Search

From 1996 to 1998, a decrease in positive donation rates has been observed for HIV, HCV and HBs Ag in first-time donors, while these rates remained stable for HTLV. In repeat donors, the same decrease was observed for HCV and HBs Ag while the rates remained stable for HIV. No HTLV-positive donations from repeat donors were noted in 1998. About half of the HIV-positive repeat donors were regular donors (less than two years between the two donations), as well as 88% of HBV-infected repeat donors. Inversely, only 20% of HCV-positive repeat donors were regular donors. Anti-HBc antibodies have been found in 20% of HIV-infected donors, in 22% of HCV-infected donors, and were associated with HBs Ag in 99% of the cases. Elevated ALT was observed in 47% of donors with anti-HCV and in 10% of donors with HBs Ag. The major risk factors are at-risk sexual behavior for HIV and use of intravenous drugs and nosocomial infections for HCV. Being a native of an endemic country has been found to be the major risk for HBV. The major HTLV risk factor was directly or indirectly linked to the Caribbean area.

Background: We evaluated and analysed risk factors of HCV-infected blood donors according to HCV genotypes in order to improve the transfusion policy and safety of blood supply., Materials and Methods: HCV-RNA was analysed in sera from 518 anti-HCV-positive blood donors, who were invited to medical consultation and interview as to risk factors by means of an extensive questionnaire. HCV genotyping was done on all samples positive for HCV-RNA., Results: Of the 518 sera, 399 (77%) were HCV-RNA positive, and 394 of 399 HCV genotypes were identified. Major genotypes were 1b (34.3%), 3a (24%), 1a (19.5%) and 2 (11.4%). Of the donors, 289 (55.8%) were interviewed regarding their risk behaviour: 27% were former intravenous drug users (IVDUs), 26% had been transfused, 8% had a history of invasive diagnostic procedures, and 13% a history of surgery. Among the 224 interviewed donors, genotypes 1a and 3a were mainly associated with IVDU (51 and 45% respectively) and genotype 1b, with transfusion and nosocomial infections (40 and 25%, respectively)., Conclusion: In this population of anti-HCV-positive blood donors, nosocomial infection may be a route of HCV spread, but the main risk factor remains IVDU, particularly in young men. The transfusion policy will improve if predonation interviews of such young men are done with a specific and sensitive questionnaire., (Copyright 2000 S. Karger AG, Basel)

A comparative evaluation of the sensitivity of anti-HIV screening assays has been recently performed with a selected panel of 65 samples which included HIV1 group M (per-seroconversions, seroconversions and seropositives infected with genotypes A, B, C, D, E), HIV1 group O and HIV2. The results obtained with the 21 ELISA HIV1 + HIV2 screening assays are presented. Among these 21 assays, four are combined anti-HIV and p24 Ag assays. All the assays except four fulfilled the criteria defined at the beginning of the study, i.e., positive results on all the seropositives including seroconversions and positive results on at least 50% of the per-seroconversions. The main differences were observed with the ten per-seroconversion samples, the number of positive results on such samples varying from three to ten. The constant improvement of anti-HIV screening tests which leads one to shorten the 'window' period permits and earlier diagnosis of HIV infection and a progressive decrease of the transfusional risk.

Background: Previous studies, detecting GB virus-C (GBV-C) or hepatitis G virus (HGV) RNA by using reverse transcriptase polymerase chain reaction (RT-PCR), have shown that haemodialysis (HD) patients had a high risk of being infected and viraemic with this virus. A past GBV-C/HGV contact can now be detected by testing for antibodies directed against the GBV-C/HGV envelope protein E2 (anti-E2)., Methods: In order to evaluate GBV-C/HGV contact, 120 patients undergoing chronic HD were tested for GBV-C/HGV RNA by RT-PCR and anti-E2 antibodies by ELISA. GBV-C/HGV viraemic patients were followed prospectively for 18 months, and retrospectively when sera were stored. The total follow-up was between 18 and 78 months., Results: GBV-C/HGV RNA was detected in 17 patients (14%), and 18 patients (15%) had a significant level of anti-E2 antibodies. No positive anti-E2 specimens were also positive for GBV-C/HGV RNA and vice versa. A total of 35 patients (29%) were contaminated with GBV-C/HGV. Sixteen of the 17 viraemic patients had a persistent viraemia (follow-up 18-78 months) and one cleared the virus during the study period. A past or present GBV-C/HGV contact was statistically correlated with the duration of HD and hepatitis C virus (HCV) infection, but was independent of age, hepatitis B virus (HBV) infection, and alanine aminotransferase (ALT) level., Conclusions: Twenty-nine per cent of patients who underwent HD in our centre have been infected by GBV-C/HGV, 49% were still viraemic and 51% have developed anti-E2 antibodies, indicating a past contact with GBV-C/HGV. Our results demonstrate that the prevalence of GBV-C/HGV contact in HD was underestimated when only RT-PCR was used. Therefore GBV-C/HGV contact is probably much more frequent in HD than previous studies would suggest and is at this time not correlated with hepatotoxicity. Anti-HCV antibodies blood screening since 1990 and recent changes in managing HD patients have probably reduced GBV-C/HGV contact in the same way.

The prevalence of HIV, HTLV, HBV and HCV infections has been calculated by age and sex of blood donors and not, as generally done, according to the number of donations. This study has been conducted on the basis of two surveys. The first one collected information about the sex and age of the seropositive donors. A second survey, begun in 1992, collected information about the demographic characteristics of blood donors. This population has a higher male to female sex ratio (1:2 versus 1:0) and is younger than the general population. Thus, the prevalence of these viral infections has been determined according to sex, age and type of donors (first-time or repeat) from 1992 to 1996 and the trends have been analysed. The main results are the following: a decreasing prevalence of HIV in first-time donors from 1992 to 1996, more marked in men than in women and in the 18-29 year age group than in the other age groups; a slighter decrease in prevalence of HBV and HCV in first-time donors from 1992 to 1996 with no difference in this decrease between sex and age groups. HBs Ag prevalence in first-time donors was twice as high in men than in women and was highest in donors aged from 40 to 49 years in both sexes. Prevalence of antibodies to HCV in first-time donors was comparable in both sexes but varied greatly with age. In men, a peak was observed in the 30-39 age group and in women, the highest prevalence was seen in the 50-65 age group.

Natural variation in hepatitis B virus (HBV) was studied in asymptomatic carriers originating from countries of high endemicity. HBV DNA was detected by dot blot and/or polymerase chain reaction (PCR) in 34 of the 184 members of 22 new immigrant families who agreed to be tested after one of their children had been found to have current or past hepatitis B in a school survey. PCR products from both the S and distal-X pre-C regions were sequenced. One vaccinated child had the classical "escape" mutation at amino acid position 126 in the S-gene and two other children and two adults had other substitutions at amino acid positions 133, 120, 165, and 159. Mutations were more frequent in the distal-X pre-C region and included two pre-C mutants and 13 other amino acid substitutions. The strains originating in the various countries were placed in almost identical groups by phylogenetic analysis using each amplicon, and determination of subtype by antigenic analysis gave the same result as sequencing. The S-data allowed recognition of three dominant strains within genotype B, while the distal-X pre-C data provided better discrimination between family groups. No change was found when the sequence of samples obtained for the study was compared with those collected from 14 of the children two years earlier. There was some evidence of horizontal spread in addition to vertical transmission. Reports of mutations of HBV in patients with severe or unusual clinical features should be interpreted with caution until the prevalence of the mutant in asymptomatic carriers has been determined.

To improve the safety of the blood supply, HTLV screening of blood donations became mandatory in different countries. In Japan and in Europe, the majority of HTLV-infected donors are HTLV-1 whereas in the USA more than half of them are HTLV-II-positive. The prevalence of HTLV-infected donors is low in European Countries as is the rate of seroconversion. Consequently, to test donors only once would have a high efficiency. This procedure is already in use in certain countries. Furthermore, if the use of leucodepleted cell concentrates is generalized, the policies of HTLV screening will still be further modified.

Background and Objectives: In order to compare sensitivity, five anti-hepatitis C virus (HCV) immunoblot assays were tested (Deciscan plus, Inno-Lia III, Matrix, Murex Western blot and RIBA-3)., Materials and Methods: The test panel (50 samples for each assay) included 6 anti-HCV-negative samples and 44 samples from 36 HCV-infected subjects., Results: There were minor differences in core reactivity among the assays. The smallest number of NS3-reactive results occurred with the Murex and Matrix assays, and the smallest number of NS4 reactives with RIBA-3 and Matrix. Among the 20 discrepant results for NS5 there was one clear false-negative with Inno-Lia. Only 28 of the 50 samples of the panel gave the same results in all the assays: 5 negatives and 23 positives. One of the 6 negative samples were indeterminate in 3 assays. Eighteen of the 21 other divergent results were interpreted as either indeterminate or positive, a common reactivity being exhibited by all 5 assays. The most important discrepancies occurred on 3 HCV-RNA-positive samples which came up negative in some assays: 2 samples with isolated NS3 reactivity were negative by Matrix and Murex Western blot, 1 of them being also negative by Inno-Lia III; another sample was negative by RIBA-3 and Matrix due to weak signals (< 1) on core and NS3 proteins, which did not exceed 1+ with the other assays., Conclusions: With more uniform criteria for interpretation, the results would have been less divergent. Some assays should improve their sensitivity to the NS3 protein.

A decrease of positive donation rates for antibodies to HIV, to HCV and for HBs Ag has been observed between 1993 and 1995 both in first-time and regular donations. In first-time donors, the most important decrease has been observed for HIV and in regular donors for HCV and HBs Ag. The interval between the negative and the positive donations was inferior to 1 year for 50% of regular donors and was superior to 2 years for 20 to 30%. About 30% of HIV positive donations were positive for other markers: 23% for anti-HBc and 10% for anti-HCV. About 40% of HCV positive donations had an elevated ALT level. Risk factors related to HIV heterosexual transmission appear to be the most difficult to identify during the donor selection and the least often associated with other markers. In recently HCV-infected donors, the main risk factors were IV drug addiction (25%) and nosocomial infection (30%). The major HTLV risk factor was directly or indirectly linked to the Caribbean area. Important differences between continental France and overseas territories were observed for HIV and HBs Ag rates.

In 1974, the existence of hepatitis serologically distinct from hepatitis A and B was recognized. They were tentatively designated non-A non-B. They accounted for 90% of post-transfusional hepatitis. During 15 years numerous studies failed to identify agent(s) responsible for these hepatitis. In 1989 the virus responsible for parenteral non-A non-B hepatitis was identified and named hepatitis C virus. Shortly after, the virus responsible for enteral non-A, non-B was also discovered (hepatitis E virus). During these 15 years, a 60% reduction of post-transfusional hepatitis was obtained both by the measures instituted to prevent AIDS transmission and by the introduction of surrogate assays (ALT levels and anti-HBc antibody).

Controls were performed using a common internal panel specific for anti-HIV, anti-HTLV and HBs Ag. During the past 32 months, 5 anti-HIV1 + 2 antibody kits (Abbott, Behring, Biotest, Murex D. and Organon T., total of 199 lots), 4 anti-HTLV I/II antibody kits (Abbott, Murex D., Organon T. and Ortho C.D., total of 153 lots) and 5 HBs Ag kits (Abbott, S.D. Pasteur, Murex D., Organon T. and Ortho C.D., total of 244 lots) were used and controlled by the 14 participating laboratories. Analysis of the results showed the values obtained for the most representative sample of each panel to be within the limits m +/- 2 SD in 95 to 100% of the HIV1 + 2 kits, in 94 to 97% of the HTLV kits and in 92 to 100% of the HBs Ag kits. The specificity of the kits evaluated was on an average equal or superior to 99.5%, as required by the French Drug Agency in a blood donor population.

The agent responsible of more than 80% of the parenterally transmitted non-A-non-B hepatitis, designated hepatitis C virus (HCV), was identified in 1988 thanks to the isolation of the first cDNA reactive clone which was derived from experimentally infected chimpanzees RNA. The recombinant protein expressed from this clone located in the NS4 region of the HCV, allowed to establish the whole HCV-RNA sequence and to develop the first generation enzyme-linked immunoassays for detecting anti-HCV antibodies. Subsequently, other recombinant viral antigens derived from other HCV genome regions, were produced and used to develop second generation screening and confirmatory assays (1991). At least, thanks to a better presentation of the epitopes, since 1993 the performance of third generation reagents have been improved. Nevertheless, in spite of those modifications, the performance of both screening and confirmatory assays still needs to be improved. Moreover, in cases of difficulties of HCV infection diagnosis with serological tests, HCV-RNA detection with genomic amplification tools represents a useful alternative.

This study estimates the risk of transmitting human immunodeficiency virus (HIV), human T lymphotropic virus (HTLV), hepatitis C virus (HCV) and hepatitis B virus (HBV) from blood units using a seroconversion incidence model. Data from 13 blood transfusion centers collecting about 1 million donations per year and belonging to the Retrovirus and the Viral Hepatitis study groups were analyzed during the 3 year study period (1992-1994) for HIV, HTLV, and HBV and a 2 year study period for HCV (1993-1994). Seroconversion incidence rates were calculated and multiplied by estimates of the serological window period for each agent to obtain residual risk. The risk that an infectious donation was made during the window period was estimated to be 1 in 2 millions (95% CI: 1/10(7)-1/450000) for HTLV, 1 in 588000 (1/3 300000-1/227000) for HIV, 1 in 217000 (1/714000-1/83000) for HCV and 1 in 112000 (1/333000-1/43500) for HBV. This risk was estimated for the totality of donations collected in France for HIV and HTLV. For HIV it was the same as above (1 in 588000) and for HTLV it was much lower (1 in 7 millions).

Background: To verify the criteria for human T-lymphotropic virus (HTLV) seropositivity in Western blot (WB) proposed by the Retrovirus Study Group of the French Society of Blood Transfusion, 186 blood donations that were repeatedly reactive in HTLV enzyme-linked immunosorbent assay, selected according to their WB pattern, were tested by polymerase chain reaction (PCR) and radioimmunoprecipitation assay (RIPA)., Study Design and Methods: In two commercially available WBs, 12 samples were confirmed as positive (rgp21+p19+p24) and 174 were interpreted as indeterminate (one or two reactivities to these proteins). The primer pairs used for the PCR allowed the amplification of type I (HTLV-I) or type II (HTLV-II) (or both) sequences. The RIPA was performed with two 35S-labeled cell lines: HTLV-I infected HUT 102/B2 and HTLV-II-infected MoT., Results: Of the 12 positive samples, 11 were classified as HTLV-I-positive and one as HTLV-II-positive. Among the 174 indeterminate samples, three (WB pattern: rgp21+, p19+, p24-) were HTLV-I positive in PCR (one of them was positive in RIPA also); the other 171 were HTLV negative., Conclusion: In the study of a population in which 97 percent of HTLV infections are due to HTLV-I, these data support the three-protein criteria (rgp21, p19, and p24) for a positive blot reading. No HTLV infection was observed when rgp21 did not react. Consequently, p19 and/or p24 band patterns represent false reactivity and do not require PCR or RIPA confirmation. To discriminate between false- and true-positive results in the absence of MTA-1 or K55 reactivity, PCR and/or RIPA is required only when rgp21 reactivity is associated with one gag band (p19 or p24).

As it has been observed since the beginning of anti-HIV screening in blood donations, the rate of seropositive donations has been still decreasing during these 4 last years: 0.090/1000 in 1991 to 0.042/1000 in 1994. This decrease has been observed in blood donations from first-time donors (0.38 to 0.17/1000) and from regular donors (0.060 to 0.030/1000). However, the residual risk from cellular components, such as it is estimated, seems to be stable. The proportion of blood donations positive for both anti-HIV and anti-HBc was constantly decreasing from year to year: 63% between 1985 and 1988 and 25% in 1994. The repartition of seropositive donors into sex, ages and at-risk groups during this recent period was the same as previously observed.

The sensitivity of the most recent generation of anti-hepatitis C virus (anti-HCV) screening tests from seven manufacturers was evaluated with a common panel of 530 specimens from 320 HCV-infected subjects. This panel included 221 samples from 57 seroconverters (53 pre-sero conversion negative specimens and 168 positive samples) and 309 selected specimens from 263 other HCV-infected patients of which 19% exhibited NS3 or core reactivity alone with the presence of HCV-RNA assessed by PCR. None of the seven screening tests detected all infectious and antibody-positive specimens. However, important differences were observed between these assays in the number of false-negative results, which seemed mainly due to nonreactivity of antibody to the NS3 antigen.

A comparative evaluation of the sensitivity of anti-HIV screening assays has been recently performed with a selected panel including all the actually known difficulties of HIV serology: Very recent seroconversions (per-seroconversions) and recent HIV1/M seroconversions, HIV1/M seropositive with a subtype different from B, HIV1 group 0 and HIV2. The criteria of sensitivity were to recognize as positive all the seropositive samples and at least 2 of the 8 per-seroconversions. The 18 combined ELISA fulfilled these criteria, except for one assay with a deficient HIV2 sensitivity. However, all these assays do not have the same level of sensitivity. The most important differences were observed with the pre-seroconversion samples, the number of positive results on such samples varying from 2 to 8. The capacity of a screening assay to early detect an HIV-infected subject is a supplementary criterium to retain, particularly in blood transfusion screening, in order to shorten the "window" period.

Samples from 128 haemodialysed patients were tested by anti-HCV 2nd- and 3rd-generation assays from Ortho: 53 were positive by ELISA 2.0 and 54 (42%) by ELISA 3.0. The 54 anti-HCV-positive patients were tested by RIBA-2 and RIBA-3 and by PCR for the detection of HCV-RNA: 46 of the 47 patients (98%) reactive by RIBA-2 and 48 of the 51 patients (94%) reactive by RIBA-3 were HCV-RNA positive. Three patients with RIBA-3 indeterminate results were HCV-RNA negative. Among the 74 anti-HCV negative patients, 29 were tested by PCR with negative results. Two distinct episodes of hepatitis C have been observed in two patients during the follow-up and 44 of the 50 patients (88%) known positive for anti-HCV since at least 1989 were still viraemic in 1993. A very high correlation was found between anti-HCV antibodies reactive by RIBA and the presence of HCV-RNA. A lack of protection after a resolved infection and a high frequency of chronic disease have been observed as well as a reinfection or a reactivation of the infection in two patients.

Background: The results obtained in sequential specimens from recently infected subjects generally provide the best means of comparing the sensitivity of assays., Study Design and Methods: The sensitivity of second- and third-generation assays for antibody to hepatitis C virus (HCV) was compared on sequential specimens, generally collected at monthly intervals from 45 patients undergoing hemodialysis who seroconverted for HCV between 1980 and 1990., Results: Fifteen patients (33%) were positive earlier in the third-generation enzyme-linked immunosorbent assay (ELISA), with a mean difference of 17 days (range, 7-30) between the last negative and the first positive specimens. At the first rise in alanine aminotransferase, and at its peak, 63 and 91 percent of the patients, respectively, were anti-HCV positive in the third-generation ELISA. Third-generation recombinant immunoblot assay (RIBA) reacted at the same time as third-generation ELISA. Of the first specimens that were positive in second-generation ELISA, 44 percent reacted and 56 percent were indeterminate in third-generation RIBA, while 10 percent reacted, 72 percent were indeterminate, and 18 percent did not react in second-generation RIBA. From the beginning to the end of the follow-up, antibody to c33c was the most prevalent, followed in descending order by antibody to c22-3, antibody to c100-3, and antibody to NS5: 56, 54, 26, and 18 percent, respectively, at time 0, and 100, 86, 83, and 31 percent, respectively, 12 months later., Conclusion: Third-generation assays (both ELISA and RIBA) were more sensitive than second-generation assays in the diagnosis of HCV infection, in that positive results were obtained earlier and a higher proportion of specimens were confirmed positive in RIBA testing.

A prospective non-A, non-B follow-up program, implemented in a hepatitis B surface antigen-free dialysis unit, enabled us to report on the natural history of hepatitis C virus (HCV) infection in hemodialyzed patients between 1980 and 1992. For this program, every patient was prospectively monitored every two weeks for alanine amino transferase (ALT) activity, and every month for gammaglutamyl transpeptidase (GGT) activity and systematic collection of frozen sera. Sequences of stored sera from 217 patients were repeatedly tested for anti-HCV antibodies using second generation assays. Eighty-six of the 217 patients (39.6%), including 61 of the 67 patients with non-A, non-B hepatitis (91%), had HCV infection repeatedly evidenced by positive ELISA in all, and confirmed by RIBA in 84 of 86 (97.5%). In addition, 19 out of 23 patients (82.6%) were positive for HCV RNA by the polymerase chain reaction (PCR). Of the 86 anti-HCV positive patients, 41 had previously acquired HCV infection, and 45 seroconverted during chronic dialysis. Of these, all but one patient developed hepatitis with raised ALT activity which lasted for at least six months in all. Only 29 of 45 patients (64.5%) had a history of blood transfusion. Seventy-eight of the 86 patients (91%) who were followed up for one to 11.5 years (median 5) retained anti-HCV for several years. Nineteen liver biopsies performed in 16 patients showed chronic active hepatitis in 8 (50%) and hepatocellular carcinoma without cirrhosis in one patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Nine patients with atypical HIV-1 western blot profiles were diagnosed as having HIV-1 subtype O infection. All the patients were living in France; eight originated from Cameroon and one from France. Lymphocyte DNA amplification by the polymerase chain reaction was only positive when HIV-1 subtype O specific primers were used. Preliminary sequence analysis of amplified products and serological reactivity against a specific subtype O synthetic env peptide confirmed HIV-1 subtype O infection. HIV-1/HIV-2 enzyme-linked immunosorbent assays, especially those based on env peptides or on the sandwich format, can be negative in HIV-1 subtype O infection.

The antigenic determinants for the main hepatitis B virus (HBV) subtypes adw, adr, ayw and ayr lie in the S (surface) polypeptide. Two amino acid residues in particular, encoded by the S gene at codon positions 122 and 160, have been postulated to determine the different antigenic subtypes. In contrast, the 165 nucleotide pre-S2 gene encodes an immunodominant region common to all subtypes that can give rise to neutralizing antibodies. We have characterized the pre-S2 gene sequences of 29 HBV strains of the three main subtypes, adw, ayw and adr. Seven base positions showed variation that was entirely subtype-specific, with six of these variations leading to subtype-specific amino acid differences. This finding affords the possibility of using pre-S2 sequences for genetic subtyping. Two ayw strains from unrelated patients infected in the Middle East had identical pre-S2 sequences with a block of 12 nucleotides deleted. A geographical correlation with subtype observed from serological results was also apparent from phylogenetic analysis of DNA identities within the pre-S2 region. The results support the concept that the main HBV subtypes truly represent families of phylogenetically different strains.

HBsAg subtypes were defined by means of adsorbed polyclonal antisera; however, HBsAg subtyping is currently usually carried out with monoclonal antibodies (Mab). We developed a complementary subtyping method based on the polymerase chain reaction. Reference samples belonging to all known HBsAg subtypes could be detected and grouped into four different categories (ayw1/ayw4/ayr, ayw2/ayw3, adw2/adrq+/adrq-, adw4). Thirteen HBsAg-positive serum samples previously subtyped as ad by means of monoclonal antibodies fell into the adw2/adrq+/adrq- group, as well as 13 ay samples into the ayw2/ayw3 group. These results could be confirmed by means of reference polyclonal antisera in nine ad cases (all adw2) and in seven ay cases (all ayw3); the remaining seven were below the detection limit of the polyclonal assay. Four samples which were not recognized by any of the d/y subtype-specific Mab were shown to contain ayw2/ayw3 sequences. Only one contained sufficient HBsAg to be confirmed as ayw3 by means of reference antisera. Three of five sera showing simultaneous reactivity both for d and y-specific Mab were classified as adw4 by PCR, as was one by reference polyclonal antisera. The y-specific monoclonal antibody cross-reacted with the adw4 subtype. Single adw2 sequences were amplified in one of the remaining two cases, as well as single ayw2/ayw3 sequences in the other, suggesting that they showed true coexistence of two strains of different subtype, only one of which was in active replication state. It is concluded that the method described is useful in the solution of some undefined cases obtained with the monoclonal-based assays.

Objectives: Patients with chronic renal failure respond rather poorly to hepatitis B vaccines. A better response could be expected from recombinant vaccines including both the S and the pre-S2 antigens. We therefore prospectively compared the immunogenicity of plasma-derived Hevac B vaccine (H) with that of recombinant GenHevac B vaccine (G)., Methods: Vaccinations were performed in 120 non-dialyzed patients with chronic renal failure. The patients were randomly divided into two groups. Group G included 60 patients (24 males, mean age 58 +/- 16 years, mean creatinine clearance 25.3 +/- 12.6 ml/min) who were given the Hevac B vaccine at the dose of 5 micrograms. Group H included 60 patients (31 males, mean age 60 +/- 15 years, mean creatinine clearance 24.4 +/- 11.1 ml/min) who were given GenHevac B vaccine at the dose of 20 micrograms. All vaccinations were repeated at 0, 1, 2, 4 and 12 months., Results: Following the fourth injection, seroconversion (anti-Hbs > or = 2 mlU/ml) was observed in 50/59 (85%) of the patients in group G versus 38/58 (67%) in group H (p < 0.02). Seroprotection (> or = 10 mlU/ml) was obtained in 42/59 (71%) vs 34/58 (59%), (NS) in the two groups respectively with a geometric mean titer of 112 versus 229 mlU/ml (NS) in responders. Following the booster injection at the 12th month, seroconversion was achieved in 48/51 (94%) vs 40/53 (76%) (p < 0.01) and seroprotection in 84% vs 70% (p = 0.053) respectively. The mean geometric titers were 879 and 1001 mlU/ml., Conclusions: Recombinant GenHevac B vaccine elicits seroconversion and seroprotection in a higher proportion of patients with chronic renal failure than the plasma-derived Hevac B vaccine, with comparably high antibody titers in responders. Therefore, GenHevac B vaccine should be recommended for vaccinating patients with chronic renal failure against hepatitis B.

Immunogenicity of the recombinant GenHevac B vaccine (G), containing both the S and the preS2 antigen, was compared with that of the plasma-derived Hevac B (H) vaccine in 120 chronic uremic predialysis patients. Sixty received 20 micrograms/dose of G and 60 received 5 micrograms/dose of H at 0, 1, 2, 4, and 12 months. Two months after the fourth injection, seroconversion (antibody to hepatitis B surface antigen [HBs], > or = 2 mIU/mL) was seen in 85% of group G and 67% of group H patients (P < .02); seroprotection (anti-HBs, > or = 10 mIU/mL) was seen in 71% and 59%, respectively. The geometric mean titers (GMT) of anti-HBs in responders were 112 and 229 mIU/mL, respectively. After booster injection at month 12, seroconversion occurred in 94% and 76% and seroprotection in 84% and 70%, with anti-HBs GMTs of 879 and 1001 mIU/mL in groups G and H, respectively. The recombinant GenHevac B vaccine elicited seroconversion and seroprotection in a higher proportion of chronic uremic patients, with comparably high anti-HBs antibody titers in responders.

The genomes of six hepatitis B viral (HBV) strains were sequenced from 10 overlapping amplificates obtained by the polymerase chain reaction. Four of the strains, specifying subtypes ayw4 and adw4q-, represented on the basis of divergency within the S gene two new genomic groups identified by us. The other two strains, encoding adrq- and of Pacific origin, belonged to genomic group C. The relation of these genomes to 21 published human, 1 chimpanzee, and 4 rodent hepadnaviral genomes was analyzed by constructing a phylogenetic dendrogram. Thereby, the segregation of human HBV strains into six genomic groups was confirmed. A consistent grouping of the genomes compared was also obtained in dendrograms based on the P and S genes, although the branching order differed from that based on the entire genomes. Each of the two representatives of genomic groups E and F differed by 8.1 to 13.6% and by 12.8 to 15.5% from the genomes of the other groups and by 1.5 and 3.7% from each other. The two Pacific group C strains differed by 2.7% from each other and by 4.1 to 5.4% from other group C genomes, suggesting that they diverged early from the other group C genomes. The F strains formed the most divergent group of HBV genomes, which may be explained by their representing the original strains of the New World. Within the structural gene products, 17 and 34 amino acids unique for human HBV strains were recorded in the sequenced E and F strains, respectively. Most notable is the Ser81 to Ala81 substitution in an immunodominant region of HBcAg, and the four extra cysteine residues in HBsAg at residues 19, 183, 206, and 220, which might be engaged in additional disulphide bridges. Five residues shared by E and F strains were also unique for human HBV strains. Two of these, Leu127 and Ser140 in HBsAg, were the only substitutions that may explain the w4 reactivity shared by these HBV strains. Interestingly, the Ser140 substitution occurs in an immunodominant loop of the a determinant claimed to be important for the protective immune response to HBV vaccination.

The results concerning the hepatitis C antibodies screening tests sensitivity are presented by Viral Hepatitis Study Group of the French Society of Blood Transfusion. This evaluation was carried out in 1993, with five tests available for Hepatitis C Viral (HCV) antibodies screening. Several panels of human blood samples, collected by members of Viral Hepatitis Study Group, were used. For those specimens the data about whole serology (various reactivities against viral antigens) clinical history and other explorations (molecular biology, liver histology, other viral infections) are described. If possible all those results are used to describe some interpretation criteria for the HCV serology and sensitivity obtained for each screening test.

The combined HIV1 + HIV2 assays allow to screen simultaneously the subjects infected by HIV1 or by HIV2 (About 80 HIV1 for 1 HIV2 in blood donations in France). An improvement of both sensitivity and specificity was obtained by using artificial proteins which have been selected for having the most immuno-dominant epitopes. The sensitivity is defined by the study of samples from recent and very recent seroconverters and the specificity by testing 2000 unselected blood donors. All the early seroconversions must be recognized as positive and less than 0.5% false positive results must be found in blood donors. HIV1 variants, temporarily named sub-type O have brought a new difficulty to the HIV serology, due to a weak homology, especially in "env" domains, between these variants and the reference HIV1 strains. Subjects living in France and infected by this HIV1 variant seem rare and the screening assays which miss some of these infected individuals seem capable to modify their reagents in order to recognize all of them.

The transfusion-related risk of transmission of hepatitis C virus (HCV) was evaluated in France for the periods before and after exclusion of donor blood units with the surrogate markers elevated alanine aminotransferase (ALT) levels and antibody to hepatitis B core antigen (anti-HBc). A total of 1,412 blood recipients undergoing surgery were followed up prospectively in the period from 1986 to 1989. The stored serum samples were tested for antibodies to HCV by an enzyme immunoassay (EIA) and the result in reactive sera confirmed by a recombinant immunoblot assay (RIBA). The risk of HCV transmission was estimated by the maximum likelihood method for a subpopulation of 892 recipients divided into three groups. Of 55 (3.9%) EIA positive patients, 56.4% were found to be positive prior to transfusion. HCV seroconversion (positive RIBA) occurred in 22 patients (1.6%). The risk of HCV transmission per 1,000 transfused blood units decreased significantly from 4.11 in Group 1 (receiving non-screened blood) to 3.43 in Group II (receiving ALT screened blood) and to 1.40 in Group III (receiving ALT and anti-HBc screened blood). These results demonstrate that screening of donors for surrogate markers had reduced the risk of HCV transmission before the introduction of a systematic anti-HCV screening policy in France in March 1990.

In France, HIV seroprevalence in blood donations still decreased from 1990 to 1992 with an important diminution in 1992, in first time donors as well as in regular donors. During the last 1992 semester, this prevalence reached 0.051%: 0.19% and 0.026% in donations from first time and regular donors respectively. The residual risk was estimated to be 1 for 580,000 donations in 1992 (CI 95% = 1/2,000,000 to 1/330,000). Sex ratio was 3.7 and 3.4 in 1990 and 1991 and increased to 5.5 in 1992 due to a very small number of seropositive women, which seems to be an important epidemiological indicator. The major at-risk group is still represented by homo-bisexual men.

A 681 nucleotide fragment of the hepatitis B virus (HBV) genome was sequenced that corresponded to the complete gene for hepatitis B surface antigen (HBsAg) in 80 HBsAg- and hepatitis B e antigen (HBeAg)-positive sera of diverse geographical origins. These and 42 previously published HBV sequences within the S gene were used for the construction of a dendrogram. In this comparison, each of the 122 HBsAg genes was found to be related to one or other of the six previously identified genomic groups of HBV, A to F. The HBV strains within each genomic group showed a characteristic geographical distribution. Group A genomes were represented by 23 strains mainly originating in northern Europe and sub-Saharan Africa. The group B and C genomes, represented by 17 and 28 strains respectively, were confined to populations with origins in eastern Asia and the Far East. The group D genomes, represented by 38 strains, were found worldwide, but were the predominant strains in the Mediterranean area, the Near and Middle East, and in south Asia. Group E genomes, represented by nine strains, were indigenous to western sub-Saharan Africa as far south as Angola. There were indications that the F group, made up of six strains, represented the genomic group of HBV among populations with origins in the New World. Thus, HBV has diverged into genomic groups according to the distribution of mankind in the different continents. As well as giving information on the genetic relationship of HBV strains of different geographical origin, this study also provides information on the primary structure of HBsAg in different regions of the world. Such data might prove valuable in explaining the reported failures to obtain protection with current HBV vaccines.

Objective: To evaluate the serological and epidemiological characteristics of HTLV-I/II-positive blood donors in continental France during the first 6 months of universal screening of blood donations (n = 1,816,927)., Method: A collaborative investigation of all confirmed anti-HTLV-I/II-positive samples reported by blood transfusion centres was performed. Seventy-three out of 77 reported samples were retested at two reference laboratories. Epidemiological data on risk factors were compiled., Results: Of the 73 retested samples, 66 were confirmed to be HTLV-I-positive and one to be HTLV-II-positive; six samples were designated false-positive, mainly because of non-specific reactivity to recombinant gp21 in Western blot. The overall prevalence of HTLV-I/II in continental France is 0.039 per thousand. The main risk factor identified for HTLV-I infection was directly (origin) or indirectly (heterosexual contact) linked to endemicity in the Caribbean. The cost per case of avoided contamination in the 6-month period of this study was 1.36 million French francs., Conclusions: Sixty-two per cent of HTLV-I/II-infected blood donations would not have been discarded through the previous targeted HTLV screening or through other mandatory tests, including anti-hepatitis B core. To avoid false-positive results, we propose a new algorithm of diagnosis.

HCV RNA was determined by the polymerase chain reaction (PCR) in 41 haemodialysed patients with a known anti-HCV status (ELISA and RIBA-2) and a monthly alanine aminotransferase (ALT) level determination. No histological examination of the liver tissue was available. Four samples from each patient were collected at 6 month intervals for 18 months. Seven patients negative for anti-HCV during the entire follow-up gave negative PCR results on the four samples. Two patients who were anti-HCV-negative upon entry into the study seroconverted to HCV during follow-up. HCV RNA was detected during the acute phase of hepatitis. HCV RNA was no longer detectable after antiviral therapy was administered to one patient. Out of 27 anti-HCV-positive patients, 24 had persistent viraemia, 2 had transient viraemia (1 sample PCR-negative and 3 samples PCR-positive) and 1 was PCR-negative on the 4 samples. Thirteen of the 26 viraemic patients had a normal ALT level during the preceding 3 years. Three patients with a C22-3 band alone by RIBA-2 were negative by PCR, whereas two patients with a C33-c band alone were PCR-positive on the four samples. These results suggest that HCV viraemia was strongly associated with anti-HCV in haemodialysed patients with or without biological hepatitis.

The complete nucleotide sequences of six hepatitis B viral (HBV) genomes were determined by dideoxy chain termination sequencing of ten overlapping nucleotide fragments obtained by the polymerase chain reaction. Four of the genomes belonged to the two genomic groups E and F of HBV which have been previously identified by us on the basis of sequence divergences within the S gene. Genomic group E encodes the HBsAg subtype ayw4, group F adw4q-. The other two genomes were of Pacific origin within group C and encoded adrq-. The relationship of these complete human HBV genomes to 21 that have been previously published, together with one chimpanzee virus and four rodent hepadnaviral genomes, was investigated by constructing a phylogenetic tree utilizing a combination of distance matrix and approximate parsimonious methods. Thereby, the previously demonstrated segregation of human HBV strains into six genomic groups was confirmed. Both of the representatives of the groups E and F were found to differ by 8.1-13.6% and by 12.8-15.5% from the genomes of the other genomic groups and by 1.5 and 3.7% from each other. Since they differed by more than 8% from the genomes in the other groups, the limit originally used to define HBV, genomic groups their status as new genomic groups was confirmed. The two Pacific group C strains were found to differ by 2.7% from each other and by 4.1 to 5.4% from other group C genomes, suggesting that they diverged early from the other group C genomes. According to both the overall similarity and the phylogenetic dendrogram the F strains formed the most divergent cluster of HBV genomes favoring the concept that they represented the original HBV strains of the New World. The next split in the dendrogram segregated the A, D, E and the chimpanzee strains from the Asian B and C strains. Information on the nucleotide sequences and their encoded products of HBV strains of different genomic groups will provide a basis to understand biological variations of the HBV infection in different parts of the world.

Amino acid residues 101 to 180 of hepatitis B surface antigen (HBsAg) were predicted by sequencing the corresponding part of the S gene of hepatitis B virus (HBV) DNA in 46 HBsAg-positive sera, which had been subtyped by immunodiffusion with respect to d/y, w/r, w1 to w4 and q. The sequences of the nine different HBV serotypes defined by these specificities were found to be homogeneous proving that they represent consistent variations of HBV at the genomic level. Residue 127 was found to be important as were Pro, Thr and Leu for w1/w2, w3 and w4, respectively. Five residues were found to differ between ayw1 and ayw2. These were at positions 134 (Phe instead of Tyr), 143 (Thr instead of Ser), 159 (Ala instead of Gly), 161 (Tyr instead of Phe) and 168 (Val instead of Ala). However, all these residues were shared by ayw1 and adw2, implying that Arg122 was also important for w1 expression. All genomes expressing r, apart from one ayr strain, had an Ile126, which might explain the pseudo-allelism of w1 to w4 in relation to r, since this substitution might influence the w epitope. There were two regions where adw4q- and adrq- differed from all the q+ subtypes. These were located at residues 158 and 159, and at residues 177 and 178, where both the q- subtypes had amino acid substitutions in adjacent positions. The mapping of the epitopes defining these antigenic specificities will help to link information on the world-wide distribution of HBsAg subtypes to future molecular epidemiology with regard to HBV.

Hepatitis C virus (HCV) discovery and introduction of anti-HCV antibodies screening in blood transfusion imply the necessity of a good blood donations and blood donors policy. Detection of a seropositivity during the screening must be completed with a confirmatory test. The results are directly used to inform donors and define the blood products policy. Donors with positive results on confirmatory test are discarded and have physical and biological examinations in hepatology. Individuals with indeterminate or negative results must be retested for the HCV serology. Furthermore, because of a rapid improvement in the fields of technology, diagnosis and therapy of HCV, an adaptation of the policy is necessary.