients with chronic infection and 14 subjects who cleared HCV in the past were stained with anti‐CD3, anti‐CD4, anti‐CD8, anti‐PD‐1 and anti‐Tim‐3 antibodies and, in 12 HLA‐A*02‐positive subjects, MHC class I pentamer with HCV NS3₁₄₀₆ epitope. In chronic and past HCV infection, proportions of total DP T cells and PD‐1+ DP T cells were similar but significantly higher than in healthy controls. DP T cells were more likely to be PD‐1+ than either CD4+ or CD8+ single positive (SP) T cells. HCV‐specific cells were present in higher proportions among DP T cells than among CD8+ SP T cells in both patient groups. Furthermore, while the majority of HCV‐specific DP T cells were PD‐1+, the proportion of HCV‐specific CD8+ T cells which were PD‐1+ was 4.9 and 1.9 times lower (chronic and past infection, respectively). PD‐1 and Tim‐3 were predominantly expressed on CD4^highCD8^low and CD4^lowCD8^high cells, respectively, and co‐expression of both markers was uncommon.     

Generation of cellular immune responses to HCV NS5 protein through in vivo activation of dendritic cells

Summary. Chronic hepatitis C (HCV) infection is a substantial medical problem that leads to progressive liver disease, cirrhosis, and hepatocellular carcinoma (HCC). The aim of this study was to achieve sustained cellular immune responses in vivo to a HCV nonstructural protein using dendritic cell (DC)‐based immunization approach. We targeted the HCV NS5 protein to DCs in vivo by injecting microparticles loaded with this antigen. The DC population was expanded in BALB/C mice (H‐2^d) by hydrodynamic injection of a plasmid pUMVC3‐hFLex expressing the secreted portion of the human Fms‐like tyrosine kinase receptor‐3 ligand (hFlt3). Mice were subsequently injected with microparticles coated with HCV NS5 protein via the tail vein. Cellular immune responses were determined with respect to secretion of INFγ and IL2 by CD4⁺ cells and cytotoxic T‐lymphocyte (CTL) assays in vitro; inhibition of tumour cell growth was employed for the assessment of CD8⁺ generated activity in vivo. We found that Flt3L treatment expanded the DC population in the spleen to 43%, and such cells displayed a striking upregulation of CD86 as well as CD80 and CD40 co‐stimulating molecules. Viral antigen‐specific T_H1 cytokine secretion by splenocytes was generated, and CTL activity against syngeneic NS5 expressing myeloma target cells was observed. In addition, these cells inhibited tumour growth indicating that NS5‐specific robust CTL activity was operative in vivo. Thus, the capability of activating DCs in vivo using the methods described is valuable as a therapeutic vaccine strategy for chronic HCV infection.     

Individual myeloma‐specific T‐cell clones eliminate tumour cells and correlate with clinical outcomes in patients with multiple myeloma

Despite novel treatment strategies, multiple myeloma (MM) remains an incurable disease with low immunogenicity and multiple immune defects. We developed an ex vivo strategy for inducing myeloma‐specific cytotoxic T lymphocytes (CTLs) and demonstrate the possibility of identification and long‐term in vivo monitoring of individual myeloma‐specific T‐cell clones using the most sensitive clonotypic assay that is able to detect low frequencies of T‐cell clones (1 clonotypic cell in 10⁶ cells). Ten patients with MM were examined for the presence of tumour‐reactive T cells using dendritic cells loaded with autologous tumour cells. All patients had detectable myeloma‐reactive T cells in vitro. Expanded myeloma‐reactive T cells demonstrated specific cytotoxic effects against autologous tumour cells in vitro (median 39·6% at an effector:target ratio of 40:1). The clonality of myeloma‐specific T cells was studied with a clonotypic assay, which demonstrated both oligoclonal and monoclonal populations of myeloma‐specific T cells. CD8⁺ CTLs were the most immunodominant myeloma‐specific T‐cell clones and clinical responses were closely associated with the in vivo expansion and long‐term persistence of individual CD8⁺ T‐cell clones, usually at very low frequencies (10^?3–10^?6). We conclude that the clonotypic assay is the most sensitive tool for immunomonitoring of low‐frequency T cells.     

Early IL‐10 predominant responses are associated with progression to chronic hepatitis C virus infection in injecting drug users

Summary. The critical events in clearance or persistence of hepatitis C virus (HCV) infection are unknown but likely to be determined early in acute infection. Type 1 and type 2 cytokine production was assessed by HCV peptide ELISpot and multiplex in vitro cytokine production assays in longitudinally collected samples from 20 untreated participants enrolled in the Australian Trial in Acute Hepatitis C (ATAHC); a prospective cohort of acute HCV infection (77% injecting drug users, IDU). Significantly higher interleukin‐10 (IL‐10) production (P = 0.048), in the relative absence of interferon‐gamma (IFN‐γ) and IL‐2 production, was present early in HCV infection in those who progressed to chronic infection. In contrast, viral clearance was associated with a greater magnitude and broader specificity of IFN‐γ (magnitude P < 0.001, breadth P = 0.004) and IL‐2 responses, in the relative absence of IL‐10. Early IL‐10 production was correlated with higher HCV RNA level at baseline (P = 0.046) and week 12 (P = 0.018), while IFN‐γ and IL‐2 production was inversely correlated with HCV RNA level at baseline (IFN‐γP = 0.020, IL‐2 P = 0.050) and week 48 (IFN‐γP = 0.045, IL‐2 P = 0.026). Intracellular staining (ICS) indicated the HCV‐specific IFN‐γ response was primarily from CD8⁺ T cells and NK cells, whereas IL‐10 production was predominantly from monocytes, with a subset of IL‐10 producing CD8⁺ T cells present only in those who progressed to chronic infection. IL‐10, an immunoregulatory cytokine, appears to play a key role in progression to chronic HCV infection.     

Characteristics of regulatory T‐cell function in patients with chronic hepatitis B and C coinfection

Regulatory T cells (Tregs) affect the pathogenesis and disease progression of chronic viral hepatitis. This study evaluated the frequency and function of Tregs in patients with chronic HBV/HCV coinfection. Seventy‐four untreated HBV/HCV co‐infected patients were enrolled in this study. These subjects were divided into four subgroups: HBV‐active/HCV‐active (BACA), HBV‐inactive/HCV‐active (BICA), HBV‐active/HCV‐inactive (BACI) and HBV‐inactive/HCV‐inactive (BICI). Treg frequency was calculated as the fraction of CD4⁺Foxp3⁺T cells among CD4⁺T cells. Treg‐mediated inhibition was measured as percent of inhibition of T‐cell proliferation. The expression of interferon (IFN)‐γ, tumour necrosis factor (TNF)‐α and interleukin (IL)‐10 with/without Treg inhibition was also studied. Among the patients, there were 8 cases of BACA (10.8%), 38 of BICA (51.4%), 14 of BACI (18.9%) and 14 of BICI (18.9%). The frequency of CD4⁺Foxp3⁺T cells was comparable between the four groups. The inhibitory function of Tregs among the patients in the BACA and BICA was higher than that in the BICI (BACA vs BICI, P = .0210; BICA vs BICI, P = .0301). Patients in the BACA and BICA had higher fibrosis‐4 (FIB‐4) scores and serum ALT levels and lower serum albumin levels than those of the other groups. ALT abnormality was significantly and independently associated with a higher Treg immunosuppressive ability. The IFN‐γ expression of the effector T cells in the BACA was higher than that of the other groups. In conclusion, the inhibitory function of Tregs is higher among the HBV/HCV co‐infected patients with active HCV infection. ALT abnormality plays a dominant role in Treg function.     

Circulating myeloid‐derived suppressor cells correlate with clinical outcome in Hodgkin Lymphoma patients treated up‐front with a risk‐adapted strategy

In the attempt to find a peripheral blood biological marker that could mirror the dysregulated microenvironment of Hodgkin Lymphoma (HL), we analysed the amount of myeloid‐derived suppressor cells (MDSC), including the three main sub‐types (monocytic, granulocytic and CD34 + fraction). The absolute MDSC count was investigated in 60 consecutive newly diagnosed HL patients and correlated with clinical variables at diagnosis and outcome. Patients received standard‐of‐care chemotherapy with the exception of interim fluorodeoxyglucose positron emission tomography (PET‐2)‐positive patients, who were switched early to a salvage regimen. All MDSC subsets were increased in HL patients compared to normal subjects (P < 0·0001) and were higher in non‐responders. However, a strong prognostic significance was limited to immature (CD34⁺) MDSC. A cut‐off level of 0·0045 × 10⁹/l for CD34⁺MDSC resulted in 89% (95% confidence interval [CI] 52–99%) sensitivity and 92% (95% CI 81–98%) specificity. The positive predictive value to predict progression‐free survival was 0·90 for PET‐2 and 0·98 for CD34⁺MDSC count; the negative predictive value was 0·57 for PET‐2 and 0·73 for CD34⁺MDSC. PFS was significantly shorter in patients with more than 0·0045 × 10⁹ CD34⁺MDSC cells/l at diagnosis and/or PET‐2 positivity (P < 0·0001). In conclusion, all circulating MDSC subsets are increased in HL; CD34⁺MDSC predict short PFS, similarly to PET‐2 but with the advantage of being available at diagnosis.     

Effects of rituximab and dexamethasone on regulatory and proinflammatory B‐cell subsets in patients with primary immune thrombocytopenia

Objective

To investigate the cytokine production and surface marker composition of B cells in adult patients with newly diagnosed primary immune thrombocytopenia (ITP) before and 12 months after treatment with rituximab + dexamethasone (RTX+DXM) or dexamethasone (DXM).

Methods

Peripheral blood mononuclear cells were isolated from nine patients treated with RTX+DXM, seven patients treated with DXM, and seven healthy donors. Expression of the cell‐surface markers CD5, CD27, CD25, and CD19, and intracellular content of IL‐6 and IL‐10 were measured by flow cytometry.

Results

PBMCs from ITP patients at baseline contained a lower proportion of IL‐10⁺ B cells (P < .01) and IL‐6⁺ B cells (P < .01) than healthy controls. All patients responded to therapy and levels were normalized at 12 months. The proportion of CD5⁺ B cells increased (P < .01) and CD27⁺ memory B cells decreased (P < .05) 12 months after treatment with RTX+DXM compared to baseline, with an inverse correlation between platelet numbers and the proportion of CD27⁺ B cells (R = ?0.71; P < .05).

Conclusion

Both treatment regimens normalized the frequencies of cytokine‐producing B cells. The additional increase in CD5⁺ B cells after RTX+DXM is compatible with induction of Bregs.     

Increased levels of IL‐21 responses are associated with the severity of liver injury in patients with chronic active hepatitis B

Interleukin‐21 (IL‐21) participates in tissue damage in various immune‐mediated diseases. Its role in the pathogenesis of chronic active hepatitis B (CAHB) has not been clarified. The frequency of circulating IL‐21⁺ T cells and the levels of serum and intrahepatic IL‐21 have been characterized in 70 CAHB patients, 32 inactive carrier (IC), 18 chronic hepatitis C (CHC) and 20 healthy controls (HC). Their potential association with liver injury was analysed. The percentages of IL‐21⁺CD3⁺CD8⁻ and IL‐21⁺CD3⁺CD8⁺ T cells and the levels of serum IL‐21 in CAHB patients were significantly higher than that in the IC, CHC patients and HC (P < 0.001) and were correlated positively with the levels of serum alanine aminotransferase (ALT, r = 0.424, P < 0.001; r = 0.392, P = 0.001) and aspartate aminotransferase (AST, r = 0.388, P = 0.001; r = 0.329, P = 0.005) in CAHB patients, respectively. The levels of IL‐21 expression in the liver tissues were associated significantly with increased degrees of inflammation and fibrosis in CAHB patients (P < 0.01 or P < 0.05). Our findings suggest that aberrant IL‐21 responses may be associated with the progression of CHB.     

An immunophenotypic pre‐treatment predictor for poor response to induction chemotherapy in older acute myeloid leukaemia patients: blood frequency of CD34+ CD38low blasts

Many older patients with acute myeloid leukaemia (AML) that receive standard intensive chemotherapy fail to achieve complete remission (CR). Upfront identification of patients unlikely to benefit from standard induction chemotherapy would be important for exploration of novel therapies. This study evaluated if a flow cytometric assay measuring pre‐treatment CD34⁺ CD38^low blast frequency could predict therapeutic‐resistance in 736 AML patients entered into the UK National Cancer Research Institute AML16 trial. High peripheral blood CD34⁺ CD38^low blast frequency (>7% of leucocytes), present in 18% of assessable patients, conferred significantly reduced CR rates (38% vs. 76%, P < 0·0001) and poor survival, and was independently prognostic for all endpoints of treatment resistance by multivariate analysis.     

Expansion of CD4+CD25+FoxP3+ regulatory T cells in hepatitis C virus‐related chronic hepatitis,cirrhosis and hepatocellular carcinoma

Aim: Regulatory T (Treg) cells may play a pivotal role in the persistence of hepatitis C virus (HCV) infection and the development of hepatocellular carcinoma (HCC). Therefore, we examined their frequency in peripheral blood from patients with HCV‐positive chronic hepatitis (CH), cirrhosis (LC) and HCC. Methods: Treg cells were identified as CD4⁺, CD25⁺ and FoxP3⁺ T lymphocytes using three‐color FACS. The frequency of Treg cells was expressed as a percentage of the total CD4⁺ T lymphocytes, and the phenotype of Treg cells was examined using CD45RA. Results: Treg cells were significantly increased in CH (5.88 ± 0.19%, n = 76; P < 0.01), LC (6.10 ± 0.28%, n = 40; P < 0.001) and HCC (6.80 ± 0.30%, n = 57; P < 0.0001) compared to healthy control (5.13 ± 0.25%, n = 31). However, Treg cells were not increased with the progression of fibrosis or the grade of inflammations. Treg cells were slightly increased in early‐stage HCC (6.91 ± 0.40%) compared with advanced‐stage HCC (6.58 ± 0.39%), but these results were not statistically significant. In a serial examination, a distinct increase in Treg cells after local therapy for early‐stage HCC was a hallmark of early recurrence. Most expanded Treg cells in HCC were CD45RA^‐, suggesting that a memory‐type Treg population had differentiated in the periphery and not in the thymus. Conclusion: We observed an increase in Treg cells in HCV‐related chronic liver disease, particularly in HCC, and these cells were shown to be memory‐type Treg cells.     

Stronger hepatitis C virus‐specific CD8+ T‐cell responses in HIV coinfection

Summary. Hepatitis C virus (HCV) is a widespread chronic infection that shares routes of transmission with human immunodeficiency virus (HIV). Thus, coinfection with these viruses is a relatively common and growing problem. In general, liver disease develops over years with HIV coinfection, when compared to decades in HCV monoinfection. The role of the immune system in the accelerated pathogenesis of liver disease in HIV/HCV coinfection is not clear. In this study, we compared the frequency, magnitude, breadth and specificity of peripheral blood CD4⁺ and CD8⁺ T‐cell responses between HCV‐monoinfected and HCV/HIV‐coinfected individuals and between HIV/HCV‐coinfected subgroups distinguished by anti‐HCV antibody and HCV RNA status. While HIV coinfection tended to reduce the frequency and breadth of anti‐HCV CD8⁺ T‐cell responses in general, responses that were present were substantially stronger than in monoinfection. In all groups, HCV‐specific CD4⁺ T‐cell responses were rare and weak, independent of either nadir or concurrent CD4⁺ T‐cell counts of HIV‐infected individuals. Subgroup analysis demonstrated restricted breadth of CD8⁺ HCV‐specific T‐cell responses and lower B‐cell counts in HIV/HCV‐coinfected individuals without anti‐HCV antibodies. The greatest difference between HIV/HCV‐coinfected and HCV‐monoinfected groups was substantially stronger HCV‐specific CD8⁺ T‐cell responses in the HIV‐coinfected group, which may relate to accelerated liver disease in this setting.     

The cardioprotective effect of melatonin and exendin‐4 treatment in a rat model of cardiorenal syndrome

We investigated the cardioprotective effect of melatonin (Mel) and exendin‐4 (Ex4) treatment in a rat model of cardiorenal syndrome (CRS). Adult male SD rats (n=48) were randomly and equally divided into sham control (SC), dilated cardiomyopathy (DCM) (doxorubicin 7 mg/kg i.p. every five days/4 doses), CRS (defined as DCM+CKD) only, CRS‐Mel (20 mg/kg/d), CRS‐Ex4 (10 μg/kg/d), and CRS‐Mel‐Ex4 groups. In vitro results showed protein expressions of oxidative stress (NOX‐1/NOX‐2/oxidized protein), DNA/mitochondrial damage (γ‐H2AX/cytosolic cytochrome c), apoptosis (cleaved caspase‐3/PARP), and senescence (β‐galactosidase cells) biomarkers were upregulated, whereas mitochondrial ATP level was decreased in doxorubicin/p‐cresol‐treated H9c2 cells that were revised by Mel and Ex4 treatments (all P<.001). By day 60, LVEF was highest in the SC and lowest in the CRS, significantly lower in the DCM than in other treatment groups, lower in the CRS‐Mel and CRS‐Ex4 than in the CRS‐Mel‐Ex4, and lower in the CRS‐Mel than in the CRS‐Ex4, whereas LV chamber size and histopathology score showed a pattern opposite to that of LVEF among all groups (all P<.001). Plasma creatinine level was highest in the CRS and lowest in the SC and progressively decreased from the CRS‐Mel, CRS‐Ex4, CRS‐Mel‐Ex4 to DCM (P<.0001). Protein expressions of inflammation (TNF‐α/NF‐κB/MMP‐2/MMP‐9/IL‐1β), apoptosis/DNA damage (Bax/c‐caspase‐3/c‐PARP/γ‐H2AX), fibrosis (Smad3/TGF‐β), oxidative stress (NOX‐1/NOX‐2/NOX‐4/oxidized protein), cardiac hypertrophy/pressure overload (BNP/β‐MHC), and cardiac integrity (Cx43/α‐MHC) biomarkers in LV myocardium showed an opposite pattern compared to that of LVEF among all groups (all P<.001). Fibrotic area, DNA damage (γ‐H2AX⁺/53BP1⁺CD90⁺/XRCC1⁺CD90⁺), and inflammation (CD14⁺/CD68⁺) biomarkers in LV myocardium displayed a pattern opposite to that of LVEF among all groups (all P<.001). Combined melatonin and exendin‐4 treatment suppressed CRS‐induced deterioration of LVEF and LV remodeling.     

Differential in vitro CD4+/CD8+ T‐cell response to live vs. killed Leishmania major

Clinical trials of killed Leishmania vaccines showed a limited efficacy compared with leishmanization (LZ). The reason for this difference in protection against cutaneous leishmaniasis (CL) is not known and in vivo studies on T‐cell function may provide valuable information. Nevertheless, there are limited studies on the nature of the stimulatory effects of live vs. killed parasites on human T cells in vitro. A total of nine Leishmanin Skin Test+ volunteers with a history of self‐healing CL (HCL) and seven healthy volunteers were included in this study. 5,6‐carboxyfluroescein diacetate succinimidyl ester‐labelled CD4⁺/CD8⁺ lymphocytes were cultured with killed Leishmania Lysate (Killed LL) or live Leishmania major (Live LM) and analysed for proliferation using flow cytometry. Culture supernatants were used for cytokine titration. In HCL volunteers, upon stimulation with killed LL, the number of proliferated CD4⁺/CD8⁺ cells was significantly more than that of unstimulated (P < 0·001) or live LM stimulated (P < 0·05) cells, or cells from controls (CD4⁺/CD8⁺: P < 0·05/P < 0·001). Stimulation of CD4⁺ cells with Live LM (P < 0·001) or Killed LL (P < 0·05) induced a significantly higher IFN‐γ production compared with that of controls, but Live LM induced significantly (P < 0·05) more IFN‐γ than Killed LL. A significantly (P < 0·05) higher IFN‐γ production was observed when CD8⁺ cells were stimulated with Live LM. Cells from HCL volunteers showed significantly more IL‐10 production to Live LM stimulation compared with that of controls (CD4⁺: P < 0·05 /CD8⁺: P < 0·001) or cells stimulated with Killed LL (CD4⁺/CD8⁺: P < 0·001/P < 0·0005). Whereas Killed LL induced more proliferation response in purified T cells, Live LM induced cytokine production without significant induction of proliferation. The results from healed CL volunteers in this study could be implicated in further studies on T‐cell response in vaccinated individuals.