Relationship between T lymphocyte responsiveness and T-helper1/T-helper2 type cytokine release in chronic hepatitis C: a critical reappraisal.

Recruitment of virus-specific T lymphocyte subpopulations to liver sites in chronic hepatitis C virus (HCV) infection implies a key role for the immune response in host-virus interaction. In spite of a multispecific and polyclonal cytotoxic function exerted by CD8+ lymphocytes, CD4-mediated activity is weak. This allows the infection to persist which in turn is responsible for the development of chronic hepatitis C (CH-C). Such a finding outlines the occurrence of a possible relationship between cytokine (CK) production by CD4 subsets, i.e. T helper (Th)1 or Th2 cells, and the clinical outcome. A prevalence of Th1-derived CK occurs in infected liver, while increased amounts of Th2-related CK are usually found in peripheral blood. Moreover, peripheral blood mononuclear cell (PBMC) cultures from CH-C subjects exhibit an impaired interferon (IFN)-gamma production and an increase of interleukin (IL)-12 p70 release after stimulation. The latter pattern seems to be due to the enhanced release of IL-12 p40 homodimers, which antagonize IL-12 p70 bioactivity and favour IL-10-induced effects. These results suggest that further extensive studies on the imbalance of the CK network at a molecular level are required to improve the therapeutical approach in CH-C subjects.

[Autoantibodies in chronic hepatitis C. Markers of autoimmunity or non-specific events?]. / Autoanticorpi nell'epatite cronica da virus C. Marcatori di autoimmunità o eventi aspecifici?

In the light of the high prevalence of non organ-specific autoantibodies in chronic hepatitis C, the possibility that such a finding may represent the consequence of a viral, autoimmune or overlapping disease should be considered, which may in turn require a different therapeutical approach. It is known, anyway, that the diagnosis of autoimmune hepatitis is based on a set of epidemiological, clinical, biochemical, histological criteria and autoantibody pattern. In 113 cases of chronic hepatitis with HCV infection, we determined the presence of non organ-specific autoantibodies [anti-nuclear (ANA), anti-smooth muscle (SMA), anti-liver-kidney microsomal antibodies (LKM), anti-mithocondrial antibodies (AMA)] and described the epidemiological, clinical, biochemical, histological characteristics and therapeutic response to interferon. 40 patients (35%) exhibited non organ-specific autoantibodies: 25 patients were SMA positive (Vasal pattern), 4 ANA positive (Speckled pattern), 7 ANA (Speckled pattern) + SMA (Vasal pattern) positive and 4 LKM positive. All subjects with HCV infection and autoantibodies did not display additional criterias of autoimmunity, including the same outcome to interferon therapy when compared to HCV positive patients without autoantibodies. The failure to determine clinical features, associated to autoimmunity in HCV positive patients with autoantibodies, suggests that autoantibody occurrence may represent a fortuitous event during the course of HCV infection.

[Acute disseminated encephalomyelitis as initial clinical manifestation of common variable immunodeficiency. A case report]. / Encefalomielite acuta disseminata come manifestazione clinica iniziale nel deficit immunologico comune variabile. Descrizione di un caso.

Common variable immunodeficiency (CVID) is a primary immunodeficiency disease characterized by severe and recurrent infections which affect both lung and gastrointestinal systems. On the contrary, central nervous system involvement, related to virus infections, is an important, rare and usually fatal complication occurring in a later phase of the disease. Furthermore, CVID may predispose to a variety of autoimmune diseases. Here, we report the case of a 20 years old girl who developed acute disseminated encephalomyelitis as the first clinical feature in CVID. The infective agent was not determined and there was no history of recent vaccinations. CVID was diagnosed on the basis of the significant reduction of serum immunoglobulin concentration, in the absence of either diseases responsible for secondary immunodeficiency or functional and/or quantitative abnormalities of lymphocyte subsets, phagocytes and complement fractions. The treatment with high doses of native intravenous immunoglobulins (IVIG) combined with corticosteroids in the early phase led to a complete recovery with restitutio ad integrum. This case outlines the possible relationship between autoimmune diseases and infections in CVID, as suggested by the finding of either viral encephalitis in CVID patients and the well-known autoimmune pathogenesis of acute disseminated encephalomyelitis. In such a condition, the combination of IVIG and corticosteroids may offer considerable advantages in terms of therapeutical efficacy.

Transforming growth factor beta1 and soluble Fas serum levels in hepatocellular carcinoma.

In this study we assessed the usefulness of serum Transforming Growth Factor-beta1 (TGF-beta1) and soluble Fas (sFas) in distinguishing liver cirrhosis (LC) with and without hepatocellular carcinoma (HCC) as compared with alpha-fetoprotein (AFP). Serum TGF-beta1 and sFas levels were measured by ELISA in 51 LC patients, 54 patients with HCC and 30 healthy donors. Considering as a cut-off limit (mean+1SD of controls) 74 pg/ml and 637 pg/ml for TGF-beta1 and sFas, respectively, we computed serum concentrations of TGF-beta1 and sFas as a score (mean+/-SD). The positive frequency of serum TGF-beta1 levels in HCC patients (54%) was greater than in LC patients (26%) and healthy donors (3%). TGF-beta1 levels were higher in HCC (1.6+/-0.5) than in LC (1.1+/-0.2) (P<0.0001) and healthy donors (0.6+/-0.2). Using a cut-off limit of 82 pg/ml (mean+2SD), the positive frequency of TGF-beta1 was 20% in HCC patients. None of the controls and LC patients had TGF-beta1 levels higher than 82 pg/ml. The positive frequency of serum sFas levels was 100% in HCC patients, 98% in LC patients and 3% in healthy controls. Serum sFas levels were higher in HCC (2.5+/-0.7) than in LC (1.9+/-0.5) (P<0. 001) and healthy donors (0.6+/-0.3). No significant change of positive frequency was obtained by setting sFas cut-off at higher levels. sFas values did not correlate with TGF-beta1 levels. No relationship was found between TGF-beta1 amounts and AFP levels. However, in the 23% of HCC patients, with normal AFP values TGF-beta1 levels were higher than the cut off. These findings suggest the potential usefulness for TGF-beta1 assay in AFP-negative HCC.

Relationship between interferon-gamma, interleukin-10, and interleukin-12 production in chronic hepatitis C and in vitro effects of interferon-alpha.

In the current study, increased interferon (IFN)-gamma, interleukin (IL)-10, and IL-12 p40 serum levels were observed in patients with chronic hepatitis C (CHC) compared to controls. Patients also displayed an increased spontaneous IFN-gamma release but a deficient peripheral blood mononuclear cells (PBMC) IFN-gamma production following stimulation with Staphylococcus aureus Cowan I strain (SAC). No difference was found with reference to spontaneous or phytohaemagglutinin (PHA)-induced IL-10 release between patients and controls, whereas a higher IL-12 p70 and IL-12 p40 secretion triggered by SAC was observed in patients. Moreover, IL-12 p40/p70 ratio following SAC stimulation was higher in patients compared to controls and a negative correlation was found between this ratio and IFN-gamma amounts. Recombinant IL-12 (rIL-12) as well as neutralizing anti-IL-10 monoclonal antibodies (mAbs) were able to restore the compromised IFN-gamma production. Of note, anti-IL-10 supplementation induced a lower IL-12 p40/p70 ratio in HCV subjects as compared to controls. Finally, IFN-alpha upregulated in vitro IFN-gamma, IL-10, and IL-12 p70 release but not IL-12 p40 secretion, this giving rise to a normalization of IL-12 p40/p70 ratio. The data suggest the occurrence of an enhanced responsiveness to IL-10 modulating effects, likely mediated by an imbalance of IL-12 p40/p70 ratio, in chronic HCV infection. Cytokine balance restoration might thus contribute to achieve therapeutical results in chronic hepatitis C.

Beneficial effects of postmenopausal hormone replacement therapy with transdermal estradiol on sensitivity to activated protein C.

Many hemostatic and fibrinolytic parameters have been evaluated following hormone replacement therapy (HRT) but little is known about its influence on the anticoagulant response to activated protein C (APC-sensitivity). For this purpose, we studied the effect of transdermal 17-beta-estradiol (50 microg/24 h) by a continuous regimen on the APC-sensitivity, in 28 postmenopausal hysterectomized women (mean age, 47 years; range, 44-65 years). We also measured the plasma proteins directly involved in the protein C anticoagulant pathway, such as activities of factor VIII (VIII:C), factor V and free protein S. Von Willebrand factor (vWF) antigen, the carrier protein of factor VIII, was also determined. Blood sampling was done at baseline and after 16-week therapy. A significant increase in the normalized APC-sensitivity ratio (n-APC-SR) values (mean +/- SD: pre-trial, 0.88 +/- 0.14; post-trial, 1.01 +/- 0.12; P < 0.001) and a significant decrease of factor VIII:C plasma levels (pre-trial, 1.13 +/- 0.29 IU/ml; post-trial, 0.98 +/- 0.20 IU/ ml; P = 0.001) were found. No difference was observed in factor V, protein S and vWF plasma levels. Correlation studies demonstrated only a significant negative correlation between the percent change in n-APC-SR and the percent change in factor VIII:C (r = -0.574; P = 0.001). Our findings clearly show that HRT with transdermal estradiol improves the anticoagulant response to APC, probably as a result of a decreased factor VIII:C. We also suggest that a similar but opposite mechanism may occur for perorally administered estrogens used in the HRT. These results may have some clinical implications about the reported increase of the risk for venous thromboembolism following HRT.

sICAM-1, sCD95 and sCD95L levels in chronic liver diseases of different etiology.

The release of soluble circulating molecules represents a prominent feature during the course of immune-mediated clinical conditions. To further assess the relationship between serum concentrations of adhesion or apoptotic-related soluble structures and liver diseases, we evaluated the levels of intercellular adhesion molecule-1 (sICAM-1), Fas receptor (CD95) and Fas ligand (sCD95L) in a group of patients affected by Hepatitis C Virus (HCV)-induced chronic hepatitis (CH-C), HCV-positive liver cirrhosis with superimposed hepatocellular carcinoma (HCC), autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC) and alcoholic liver cirrhosis (ALC). Results show that sICAM-1 values were in all instances significantly elevated when compared to those seen in healthy donors. Similar findings were noted in subjects with liver diseases in terms of sCD95 concentrations, even if to a different degree of statistical significance. Finally, sCD95L amounts were augmented in AIH, PBC, ALC and CH-C in comparison to controls, while in the HCC counterpart sCD95L levels fell within normal range. All together, these findings emphasize the occurrence of circulating soluble molecules in patients with various chronic liver diseases, likely reflecting the involvement of several pathogenetic mechanisms.

[Hepatitis C virus infection mimicking hemorrhagic fever: a case report] / L'infezione da virus dell'epatite C che si manifesta come febbre emorragica: descrizione di un caso.

Acute C hepatitis, compared with hepatitis A or B, may sometimes be associated with extrahepatic manifestations of a haematologic nature. The first case of hepatitis associated with aplastic anemia was reported by Lorenz in 1955. We observed a patient who developed acute hepatitis, associated with febrile purpura: pancytopenia was present, but not aplasia. This association is frequent in Flavivirus-related infections, like Dengue and Yellow Fever, and principally affects children and young people. HCV belongs to the Flavivirus family and so in this case clinical signs may have developed as a consequence of HCV infection.

Soluble HLA class I antigens in chronic hepatitis C: a disease-associated manifestation or molecules modulating immunoresponsiveness?

The occurrence of high levels of soluble human leukocyte class I antigens (sHLA-I) represents an usual finding during the course of different clinical conditions, such as viral infections and autoimmune disorders. On the other hand, the well known property of sHLA-I to modulate T cell responsiveness could be taken as an advantage to improve long-term allograft acceptance. Recent data have pointed out that subjects with chronic hepatitis C virus (HCV) infection exhibit high amounts of sHLA-I, a pattern which has also been used for monitoring host responsiveness to interferon alpha (IFN-alpha) therapy. However, the lack of correlation between lymphocyte infiltration at liver site and disease biological activity suggests a potential role for sHLA-I in T cell dysfunction during chronic hepatitis C. sHLA-I antigens may, in fact, either interact with T cell receptor delivering an inhibitory signal or trigger cytotoxic T lymphocyte apoptosis by inducing CD95 ligand expression. Both events seem to favour HCV replication and liver tissue damage progression. Alltogether, these findings indicate that, besides viral variant generation and HCV core-mediated immunosuppression, sHLA-I may contribute to the imbalance of immunoresponsiveness during chronic HCV infection.

[Autoimmune hemolytic anemia in chronic hepatitis C virus infection treated with alpha-interferon: a therapy-related event or extra-hepatic immunologic manifestation?]. / Anemia emolitica autoimmunitaria in corso di infezione cronica da virus C trattata con interferone alfa. Evento correlato alla terapia o manifestazione immunologica extraepatica?

We report a case of Coombs' positive autoimmune haemolytic anaemia occurring in a patient with chronic hepatitis C virus infection, after five months of alpha-interferon administration. Prednisolone treatment induced a complete remission of both clinical and hematological findings after two months, while Coombs' tests became negative after three months. This points out the possibility of an additional unusual extrahepatic autoimmune feature during the course of hepatitis C virus infection.

[Pericardial involvement as initial manifestation of multiple myeloma]. / Interessamento pericardico come manifestazione iniziale di mieloma multiplo.

Pericardial involvement is a rare complication of multiple myeloma, caused by amyloidosis, infections, or plasmacell infiltration, usually at late or terminal disease stage. We report a patient with pericarditis coming from a department of Cardiology where a preceding (15 years before) diagnosis of breast cancer and present bloody pericardial effusion with probably malignant cells permitted at first to orientate towards metastatic pericardial involvement in breast cancer. Laboratory findings (pancytopenia, hypogammaglobulinemia, proteinuria) suggested to perform bone marrow aspirate, serum and concentrated urine immunoelectrophoresis, measurement of 24-h urine protein excretion, and further cytologic and immunocytochemical assay of pericardial fluid. Acquired data allowed to diagnose light chain multiple myeloma with pericardial involvement caused by plasmacell infiltration. We diagnosed this complication, representing first and main clinical feature of multiple myeloma, owing to a complete clinical and laboratory evaluation and repetition of cytologic and immunocytochemical assay of pericardial fluid.

Liver tissue expression of CD80 and CD95 antigens in chronic hepatitis C: relationship with biological and histological disease activities.

The well known discrepancy between cytotoxic T lymphocyte (CTL) infiltration in the liver and disease biological activity, as assessed by alanine aminotransferase (ALT) levels, during the course of chronic hepatitis C virus (HCV) infection, suggests the possible failure of cytotoxic mechanisms devoted to virus clearance. To further investigate the biological events involved in CTL-mediated lysis, i.e. B7/CD28 costimulatory and Fas/Fas-ligand pathways, the CD80 and CD95 antigen expression in liver tissue specimens from chronically HCV-infected patients was evaluated. The results were analysed in relation to serum ALT values and the histological activity (HAI) of liver disease. The data provide evidence for a strong and comparable hepatocyte CD80 and C95 structure expression in chronically HCV-infected livers. CD80- and CD95-carrying liver cells were more frequently distributed at the periportal region of the hepatic lobule, above all near piecemeal necrosis areas, among infiltrating CTL. On the other hand, a negative correlation was found between liver tissue expression of both antigens and serum ALT activity. The relationship with HAI was not statistically significant. The results imply that HCV infection triggers CD80 and CD95 molecule expression on hepatocytes. Further studies are required to clarify the relevance of such a finding in the context of virus-host interactions.

Treatment with recombinant activated factor VII in a patient with hemophilia A and an inhibitor: advantages of administration by continuous infusion over bolus intermittent injections.

Recent studies have shown that treatment with a continuous infusion of recombinant activated factor VII (rFVIIa) is far more convenient than administration by bolus intermittent injections and may allow a substantial reduction in the dose. We present the case of a 26-year-old patient with hemophilia A, who had a high-titer inhibitor to both human and porcine factor VIII, and who had recently been admitted to hospital because of a bilateral severe ilio-psoas hematoma. Two subsequent courses of treatment with rFVIIa by bolus intermittent injection showed only a partial efficacy. A further administration of rFVIIa was therefore carried out using a continuous infusion regimen that proved to be fully efficacious. During the continuous infusion course levels of factor VII coagulant activity were in the range 18.2-5.2 U/ml, while the prothrombin time, expressed as an International Normalized Ratio, remained within the range 0.57-0.71. The continuous infusion, compared with the administration of the bolus intermittent infusion, reduced the amount of rFVIIa required by approximately 40-50%. Statistical analysis demonstrated that there was a strong positive correlation between the rate of infusion of rFVIIa and levels of factor VII coagulant activity (r = +0.941; P < 0.001), and a very significant negative correlation between levels of factor VII coagulant activity and prothrombin time values (r = -0.897; P < 0.001). In accordance with previous findings, our experience confirms that, when prolonged therapy is required, treatment with rFVIIa by continuous infusion is more convenient than administration of bolus intermittent injections, and may allow the saving of a large amount of drug. Moreover, we suggest potential additional advantages of the continuous infusion regimen over bolus intermittent injections, such as a better efficacy and a stronger correlation between prothrombin time and factor VII coagulant activity levels.

Influence of factor VIII/von Willebrand complex on the activated protein C-resistance phenotype and on the risk for venous thromboembolism in heterozygous carriers of the factor V Leiden mutation.

High factor VIII plasma levels have been shown to represent a common increased risk for venous thromboembolism (VTE) and may cause an activated protein C (APC) resistance in the absence of the factor V Leiden mutation, but there are no studies specifically aimed to establish if high factor VIII and von Willebrand factor (vWF) concentrations may influence the APC sensitivity ratio (APC-SR) and increase the risk for VTE in the presence of the factor V Leiden mutation. For this purpose, we performed a retrospective case-control study to investigate the influence of the procoagulant factor VIII (VIII:C) and the antigen of vWF (vWF:Ag) on the normalized APC-SR (n-APC-SR) and on the risk for VTE, in two selected groups of 30 symptomatic (Group I) and 32 asymptomatic (Group II) related heterozygotes for the factor V Leiden mutation. Differences between the two groups (Group I versus Group II) were: n-APC-SR, 0.57+/-0.06 versus 0.63+/-0.08, P = 0.001; factor VIII:C, 1.49+/-0.42 versus 1.13+/-0.28 IU/ml, P<0.001; vWF:Ag, 1.46+/-0.53 versus 1.26+/-0.32 IU/ml, NS. As a whole (Group I + Group II), Pearson correlation coefficients were: n-APC-SR versus factor VIII:C, r = -0.410, P = 0.001; n-APC-SR versus vWF:Ag, r = -0.309, P = 0.01; factor VIII:C versus vWF:Ag, r = +0.640, P<0.0001. The relative risk for VTE in individuals with the factor VIII:C concentration > 1.5 IU/ml was 2.5 (95% confidence interval 1.6-3.9). We concluded that high factor VIII:C levels, probably in the effect of vWF, play a determinant role in worsening the APC-resistance phenotype and represent a common additional risk factor for VTE in heterozygous carriers of the factor V Leiden mutation.

Costimulatory molecules and cytotoxic T cells in chronic hepatitis C: defence mechanisms devoted to host integrity or harmful events favouring liver injury progression? A review.

The recruitment of antigen-specific lymphocytes at liver site represents a prominent feature in patients chronically infected with hepatitis C virus (HCV). However, despite the strong and multispecific response, chronic infection leads in a significant number of cases to the development of cirrhosis and hepatocellular carcinoma. The finding that the expression of CD80 structure positively correlates with disease histological worsening points out a role for the costimulatory pathway in the progression of liver cell injury. On the other hand, the demonstration of CD95 and CD95-ligand positive cells in the context of periportal areas, a pattern which is not strictly associated to HCV tissue distribution, indicates the occurrence of either virus-infected or innocent bystander hepatocyte killing. Nonetheless, the persistence of HCV, in spite of cytotoxic T lymphocyte (CTL) liver recruitment, suggests a possible in-situ imbalance of cytotoxic activities, above all referred to perforin-granzyme-dependent necrosis. Altogether, these findings outline that several factors might be involved in HCV-driven immunopathogenesis. Therefore, the fully clarification of these mechanisms may offer a suitable therapeutical approach for the improvement of clinical outcome in chronic hepatitis C.

Immunoresponsiveness in chronic hepatitis C patients: correlation between tissue and serum findings.

In the present study, intrahepatic CD8+ lymphocyte infiltrates as well as HLA class I and CD54 (ICAM-1) antigen expression at both tissue and serum levels were evaluated in 54 untreated patients with chronic hepatitis C stratified on the basis of histological diagnosis (Chronic Persistent Hepatitis/Chronic Lobular Hepatitis -CPH/CLH- and Chronic Active Hepatitis -CAH-: 22 and 32 subjects, respectively). The relationships between soluble HLA-I (sHLA-I) and ICAM-1 (sICAM-1) serum levels and their membrane-bound counterparts, CD8+ liver infiltration and serum alanine aminotransferase (ALT) were also studied. A strong HLA-I and CD54 tissue expression, associated to the presence of CD8+ cell infiltrates in necro-inflammatory areas, and elevated sHLA-I and sICAM-1 serum amounts were observed in all patients. At the same time, no difference was found at tissue level between the two groups of patients with respect to the mean scores of HLA-I and CD54 expression, while CAH subjects displayed a significantly higher CD8 periportal and lobular reactivity in comparison to the other subset. Serological assays outlined higher values of circulating HLA-I molecules in CPH/CLH patients and higher sICAM-1 levels in the CAH group. Finally, a negative correlation was found between sHLA-I and ALT in CAH subjects while, in all patients, sICAM-1 positively correlated with both CD8 tissue infiltration and ALT. Our findings confirm the occurrence of an immune activation status during chronic hepatitis C and suggest that sHLA-I molecules might play a down-modulating role on immunoresponsiveness of these patients.

The prevalence of hepatitis C virus types in patients of the same geographic area, according to the source of infection and liver disease.

BACKGROUND: The duration and stage of hepatitis C might be associated with the source of infection and hepatitis C virus (HCV) types. OBJECTIVE: We studied the relationship among the different HCV types, source, duration, and stage of infection in 100 patients from the Apulia, southern Italy, selected from consecutive clinical records. They were 20 parenterally infected haemophiliacs with 10-20 years of disease history, but without cirrhosis; 20 patients (matched for sex, age and disease) and without known risk factor for parenteral infections; 60 patients with community acquired infection (ten with CAH and ten with cirrhosis with less than 20 years disease history; 20 with cirrhosis and hepatocellular carcinoma (HCC) and more than 20 years of liver disease and 20 matched cases with cirrhosis without HCC). RESULTS: Type 1 and 2 HCVs had comparable prevalence in patients with long lasting and recent HCV infection, 56 and 64%, 26 and 30% respectively. HCV type 3 was found in 6.5-12% of the patients with recent HCV infection, but it was not detected in those with infection longer than 20 years. Type 1 b HCV was more frequently found in HCC patients (68% of cases) than in the other forms of liver disease. The opposite was observed for HCV types (2 and 3). CONCLUSIONS: The prevalence of the different HCV types appears associated with the source and duration of the infection. The interesting association between HCV type 1 b and HCC prompts further studies in larger series of patients.

Induction of cell migration by matrix metalloprotease-2 cleavage of laminin-5.

Structural changes in the extracellular matrix are necessary for cell migration during tissue remodeling and tumor invasion. Specific cleavage of laminin-5 (Ln-5) by matrix metalloprotease-2 (MMP2) was shown to induce migration of breast epithelial cells. MMP2 cleaved the Ln-5 gamma2 subunit at residue 587, exposing a putative cryptic promigratory site on Ln-5 that triggers cell motility. This altered form of Ln-5 is found in tumors and in tissues undergoing remodeling, but not in quiescent tissues. Cleavage of Ln-5 by MMP2 and the resulting activation of the Ln-5 cryptic site may provide new targets for modulation of tumor cell invasion and tissue remodeling.

In-situ immunophenotyping study of hepatic-infiltrating cytotoxic cells in chronic active hepatitis C.

OBJECTIVE: Beside the hypothesis of a direct viral cytopathy, several lines of evidence argue in favour of hepatic damage triggered by immune-mediated mechanisms in hepatitis C virus (HCV) infection. The intrahepatic localization of HCV antigen-specific cytotoxic T-lymphocytes (CTLs) to disease sites has been described; however, very few data are available about the degree and the role of hepatic-infiltrating natural killer (NK) cells in chronically HCV-infected subjects. DESIGN: In a series of percutaneous needle liver biopsies obtained from 35 consecutive untreated patients with chronic active hepatitis C, we performed an in-situ immunophenotyping study to evaluate the degree of cytotoxic NK cell infiltration as compared to CTLs, the hepatocyte expression of human major histocompatibility complex antigens class I and class II (HLA-I and HLA-II), and cell adhesion molecules (CAM) in the context of liver inflammatory infiltrates. The data were correlated with the histological activity index (HAI) of disease. RESULTS: In-situ immunophenotyping analysis of CAM provided evidence for the intrahepatic expression of leucocyte adhesion molecules (CD11a and CD2) and their corresponding ligands on hepatocytes (CD54 and CD58) in all cases. A significant parallel expression of CD11a and CD54 as well as CD2 and CD58 structures, restricted to hepatic lobules within the disease sites, was also observed, even if their induction exhibited different degrees of correlation with biological and/or histological activities. A membranous pattern of HLA-I and HLA-II antigen expression on hepatocyte clusters was found in all tissue samples, although HLA-I expression was significantly higher than HLA-II. Moreover, lymphocyte subset analysis displayed a CD8+ T-cell lobular infiltration within inflammatory and/or spotty necrosis areas in all cases, while CD4+ T-cells were confined to the portal and periportal levels. A few scattered CD56+ and CD16+ NK cells, mainly distributed at periportal areas within inflammatory and/or necrotic foci, were detected in 7/35 (20%) and in 5/35 (14.2%) cases, respectively. On the other hand, CD8+ T-cell lobular expression exhibited a linear correlation with HAI (r: 0.698, P < 0.01). Finally, cytotoxic cell infiltration degree did not correlate with HCV serotypes. CONCLUSION: Our findings suggest a limited role for NK cells in the immune mechanism of liver injury in chronic active hepatitis C, while providing further support for the involvement of CD8+ T-cells at disease sites.