Rudolf A. Heijtink

Failure of neonatal hepatitis B vaccination: the role of HBV-DNA levels in hepatitis B carrier mothers and HLA antigens in neonates

In a hepatitis B vaccination program (1982-1992), 705 infants born to HBsAg-positive mothers received HBIg within 2 h of birth and were vaccinated according to a three- or four-dose vaccination schedule, starting either at 3 months or directly after birth. Eight children HBsAg-positive during the first year of life (group 1: infected nonresponders). To determine whether failure of the hepatitis B vaccination was due to perinatal high-level maternal viraemia or genetically determined infant nonresponsiveness to the vaccine, we measured HBsAg and anti-HBs levels in infants and HBeAg and hepatitis B virus-DNA levels in maternal serum, and determined the HLA type of the infants. Controls included 14 infants with a normal anti-HBs response 1 year after vaccination (group 2: noninfected responders) and all eight infants without HBsAg and anti-HBs 1 year after vaccination (group 3: noninfected low responders). HBsAg, HBeAg and anti-HBs were measured by radioimmunoassay (Abbott Laboratories), hepatitis B virus-DNA was measured quantitatively by solution hybridization for groups 1, 2, and 3 (Abbott hepatitis B virus-DNA assay, Abbott Laboratories), and HLA was characterized by microcytotoxicity test for groups 1 and 3. All infants in groups 1 and 2 were born to HBeAg carrier mothers, and those in group 3 to HBeAg-negative mothers. Hepatitis B virus-DNA levels in maternal serum in group 1 were significantly higher than in group 2 (Wilcoxon rank-sum test: p < 0.01). Hepatitis B virus-DNA was not observed in group 3 maternal serum samples.(ABSTRACT TRUNCATED AT 250 WORDS)

DOUBLE-BLIND STUDY OF LEUCOCYTE INTERFERON ADMINISTRATION IN CHRONIC HBsAg-POSITIVE HEPATITIS

In a double-blind study human leucocyte interferon was given for six weeks to 8 of 16 patients with chronic HBsAg-positive hepatitis. In the first week 12 x 10(6) reference units were administered daily, and thereafter the dose was halved every week. During the first two weeks leucopenia was observed in 6 of the 8 interferon-treated patients. Apart from a drop in DNA-polymerase activity in the first week, no effect was found on indices of hepatitis-B-virus infection.

Conversion of 2′,3′-dideoxyadenosine (ddA) and 2′,3′-didehydro-2′,3′-dideoxyadenosine (d4A) to their corresponding aryloxyphosphoramidate derivatives markedly potentiates their activity against human immunodeficiency virus and hepatitis B virus

2′,3′‐Dideoxyadenosine (ddA), 2′,3′‐didehydro‐2′,3′‐dideoxyadenosine (d4A) and their lipophilic 5′‐monophosphate triester (aryloxyphosphoramidate) prodrugs were evaluated for their anti‐retrovirus and anti‐hepatitis B virus activity in various cell culture models. The aryloxyphosphoramidate derivatives of ddA (Cf 1093) and d4A (Cf 1001) showed markedly superior (100–1000‐fold) efficacies than the parent drugs against human immunodeficiency virus type 1 (HIV‐1), HIV‐2, simian immunodeficiency virus (SIV), Moloney murine sarcoma virus (MSV) and human hepatitis B virus (HBV) replication regardless of the cell type in which the virus replication was studied (i.e., human T‐lymphocyte CEM, MT‐4, Molt/4 and C8166 cells, peripheral blood lymphocytes (PBL), monocyte/macrophages (M/M), murine embryo fibroblasts and human hepatocyte cells). Also the selectivity index (ratio of cytotoxic concentration/antivirally effective concentration) of both aryloxyphosphoramidate prodrugs was markedly increased. In particular the d4A prodrug Cf 1001 showed a selectivity index of 300–3000 as compared with 2–3 for the parental d4A in established laboratory cell lines. Also Cf 1001 had a selectivity index of 400–650 in HIV‐1‐infected PBL and M/M, respectively. Both Cf 1001 and Cf 1093 were equally efficient as 3TC (lamivudine) in inhibiting HBV replication in hepatocytes, and rank among the most potent HIV and HBV inhibitors reported so far in cell culture.

Measurement of HBsAg to monitor hepatitis B viral replication in patients on α-interferon therapy

HBsAg was measured quantitatively in serum samples collected serially before and after the HBeAg seroconversion date from 69 patients with HBeAg seroconversion and 17 patients with both HBeAg and HBsAg seroconversion. In patients with only HBeAg seroconversion the median HBsAg level decreased from 8.39 micrograms/ml (range 0.01-57.51) before HBeAg seroconversion to 3.53 micrograms/ml (range 0.002-68.66) after seroconversion (P < 0.001). No significant drop in HBsAg was found for the control group (18 HBeAg-positive patients without seroconversion). From 12 other patients on alpha-interferon therapy HBsAg was quantitatively assayed monthly during and after therapy; HBsAg levels were compared to the levels of HBV-DNA and HBeAg. We observed a good correlation between the HBsAg level and both the HBV-DNA (r = 0.76; P < 0.001) and the HBeAg (r = 0.70; P < 0.001) level, irrespective of the response to alpha-interferon. Quantified assessment of HBsAg appears promising as a simple and cheap method for monitoring viral replication in chronic hepatitis B in patients undergoing interferon therapy.

Efficacy of interferon dose and prediction of response in chronic hepatitis C: Benelux study in 336 patients

BACKGROUND/AIMS In an attempt to improve the limited efficacy of treatment of chronic hepatitis C with interferon-alpha 3 MU tiw, we studied the effects of double-dose therapy followed by downward titration, and analyzed the pre- and pertreatment factors associated with response or non-response. METHODS Three hundred and fifty-four consecutive patients in 19 centers were randomized to interferon-alpha 3 MU tiw for 6 months or 6 MU tiw for 8 weeks followed by down-titration (3,1 MU tiw) till alanine aminotransferase remained normal and plasma HCV RNA was repeatedly undetectable. The primary outcome measure was sustained alanine aminotransferase and HCV RNA response 6 months after treatment. RESULTS Three hundred and thirty-six patients received treatment. The sustained response rate for patients receiving 3 MU tiw for 6 months was 14% (9-21%,) and for patients receiving double dose tiw for 8 weeks and thereafter titrated therapy 15% (10-21%) (p=0.8). Pretreatment factors associated with a sustained alanine aminotransferase plus HCV RNA response were the absence of cirrhosis, presence of genotype 2 or 3, a low viral load and, in addition, a low alanine aminotransferase/aspartate aminotransferase ratio; a model was developed to allow estimation of the chance of response for the individual patient. The most powerful predictor of sustained response, however, was plasma HCV RNA at week 4; a positive test virtually precluded a sustained response (1.7%, 0.4-5.0%). If week 4 HCV RNA was not detectable, the chance of a sustained response was 21% (12-34%) for genotype 1 versus 40% (28-54%) for the others (p=0.02). Six MU tiw led to a significantly higher week 4 HCV RNA response (47% not detectable) than 3 MU (37%) (p=0.02). During down-titration this difference in viral on-treatment response was lost. CONCLUSIONS In the treatment of hepatitis C, an early HCV RNA response is a prerequisite for long-term efficacy. Doubling the initial interferon dose increases this early response, but subsequent downward titration negates this effect, especially in genotype 1.

Serum HBeAg quantitation during antiviral therapy for chronic hepatitis B

Hepatitis Be antigen (HBeAg) seroconversion is considered the principal short‐term goal of antiviral therapy in chronic hepatitis B. To test whether the pre‐ and per‐treatment HBeAg quantitation has a higher predictive value than that of hepatitis B virus DNA (HBV‐DNA) quantitation for the outcome of antiviral therapy in chronic hepatitis B. A quantitative measurement of HBV‐DNA and HBeAg (AxSYM HBe 2.0 Quantitative, Abbott Laboratories) was undertaken in serial serum samples from 30 patients with 16‐week interferon‐α (IFN‐α) treatment (follow‐up 36 weeks; 14 responders) and from 15 patients with 24‐week lamivudine treatment (follow‐up 24 weeks; 2 responders).

The influence of contamination of culture medium with hepatitis B virus on the outcome of in vitro fertilization pregnancies

Heat-inactivated human serum is added to the culture medium used for in vitro fertilization and other forms of assisted conception. Because one batch of pooled serum contained hepatitis B virus, an epidemic occurred among women participating in the treatment program. Seventy-nine women had serologic proof of hepatitis B infection. This incident gave the opportunity to study the effect of hepatitis B virus on pregnancy outcome and the newborn. The situation is unique because the preimplantation embryo was exposed to hepatitis B virus or the pregnancy was complicated by a (sub)clinical infection. Twenty-four women were or became pregnant while having an acute hepatitis B infection. Five pregnancies ended in abortion. The remaining 19 pregnancies ended in the birth of 24 children. No evidence for any harmful effect of exposure to hepatitis B virus in the embryonic or fetal period on the newborn could be found.

Repeated courses of α-interferon for treatment of chronic hepatitis type B

In chronic hepatitis B transition from active replication to viral latency (HBeAg seroconversion) usually leads to remission of the disease. α-Interferon (IFN) therapy induces HBeAg seroconversion in about one-third of the patients, thus leaving the majority of patients with persistent disease. Eighteen chronic hepatitis B patients who did not respond (HBeAg seroconversion and clearance of HBV-DNA) to an initial 16-week course of IFN subsequently received IFN again after at least 6 months of no therapy. The repeated therapy consisted of 1.5–5 MU lymphoblastoid IFN daily for 16 weeks. Treatment effects were monitored by quantitative measurement of HBeAg and HBV-DNA. To analyze whether the results were related to patient characteristics known to affect the response to initial treatment, a predicted response rate, based on pre-treatment factors, was determined. After a follow-up of 52 weeks, 2 of the 18 patients (11%) had responded to therapy. Two additional patients became HBV-DNA-negative with sustained HBeAg positivity. All patients remained HBsAg-positive. According to the pre-treatment parameters, a response was predicted for 9 of the 18 patients (50%). This predicted response rate was significantly higher than the actual response rate ( p =0.03). In conclusion, this pilot study with moderate dosages of IFN suggests that the HBeAg seroconversion rate after repeated IFN treatment is low for previous non-responders and probably is not related to important clinical characteristics that influence the response to initial IFN treatment. A large controlled trial with higher doses of IFN is desirable to further evaluate the benefits of retreatment.

Immune response to hepatitis B vaccine in pregnant women receiving post-exposure prophylaxis

Hepatitis B immunoglobulin and vaccine were given as post-exposure prophylaxis to 73 women after an outbreak of hepatitis B due to in vitro fertilization treatment. The immunization schedule consisted of 5 ml of hepatitis B immunoglobulin (125 IU/ml) at months 0 and 1 and recombinant hepatitis B vaccine (10 micrograms of HBvaxDNA) at months 0, 1, 2 and 6. The safety and immunogenicity of hepatitis B vaccine were studied in 16 women who became pregnant after in vitro fertilization; 57 non-pregnant women receiving the same treatment served as controls. Blood samples were drawn at 0, 1, 2, 6 and 7 months. One patient had a clinical abortion 2 days after initial immunization; other side effects of vaccination were not found in vaccinees or in their offspring. All vaccinees exhibited antibodies against hepatitis B surface antigen after vaccination but relatively low peak geometric mean titers of 258 IU/l and 684 IU/l were attained in pregnant and non-pregnant women, respectively. There were no significant differences in seroconversion rates and geometric mean titers between the two groups although the immune response to hepatitis B vaccine was slower and lower in pregnant women at all times. Our results suggest that when post-exposure prophylaxis for hepatitis B infection is indicated, passive active immunization can be started safely during pregnancy. The relative weak response to the vaccine calls for monitoring of the anti-HBs 1 month after the initial series of vaccinations.

Anti-hepatitis B virus activity of a mixture of two monoclonal antibodies in an “inhibition in solution” assay

Two human monoclonal antibodies with anti‐hepatitis B activity were investigated separately and as a mixture by means of an “inhibition in solution” assay. With this assay the capacity of anti‐HBs antibodies to inhibit the binding of hepatitis B surface antigen (HBsAg) with solid‐phase anti‐HBs (Ausria II, Abbott Laboratories) was studied. Both HBsAg of different subtypes and purified Dane particles were used. One of the monoclonal antibodies (9H9) was directed against a conformational epitope (anti‐“a” like) but induced incomplete inhibition (80% to 90%) of all HBsAg subtypes; the other (4–7B), active against a linear epitope, caused full inhibition of all HBsAg subtypes except one (HBsAg/adw4). In vitro, a mixture of these two monoclonal antibodies was active against HBsAg from liver transplant recipients, including those with suspected variant viruses. (HEPATOLOGY 1995; 22:1078–1083.).