Regulatory T cell-subset imbalance in chronic active hepatitis

Peripheral T-lymphocyte subpopulations in different clinical stages of chronic HBV infection correlate with HBV load

AIM

To characterize the peripheral T-cell subpopulation profiles and their correlation with hepatitis B virus (HBV) replication in different clinical stages of chronic HBV infection.

METHODS

A total of 422 patients with chronic HBV infection were enrolled in this study. The patients were divided into three stages: immune-tolerant stage, immune active stage, and immune-inactive carrier stage. Composition of peripheral T-cell subpopulations was determined by flow cytometry. HBV markers were detected by enzyme-linked immunosorbent assay. Serum HBV DNA load was assessed by quantitative real-time polymerase chain reaction.

RESULTS

CD8(+) T-cells were significantly higher in patients at the immune-tolerant stage than in patients at the immune-active and -inactive carrier stages (36.87 +/- 7.58 vs 34.37 +/- 9.07, 36.87 +/- 7.58 vs 28.09 +/- 5.64, P < 0.001). The peripheral blood in patients at the immune-tolerant and immune active stages contained more CD8(+) T-cells than CD4(+) T-cells (36.87 +/- 7.58 vs 30.23 +/- 6.35, 34.37 +/- 9.07 vs 30.92 +/- 7.40, P < 0.01), whereas the peripheral blood in patients at the immune-inactive carrier stage and in normal controls contained less CD8(+) T-cells than CD4(+) T-cells (28.09 +/- 5.64 vs 36.85 +/- 6.06, 24.02 +/- 4.35 vs 38.94 +/- 3.39, P < 0.01). ANOVA linear trend test showed that CD8(+) T-cells were significantly increased in patients with a high viral load (39.41 +/- 7.36, 33.83 +/- 7.50, 31.81 +/- 5.95 and 26.89 +/- 5.71, P < 0.001), while CD4(+) T-cells were significantly increased in patients with a low HBV DNA load (37.45 +/- 6.14, 33.33 +/- 5.61, 31.58 +/- 6.99 and 27.56 +/- 5.49, P < 0.001). Multiple regression analysis displayed that log copies of HBV DNA still maintained its highly significant coefficients for T-cell subpopulations, and was the strongest predictors for variations in CD3(+), CD4(+) and CD8(+) cells and CD4(+)/CD8(+) ratio after adjustment for age at HBV-infection, maternal HBV-infection status, presence of hepatitis B e antigen and HBV mutation.

CONCLUSION

Differences in peripheral T-cell subpopulation profiles can be found in different clinical stages of chronic HBV infection. T-cell impairment is significantly associated with HBV load.

Quantitative monitoring of serum hepatitis B virus DNA and blood lymphocyte subsets during combined prednisolone and interferon-alpha therapy in patients with chronic hepatitis B

Several investigators have reported a significantly reduced CD4/CD8 ratio, as defined by monoclonal antibodies, in the peripheral blood of Caucasian patients with chronic active hepatitis B (CAHB). In Asian patients with chronic hepatitis B, quantitative analyses of subpopulations of peripheral blood lymphocytes have not been able to confirm these findings. In this work, we analysed the frequency of peripheral blood lymphocyte subsets in 10 Chinese patients with histologically proven CAHB and seven healthy Chinese individuals. Four of the 10 CAHB patients received combined prednisolone/interferon-alpha2b (IFN-alpha2b) therapy. Peripheral blood samples were consecutively collected for analysis of lymphocyte subpopulations using an indirect immunofluorescence (IF) method, and hepatitis B virus (HBV) DNA was quantified by a chemiluminescent, molecular-hybridization assay. Peripheral blood mononuclear cells from seven Chinese control individuals comprised 63 +/- 3% CD3+ cells, of which 41 +/- 4% were of CD4+ and 23 +/- 2% of CD8+ subsets. The mean CD4/CD8 ratio in the healthy controls was 1.9 (95% confidence interval = 1.1-2.7). The CD4/CD8 ratios were significantly reduced (P < 0.01) in the 10 patients with chronic hepatitis B, compared with those of the controls, owing to a significant increase in the number of CD8+ cells (P < 0.005). During the treatment with prednisolone, a significant increase in the CD4/CD8 ratio was observed in all treated patients. This increase was mainly caused by a decrease in the number of CD8+ cells and was accompanied by an increase in serum HBV DNA levels, which peaked during the latter part of the prednisolone cycle. During the treatment with IFN-alpha2b, a second increase in the CD4/CD8 ratio was observed, which was caused by an increase in CD4+ cells. A marked decrease in viral load was observed, during treatment with IFN-alpha2b, in patients with HBV DNA levels below 10 000 pg ml-1. Our data indicate that the CD4/CD8 ratios in Chinese CAHB patients do not differ from those of Caucasian patients with CAHB, when analysed using similar methods for the enumeration of lymphocyte subsets. Profound effects on cellular distribution and viral replication were noted during the combined prednisolone/IFN-alpha2b therapy. Additional studies of the modulatory effect of the combined therapy on the distribution of lymphocyte subsets and cytokine profiles in relation to the therapeutic outcome of HBV infection are warranted.

Composition of peripheral blood lymphocyte populations during different stages of chronic infection with hepatitis B virus

To characterize the immunological populations associated with different stages of chronic infection with hepatitis B virus (HBV), we performed flow cytometric analyses on the peripheral blood leucocytes of 29 patients with various forms of chronic hepatitis B. The clinical spectrum of the patients ranged from asymptomatic infections, in the presence of high virus production, to intermittent or recurrent exacerbations of liver injury alternating with relatively normal liver function. Patients with partial resolution of disease who experienced an initial acute flare followed by prolonged seroconversion showed decreased percentages of CD3+ cells during the seroconversion phase when levels of serum alanine transferase (ALT) had normalized. These CD3+ cells were predominantly CD4+ cells bearing the alpha beta+ T-cell receptor (TCR). In addition, we saw an increase in CD4+ and CD8+ cells bearing the gamma delta TCR in those patients who had seroconverted. No significant differences were seen between any of the groups with respect to percentage of cells with a naive (CD45RA) or memory (CD45RO) phenotype, or of cells displaying the activation markers CD38, HLA-DR or CD57. Longitudinal analyses of 15 patients failed to show any consistent pattern of changes in the immunophenotypic profile during acute flares and their resolution. Our results indicate that the turnover of circulating T lymphocytes during the apparent quiescent phase of chronic infections is higher than that during acute exacerbations, suggesting an active immunosurveillance role of T-cell subpopulations in maintaining low virus levels during seroconversion.

Flow cytometry CD4+/CD8+ ratio of liver-derived lymphocytes correlates with viral replication in chronic hepatitis B

T lymphocytes have been assumed to play an essential role in tissue injury in patients with chronic hepatitis B. As hepatitis B virus (HBV) is considered as a major factor controlling liver inflammation, we assessed whether a particular T lymphocyte subset could be preferentially detected in the liver in accordance with viral replication. Liver-derived lymphocytes and peripheral blood lymphocytes were analysed by flow cytometry in 21 patients with histologically confirmed chronic hepatitis B without cirrhosis. Viral replication was quantified by hybridization of serum HBV DNA. Eleven patients exhibited an active viral replication with serum HBV DNA ranging from 10 to 388 pg/ml at the time of the liver biopsy, whereas 10 patients had no detectable serum HBV DNA. In patients exhibiting viral replication, CD4+/CD8+ ratios of liver-derived lymphocytes were significantly higher (P < 0.05) than those obtained in patients without viral replication. In contrast, the percentage of T cells expressing the gamma/delta receptor and that of CD2+/CD57+ cells were similar in both groups of patients. Furthermore, in patients exhibiting viral replication, CD4+CD8+ ratios of liver-derived lymphocytes correlated with serum HBV DNA levels (P < 0.001). No relationship between CD4+/CD8+ ratio of liver-derived and peripheral blood lymphocytes was observed. Our data indicate that, in patients with chronic hepatitis B, the CD4+/CD8+ ratio of liver-derived lymphocytes correlates with viral replication. This suggests that in situ helper/inducer CD4+ T lymphocytes may positively regulate the cytotoxic T cell activity in patients with HBV-related chronic hepatitis.

Elevated serum interleukin-6 levels in patients with acute hepatitis

To study the mechanisms of hepatocyte injury, we examined serum interleukin-6 (IL-6) level in acute hepatitis patients. Based on their clinical features, these patients were divided into three groups, acute hepatitis (AH), severe acute hepatitis, and fulminant hepatic failure (FHF). The present study demonstrated that, in association with their clinical status, their serum IL-6 levels were gradually increased (16.5 +/- 14.5 pg/ml in AH, 26.3 +/- 19.0 pg/ml in severe AH, and 470.2 +/- 261.4 pg/ml in FHF; control level, 5.2 +/- 0.6 pg/ml). Furthermore, we found that a significant correlation between serum IL-6 level and prothrombin time existed in these patients and that the elevated serum IL-6 returned to a normal range after recovery from their hepatocyte injury. Thus, our study demonstrates that the serum IL-6 level is a possible marker for identifying the clinical status in acute hepatitis and that this cytokine may have some roles in hepatocyte injury.

Dual colour fluorescein analysis of peripheral blood T cells in auto-immune chronic active hepatitis

Both CD4 and CD8 T cells are subdivided into two phenotypically distinct sublineages via another two T cell markers, Leu-8 and CD11b antigens. The proportions of these four T cell subsets, CD4+Leu8+, CD4+Leu8-, CD8+11b+ and CD8+11b-, were studied in patients with auto-immune chronic active hepatitis (CAH) and compared with disease controls (hepatitis B surface antigen positive chronic active hepatitis) and healthy controls. We found that the proportion of CD4+Leu8+ cells was significantly reduced compared with controls (P less than 0.01), whereas those of the other cells were almost identical in all 3 groups. The absolute number of these CD4+Leu8+ cells was also lower than that of controls (P less than 0.01). Thus, the present study suggests that a reduced number of CD4+Leu8+ cells is associated with the aberrant immune response in auto-immune CAH.

Two-dimensional flow cytometric analysis of intrahepatic lymphocyte subsets from patients with chronic hepatitis

Peripheral and intrahepatic lymphocyte subsets were analyzed in 22 patients with chronic hepatitis by two-dimensional flow cytometry. Activated T cells in the liver significantly increased compared with those in the peripheral blood. Helper T cells increased, but the CD4+ cells decreased due to a marked decrease of suppressor inducer T cells. CD8+ cells increased due to a increase of both cytotoxic T and suppressor T cells. Fc-receptor-positive cells, which increased significantly, were not NK cells but Fc-receptor-bearing T cells. In comparison with immunohistochemical methods, flow cytometric analysis enables more objective quantitation and simpler two-color staining of intrahepatic lymphocytes. Our findings using this method suggest that activated T cells and helper T cells have important roles in hepatitis and that hepatocellular injury may be generated not only by cytotoxic T cells but also by Fc-receptor-bearing T cells.

Dual color fluorescence analysis of peripheral T cell subsets in hepatitis B virus-induced liver disease

By using dual color fluorescence analysis, peripheral T cells can be divided into four different subsets, Leu-2a+15+, Leu-2a+15-, Leu-3a+8+ and Leu-3a+8- cells. The ratio of these T cell subsets in hepatitis B virus-induced hepatitis patients was studied and compared with that of controls. No significant difference was found in acute hepatitis and chronic hepatitis, but an elevation of Leu-2a+15- (29.5 +/- 2.8% vs. 18.8 +/- 4.1%, p less than 0.05) as well as a reduction of Leu-2a+15+ cells (3.2 +/- 0.7% vs. 10.4 +/- 3.2%, p less than 0.05) were found in fulminant hepatitis patients. In addition, serial studies of two fulminant hepatitis patients revealed that the imbalance of these two Leu-2a cells was only found in the acute phase, but not in the recovery phase. These results indicate that the imbalance of these two Leu-2a cells is associated with the clinical status of patients with fulminant hepatitis.

Lymphocyte subpopulations in patients with alcoholic liver disease

To determine whether abnormalities of the lymphocyte populations are associated with alcoholic liver disease, we have characterized the subpopulations of lymphocytes in 30 alcoholic patients with and without liver disease. Total T lymphocytes were decreased in patients with alcoholic hepatitis and alcoholic cirrhosis. However, T4 (helper) and T8 (suppressor/cytotoxic) cells and the T4 and T8 cell ratio were similar to the values in controls. In these patients, the sums of T4/T8 cells exceeded that of total T cells, an alteration apparently related to severe liver damage. Cells reacting with antisera to immunoglobulins (B lymphocytes) and to Dr determinants were also within the normal range. In contrast, NK/K (natural killer/killer) cells were increased in the group of patients with steatosis or without liver alteration. Increase of NK/K cells was not observed in patients who were abstinent from alcohol for a period of two weeks or more, suggesting that alcohol may have been responsible for the increase in this lymphocyte population.

Cell-mediated immunity in liver disease

Four liver diseases in which cell-mediated immunity seems to be of major importance but in which the exact pathogenic event has been not fully clarified have been briefly discussed. More precise delineation of the phenotypes of mononuclear cells and the advent of in vitro techniques for the study of lymphocyte function and cytotoxicity have led to better understanding of the importance of cell-mediated immunity in some liver diseases. It seems that the liver itself may be variously affected by different immunologic reactions, not only in various diseases but also in different locations in the same disease.

Lymphocyte subsets in HLA-DR2-positive narcoleptic patients

On the basis of our recent finding that all narcoleptic patients were HLA-DR2 positive, peripheral blood lymphocyte subsets were examined in 30 HLA-DR2 positive narcoleptic patients by using monoclonal antibodies and a flow cytometry. The percentages of OKIa1+ cells and OKM1+ cells increased significantly, while no quantitative changes were observed in the T cell subsets examined in the present study. No major immunological abnormalities which altered the T cell subpopulations quantitatively were apparent in narcolepsy.

Cellular immune responses in the acute exacerbation of hepatitis B e antigen-positive type B chronic hepatitis

The compositions of lymphocytes in peripheral blood and liver biopsies from 29 patients with hepatitis B e antigen-positive type B chronic hepatitis were studied by an indirect peroxidase-labeled antibody method using monoclonal antibodies to surface antigens on pan T cells (Leu-1 +), cytotoxic/suppressor T cells (Leu-2a +), helper/inducer T cells (Leu-3a +), natural killer/killer cells (Leu-7 +), and B cells (Leu-10 +). In the peripheral blood during the acute exacerbation of chronic hepatitis B, the percentage of cytotoxic/suppressor T cells was decreased, and the ratio of helper/inducer to cytotoxic/suppressor cells was elevated corresponding to the peak of serum transaminase. In contrast, in liver biopsies obtained during acute exacerbation, numerous lymphocytes infiltrated sites of liver cell necrosis and were predominantly cytotoxic/suppressor cells. When compared with the liver biopsies obtained about 2 months after the peak of serum transaminase, cytotoxic/suppressor cells were significantly increased in those obtained during the acute exacerbation period. No significant change of the percentage of natural killer/killer cells was observed in either the peripheral blood or the liver during the acute exacerbation. These findings suggest that T cell cytotoxicity plays an important role in the mechanisms of liver cell damage in acute exacerbation of chronic hepatitis B.

Lymphocyte subpopulations in chronic Chagas' disease

Monoclonal antibodies of the Orthoclone series were used to identify total T lymphocytes (OKT3) and their helper-inducer (OKT4) and cytotoxic-suppressor (OKT8) subsets in 25 patients with chronic Chagas' disease and 25 healthy controls. No significant difference in the number of total T cells (OKT3+) circulating in the peripheral blood of patients and controls was found. However, in contrast to normal subjects, chagasic patients show quantitative alterations in both helper (OKT4+) and suppressor (OKT8+) T cell subsets. The chagasic patients have abnormal helper/suppressor ratios, with low and high values scattered around the mean. Surprisingly, high ratios were found within females while almost all males have low ratio values. These findings suggest that the putative immunoregulatory disfunctions in patients with chronic chagasic cardiomyopathy may involve both helper and suppressor T cell subsets.

Immunoregulatory T cell subsets in chronic hepatitis B virus infection: the influence of homosexuality

The purposes of this study were 2-fold: (i) To enumerate peripheral immunoregulatory T cell subsets in untreated patients with chronic hepatitis B virus (HBV) infection and (ii) to examine the relationship between disturbances in the balance of lymphocyte subsets with liver disease and the presence of homosexuality. Circulating T lymphocyte subsets were evaluated by monoclonal antibodies to the following cell antigens: OKT3 (total T cells), OKT4 (helper/inducer T cells), and OKT8 (suppressor/cytotoxic T cells). The following groups of subjects were examined: (i) 16 heterosexuals with HBV-associated chronic active hepatitis (CAHB); (ii) 10 heterosexual, healthy HBsAg carriers, and (iii) 16 male homosexuals with CAHB. Controls included 51 healthy heterosexuals and 12 healthy, noninfected male homosexuals. We were able to demonstrate that heterosexuals with CAHB had T4/T8 ratios which did not differ from those of noninfected heterosexuals. Both healthy carriers and healthy homosexuals, however, exhibited significantly lower T4/T8 ratios than did noninfected heterosexuals (p less than 0.05, p less than 0.01, respectively). In addition, homosexuals with CAHB had lower (1.5 +/- 0.1) T4/T8 ratios than did heterosexuals with CAHB (2.0 +/- 0.2). A possible mechanism for these findings is discussed. The data indicate that the presence of homosexuality may be an important factor to consider when evaluating immunoregulatory subsets in CAHB.

Studies of lymphocyte subpopulations in the liver tissue and blood of patients with chronic active hepatitis (CAH)

Monoclonal antibodies to antigens on the surfaces of mononuclear cells (MNC) were used to characterize lymphocyte subpopulations infiltrating portal areas and parenchyma of livers in 31 patients with chronic active hepatitis (CAH). The distribution and numbers of infiltrating lymphocytes were determined in serial sections immunostained by the avidin-biotin-peroxidase complex method. T lymphocytes were the major component of inflammatory cells in the portal tracts. In the peripheral blood and portal areas, T helper-inducer (T4+) cells were the more numerous subpopulation. However, the hepatic lobules and areas of "piecemeal" necrosis always contained more T suppressor-cytotoxic (T8+) cells. The latter were demonstrated in contact with HBsAg-containing hepatocytes in tissues of patients with HBsAg-positive CAH. The mean numbers of T lymphocytes infiltrating the portal and periportal areas of livers from patients with HBsAg-negative and HBsAg-positive CAH were not different. Large numbers of B cells forming distinct follicles were seen in tissues from patients with HBsAg-positive CAH. The presence of increased numbers of portal T and B lymphocytes correlated with progressive liver damage as observed in two patients studied at yearly intervals.

T-cell dysfunctions in IgA nephropathy: specific abnormalities in the regulation of IgA synthesis

This work was undertaken to determine the cellular abnormalities that could explain the high levels of serum IgA frequently found in patients with IgA nephropathy. Seventeen control subjects and twenty-seven patients who had received no therapy were studied. After in vitro pokeweed mitogen (PWM) stimulation, significantly higher amounts of IgA were produced by peripheral blood mononuclear cells (PBM) of patients when compared with those of the control group (560 +/- 97 vs 231 +/- 57 ng/ml, P less than 0.0025). No differences were observed in the synthesis of IgG and IgM. Twenty out of twenty-seven patients presented an increase in the percentages of OKT4+ cells (mean + 2 SD), in relation to the control group, with normal or elevated percentages of OKT8+ cells. The OKT4+/OKT8+ cell ratio was elevated in 12 out of 27 patients. All patients presented some abnormality in the generation of IgA-specific suppressor cells at variable doses of concanavalin A (Con A) on in vitro PWM-stimulated culture of PBM. In both assays low doses of Con A (2.5 micrograms/ml) induced a certain suppression of IgA synthesis in patients that was not observed in the majority of the control group. At these doses some patients also showed an enhancement in the synthesis of IgG and IgM. On the contrary, higher doses of Con A (50 micrograms/ml) produced significantly less IgA suppression than the controls. Normal IgA-suppression values were found at 10 micrograms/ml of Con A. T cells obtained from patients were significantly more efficient than T cells from controls in providing IgA-helper activity for normal allogeneic enriched B cells (P less than 0.025) in PWM-stimulated cocultures. These results show that patients with IgA nephropathy present, after mitogen stimulation in vitro, a specifically increased production of IgA as well as an augmentation in the activity of IgA-helper T cell and a deregulation on IgA-suppressor T-cell function. According to these data, it is suggested that the alteration observed in helper T cells might precede that of suppressor T cells. These immunoregulatory abnormalities might contribute to the pathogenesis of the disease.