IgM antibody to hepatitis C virus in acute and chronic hepatitis C.

To assess possible role of testing for IgM-specific antibody in the diagnosis and monitoring of patients with hepatitis C, we tested sera from 14 patients with acute and 97 patients with chronic non-A, non-B hepatitis for IgG and IgM antibody to hepatitis C virus. IgG antibody to hepatitis C virus was detected in 93% of acute cases and 91% of chronic cases. Of the 101 patients with IgG antibody to hepatitis C virus, 57% had IgM antibody to hepatitis C virus. None of the 20 healthy subjects or 40 patients with acute or chronic hepatitis A or hepatitis B had IgM antibody to hepatitis C virus. At the onset of clinical symptoms in acute hepatitis C, IgG antibody to hepatitis C virus was detected in 8 (57%) and IgM antibody to hepatitis C virus in 9 of 14 patients (64%). Eventually, both IgG and IgM antibody to hepatitis C virus became detectable in 13 of 14 patients with acute hepatitis C. Seven patients with antibody to hepatitis C virus resolved the acute infection within 6 mo and all seven cleared IgM antibody to hepatitis C virus, whereas two cleared IgG antibody to hepatitis C virus. Six patients had a chronic outcome of the acute infection and IgM antibody to hepatitis C virus persisted in detectable amounts for more than 6 mo in all (mean = 15.5 mo). Among 88 patients with chronic non-A, non-B hepatitis with IgG antibody to hepatitis C virus, IgM antibody to hepatitis C virus was detected in 45 (51%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Transient immunoglobulin M antibody response to hepatitis C virus capsid antigen in posttransfusion hepatitis C: putative serological marker for acute viral infection.

The development of serological assays for hepatitis C virus (HCV) has made specific diagnosis possible. However, markers useful in indicating acute-phase HCV infection have not been identified. By an immunoblotting method, we characterized the IgM and IgG antibody response against HCV capsid antigen in patients with HCV infection. Among 88% of patients with acute posttransfusion hepatitis C recruited in a prospective study, there was a transient IgM antibody response. The IgM antibody appeared shortly after onset of hepatitis (average 3.7 weeks), persisted for several months (average 18 weeks), and then disappeared. In contrast, the IgG antibody persisted long-term once it appeared. Among patients with chronic hepatitis C with milder disease activities (serum aminotransferase increase above normal levels of less than 4-fold), the IgM antibody was negative in the majority (72%). In those with acute exacerbations (aminotransferase increase of greater than 10-fold), about 55% were negative for the IgM antibody. The reactivity of the IgM antibody in the rest was weaker or became negative upon further dilution of serum. The results suggest that IgM anti-capsid antibody may serve as a marker indicating acute or active HCV infection.     

Neutralizing antibody response during acute and chronic hepatitis C virus infection

Little is known about the role of Abs in determining the outcome of hepatitis C virus (HCV) infection. By using infectious retroviral pseudotypes bearing HCV glycoproteins, we measured neutralizing Ab (nAb) responses during acute and chronic HCV infection. In seven acutely infected health care workers, only two developed a nAb response that failed to associate with viral clearance. In contrast, the majority of chronically infected patients had nAbs. To determine the kinetics of strain-specific and crossreactive nAb emergence, we studied patient H, the source of the prototype genotype 1a H77 HCV strain. An early weak nAb response, specific for the autologous virus, was detected at seroconversion. However, neutralization of heterologous viruses was detected only between 33 and 111 weeks of infection. We also examined the development of nAbs in 10 chimpanzees infected with H77 clonal virus. No nAb responses were detected in three animals that cleared virus, whereas strain-specific nAbs were detected in six of the seven chronically infected animals after approximately 50 weeks of infection. The delayed appearance of high titer crossreactive nAbs in chronically infected patients suggests that selective mechanism(s) may operate to prevent the appearance of these Abs during acute infection. The long-term persistence of these nAbs in chronically infected patients may regulate viral replication.     

Hepatitis C virus RNA and antibody response in the clinical course of acute hepatitis C virus infection.

Hepatitis C virus RNA, anti-hepatitis C virus immune response and biochemical markers of liver injury were investigated in 17 patients with acute non-A, non-B hepatitis. At the first observation, 1 to 3 wk from the clinical onset, all patients had hepatitis C virus RNA in their serum, and most (15 of 17) were positive for second-generation anti-hepatitis C virus enzyme immunoassay. Follow-up serum samples were available for 10 patients. The rate of recombinant immunoblot assay-confirmed anti-hepatitis C virus enzyme immunoassay reactivities increased from 67% in the first 3 wk to 86% after 21 wk. Elevated ALT levels were associated with hepatitis C virus RNA positivity in most of cases, but the viral nucleic acid was also detected in sera with normal or slightly increased enzyme values. None of the single antibodies tested were related to hepatitis C virus RNA positivity or to the clinical phase of the infection. Therefore hepatitis C virus RNA determination might provide important additional information as compared with anti-hepatitis C virus markers, allowing earlier diagnosis, discrimination of active infection and, possibly, prognostic evaluation.     

Significance of IgM antibody to hepatitis C virus in patients with chronic hepatitis C.

We assessed the correlation between the positivity for serum IgM antibody to hepatitis C virus and the activity of liver disease in patients with chronic hepatitis C virus infection. Serum samples were taken from 10 antibody to hepatitis C virus-positive asymptomatic patients with normal serum ALT levels, from 14 untreated patients with clinically and histologically proven chronic hepatitis C and from 26 patients with clinically and histologically proven chronic hepatitis C assigned to receive recombinant interferon alpha-2a (6 million IU three times a week for 6 mo). Each serum specimen was tested for IgM antibody to hepatitis C virus-associated C100-3 antigen by enzyme-linked immunosorbent assay. Patients were observed for at least 12 mo. All 10 patients with normal ALT values tested negative for IgM antibody to hepatitis C virus. In contrast, 33 of 40 (82%) patients with chronic hepatitis C had IgM antibody to hepatitis C virus, and a positive correlation was seen between the ALT level and the level of IgM antibody to hepatitis C virus (r = 0.803, p less than 0.001). During interferon treatment, ALT levels declined into the normal range in 18 of 26 treated patients (69%) and remained normal after stopping treatment in 8 patients (31%). In untreated patients, in treated patients who did not respond to interferon treatment and in responder patients who relapsed, no significant changes in IgM antibody to hepatitis C virus levels were seen during the study period. In contrast, IgM antibody to hepatitis C virus became undetectable by the end of interferon treatment in seven of eight patients with a sustained response.(ABSTRACT TRUNCATED AT 250 WORDS)     

Humoral immune response in Japanese acute hepatitis patients with hepatitis C virus infection.

The humoral immune response to acute infection by hepatitis C virus (HCV) is not yet perfectly clear in terms of immunoglobulin (Ig) response, diversity of HCV antigen, and the relation with hepatitis severity and antibody response. Serum IgM and IgG anti-HCV levels in patients with HCV and either acute hepatitis (AH) or fulminant hepatitis (FH) were investigated; the diversity of HCV antigen was investigated by RIBA test III. Of 22 AH patients, 12 (54.5%) were positive for IgM anti-HCV, mainly reacting to HCV core protein. The mean interval until the appearance of IgM anti-HCV after onset was 24.1+/-26.2 days. IgG anti-HCV mainly reacted to both core and NS-3 antigen, appearing 42.6+/-42.1 days after onset. From a serial study of 15 AH patients, it was considered that in seven AH patients (46. 7%), the IgM response would precede the IgG response. In another two AH patients, IgM anti-HCV was not detected during the acute disease phase. Of 48 chronic hepatitis patients with HCV-RNA, 40 patients were positive for IgM anti-HCV. Therefore, IgM anti-HCV was useful for diagnosis in some of the AH patients, but it was difficult to use for distinguishing between acute and chronic infection. All four FH patients with HCV-RNA were positive for both IgM and IgG antibody to HCV at onset. Their antibody titres were higher than those of AH patients. These results suggested that, as in FH due to HBV, FH due to HCV could induce strong and rapid humoral immunity.     

Sustained viral response of a case of acute hepatitis C virus infection via needle-stick injury

A 29-year-old nurse with a hepatitis C virus (HCV) infection caused by needle-stick injury was treated with interferon-beta starting about one year after the onset of acute hepatitis. The patient developed acute hepatitis C with symptoms of general fatigues, jaundice, and ascites 4 wk after the needle-stick injury. When these symptoms were presented, the patient was pregnant by artificial insemination. She hoped to continue her pregnancy. After delivery, biochemical liver enzyme returned to normal levels. Nevertheless, HCV RNA was positive and the pathological finding indicated a progression to chronicity. The genotype was 1b with low viral load. Daily intravenous injection of interferon-beta at the dosage of six million units was started and continued for eight weeks. HCV was eradicated without severe adverse effects. In acute hepatitis C, delaying therapy is considered to reduce the efficacy but interferon-beta therapy is one of the useful treatments for hepatitis C infection in chronic phase.     

Oxidative stress and hepatitis C viral infection.

The involvement of oxidative stress in the pathogenesis of hepatitis and hepatocellular carcinoma has been strongly suggested. Oxidative stress is produced by inflammatory processes that occur in hepatitis via immunological mechanisms. In addition, in hepatitis C virus (HCV) infectious disease, some role has been assigned to viral proteins in the induction of oxidative stress. In the presence of hepatic steatosis, insulin resistance and increased levels of some cytokines, all of which are also induced by viral protein expression, oxidative stress is enhanced in HCV infection. In this sense, the role of oxidative stress in the progression of chronic hepatitis and hepatocarcinogenesis is greater in hepatitis C than in other types of hepatitis such as hepatitis B or autoimmune hepatitis. The additive effects of oxidative stress caused by the inflammatory process and that induced by HCV proteins may, furthermore, exert synergistic effects with alterations in intracellular signaling systems such as mitogen-activated protein kinases (MAPK), which are also induced by HCV proteins. These synergistic effects may be responsible for rare characteristics, that is, the high incidence and multicentric nature of hepatocarcinogenesis in HCV infection.     

Host antibody response to viral structural and nonstructural proteins after hepatitis A virus infection.

Subgenomic hepatitis A virus (HAV) RNA sequences were translated in vitro to produce proteins representing the structural (P1) and nonstructural (P2 and P3) domains of the viral polyprotein. These proteins were used as antigens to detect the presence of antibodies in sera from acute and convalescent humans and an experimentally infected chimpanzee. All infected individuals tested had antibodies that recognized uncleaved P1 proteins as well as nonstructural proteins. Antibodies in sera from infected individuals recognized conformation-dependent epitopes that were sensitive to SDS and heat treatment. Time-course studies of the experimentally infected chimpanzee showed that antibodies to the HAV proteins were detectable between 24 and 31 days after infection and persisted for greater than 6 months. Human sera remained positive for antibodies to both structural and nonstructural antigens for at least 2 1/2 years. The data suggest that HAV nonstructural proteins could be used as serologic markers for HAV diagnosis and for evaluating field trials of inactivated vaccines.     

Serological response and detection of viraemia in acute hepatitis C virus infection.

The serological response during acute hepatitis C virus (HCV) infection was examined by enzyme-linked immunosorbent assay (ELISA) in sequential serum samples from 13 haemophiliacs following their first exposure to factor VIII concentrates contaminated with HCV. The commercially available C100-3 peptide and a new 22 kDa recombinant protein (p22) encoded by the nucleocapsid region of the viral genome were used for antibody detection, whilst a nested polymerase chain reaction (PCR) method was used for the detection of viraemia. In addition, eight sporadic cases of acute HCV infection were studied. The results in haemophiliacs demonstrated that seroconversion to the C100-3 antigen occurred in only one-third of the patients within 12 weeks of disease onset, but all of the patients had a diagnostic serological response to p22 during this phase of the disease. The new test was positive in all the sporadic cases at a time when the commercially available test was negative. Although PCR offers a sensitive method for the detection of recent HCV infection, the complex methodology makes it unsuitable for diagnostic laboratories. The new ELISA test with p22 may therefore have a useful diagnostic role in acute disease.     

New treatment strategies against hepatitis C viral infection.

Treatment of hepatitis C virus infection is currently based on a combination of pegylated interferon and ribavirin. Because efficacy of this therapy remains suboptimal and side effects sometimes problematic, major efforts have been put forward by scientists and the pharmaceutical industry to develop alternative treatments for this chronic infection. Over the past few years, clinical studies performed with some of these new agents have been presented at major international meetings. The present paper aims to review the rationale underlying the development of these new forms of treatment as well as the current available data concerning their clinical efficacy.     

The persistence of hepatitis A IgM antibody after acute clinical hepatitis A

Hepatitis A IgM antibody (IgM anti-HAV), detected by commercially available solid-phase radioimmunoassay, is an accepted marker of acute viral hepatitis A infection. However, persistence of this serological marker far beyond the acute illness and immediate convalescent period has been reported. To determine the persistence of IgM anti-HAV following clinically manifest acute hepatitis A infection, 59 patients with this diagnosis were followed prospectively until this marker disappeared or persisted for greater than 60 days. Timed from the onset of jaundice, IgM anti-HAV persisted for less than 30 to greater than 420 days; most patients became seronegative by 120 days. These findings suggest that some patients may become seronegative early in the disease course while others (13.5%) remain positive for prolonged periods greater than 200 days. Awareness of this marked variability is important in the interpretation of IgM anti-HAV as a serologic marker of recent hepatitis A infection.     

Clinicopathological predictors to predict sustained viral response rates in patients with chronic hepatitis C infection.

BACKGROUND: Treatment of patients with chronic hepatitis C virus (HCV) infection remains suboptimal, with the current pegylated interferon (PEG-IFN) and ribavirin combination therapy providing sustained viral response (SVR) rates of 54 - 63%. The aim of this study was to identify clinical, laboratory and histological findings that can predict non-response to this treatment. METHODS: Medical records of patients who had completed PEG-IFN and ribavirin therapy for chronic HCV infection between December 2002 and November 2005 and had undergone a liver biopsy prior to starting treatment were retrospectively reviewed. Data on various clinical and biochemical parameters were extracted and liver biopsy slides were reviewed by a pathologist who was blinded to the clinical and laboratory findings. RESULTS: Of 67 patients studied (mean [SD] age 46.3 [6.3] years; 36 men), 42/57 (74%) had an early viral response (EVR) and 37/64 (58%) had an SVR. On univariate analysis, absence of EVR (p=0.0002), non-white race (p=0.008), AST/ALT ratio > or = 1.0 (p=0.008), INR > or = 1.0 (p=0.02) and presence of steatosis > or = 5% on liver biopsy (p=0.03) were associated with lack of SVR. In multivariate analysis, all of these except INR were significant independent predictors of SVR. CONCLUSIONS: Absence of EVR, non-white race, AST/ALT ratio > or = 1.0 and presence of steatosis > or = 5% on liver biopsy are independent predictors of absence of SVR in patients with chronic HCV infection receiving PEG-IFN and ribavirin combination treatment.     

The role of TT virus infection in acute viral hepatitis.

Recently, transfusion-transmitted virus (TTV) was discovered to be a potential causative agent for non-A-E hepatitis. Little is known about the relation between TTV and the clinical courses of various types of acute viral hepatitis. One hundred twenty-five patients with acute viral hepatitis who were admitted to the Chiba University Hospital between 1984 and 1998 and 100 persons with normal liver function tests were tested for the presence of TTV in their sera. Serum samples were tested for TTV DNA and genotype by polymerase chain reaction (PCR). TTV DNA was detected in 15 of 35 patients (43%) with non-A-E hepatitis, 14 of 33 patients (42%) with hepatitis C, 8 of 28 patients (29%) with hepatitis A, 7 of 29 patients (24%) with hepatitis B, and 37 of 100 subjects with normal liver function tests (37%). The detection rate did not differ statistically between non-A-E hepatitis and hepatitis A, B, C, or controls. The distribution of TTV genotypes was similar in non-A-E, A, B, C types, and controls. The clinical characteristics of the acute illnesses were similar for patients with or without TTV in hepatitis non-A-E, A, B, or C. Although TTV was detected frequently in non-A-E acute hepatitis, no etiologic role for TTV could be established.