Alessandro Zanetti

Vaccine-induced escape mutant of hepatitis B virus

In southern Italy, 44 contacts of hepatitis B virus carriers, including infants of carrier mothers, became HBsAg positive despite passive and active immunisation according to standard protocols. In 32 of these vaccinees infection was confirmed by the presence of additional markers of viral replication. In 1 infant, serious disease occurred. The virus from this patient is an escape mutant with a different sequence from that of the isolate from the mother. A point mutation from guanosine to adenosine at nucleotide position 587 resulted in an aminoacid substitution from glycine to arginine in the highly antigenic a determinant of HBsAg. This mutation is stable: it is present in an isolate from the child 5 years later. In some of these patients, including this child, the a determinant, to which a large part of the vaccine-induced immunity is directed, has been partly lost. Binding to HBsAg of a monoclonal antibody, previously mapped to the region of the mutation, was reduced in the child relative to that of the mother.

Interferon Alfa-2a Therapy in Cryoglobulinemia Associated with Hepatitis C Virus

BACKGROUND Essential mixed cryoglobulinemia is frequently associated with hepatitis C virus (HCV) infection. A beneficial effect of interferon alfa therapy has been reported, but we do not know whether the antiviral activity of the drug affects the clinical and biochemical manifestations of disease. METHODS In a prospective randomized, controlled trial, we studied 53 patients with HCV-associated type II cryoglobulinemia. A group of 27 patients received recombinant interferon alfa-2a thrice weekly at a dose of 1.5 million units for a week and then 3 million units thrice weekly for the following 23 weeks. The 26 control patients did not receive anything apart from previously prescribed treatments. All patients were then followed for an additional 24 to 48 weeks. RESULTS Interferon was usually well tolerated, but it was permanently discontinued in two patients because of atrial fibrillation and depression. Two of the 26 patients in the control group were lost to follow-up. After the treatment period, serum HCV RNA was undetectable in 15 of the remaining 25 patients who received interferon alfa-2a, but in none of the controls. In comparison with the control group, the 15 patients with undetectable levels of HCV RNA in serum had significant improvement in cutaneous vasculitis (P = 0.04) and significant decreases in serum levels of anti-HCV-antibody activity (P = 0.007), cryoglobulins (P = 0.002), IgM (P = 0.002), rheumatoid factor (P = 0.001), and creatinine (P = 0.006). After treatment with interferon alfa-2a was discontinued, viremia and cryoglobulinemia recurred in all 15 HCV RNA-negative patients. On resumption of treatment, three of four patients had a virologic, clinical, and biochemical response. CONCLUSIONS The therapeutic efficacy of interferon alfa-2a in HCV-associated cryoglobulinemia is closely related to its antiviral activity, thus supporting the idea that HCV infection may be a cause of this disease.

STATEMENTS FROM THE TAORMINA EXPERT MEETING ON OCCULT HEPATITIS B VIRUS INFECTION

Giovanni Raimondo*, Jean-Pierre Allain, Maurizia R. Brunetto, Marie-Annick Buendia, Ding-Shinn Chen, Massimo Colombo, Antonio Craxi, Francesco Donato, Carlo Ferrari, Giovanni B. Gaeta, Wolfram H. Gerlich, Massimo Levrero, Stephen Locarnini, Thomas Michalak, Mario U. Mondelli, Jean-Michel Pawlotsky, Teresa Pollicino, Daniele Prati, Massimo Puoti, Didier Samuel, Daniel Shouval, Antonina Smedile, Giovanni Squadrito, Christian Trepo, Erica Villa, Hans Will, Alessandro R. Zanetti, Fabien Zoulim

Hepatitis C virus infection in patients with essential mixed cryoglobulinemia

OBJECTIVE To study the association between hepatitis C virus (HCV) infection and essential mixed cryoglobulinemia. SETTING Wards and clinics of the Ospedali Riuniti di Bergamo and Ospedale di Treviglio e Caravaggio, Italy. PATIENTS Fifty-one patients with essential mixed cryoglobulinemia associated with glomerulonephritis and 45 controls with noncryoglobulinemic glomerulopathies. MEASUREMENTS Antibodies to hepatitis C virus (anti-HCV) in sera from patients with essential mixed cryoglobulinemia and from controls, using two enzyme-linked immunosorbent assays (c100 ELISA and c22/c200 ELISA) and a recombinant immunoblot assay (4-RIBA); cryoprecipitate anti-HCV before and after use of dithiothreitol, a substance able to destroy IgM antibodies with rheumatoid factor activity, in patients with essential mixed cryoglobulinemia; serum HCV RNA by polymerase chain reaction in patients with essential mixed cryoglobulinemia. RESULTS In patients with essential mixed cryoglobulinemia, the c22/c200 ELISA detected anti-HCV in 98% of serum samples (95% CI, 90% to 100%), whereas the rate of reactivity remained at 2% (CI, 0% to 12%) in the control group (P less than 0.0001). These results were confirmed by the 4-RIBA in 66% of patients with essential mixed cryoglobulinemia. The study of cryoprecipitate by c100 ELISA showed anti-HCV in 41% (Cl, 28% to 56%) of patients. After dithiothreitol, the rate of reactivity increased to 94% (CI, 84% to 99%; P less than 0.0001 by the McNemar paired chi-square test), suggesting that the elimination of rheumatoid factor leads to unmasking of anti-HCV in cryoprecipitate. Polymerase chain reaction detected HCV RNA in 13 of 16 sera from patients with essential mixed cryoglobulinemia. CONCLUSIONS The extremely high prevalence of anti-HCV in serum and cryoprecipitate along with the frequently associated serum HCV RNA suggests a close relation between essential mixed cryoglobulinemia and chronic HCV infection.

Mother-to-infant transmission of hepatitis C virus

The rate of mother-to-infant transmission of hepatitis C virus (HCV) is approximately 5%, but is higher when the mother is co-infected with HIV Vertical transmission is restricted to infants whose mothers are viraemic. The risk of transmission increases with increasing maternal viral load but a specific cut-off value predicting infection cannot be defined. There is no specific HCV genotype which is preferentially transmitted. The mode of delivery (caesarean versus vaginal) does not appear to influence the rate of transmission, but firm evidence is lacking. There is no evidence to suggest an increased risk of HCV transmission through breast feeding. Pregnancy is not contra-indicated in HCV-infected women. Without drugs to treat established infections in mothers and infants and interventions to prevent vertical transmission, routine HCV screening is not recommended in pregnant women.

The global impact of vaccination against hepatitis B: A historical overview

Hepatitis B virus (HBV) infection is a world wide public health problem of major concern. HBV infection may lead to chronic liver disease, including cirrhosis and hepatocellular carcinoma (HCC). Vaccination is the most effective measure to control and prevent hepatitis B and its long-term serious sequelae on global scale, both in terms of cost-effectiveness and benefit-cost ratios. According to the WHO recommendations, universal vaccination has been currently implemented in 168 countries world wide with an outstanding record of safety and efficacy. The effective implementation of such programmes of vaccination has resulted in a substantial decrease in disease burden, in the carrier rate and in hepatitis B-related morbidity and mortality. A future challenge is to overcome the social and economic hurdles which still hamper the introduction of hepatitis B vaccination on a global scale.

Long-term immunogenicity of hepatitis B vaccination and policy for booster: an Italian multicentre study

BACKGROUND Universal anti-hepatitis-B vaccination of infants and adolescents was implemented in Italy in 1991. We undertook a multicentre study in previously vaccinated individuals to assess the duration of immunity and need for booster, over 10 years after vaccination. METHODS In 1212 children and 446 Italian Air Force recruits vaccinated as infants and adolescents, respectively, we measured the concentrations of antibodies to hepatitis-B surface antigen (anti-HBs) and the presence of antibodies to hepatitis-B core antigen (anti-HBc) at enrollment; postimmunisation values were not available. Individuals positive for anti-HBc were tested for hepatitis B surface antigen (HBsAg) and hepatitis B viral DNA. Individuals with anti-HBs concentrations at 10 IU/L or more were regarded as protected; those with antibody less than 10 IU/L were given a booster dose and retested 2 weeks later. Individuals showing postbooster anti-HBs concentrations of less than 10 IU/L were offered two additional vaccine doses and retested 1 month after the third dose. FINDINGS Protective anti-HBs concentrations were retained in 779 (64%, 95% CI 61.6-67) children and 398 (89%, 86.4-92.1) recruits. We recorded antibody amounts of less than 10 IU/L in 433 children (36%, 33-38.4) and 48 (11%, 7.9-13.6) recruits. One child and four recruits were positive for anti-HBc, but negative for HBsAg and hepatitis B viral DNA. Antibody concentrations were higher in recruits than in children (geometric mean titre 234.8 IU/L vs 32.1 IU/L, p=0.0001). 332 (97%) of 342 children and 46 (96%) of 48 recruits who received a booster showed an anamnestic response, whereas ten (3%) children and two (4%) recruits remained negative for anti-HBs or had antibody concentrations of less than 10 IU/L. Prebooster and postbooster antibody titres were strongly correlated with each other in both groups. All individuals given two additional vaccine doses (eight children and two recruits) showed anti-HBs amounts of more than 10 IU/L at 1 month after vaccination. INTERPRETATION Strong immunological memory persists more than 10 years after immunisation of infants and adolescents with a primary course of vaccination. Booster doses of vaccine do not seem necessary to ensure long-term protection.

Lack of Evidence of Sexual Transmission of Hepatitis C among Monogamous Couples: Results of a 10-Year Prospective Follow-Up Study

The risk of sexual transmission of hepatitis C virus (HCV) infection was evaluated among 895 monogamous heterosexual partners of HCV chronically infected individuals in a long-term prospective study, which provided a follow-up period of 8,060 person-years. Seven hundred and seventy-six (86.7%) spouses were followed for 10 yr, corresponding to 7,760 person-years of observation. One hundred and nineteen (13.3%) spouses (69 whose infected partners cleared the virus following treatment and 50 who ended their relationship or were lost at follow-up) contributed an additional 300 person-years. All couples denied practicing anal intercourse or sex during menstruation, as well as condom use. The average weekly rate of sexual intercourse was 1.8. Three HCV infections were observed during follow-up corresponding to an incidence rate of 0.37 per 1,000 person-years. However, the infecting HCV genotype in one spouse (2a) was different from that of the partner (1b), clearly excluding sexual transmission. The remaining two couples had concordant genotypes, but sequence analysis of the NS5b region of the HCV genome, coupled with phylogenetic analysis showed that the corresponding partners carried different viral isolates, again excluding the possibility of intraspousal transmission of HCV. Our data indicate that the risk of sexual transmission of HCV within heterosexual monogamous couples is extremely low or even null. No general recommendations for condom use seem required for individuals in monogamous partnerships with HCV-infected partners.

Novel hepatitis E virus (HEV) isolates from Europe: evidence for additional genotypes of HEV.

Hepatitis E infection is associated with areas in which hepatitis E virus (HEV) infection is endemic. Acute infections in industrialized nations are usually linked to travel to endemic areas. Recently, an acute hepatitis infection in a patient from the United States (US), with no recent foreign travel history, was linked to a novel strain of HEV. Although a few additional cases have been reported from patients who have not traveled to endemic areas, the source of these infections has not been determined. The objective of this study was to identify additional HEV isolates from patients with acute infection who had no recent history of travel to areas where HEV is considered endemic, and to determine the genetic relationship between these and other HEV isolates. Viral RNA was isolated from serum and polymerase chain reaction (PCR) was performed using consensus primers based on a number of HEV isolates. HEV sequence in open reading frame (ORF) 1 and ORF2 was identified in three patients from nonendemic areas, one from Italy and two from Greece. Comparative and phylogenetic analyses were performed. The Greek and Italian isolates were significantly divergent from two isolates from the US and isolates identified previously from HEV‐endemic regions. The Italian isolate was distinct from the two Greek isolates. In addition, the two Greek isolates were significantly divergent from each other. Phylogenetic analysis indicated that the Italian and two Greek isolates represent three new genotypes of HEV, distinct from the Burmese, Mexican, and US genotypes. J. Med. Virol. 57:243–251, 1999.

Serological pattern "anti-HBc alone": report on a workshop.

In areas with low hepatitis B virus (HBV) endemicity such as most parts of Europe and the United States “anti‐HBc alone” is found in 10–20% of all individuals with HBV markers, i.e., 1–4% of the population. In about 10% of these individuals HBV DNA is detected by PCR, the proportions varying greatly depending on the population studied, being highest in individuals coinfected with hepatitis C virus (HCV) (above 35%) and HIV (above 85%). A small proportion of individuals with “anti‐HBc alone” are in the window phase of an HBV infection or in a stage of late HBV immunity. For the large proportion of these individuals this is not the case and they are thought to have an unresolved HBV‐infection or a chronic infection in a late or “low grade” productive state. Currently, limited studies have been performed concerning the clinical aspects of individuals with “anti‐HBc alone” and suspected chronic HBV infection. The majority of these individuals seem to be healthy. Some chronic carriers with “anti‐HBc alone,” however, do present signs of chronic hepatitis. Individuals with “anti‐HBc alone” are potentially infectious. This is exemplified by a few case reports of HBV transmission to sexual contacts, perinatal transmission between mother and newborns and in blood recipients. Recommendations are given in relation to both the diagnostic and therapeutic procedures in the individuals with “anti‐HBc alone” and in the blood banking and transplantation services. J. Med. Virol. 62:450–455, 2000.