Spontaneous seroconversion in chronic hepatitis B: role of mutations in the precore/core gene

The mechanism underlying spontaneous clearance of hepatitis B e antigen (HBeAg) and the appearance of antibodies (anti-HBe seroconversion) in chronic hepatitis B is not known. Previous studies have demonstrated mutations within the precore/core gene before, during, and after seroconversion, suggesting that the emergence of mutations in the core gene may abrogate tolerance and that this event may act as a general principle for the initiation of the clearance of HBeAg. To investigate this hypothesis, we studied three patients with adult-acquired chronic hepatitis B virus (HBV) infection before spontaneous seroconversion by sequential sequencing and single-stranded conformation polymorphism (SSCP) analysis of the entire precore/core genome. In one patient, a new viral strain appeared six months before seroconversion, but no mutations or new viral strains could be detected in the other two patients. SSCP analysis confirmed the sequencing results and revealed no evidence for the emergence of new viral subpopulations before seroconversion. These results suggest that the appearance of nucleotide changes within the precore/core region of the dominant viral strain is not a prerequisite for the induction of seroconversion in patients with chronic hepatitis B virus infection acquired during adulthood.     

Self-expanding metal oesophageal endoprostheses: which is best?

The main problem of children with HBeAg positive hepatitis B and associated hepatitis D is progression to liver cirrhosis with decompensation of liver function and need for liver replacement therapy within 15-20 years after infection. To determine whether interferon-alpha (IFN-alpha) therapy has a positive effect on HBV replication and inflammatory activity, we evaluated clinical and serological data of 8 children treated with IFN-alpha and 6 historic control patients without treatment. 4 of the nontreated patients seroconverted from HBeAg to anti-HBe between 7 to 17 years after initial diagnosis and showed decreased inflammatory activity in the liver. In the treatment group, the rate of seroconversion to anti-HBe (3 early, 2 late seroconverters) corresponded well to former trial results obtained in patients exclusively infected by HBV. Serum aminotransferase levels decreased or normalized in seroconverted children. In chronic HBV infection with associated hepatitis D (HDV) infection--compared to the spontaneous course of the disease--IFN-alpha therapy reduced inflammatory activity by earlier seroconversion to anti-HBe in responding patients. Moreover, viral replication and infectivity of hepatitis B was markedly reduced, but no effect on replication of HDV could be documented. Although long-term effects cannot be exactly estimated, at present IFN-alpha remains the only available treatment for HBeAg and anti-HDV positive children and seems to be of benefit for responding patients.     

Genetic immunization of chimpanzees chronically infected with the hepatitis B virus, using a recombinant retroviral vector encoding the hepatitis B virus core antigen

Cytotoxic T lymphocyte (CTL) activity and CD4+ helper T cell responses to the hepatitis B virus (HBV) core antigen (HBcAg) have been implicated in clearance of acute and chronic HBV infections. We showed that intramuscular injections of a novel recombinant retroviral vector expressing an HBcAg-neomycin phosphotransferase II (HBc-NEO) fusion protein induces HBc/eAg-specific antibodies and CD4+ and CD8+ T cell responses in mice and rhesus monkeys. We have now immunized three chronically infected chimpanzees, each with 10(10) CFU of nonreplicating retroviral vector particles expressing the HBc-NEO fusion protein. Of two immunized chimpanzees examined for CTL responses, one developed HBcAg-specific CTLs and showed marginal, transient elevations of alanine aminotransferase (ALT) levels following injection. However, both chimpanzees remained positive for serum HBeAg, negative for anti-HBe antibody by conventional assays, and displayed no change in HBV viral load throughout the study. In contrast, the third chimpanzee exhibited a traditional seroconversion evidenced by a loss of serum HBeAg and the subsequent emergence of anti-HBe antibodies within 24 weeks after the first injection. Simultaneously, two transient ALT flares and a significant decrease in the serum HBV DNA levels were noted. Despite its limitations, the present study demonstrates (1) the safety of treatment with high titers of retroviral vector in chimpanzees, (2) the capability of a retroviral vector expressing HBcAg to stimulate immune responses in HBV chronic carrier chimpanzees, and (3) that retroviral vector immunization may be therapeutically beneficial in the treatment of chronic HBV infection.     

A newly identified pattern of K-ras mutations at codons 12 and 13 is associated with long-term survival in colorectal cancer

BACKGROUND/AIMS: Hepatitis B virus (HBV) core gene heterogeneity may influence the outcome of liver disease and the response to interferon (IFN) therapy in adult HBV carriers. The aim of this study was to evaluate the possible association between HBV core gene variability and evolution of chronic hepatitis in children. METHODS: We examined serum samples from 25 children with HBV chronic hepatitis and HBe antigen (HBeAg) positivity who were followed-up for a mean of 7.4 years. Seven cases spontaneously seroconverted to anti-HBe, becoming HBV healthy carriers; nine cases were successfully treated with IFN; nine cases were non-responders to IFN therapy. HBV-DNA was extracted from one serum sample ("I") collected during the HBeAg positive phase, and from a second sample ("II") collected after the anti-HBe seroconversion or, in non-responders, after stopping therapy. The entire core gene of the HBV isolates was amplified and sequenced. RESULTS: Each isolate showed single or no missense mutation independently of the clinical behavior of the patients. HBeAg-defective viruses were detected in one case in both samples and in two cases only in sample "II". CONCLUSIONS: Core gene variability does not seem to be involved either in the outcome of infection or in the response to IFN treatment in children with HBV chronic hepatitis. Considering that most of the HBV carriers in our area acquire the infection in childhood, our data suggest that core gene heterogeneity is not a major cause of progression to chronicity.     

Distinguishing between acute and symptomatic chronic hepatitis B virus infection

BACKGROUND/AIMS: Differentiating between an acute hepatitis B (AH-B) infection and an acute exacerbation of a chronic hepatitis B (CH-B) infection can present a problem for the clinician. The only current serological method of distinguishing between acute and symptomatic chronic hepatitis B virus (HBV) infection is the immunoglobulin M antibody to hepatitis B core antigen (anti-HBc) assay, which can be problematic. Therefore, in an attempt to better distinguish between acute and chronic HBV infection, sera from 26 patients with AH-B and 53 patients with CH-B were compared in a variety of experimental immunoassays. METHODS: Experimental assays have been designed to detect free antibody to hepatitis B e antigen (anti-HBe), hepatitis B e antigen (HBeAg)/anti-HBe immune complexes (ICs), and hepatitis B surface antigens (HBsAg)/antibody to hepatitis B surface antigen (anti-HBs) in the presence of excess antigen. An additional assay was developed to detect a novel anti-HBc specificity, designated antibody to woodchuck hepatitis virus (anti-HBcW), which cross-reacts with the core antigen of the woodchuck hepatitis virus. RESULTS: Sera from patients with CH-B showed significantly higher levels of free anti-HBe, HBeAg/anti-HBe ICs, and HBsAg/anti-HBs ICs compared with AH-B patient sera. Furthermore, patients with CH-B consistently produced high titer anti-HBcW, whereas patients with AH-B produced little or no anti-HBcW antibody. CONCLUSIONS: The serology of AH-B infection and symptomatic CH-B infection can be distinguished using a variety of experimental immunoassays in addition to the immunoglobulin M anti-HBc assay.     

A PET study on cortical and subcortical control of pelvic floor musculature in women

The possibility of hepatitis B virus (HBV) infection in HBsAg-negative patients has been shown. However, an "inapparent" coinfection by HBV in hepatitis C virus (HCV)-positive patients generally is not taken into account in clinical practice. Mechanisms responsible for resistance to interferon (IFN) have not been completely clarified. The aim of this study was to investigate whether an "inapparent" coinfection by HBV in anti-HCV-positive chronic liver disease patients may influence IFN response. Fourteen anti-HCV positive, HBsAg-negative but serum HBV DNA-positive patients by PCR and 111 anti-HCV-positive, HBsAg-negative and HBV DNA (PCR)-negative patients with chronic hepatitis were treated with 3 MU of recombinant alpha-2a IFN 3 times weekly for 12 months. Serum HBV DNA and HCV RNA were determined before treatment, after 6-12 months and in coincidence with ALT flare-up by PCR. HBV PCR was performed using primers specific for the S region of the HBV genome and HCV PCR with primers localised in the 5'NC region of HCV genome. IgM anti-HBc was tested using IMx Core-M Abbott assay. By the end of treatment, ALT values had become normal in 4/14 HBV DNA-positive patients (28%), but all "responders" (4/4) relapsed between 2 and 5 months after therapy. All but one patient were HCV RNA-positive before treatment, 6 were also both HBV DNA and HCV RNA-positive during ALT flare-ups. In 5 patients, only HBV DNA and in 3 patients, only HCV RNA was detected when transaminase values increased. All patients remained HBsAg-negative and anti-HCV-positive. IgM anti-HBc was detected both before treatment and during ALT elevation in 3 patients and only during ALT relapse in 3 others. Of the 111 anti-HCV positive, HBsAg-negative and HBV DNA (PCR)-negative patients with chronic hepatitis, a biochemical response to IFN treatment was observed in 54% of the cases. Relapse of ALT values was observed in 47% of the cases during a follow-up of 1 year after treatment. "Inapparent" HBV/HCV coinfection may be implicated in cases of resistance to IFN treatment. In addition, HBV replication may persist in patients in whom HCV replication was inhibited by IFN treatment. The pathogenic role of HBV in liver disease was confirmed by detection of IgM anti-HBc in some cases; the appearance of these antibodies only after IFN treatment suggests that IFN may exert a selective role in favour of HBV. Further studies will show the effect of different treatment schedules. HBV DNA and/or IgM anti-HBc detection with very sensitive methods may be important both as a prognostic factor and as a tool for better understanding interviral relationships and mechanisms involved in multiple hepatitis virus infections.     

Sequential changes in full-length genomes of hepatitis B virus accompanying acute exacerbation of chronic hepatitis B

BACKGROUND/AIM: During the course of persistent hepatitis B virus infection, viral replication markedly decreases after acute exacerbation of liver inflammation accompanied by emergence of antihepatitis B e antibody (anti-HBe) and/or anti-hepatitis B surface antibody (anti-HBs). In some cases, however, persistent viral replication continues even after such exacerbation with or without HBeAg/anti-HBe seroconversion. The aim of the present study was to investigate the extent of genetic variations of HBV in this phenomenon. METHODS: Full-length HBV genomes were amplified by polymerase chain reaction from sera of three patients before and after acute exacerbation and were directly sequenced. RESULTS: In the whole genomes of 3215 nucleotides, only six nucleotide mutations for six amino acid substitutions (2 in the surface gene, 2 in the X gene, 1 in the core gene and 1 in the polymerase gene) were observed in patient 1, 15 mutations for 14 amino acid substitutions (1 in the pre-core codon 28, 4 in the surface gene, 4 in the core gene and 5 in the polymerase gene) were observed in patient 2, and 5 mutations for 6 amino acid substitutions (2 in the surface gene, 2 in the X gene, pre-core stop codon mutation and 1 in the polymerase gene) were observed in patient 3. Substitution in the a determinant of the surface gene, which encodes target epitopes for neutralizing antibodies, as well as those in the pre-core/core gene, which encodes epitopes for cytotoxic T cells, were mainly found. CONCLUSION: HBV that remained after the emergence of anti-HBe and anti-HBs are considered to possess mutations in epitopes for both humoral and cellular immunity. These mutant HBV may be involved in the pathogenesis of persistent hepatic injury after acute exacerbation.     

Clinical and virological evaluation of the detection of pre-S1 and pre-S2 antigens in serum from patients with chronic hepatitis B

OBJECTIVES AND METHODS: We performed a prospective study to determine the clinical and virological significance of pre-S antigen detection in serum samples from patients with chronic hepatitis B virus infection. Four hundred thirty seven consecutive serum samples from 116 patients were tested for the presence of both pre-S1 and pre-S2 antigens by radioimmunoassay using specific monoclonal antibodies. RESULTS: The pre-S1 antigen/HBs antigen ratio, gave an estimation of the number of pre-S1 epitopes expressed on the surface of circulating viral particles, and was positively correlated with the intensity of viral replication intensity (P < 0.05). Moreover, the pre-S1 antigen/HBs antigen ratio was significantly higher in patients suffering from chronic hepatitis associated with viral replication (24% +/- 13); in anti-HBe positive patients, the pre-S1 antigen/HBs antigen ratio was higher in patients replicating a HBe antigen minus variant of the hepatitis B virus and suffering from chronic hepatitis (17% +/- 9) than in asymptomatic HBs antigen carriers (5% +/- 6) (P < 0.05). The pre-S2 antigen/HBs antigen ratio was not correlated with the level of viral replication or with the patient's clinical status. CONCLUSION: This study confirms that pre-S1 antigen detection is a reliable marker of hepatitis B virus replication which can be easily performed in chronically infected patients. This assay is especially useful in identifying anti-HBe positive carriers who replicate a minus pre-core mutant and could benefit from antiviral therapy.     

Relation between laboratory test results and histological hepatitis activity in individuals positive for hepatitis B surface antigen and antibodies to hepatitis B e antigen

BACKGROUND: Hepatitis B surface antigen (HBsAg) and antibodies to hepatitis B e antigen (anti-HBe) commonly coexist, and laboratory tests are often requested to assess histological hepatitis activity. An optimum panel of tests has not been found and the usefulness of hepatitis B virus (HBV) DNA assays in this context has not been established. We assessed various blood tests to find which best predicted hepatitis activity. METHODS: Routine plasma biochemical liver tests and serum HBV DNA (hybridisation and PCR assays) were assessed prospectively in 123 patients positive for HBsAg and anti-HBe. We scored histological hepatitis activity (hepatitis activity index) and determined whether chronic active hepatitis (chronic hepatitis with portal and periportal lesions) was present. We analysed the relation between laboratory data and the hepatitis activity index or risk of chronic active hepatitis by multiple regression and multiple logistic regression, respectively. FINDINGS: The analyses provided models for predicting either the hepatitis activity index or the risk of chronic active hepatitis. Aspartate aminotransferase was the most important test in the two models. The contribution of HBV DNA and other assays, especially alanine-aminotransferase activity, were of no practical importance. INTERPRETATION: Because screening by aspartate-aminotransferase activity could not be improved by the addition of other assays or HBV DNA, patients positive for HBsAg and anti-HBe could be screened for chronic active hepatitis with a single assay and counselling of patients can be improved if proper reference values are used.     

Analysis of hepatitis B virus populations in an interferon-alpha-treated patient reveals predominant mutations in the C-gene and changing e-antigenicity

It is largely unknown whether hepatitis B virus (HBV) sequence variation during chronic infection hampers HBV immune recognition or the antiviral effect of cytokines on HBV production. Here we have analyzed which region of the HBV genome changes most drastically during an interferon-alpha (IFNalpha)-stimulated immune response. In addition, we have investigated whether the mutations affect viral replication, gene expression, and immune recognition of the mutant viral proteins. The study was performed with full-length HBV genomes taken longitudinally from a patient who transiently cleared HBV and seroconverted to anti-HBe during a long-term IFNalpha treatment. We found a replacement of the predominant virus population during IFNalpha therapy The virus populations differed mainly by a cluster of nucleotide changes in the C-gene and a pre-S2 deletion. Most of the newly emerging mutations localized within core/HBe B-cell epitopes, changed HBe antigenicity toward mono- and polyclonal antibodies, and also influenced the reactivity of the anti-HBc/e antibodies of the patient. All genomes tested expressed less HBeAg than wild-type HBV, while replication and IFNalpha susceptibility were similar. These data indicate that IFNalpha therapy can lead to the emergence of HBV variants with mutations mainly affecting recognition of the core/HBe proteins by antibodies. Taken together, the type of core/HBe-specific B-cell immune response, the sequence of the corresponding epitopes, and the HBe expression level appear to contribute to the decision on viral clearance or persistence.     

Use of pharmacological agents in elucidating the mechanism of insulin action

Hepatitis B virus (HBV) mutants have recently been identified in patients with acute or fulminant as well as chronic infections. Naturally occurring mutations have been identified in all viral genes and regulatory elements. Mutations in the gene coding for the hepatitis B surface antigen (HBsAg) may result in infection or viral persistence despite the presence of antibodies against HBsAg (anti-HBs) ("vaccine escape" or "immune escape"). Mutations in the gene encoding the pre-core/core protein (pre-core stop codon mutant) result in a loss of hepatitis B e antigen (HBeAg) and sero-conversion to antibodies to HBeAg (anti-HBe) with persistence of HBV replication (HBeAg minus mutant). Mutations in the core gene may lead among others to an immune escape due to a T cell receptor antagonism. Mutations in the polymerase gene can be associated with viral persistence or resistance to nucleoside analogues. Thus, HBV mutations may affect the natural course of infection, viral clearance and response to antiviral therapy. The exact contribution of specific mutations to diagnosis and therapy of HBV infection as well as patient management in clinical practice remain to be established.     

Prevalence of mutations in core promoter/precore region in Japanese patients with chronic hepatitis B virus infection

We examined the frequency and significance of mutations in the core promoter and precore region in 103 Japanese patients with chronic hepatitis B virus (HBV) infection. HBV DNAs from the patients' sera were amplified by polymerase chain reaction and were directly sequenced. A double mutation (T1762 A1764) in the core promoter was frequently observed in the patients regardless of HBeAg status except for asymptomatic carriers with HBeAg. Furthermore, a mutation at nucleotide 1753 from T to C or G was frequently found in anti-HBe positive patients and was often accompanied by the double mutation. The A1896 mutation was found in only about one fourth of the patients with anti-HBe. These data suggest that the patients with chronic liver diseases frequently had a double mutation regardless of HBeAg status and a mutation at nucleotide 1753 might be associated with HBeAg-negative chronic hepatitis B virus infection.     

Relationship of premorbid mass and energy intake to increase of body mass during the treatment of anorexia nervosa

We studied 152 healthy pregnant women and their 156 newborns for markers of hepatitis B virus (HBV) infection in Dakar, Senegal. Of these, 120 mothers (79%) had antibodies to the hepatitis B core antigen (anti-HBc), 21 (13.8%) were hepatitis B surface antigen (HBs Ag) positive, including 2/21 (9.5%) hepatitis B core-associated antigen (HBe Ag) positive and 1/21 (4.7%) HBV DNA positive. At birth, 11 (7%) infants were HBs Ag positive; 9/11 had an HBs Ag positive mother. Ten of these HBs Ag positive-born infants were investigated at 6-7 months: 5 were strongly HBs Ag positive and developed antibodies to HBs Ag, HBc Ag or HBe Ag; these 5 (3.2% of the total) probably became chronic carriers of HBV. The 5 others were HBs Ag negative and 4/5 did not develop antibodies against HBV Ag; HBs Ag positivity at birth was likely due to contamination of the mother's blood. Thirty-one of the 145 HBs Ag negative-born infants were studied at 6-7 months and remained HBs Ag negative. However, 5 (16%) showed evidence of HBV infection occurring between 0 and 6 months, as shown by the development of antibodies to HBs Ag, HBc Ag, and/or HBe Ag. Despite the low prevalence of HBV DNA and HBe Ag in HBs Ag positive African mothers, this study shows the occurrence of perinatal transmission of HBV in West Africa, in contrast with previous studies. Perinatal HBV transmission could explain the HBV vaccination failure recently reported in children in Senegal.     

Evaluation of pedicle screw insertion monitored by intraoperative evoked electromyography

The clinical importance of hepatitis B virus (HBV) genome variability has been reported recently. One example is the occurrence of hepatitis B virus pre-core mutants, which arise during spontaneous or interferon-induced seroconversion from HBeAg to anti-HBe and are thought to be selected by immune pressure. A survey of HBV pre-core mutants and viral genotypes in 35 HBeAg negative patients during interferon therapy was carried out to understand viral pathogenesis in this form of chronic hepatitis B. Seventeen patients responded to interferon therapy as assessed by the sustained normalization of serum ALT levels and the significant decrease of viremia levels. The response rate to interferon was independent of both initial serum viral DNA level and interferon doses. During interferon therapy, a significant decrease of M0 (wild-type pre-core sequence at pos. 1887-1908), M1 (TGG to TAG at pos. 1896) or M2 (TGG to TAG at pos. 1896, and GGC to GAC at pos. 1899) positive viral genomes was found in 48%, 42%, and 33% of patients, respectively. A higher response rate to interferon therapy was observed in patients infected with HBV genotype A (70%) or M0 positive strains (75%) as compared to patients infected with genotype D/E (40%) or M1/M2 positive strains (44%). The data support the hypothesis that pre-core defective HBV represent viral mutants with an increased capacity to resist exogenous alpha interferon. These findings emphasize that characterization of HBV genome variability prior to interferon therapy may help to predict antiviral response in HBeAg negative patients.     

Pretreatment with prednisolone enhances the effect of human lymphoblastoid interferon in chronic hepatitis B

Patients (n = 213) with chronic hepatitis B were randomised to prednisolone (two weeks of 0.6 mg/kg/day, one week of 0.45 mg/kg/day and one week of 0.25 mg/kg/day) or placebo followed by two weeks rest, and were then given human lymphoblastoid interferon 10 MU daily for five days followed by 10 MU thrice weekly for 11 weeks. There were statistically significant effects of prednisolone pre-treatment on both HBeAg disappearance and HBeAg to anti-HBe seroconversion (log rank test statistics 5.43; p = 0.02 and 4.75; p = 0.03). HBeAg disappearance and HBeAg to anti-HBe seroconversion rates were 28 vs. 44% and 23 vs. 38% (placebo vs. prednisolone). Fifteen patients (7.5%) lost HBsAg. Three out of 22 cirrhotic patients (14%), one of whom received prednisolone pre-treatment, developed hepatic decompensation with a fatal outcome. Prednisolone pre-treatment, enhances the effect of lymphoblastoid interferon in chronic hepatitis B. Interferon treatment (with and without prednisolone) should be used with caution in patients with cirrhosis and avoided in patients with evidence of hepatic decompensation.     

Treatment of chronic viral hepatitis

Recent advances have been made in the treatment of chronic viral hepatitis, mainly with recombinant interferon (IFN) alpha. However, the present treatment of chronic viral hepatitis is not entirely satisfactory because the efficacy is inconstant and/or incomplete. In chronic hepatitis B IFN-alpha induces a sustained interruption of hepatitis B virus (HBV) replication, with a HBeAg to anti-HBe seroconversion in about 30% of patients. Patients most likely to respond are those with no immunosuppression, HBV infection acquired during adulthood or active liver disease with low HBV replication. Responders usually show a significant decrease in serum HBV DNA levels during the first 2 months of therapy, followed by a significant increase in the level of aminotransferases. New nucleoside analogues might be useful in combination with IFN-alpha in the treatment of those who do not respond to IFN therapy. In chronic hepatitis B-D, the rate of sustained response to IFN-alpha therapy is low. To be effective, IFN-alpha must be used at a high dosage (9-10 mega units) with a long duration (1 year). In chronic hepatitis C, IFN-alpha at a dosage of 3 mega units over 6 months, induces a sustained response in about 20% of patients. A higher dosage of IFN (5-10 mega units) and a longer duration of treatment increases the rate of sustained response but is associated with poor tolerance. Non-responders to a first course of IFN do not respond to a second course of treatment. In patients who respond but relapse after treatment, the rate of sustained response after a second course of IFN needs to be assessed. Ribavirin, which has a significant antiviral effect on hepatitis C virus, might be useful in combination with IFN-alpha. At the dosage (3-6 mega units) usually used, IFN-alpha is relatively well tolerated. In about 10% of the patients therapy is interrupted, mainly because of severe fatigue, thyroid dysfunction or depression.     

Safety and efficacy of interferon retreatment in children with chronic hepatitis B

More than 50% of children with chronic hepatitis B do not respond to treatment with alpha-interferon. Since these patients continue to display high viral replication and progressive liver disease, retreatment should be considered. To date it has not been well evaluated whether a second course of treatment could increase the response rate. In two alpha-interferon retreatment trials in adult patients the response rate, defined by seroconversion from HBeAg to anti-HBe, ranged between 11% and 44%. One beta-interferon retreatment study in children reported a seroconversion rate of 32%. Regrettably, none of the studies included a control group observing the 'spontaneous' seroconversion rate after a first interferon cycle. Thus, a nonrandomized alpha-interferon retreatment study in children including control patients was performed. Alpha-interferon for retreatment was administered 3 times a week for 16-24 weeks in 15 children (5-16 years) at least 6 months after ceasing the first cycle. Four children received 5 MU/m2 of a natural alpha-interferon and 11 children 9 MU/m2 recombinant alpha-interferon 2b. Follow up was 18-47 months after initial treatment. In parallel, a control group of 19 unretreated children with comparable clinical and demographic data was followed for 12-39 months. HBeAg seroconversion was observed in 5 (33%) of the retreated children and in 5 (26%) of the control patients during follow up. The difference is not significant. In the initially nonresponding children, those with high ALT levels before the first treatment showed late HBeAg seroconversion more frequently than those with low ALT levels (P=0.017) irrespective of retreatment. The ALT level before retreatment was not a predictor for response. CONCLUSIONS: A second cycle of alpha-interferon during the 3 years following the first treatment in nonresponding children with chronic hepatitis B can be safely performed but did not increase HBeAg/anti-HBe seroconversion compared with the spontaneous seroconversion rate of patients without retreatment.     

Evaluation of a commercial enzyme-linked immunosorbent assay for detection of immunoglobulin M antibody in diagnosis of human leptospiral infection

The PanBio Leptospira immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) is a commercially available screening test for the diagnosis of acute leptospiral infection. The ability of the test to diagnose early or recent Leptospira interrogans infection was assessed by testing sera with known microagglutination test (MAT) titers to serovars pomona, hardjo, copenhageni, and australis. The IgM ELISA detected all 41 cases of early or recent leptospiral infection (sensitivity, 100%), with a positive ELISA result seen in many cases before MAT antibody titers reached 1:50. Thirty-eight of 41 patients showed seroconversion (fourfold or greater increase in titer by MAT, 2 of 41 patients had a single sample with elevated titer, and 1 patient from whom leptospires were isolated from a blood sample failed to show MAT titers, despite a seroconversion (negative to positive result) in the ELISA. Follow-up sera obtained from 8 of 12 patients (67%) for 3 to 48 months after the acute stage of illness showed persisting IgM antibody. However, the range of levels detected in these samples (maximum ELISA ratio, 2.0) was lower than the range seen when infection was recent. Reactivity in the IgM ELISA was observed for only 1 of 59 serum samples from asymptomatic donors (specificity, 98%) and 16 of 233 serum samples from patients with Ross River virus, brucella, Epstein-Barr virus, cytomegalovirus, mycoplasma, Q-fever, toxoplasma, hepatitis A virus, Treponema pallidum, or Borrelia burgdorferi infection (specificity, 93%), with the majority of these patients showing lower levels of IgM in comparison to those in patients with leptospiral infection. We conclude that this ELISA is sufficiently sensitive for use as an initial screen for leptospiral infections, with subsequent confirmation of positive test results by MAT.