Altered intracellular expression of the chemokines MIP-1alpha, MIP-1beta and IL-8 by peripheral blood CD4+ and CD8+ T cells in mild allergic asthma.

BACKGROUND: The ability of chemokines to regulate Th1 and Th2 responses suggests a role in the pathogenesis of atopic disorders such as allergic asthma where Th2 response dominance has been observed. Although the impact of allergic asthma on local chemokine production in the lung has been the subject of investigation, little is know about the influence of disease progression on peripheral chemokine production. We now report use of whole blood culture and flow cytometry to assess the influence of mild allergic asthma on peripheral T-cell chemokine expression. METHODS: Study participants included patients with mild allergic asthma (n = 7) and nonasthmatic controls (n = 7). Following in vitro stimulation of peripheral venous blood with phorbol 12-myristate acetate (PMA) and ionomycin, flow cytometry was used to estimate the percentage of CD4+ and CD8+ T cells producing a number of chemokines, including macrophage inflammatory proteins MIP-1alpha and MIP-1beta, RANTES (regulated on activation, T-cell expressed and secreted), monocytic chemotactic protein-1 (MCP)-1, and interleukin (IL)-8, or the cytokines interferon (IFN)-gamma and IL-4. Serum levels of MIP-1alpha, MIP-1beta, RANTES, MCP-1, IL-8, IFN-gamma and IL-4 were also assessed by quantitative ELISA. RESULTS: Intracellular expression of MIP-1beta by CD4+ and CD8+ T cells from allergic asthmatics was significantly reduced in comparison to that observed for nonasthmatics (median = 2.29% (1.75-3.50) vs 4.57% (3.38-6.64), P = 0.05; 14.20% (13.18-17.88) vs 44.10% (30.38-48.70), P = 0.01). Similarly, intracellular expression of MIP-1alpha by CD8+ T cells from allergic asthmatics was also significantly lower (3.67% (1.17-5.42) vs 17.10% (4.97-20.43), P = 0.05). Conversely, IL-8 expression by both CD4+ and CD8+ T cells from allergic asthmatics demonstrated significant enhancement (9.93% (7.77-11.28) vs 4.14% (3.61-7.11), P = 0.05; 8.40% (6.97-10.04) vs 4.98% (3.37-6.08), P = 0.05). Examination of intracellular IFN-gamma and IL-4 revealed no significant difference in the expression of either cytokine by CD4+ T-cells from allergic asthmatics and nonasthmatics. In contrast, expression of IFN-gamma was significantly reduced in CD8+ T-cells from allergic asthmatics (24.60% (21.08-32.50) vs 48.40% (41.50-55.28), P = 0.01). CONCLUSIONS: The occurrence in mild allergic asthma of peripheral T-cell chemokine expression suggestive of a diminished Th1 response, coinciding with marginal change in cytokine profiles indicative of a Th2 response bias, confirms the importance of chemokine involvement in the etiology of allergic asthma. The ability to use whole blood culture to estimate chemokine expression in T cell subsets may ultimately provide a practical means to evaluate disease status and to monitor early intervention therapies which target chemokines.

[Hepatitis B virus infection: diagnosis, clinical sequelae, therapy and prevention]. / Hepatitis B Virusinfektion: Diagnose, klinische Folgen, Therapie und Prophylaxe.

This article gives an overview on the clinical epidemiology of hepatitis B in Switzerland. It considers structure of the hepatitis B virus, serologic diagnosis of hepatitis B and its prevention and treatment. The main conclusions are as follows: 1. Hepatitis B prophylaxis is available. Juveniles should be vaccinated before taking up sexual activity. Pregnant women should be tested and their offspring immunised actively and passively when there is evidence of infection. 2. In cases of acute hepatitis B contact persons should be tested and vaccinated where appropriate. Treatment is not indicated. 3. For the treatment of chronic hepatitis B interferons and lamivudine are currently available. Advantages and shortfalls of the different forms of treatment are discussed.

Long-term evaluation of T-cell subset changes after effective combination antiretroviral therapy during asymptomatic HIV-infection.

Demonstration of long-lived HIV-reservoirs resistant to the effects of combination antiretroviral therapy raises concern over the ability of treatment to maintain long-term beneficial alterations in T-cell subset composition. To address this issue, we have examined the effect of antiretroviral therapy on T-cell subset change during early HIV-infection in a 2-year prospective open-label trial composed of treatment-naive asymptomatic HIV-infected patients with CD4+ T-cell counts > or =400 cells/microl. Therapy consisted of double (zidovudine and lamivudine) or triple (zidovudine, lamivudine, and ritonavir) combination antiretroviral therapy. Retrospective analysis based on magnitude of viral suppression was used to characterize responder and nonresponder groups. Among responders, long-term antiretroviral therapy maintained a significant increase in numbers of total CD4+, naive CD4+/CD45RA+, and memory CD4+/CD45RO+ T cells. A concomitant significant decrease in numbers of memory CD8+/CD45RO+ and both activated CD8+/HLA-DR+ and CD8+/CD38+ T cells was also maintained. In contrast, long-term antiretroviral therapy among nonresponders led only to a significant increase in the numbers of CD4+ T cells and a significant reduction in numbers of activated CD8+/HLA-DR+ T cells. The long-term ability of antiretroviral therapy during early asymptomatic HIV-infection to maintain reversal of disease-induced T-cell activation and maturation abnormalities continues to support the concept that immunologic advantage is gained by commencing early aggressive antiretroviral therapy. Nevertheless, continued management of T-cell subset recovery is significantly more effective in the presence of completely suppressed viral replication.

[Hepatitis C virus infection. Overview. SEVHEP (Swiss Experts on Viral Hepatitis)]. / Hepatitis C-Virus-Infektion. Ubersicht. SEVHEP. Schweizer Experten für Virale Hepatitis.

The hepatitis C virus (HCV) shows a pronounced polymorphism with six genotypes and many subtypes. The virus is generally not cytopathogenic. Immunological defence mechanisms are probably essential for the pathogenecity. An acute hepatitis is relatively rare; the infection becomes chronic in over 70%. The data on the occurrence of chronic hepatitis, cirrhosis and hepatocellular carcinoma are conflicting. The age at infection, the gender, coinfections with HBV and HIV and alcohol consumption play a role. The basis of diagnostics is the anti-HCV screening test with clear indications for the measurement of the genotype and of HCV-RNA. The combination of interferon-alpha and Ribavirin is the therapy of choice with improved success. HCV is most often transmitted through contaminated syringes and needles, i.v. drug users having the greatest incidence and prevalence. Vertical and sexual HCV transmission is relatively rare. It is estimated that the HCV prevalence in Switzerland is 0.75-1%, afflicting 50,000-70,000 individuals. Over the next years the number of HCV associated decompensated liver cirrhosis, liver transplantation and death will grow. Efforts of collaboration in the field are undertaken including the establishment of a Swiss HCV cohort study.

Recombinant gp160 as a therapeutic vaccine for HIV-infection: results of a large randomized, controlled trial. European Multinational IMMUNO AIDS Vaccine Study Group.

OBJECTIVES: The primary objective of this study was to expand the safety and immunogenicity database of recombinant gp160 as a therapeutic vaccine in the treatment of HIV-infection. Preliminary efficacy data was also sought. DESIGN: This trial was a randomized, double-blind, placebo-controlled study. Two-hundred and eight volunteers, 96 therapy-naive with CD4 cell count >500x10(6)/l (group A) and 112 with CD4 cell count of 200-500x10(6)/l (group B, 51 out of 112 on treatment with one or two nucleoside analogues), received monthly injections of rgp160 IIIB vaccine or placebo for the first 6 months of the study; booster immunizations with rgp160 MN or placebo were given at times 15, 18, and 21 months. METHODS: Safety and immunogenicity data were obtained and measurements of CD4 cell count, plasma viral RNA, and proviral DNA were performed. Clinical outcome was recorded for the 24 months of study. RESULTS: The vaccine was safe and well tolerated. Despite the induction of new rgp160-specific lymphoproliferative responses and the presence of positive delayed type hypersensitivity skin tests to rgp160 at the end of the 24 month study, no effect on the natural history of HIV infection was detected. Within 24 months, AIDS-defining illnesses had occurred in 19 of the vaccinated volunteers and in 18 of the placebo recipients. Persons with higher plasma viral RNA levels and higher proviral DNA had a more rapid decline in CD4 cell count when compared to persons with lower values. Vaccine did not alter viral RNA or proviral DNA levels. CONCLUSION: There was no clinical benefit to therapeutic immunizations with rgp160, despite the induction of new lymphoproliferative responses.

Highly active antiretroviral therapy during early HIV infection reverses T-cell activation and maturation abnormalities. Swiss HIV Cohort Study.

OBJECTIVES: To evaluate the impact of early initiation of highly active antiretroviral therapy (HAART) on disease-induced T-cell activation and maturation abnormalities during asymptomatic HIV infection. DESIGN: A prospective open-label trial of zidovudine, lamivudine and ritonavir in treatment-naive asymptomatic HIV-infected individuals with CD4 cells > or = 400 x 10(6)/l. METHODS: Peripheral blood CD4+ and CD8+ T cells derived from 15 asymptomatic HIV-infected individuals (median baseline CD4+ cells, 608 x 10(6)/l; CD8+ cells, 894 x 10(6)/l; plasma HIV RNA, 3.93 log10 copies/ml) undergoing therapy with zidovudine (300 mg twice daily), lamivudine (150 mg twice daily), and ritonavir (600 mg twice daily) were assessed for changes in expression of phenotypic markers of T-cell activation (HLA-DR and CD38) and maturation (CD45RA and CD45RO). At weeks 0, 2, 4, 8, 12, 16, 20 and 24, T-cell subsets were quantified by flow cytometry and plasma HIV viral loads determined using reverse transcription PCR. RESULTS: HAART-induced decrease in plasma HIV RNA levels coincided with a significant reduction in numbers of activated CD4+/HLA-DR+ (maximum change, -36%; P < or = 0.05), CD8+/HLA-DR+ (maximum change, -66%; P < or = 0.005) and CD8+/CD38+ (maximum change, -51%; P < or = 0.01) T cells. A concomitant significant increase in numbers of naive CD4+/CD45RA+ (maximum change, +12%; P < or = 0.005) and memory CD4+/CD45RO+ (maximum change, +6%; P < or = 0.05) T cells was also evident, which contrasted with a significant decrease in memory CD8+/CD45RO+ cells (maximum change, -42%; P < or = 0.005). CONCLUSION: The observed ability of HAART during early asymptomatic HIV infection to initiate rapid reversal of disease-induced T-cell activation and maturation abnormalities, while preserving pretherapy levels of immune function, supports the concept that therapeutic advantage is to be gained by commencing early aggressive antiretroviral therapy.

[Hepatitis B virus and pathogenesis]. / Hepatitis-B-Virus und Pathogenese.

The hepatitis B virus belongs to the hepadna viruses family. Its genome consists of an incompletely double stranded DNA. The preS/S domain encodes proteins which make up the outer viral coat containing the HBs surface antigen (HBsAg). Other viral genes programme for structures inside the virus and for various regulatory enzymes. HBV mainly infects hepatocytes. The virus replicates in the cytoplasm and is primarily non-cytopathogenic. HBV can also integrate into the host cell. Various stable genotypes and subtypes are known, which have a characteristic geographic distribution. They all share a common HBsAg epitop, which has allowed the development of a vaccine which is efficient world-wide. The protective principle consists of inducing protective anti-HBs. The infected cell has to be destroyed to eliminate the virus. Cellular immune defence mechanisms are mainly relevant, the principle effectors being cytotoxic T lymphocytes, activated monocytes/macrophages and cytokines such as interferon-gamma. The natural course of infection is highly variable, comprising viral elimination with or without acute hepatitis and chronic infection which might lead to chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. This is due to the balance respectively to the inbalance between the viral replication capacity and the immune defence mechanisms.

[Serologic diagnosis and follow-up of hepatitis B]. / Serologische Diagnose und Verlaufsbeurteilung der Hepatitis B.

This paper is a short summary on the usefulness of two antigens (HBsAg and HBeAg), three antibodies (anti-HBc, anti-HBe and anti-HBs) and of HBV DNA, as markers for the diagnosis and the follow-up of hepatitis B. The significance of each of these markers at the various stages of disease history, a few patterns of co-existence of some of these markers and the occurrence of mutations in the core and pre-core regions of the genome are also described. The various indications for measuring HBV DNA, in addition to the classical serological markers, are also mentioned.

[Chronic hepatitis B and C in HIV-infected patients]. / Chronische Hepatitis B und C bei HIV-infizierten Patienten.

BACKGROUND AND AIM: This retrospective study examined the prevalence of co-infections with hepatitis B virus (HBV) and hepatitis C virus (HCV) and the frequency of chronic hepatitis in HIV-infected patients with respect to both the different risk groups and the serological results. PATIENTS AND METHODS: All Zurich participants of the Swiss HIV Cohort Study were evaluated who had available results of hepatitis B and C serology and ALT. RESULTS: Of the total 279 patients, 52% belonged to the intravenous drug user, 34% to the homosexual, and 11% to the heterosexual risk category. Serologically, previously acquired infection with HBV alone could be demonstrated in 92 (33%), HCV alone in 9 (3%), and both HBV and HCV in 130 (47%) patients. Only 3% of patients with sexually acquired HIV infection had anti-HCV antibodies, whereas co-infection with HBV and HCV was present in 87% of intravenous drug users. Among the 222 patients with previous HBV contact, 25 (11%) had positive HBsAg and 91 (41%) had "anti-HBc alone", both assumed to represent active HBV infection. 66 (24%) of 279 patients had chronic hepatitis with ALT elevation lasting > or = 6 months. Chronic hepatitis was present in 46% of those with active HBV and HCV co-infection, in 36% of those with HCV infection alone and in 18% of those with active HBV infection alone (P < 0.001). Of the 66 cases of chronic hepatitis, 58 were associated with HCV infection, and only 2 cases had no serological signs of active HBV or HCV infection. CONCLUSION: In patients with sexually acquired HIV infection, HBV had frequently been co-transmitted. In contrast, almost all of those infected by means of intravenous drug use had a co-infection with both HBV and HCV. The latter seems to play the strongest role in the development of chronic hepatitis with persistent ALT elevation. A chronic ALT elevation was almost always associated with serologically active HBV or HCV infection.

Frequent chronic hepatitis B virus infection in HIV-infected patients positive for antibody to hepatitis B core antigen only. Swiss HIV Cohort Study.

Persons with immune deficiency may present with atypical results in serological tests for hepatitis B virus (HBV). Frozen serum specimens that were sequentially obtained over time from a cohort of 57 HIV-infected patients, all of whom tested positive only for antibody to hepatitis B core antigen (anti-HBcAg), were therefore retested for HBV markers, including HBV DNA. The results were assessed for their time course and correlated with clinical data and alanine aminotransferase (ALT) values. Forty-eight patients were male; intravenous drug users constituted the principal risk group (n = 30), followed by homosexual men (n = 22). Thirty-three persons tested positive for antibody to hepatitis C virus (anti-HCV). During a median of 31 months from the first to the last serum, anti-HBcAg remained the sole marker of HBV infection in 98.2% of the patients. Polymerase chain reaction (PCR) to detect DNA for HBV core and HBV surface gene was positive in 126 (62.4%) and 121 (59.9%) of all 202 serum samples, respectively. Over time, HBV DNA was detected at least once in 51 (89.5%) patients. In contrast, decomplexed hepatitis B surface antigen (HBsAg) was detected at least once in 14 (24.6%) patients. Among patients positive for HBV DNA and negative for anti-HCV, eight (36.4%) of 22 had chronic hepatitis (ALT elevation > or = 6 months) that was attributable only to persisting HBV infection. Similarly, 12 (41.4%) of 29 patients positive for both HBV DNA and anti-HCV had chronic viral hepatitis, but their ALT values were significantly higher. In HIV-infected patients, anti-HBcAg as the sole serological HBV marker detected must be considered indicative of chronic HBV infection and is in part associated with chronic hepatitis and ALT elevation.

Hepatitis B: virus, pathogenesis and treatment.

The hepatitis B virus (HBV) is a coated, incompletely double-stranded DNA virus with some outstanding features. (1) All three coat proteins of HBV contain HBsAg, which is highly immunogenic inducing anti-HBs. These antibodies are protective for HBV outer cells (humoural immunity). Structural viral proteins induce specific T-lymphocytes, which are able to eliminate HBV-infected cells (cytotoxic T-cells; cellular immunity). (2) Intracellular HBV primarily causes little or no damage (non-cytopathogenic), which is an excellent strategy of viral survival. However, viral oligo-peptides of 8-15 amino acids are loaded on host cell MHC-class 1 molecules and are transported to the cell surface. Thus, HBV-specific T-lymphocytes are able to detect infected cells and destroy them, an ingenious defence strategy. However, this cell deletion triggered by inflammation cells may result in acute hepatitis. If HBV is not eliminated, a delicate balance between viral replication and immunodefence prevails which may lead to chronic hepatitis and liver cirrhosis. (3) In chronically infected cells HBV may become partly cytopathogenic--a process still poorly understood--and the viral DNA may integrate into the host cell DNA (through a viral transcriptase). If integration leads to activation of crucial host genes a hepatocellular carcinoma results. These outstanding features are responsible for the highly variable course of HBV infection and its final outcome, e.g. when the load of HBV-infected cells is still low at the time when an efficient immune defence starts, the infection is self-limited and asymptomatic, and immunity results. When there is no immune defence or a defective immune defence (immune tolerance of new-borns or immunosuppressed individuals) the HBV infection very often becomes chronic. In these cases, no acute hepatitis occurs, but hepatocellular carcinoma may result. Treatment with Interferon has become accepted, resulting in up to 30 to 40% of cases in the elimination of the virus. However, treatment is laborious and expensive, and the mechanism of action is still poorly understood (anti-viral and/or immune-modulating).

Simple monitoring of antiretroviral therapy with a signal-amplification-boosted HIV-1 p24 antigen assay with heat-denatured plasma.

OBJECTIVE: Virus load determination has become indispensable for the management of HIV patients, but depends on expensive assays of a low throughput. We evaluated whether a highly improved HIV-1 p24 antigen detection procedure which involves heat-mediated immune complex dissociation and signal-amplification-boosted enzyme-linked immunosorbent assay (ELISA) was suitable for antiretroviral treatment monitoring. DESIGN AND METHODS: Virus load in plasma was determined for 127 plasma samples taken at 0, 2, 6, 12, 18, 24, 30 and 36 weeks from 23 patients with CD4+ T cells < 50 x 10(6)/l who received indinavir 800 mg three times daily in addition to prior antiretroviral treatment. Tests included polymerase chain reaction (PCR) for viral RNA, measured prospectively with the Roche Amplicor kit, and retrospective batch testing of heat-denatured samples for p24 antigen by the DuPont HIV-1 p24 Core Profile ELISA linked with a tyramide signal amplification step. Particle-associated reverse transcriptase (RT) by the product-enhanced RT (PERT) assay was determined as an independent third-opinion viral load marker. RESULTS: p24 antigen was detected as sensitively as viral RNA. Overall detection during a median observation time of 25 weeks (range, 0-39) amounted to 75.6% for antigen and 73.6% for RNA. The antigen detection limit was 0.2 pg/ml. Antigen was detectable in all 23 baseline samples, whereas RNA was undetectable in one. Antigen and RNA levels in 79 samples positive for both markers correlated with r = 0.714 (P < 0.0001). Average changes in levels of p24 antigen and RNA at eight timepoints correlated with r = 0.982 (P < 0.0001). In individual patients, the two parameters behaved similarly, and in certain cases virtually identically. RT activity was measurable in all samples. CONCLUSIONS: The performance of this antigen detection procedure is comparable to RNA PCR, thus providing a simple, high throughput alternative in monitoring the efficacy of antiretroviral treatment.

Change in circulating levels of the chemokines macrophage inflammatory proteins 1 alpha and 11 beta, RANTES, monocyte chemotactic protein-1 and interleukin-16 following treatment of severely immunodeficient HIV-infected individuals with indinavir.

OBJECTIVE: To evaluate the in vivo relationship between HIV replication and circulating levels of the chemokines macrophage inflammatory protein (MIP)-1 alpha, MIP-1 beta, RANTES (acronym for Regulated upon Activation, Normal T-cell Expressed and presumably Secreted), interleukin (IL)-16 and monocyte chemotactic protein (MCP)-1, which have recently been characterized as factors capable of regulating in vitro HIV replication. DESIGN AND METHODS: We have compared changes in plasma HIV-RNA levels and circulating levels of MIP-1 alpha, MIP-1 beta, RANTES, IL-16 and MCP-1 in 20 severely immunodeficient HIV-infected individuals (CD4+ T cells = 14 +/- 3 cells x 10(6)/l; plasma HIV RNA = 4.45 +/- 0.27 log 10 copies/ml) undergoing treatment with the HIV protease inhibitor indinavir that added to pre-existing nucleoside-based therapy. At weeks 0, 2, 6 and 12, viral load was quantified using a commercial reverse-transcription polymerase chain reaction assay, peripheral blood T-cell subpopulations assessed by flow cytometry, and chemokine levels quantified using commercial sandwich enzyme-linked immunosorbent assay kits. RESULTS: Following initiation of indinavir-based therapy, significant decreases in plasma HIV-RNA levels (change = 2.0 +/- 0.75 log 10 copies/ml) were observed in conjunction with significant increases in absolute CD4+ (change = 83 +/- 19 cells x 10(6)/l) and CD8+ (change = 293 +/- 96 cells x 10(6)/l) T-cell numbers. Concomitantly, significant increases in MIP-1 alpha (19% increase), MIP-1 beta (14% increase), RANTES (15% increase) and IL-16 (1213% increase) levels occurred. In contrast, MCP-1 levels decreased significantly (47% decrease). CONCLUSION: The in vivo demonstration of an association between diminishing plasma HIV-RNA levels and the emergence of a circulating chemokine profile capable of inhibiting HIV replication corroborates recent in vitro observations and provides evidence for the restoration of chemokine capacity by HIV protease inhibitor-based therapy.

[Progress in hepatitis diagnosis]. / Fortschritte in der Hepatitisdiagnostik.

Until today only five pathogens of viral hepatitis have been discovered: hepatitis virus A (HAV), B (HBV), C (HCV), D (HDV) and E (HEV). An update on the state of the art of actually established diagnostic procedures is briefly summarized. Some recent topics and problems are covered more extensively; in the case of HBV the value of HBsAG concentration as a prognostic marker, the finding 'anti-HBc only' the role of HBV mutants, the determination of circulating HBV genomic material, and modalities for HBV vaccination control; in the case of HCV the indications for study of its viral genomic material and the role of HCV subspecies are explained. Finally, first results on HEV prevalence in Switzerland are introduced.

Detection of HBs antigen in "anti-HBc alone" positive sera.

The immunoserological finding "anti-HBc alone" is often observed in defined groups of individuals, such as patients with inflammatory hepatopathies, patients on hemodialyses or with organ transplants, i.v. drug users and homosexuals, but it also occurs in up to 1% of Swiss blood-donors. In order to gain further information about whether "anti-HBc alone" reflects late immunity or points to an ongoing or a recently passed hepatitis B virus infection, 153 serum samples were tested for immune-complex-dissociated HBs-antigen, using acid treatment for complex dissociation. Of the samples tested 31% contained complexed HBsAg, the highest rates being found in individuals with hepatopathies (up to 80%), in i.v. drug users (up to 63%) and in hemodialysis patients (40%). The 153 sera were also tested for HBV-DNA by nested PCR. Sixty (39%) probes yielded positive results, comprising 29 (48%) of 60 sera with immune-complexed HBsAg but only 18 (19%) of 93 probes without complexed HBsAg. The results point to the possibility that at least some of the individuals with "anti-HBc alone" still have an ongoing HBV-infection.

[Functional IgG subclass determinations in patients with suspected humoral immune defects using the LIBA technique]. / Funktionelle IgG-Subklassenuntersuchungen bei Patienten mit Verdacht auf humoralen Immundefekt mittels LIBA-Technik.

In patients with recurrent infections, "intrinsic" asthma and lymphoma the specific binding capacity of IgG subclass 2 against pneumococcus was determined by line-immuno-binding-assay (LIBA). The results show that LIBA represents a simple and specific test system suitable as diagnostic parameter in patients with a suspected humoral defect.

Chronic viral hepatitis B and C: an argument against the conventional classification of chronic hepatitis.

The classification of chronic hepatitis distinguishing benign chronic persistent hepatitis from severe chronic active hepatitis was constructed without knowledge of well-defined aetiological factors. Better understanding of the different hepatitis-viruses has shed new light on this subject. Chronic viral hepatitis B and C each show typical histological patterns. The validity of the conventional classification has been evaluated by a comparative study of chronic viral hepatitis B and C. 130 biopsies from 110 patients with chronic hepatitis C (CH-C) proven serologically by antibodies (second generation testing) were compared with 105 biopsies from 73 patients with chronic hepatitis B (CH-B). These were scored semi-quantatively. In CH-C, lymphoid follicles and/or aggregates were found in 88.5%, fatty degeneration in 51%, bile duct lesions in 46.2%, and Mallory body-like material in the hepatocytes in 9.2%. The portal lymphocytic infiltration generally predominated over the necro-inflammatory lesions of the parenchyma. Chronic persistent hepatitis (defined by the presence of portal hepatitis) was present exclusively in CH-C. Chronic lobular hepatitis was found exclusively in CH-B. We conclude that the histological criteria described for CH-C are highly suggestive of the diagnosis, that the artificial subdivision of chronic hepatitis into CPH and CAH is obsolete and that the histological assessment of chronic hepatitis should consist of a grading of inflammatory activity (minimal, mild, moderate, severe) and staging of fibrosis (extent of distortion of architecture). The final diagnosis should be based on the demonstration of the aetiological agent.