Interferon-α-Enhanced CD100/Plexin-B1/B2 Interactions Promote Natural Killer Cell Functions in Patients with Chronic Hepatitis C Virus Infection.

BACKGROUND: CD100, also known as Sema4D, is an immune semaphorin constitutively expressed on natural killer (NK) cells and T cells. As an immune activation molecule, CD100 has important immunoregulatory effects on NK functions by enhancing the interactions between NK cells and target cells. The aim of this study was to investigate whether hepatitis C virus (HCV) infection affects CD100 expression, and whether interferon-α treatment enhances NK killing activity to facilitate HCV clearance via CD100. METHODS: Expression of CD100 on NK cells was evaluated by flow cytometry in patients with chronic HCV infection, with or without pegylated interferon-α-based therapy. NK cell cytotoxicity and interferon (IFN)-γ production were measured by flow cytometry upon culturing the NK cells with K562 and Huh7.5 or HCV JFH-1-infected Huh7.5 cells. RESULTS: The frequency of CD100+ NK cells in HCV-infected individuals was slightly suppressed compared to healthy subjects. IFN-α treatment could significantly upregulate CD100 expression, which was confirmed by in vitro studies using peripheral blood mononuclear cells cocultured with HCV-expressing Huh7.5 cells or IFN-α. Importantly, the expression of CD100 on NK cells from HCV patients was inversely associated with the HCV-RNA levels in the early phase of IFN-α therapy, and the IFN-α upregulated CD100 led to an enhanced NK killing activity through ligations with its receptors plexin-B1/B2 on target cells. CONCLUSION: These results implied a novel mechanism by which IFN-α enhanced CD100/Plexin-B1/B2 interaction plays an important role in promoting NK functions in patients with chronic hepatitis C.

Upregulated Expression of A20 on Monocytes is Associated With Increased Severity of Acute-on-Chronic Hepatitis B Liver Failure: A Case-Control Study.

A20 expression is increased in various inflammatory diseases. However, the role of A20 in acute-on-chronic liver failure is unknown. This study was to evaluate A20 expression on monocytes and its associations with the severity of acute-on-chronic hepatitis B liver failure (ACHBLF). Thirty-seven patients with ACHBLF, 20 patients with chronic hepatitis B (CHB), and 15 healthy controls (HC) were enrolled in this case-control study. A20-positive monocytes were identified using flow cytometry. Serum levels of interleukin (IL)-10, IL-12p70, and TNF-α were determined using bead cytometry. A20 and IL-10 expressions were examined in THP-1 cells stimulated by lipopolysaccharide (LPS). The frequency of A20+ monocytes was significantly increased in patients with ACHBLF compared with HC (median [interquartile range, IQR]: 15.7 [22.8]% vs 2.5 [4.7]%, P < 0.001). Increased monocyte A20 expression was detected during the progression phase (including the mild/moderate and severe grades of ACHBLF) compared with patients in the recovery phase (both P < 0.05), and in the ACHBLF worsening group compared with patients in the improvement group (P < 0.001). LPS treatment upregulated A20 and IL-10 expressions in THP-1 cells. A20 expression on monocytes from patients with ACHBLF was positively correlated with total bilirubin (r = 0.60, P = 0.0001), direct bilirubin (r = 0.63, P < 0.0001), and MELD score (r = 0.43, P = 0.008), and inversely with prothrombin activity (r = -0.33, P = 0.046). IL-10 and TLR4 expression levels in monocytes, and serum levels of IL-10, IL-12p70, and TNF-α were increased in patients with ACHBLF compared with patients with CHB and HC. Increased A20 expression on monocytes was associated with the severity of ACHBLF.

CD100 up-regulation induced by interferon-α on B cells is related to hepatitis C virus infection.

OBJECTIVES: CD100, also known as Sema4D, is a member of the semaphorin family and has important regulatory functions that promote immune cell activation and responses. The role of CD100 expression on B cells in immune regulation during chronic hepatitis C virus (HCV) infection remains unclear. MATERIALS AND METHODS: We longitudinally investigated the altered expression of CD100, its receptor CD72, and other activation markers CD69 and CD86 on B cells in 20 chronic HCV-infected patients before and after treatment with pegylated interferon-alpha (Peg-IFN-α) and ribavirin (RBV) by flow cytometry. RESULTS: The frequency of CD5+ B cells as well as the expression levels of CD100, CD69 and CD86 was significantly increased in chronic HCV patients and returned to normal in patients with sustained virological response after discontinuation of IFN-α/RBV therapy. Upon IFN-α treatment, CD100 expression on B cells and the two subsets was further up-regulated in patients who achieved early virological response, and this was confirmed by in vitro experiments. Moreover, the increased CD100 expression via IFN-α was inversely correlated with the decline of the HCV-RNA titer during early-phase treatment. CONCLUSIONS: Peripheral B cells show an activated phenotype during chronic HCV infection. Moreover, IFN-α therapy facilitates the reversion of disrupted B cell homeostasis, and up-regulated expression of CD100 may be indirectly related to HCV clearance.

[Alteration of CD100 expression on natural killer cells in chronic patients with hepatitis C virus before and after initiation of antiviral treatment].

OBJECTIVE: To investigate the changes of total natural killer (NK) cell number and its subset proportions and the expression levels of activation factor CD100 on NK cells in chronically hepatitis C virus (HCV) infected patients before and after initiation of antiviral treatment. METHODS: The frequencies of total NK cells and their subsets as well as CD100 expression on NK cells in HCV infected patients were detected by flow cytometry. The level of soluble CD100 (sCD100) in serum was measured by ELISA. The correlations of CD100 with alanine aminotransferase (ALT) and HCV-RNA were analyzed using Spearman correlation test. RESULTS: The proportion of CD56(dim) NK cell subset decreased, whereas CD56(neg) subset increased in chronic HCV infected patients as compared with healthy controls (P<0.05). The proportion of CD56(bright) NK cells was elevated and that of CD56(neg) NK subsets was reduced in HCV infected patients with early virological response (EVR) (P<0.05); however, total NK cells and their subsets returned to the normal in patients with sustained virological response (SVR) after the initiation of antiviral treatment. We also observed that sCD100 level declined significantly (P<0.05), whereas CD100 expression on NK cells slightly decreased as compared with healthy controls, but the difference was not statistically significant. The levels of sCD100 and CD100 expression on NK cells were markedly up-regulated in EVR patients (P<0.05) and dropped to the normal in SVR patients. Spearman correlation analysis showed that CD100 expression was positively related to ALT level and negatively associated with HCV-RNA titer in HCV infected patients (P<0.05). CONCLUSION: Decreased CD100 expression may be associated with viral persistence. As one of immune molecules regulated by IFN-α, CD100 seems to be involved in HCV clearance by NK cells.

[Life quality analysis of hepatitis C patients with liver cirrhosis undergoing antiviral therapy following splenectomy].

OBJECTIVE: To evaluate the effect of antiviral therapy on the quality of life (QOL) of patients with chronic hepatitis C (CHC) and cirrhosis during the 5-year period following splenectomy to treat hypersplenism. METHODS: Data of patients with CHC and cirrhosis who had undergone treatment for hypersplenism were retrospectively selected from the hospital database of medical records. The patients were first grouped according to the hypersplenism treatment: splenectomy (group A, 28 cases) and conservative/non-operative (group B, 30 cases). Sub-grouping was carried out according to the CHC treatment: interferon-alpha-2a and ribavirin (15 cases in the A1 group, and 19 cases in the B1 group) and non-antiviral (13 cases in the A2 group, and 11 cases in the B2 group). To determine the intergroup differences in QOL during the 5-year period following the hypersplenism treatment, the QOL was assessed by chronic liver disease questionnaire (CLDQ), listing of specific symptoms (SS), and the World Health Organization QOL scale (WHOQOL-BREF). RESULTS: Between-group statistical comparison of the subjective feeling, physiological status, mental state, and social life relationship of the patients showed no significant differences among the patients who received splenectomy compared to those who received the conservative treatment. However, the QOL of splenectomy-treated patients who received non-antiviral CHC treatment was worse than that of the patients who were given conservative treatment for the hypersplenism and antiviral therapy for the CHC. The patients who received splenectomy and antiviral therapy had better QOL than the other patient group(3.69 +/- 0.75 vs 2.15 +/- 0.98, P = 0.0003). CONCLUSION: Splenectomy followed by antiviral therapy may improve the QOL of patients with CHC-related cirrhosis and hypersplenism.