[Safety of blood products and B19 parvovirus]. / Sécurité des produits sanguins labiles et parvovirus B19.

More than 25 years after the discovery of the parvovirus B19 (B19), the issue of the safety of blood components and the screening of this virus in blood donations is still debated. Although more often transmitted by respiratory route, B19 may also be transmitted by transfusion of blood components. This risk of exposure has been estimated to a frequency ranging from 1/625 to 1/50,000, according to the sensitivity of the detection methods and to seasonal epidemiologic circumstances. Usually, B19 is responsible for benign pathologies. However, such an infection can have a serious clinical outcome in three categories of susceptible recipients: (i) patients with shortened red cell survival (thalassemia major, sickle cell disease, other hemolytic diseases); (ii) immunocompromised patients (previously exposed to B19 or not) (iii) and pregnant women (not previously exposed the B19), with a risk of hydrops fetalis or of intrauterine death. Selected blood components, not collected during the short but highly viremic pre-seroconversion phase, could be reserved for these three groups of at-risk recipients. The screening of such viremic donations could be performed with nucleic acid testing (NAT), but an alternate strategy could be the selection of B19 immunised donors far from the primo-infection (positive for B19 IgG and negative for B19 IgM, or only positive for IgG at two controls distant of several months). However, the existence of persistently B19-infected individuals carrying B19 DNA despite the presence of specific IgG (estimated at 1% of blood donors) could constitute a potential threat for transfused immunocompromised recipients. The screening of such donors, which could be performed through a very highly sensitive NAT, would be justified only if the infectivity of such blood donations is demonstrated. If not, a screening of blood donors positive for B19 IgG would be a sufficient preventive measure.

[Screening tests combined with p24 antigen and anti-HIV antibodies in early detection of HIV-1]. / Les tests de dépistage combiné de l'antigène p24 et des anticorps anti-VIH dans l'infection précoce à VIH-1.

The five available p24 Ag/anti-HIV combined tests were compared to the six third-generation anti-HIV assays mainly used in blood transfusion centers. Among 70 selected HIV-1 positive samples (12 samples from early infected blood donors and 58 from ten commercial panels), 59 were positive with at least one assay. False negative results were observed for zero to six samples with p24 Ag/Ab assays versus seven to 19 with antibody (Ab) tests. In five cases, one or more combined assays gave a positive signal later than the most sensitive Ab screening test. One sample with a high p24 Ag titer was missed by one combined test. The mean time delay between the most sensitive test and the second one was 0.3 to 2 days. The p24 Ag limit of detection was investigated with seven dilutions of the HIV Ag reference. The threshold of the p24 Ag detection was found to be between 65 and 250 pg/mL of HIV Ag. For four of the five combined assays, p24 Ag detectability was assessed with dilutions of infected culture cell supernatants from 13 HIV-1 different genotype strains exhibiting HIV Ag titers from 300 to 450 pg/mL. One of the four combined assays gave negative results but close to the cut-off for three supernatant dilutions (1 B, 1 F, 1 HIV-1/O) and one missed the HIV-1/O dilution. The p24 Ag/Ab combined assays permit an earlier diagnosis of HIV infection than third generation assays even if the yield in terms of reduction of the window period is moderate. They are less sensitive than p24 Ag screening assays for the detection of this marker. Consequently, the p24 Ag/Ab assays have not been used for the diagnosis of a primary infection instead of p24 Ag screening tests. They must be considered only as good tools for the detection of HIV infection.

[Interpretation of hepatitis C virus serology: immunoblot and genome amplification]. / Interprétation de la sérologie du virus de l'hépatite C: immunoblot et amplification génomique.

In France, screening for anti-hepatitis C virus (HCV) among blood donors has been performed since 1 March 1990. It is usually carried out using enzyme immunoassays (EIA). Positive or dubious results may be linked to false positive EIA reactions. Therefore the use of an immunoblot assay such as RIBA can be very useful to assess false positive signals. Moreover, the analysis of the different antibody reactivities makes it possible to evoke a viremic status or not. The follow-up provides essential information on recent seroconversion. However, some profiles do not allow a conclusion to be drawn between chronicity and serological sequel. In these cases, polymerase chain reaction (PCR) has to be implemented in order to conclude between the two.

Large-scale screening for human parvovirus B19 DNA by PCR: application to the quality control of plasma for fractionation.

BACKGROUND AND OBJECTIVES: Because human parvovirus B19 (B19) has been transmitted by various plasma-derived medicinal products, the 'Laboratoire français du Fractionnement et des Biotechnologies' (LFB) implemented PCR screening of plasma pool samples for B19 DNA as part of the quality control of plasma source material. MATERIALS AND METHODS: Plasma pool samples (average of 46.5 donations) were tested for B19 DNA by PCR and by immunological detection of PCR products. The viral DNA content was determined by means of a TaqMantrade mark-based, quantitative PCR. RESULTS: From plasma corresponding to 2-year collections in France, and representing 4.26 million donations from approximately 1.25 million voluntary unpaid donors, the average frequency of positive donations was 1/5,950 and reached 1/1,420 during an epidemic. Levels of B19 DNA in positive pools ranged from <10(2) to 10(11) copies/ml. CONCLUSION: A large-scale PCR plasma screening increased the safety of LFB's wide range of products with respect to B19, a virus particularly resistant to physicochemical inactivation procedures.

[HTLV-I and HTLV-II virus]. / Virus HTLV-I et HTLV-II.

HTLV genomic and antigenic features, replication way as well as associated pathology are recalled herein. The epidemiologic angle and the different transmission ways are also related. HTLV infection diagnostic implements are detailed: screening and specially confirmatory tests are brought to light with the help of concrete examples interpreted according to the criteria defined by the Retrovirus Study Group of the French Blood Transfusion Society.

Multi-center European evaluation of HIV testing on serum and saliva samples.

OBJECTIVE: to evaluate the reliability of HIV antibody testing on saliva. DESIGN: matched serum and saliva samples were collected from both seronegative (n = 344) and seropositive (n = 125) individuals in five European countries. Duplicate saliva samples collected with Omni-Sal devices provided by Saliva Diagnostic System (SDS) were pooled before analysis. METHODS: all samples were analyzed by Recombinant HIV1 EIA Cambridge Bioscience and 2nd generation Abbott HIV 1&2 1A80. EIA procedures were adapted for saliva testing by modification of sample dilution and/or cut-off calculation. All saliva recording positive and/or doubtful EIA results were further analyzed by Western blot as a confirmatory method. RESULTS: EIA results obtained from sera analysis from both seropositives and seronegatives allowed for calculation of the tests' sensitivity (HIV1 Biotech: 99.2%-100%; Abbott: 100%) and specificity (both tests 100%). In the series of 125 saliva samples collected from seropositives, the EIA results were as follows: with Biotech (3 negative, 3 in the grey-zone and 119 reactive) and with Abbott (1 negative, 1 in the grey-zone and 123 reactive). One saliva sample found negative by both EIA tests, although fulfilling HIV1 WB criteria of positivity, was collected from an HIV2 infected person. Out of 125 saliva samples collected from seropositives, 121 produced positive Western Blot profiles, 4 were indeterminate and 1 was found negative whereas 125/125 sera were found positive. CONCLUSION: the reliability of HIV testing of saliva is dependent on the sensitivity of EIA tests and on the criteria used for the interpretation of Western blot tests as well. Although saliva testing offers numerous advantages for epidemiological purposes, it should not be recommended for diagnosis.

Tumor necrosis factor receptor expression in HIV-1-infected CD4+ T cells.

We investigated whether HIV-1 can regulate tumor necrosis factor receptor (TNFR) expression in SupT-1, a CD4+ T-cell line. The cells were infected with HIV-1 containing 1,000 cpm RT activity, as early as day 3 after infection and all along the culture the supernatant level of core protein p24 was > 250 pg/ml, and on days 6 and 9 after infection, p24 was found in 10% of the cells as determined by indirect immunofluorescence assay. The cells were growing without loss of viability. The study of TNFR expression was based on a microassay for measurement of binding of 125I-TNF alpha to cells, in which free and cell-bound ligand separation was performed by centrifugation through oil. Scatchard analysis of TNF alpha binding on days 6 and 9 after infection revealed a 90% increase in the expression of high-affinity membrane receptors in HIV+SupT-1 culture compared with uninfected cells (mean +/- S.D. = 501 +/- 148.5 vs. 263 +/- 77.8 receptors/cell, n = 9, P < 0.001) with no change in dissociation constants (mean +/- S.D. = 4.36 +/- 1.06 vs. 4.00 +/- 1.12 x 10(-10) M).

Soluble CD23 in human immunodeficiency virus type 1 infected patients.

The level of sCD23 produced in the course of human immunodeficiency virus (HIV) infection was measured in patients grouped according to the Centers for Disease Control by using an immunoradiometric assay. Soluble CD23 was evaluated in supernatants of peripheral blood mononuclear cell (PBMC) (10(6) cells/ml) stimulated by phytohemagglutinin (PHA). Compared with healthy controls (m +/- S.D. = 1.0 +/- 0.34 U/ml, n = 7), higher values were observed in some of the patients of group II (asymptomatic) (m +/- S.D. = 2 +/- 1.33, n = 9) and some of the patients of group IV (AIDS) (m +/- S.D. = 1.3 +/- 1.40, n = 8). Those results prompted us to compare the plasma levels of sCD23 in group II and group IV HIV-infected patients and in healthy individuals. Soluble CD23 plasma levels in healthy patients (n = 42) ranged from 0 to 1.5 U/ml (m +/- S.D. = 0.9 +/- 0.33), in group II patients (n = 17) from 0 to 3 U/ml (m +/- S.D. = 0.92 +/- 0.83) and in group IV patients (n = 73) from 0 to 2.9 U/ml (m +/- S.D. = 1.15 +/- 0.71). The differences between the patients and the healthy individuals were not statistically significant but individual sCD23 values higher than 2 U/ml were obtained in 6% of the group II patients and 16.7% of the group IV patients. Increased values of sCD23 were obtained in plasma from patients with secondary infectious diseases (groups IV-Cl and IV-C2) and from patients without secondary infectious diseases (group II, group IV-A and group IV-B).(ABSTRACT TRUNCATED AT 250 WORDS)

Granulocyte-macrophage colony-stimulating factor and tumor necrosis factor alpha in patients with human immunodeficiency virus (HIV) type 1 infection.

Variations in cytokine production in patients with human immunodeficiency virus (HIV) infection could be involved in the physiopathology and in the progression of the disease. Therefore we studied the level of granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor alpha (TNF alpha) produced in patients with HIV infection at stage II (asymptomatic seropositives) and stage IV (AIDS) of the CDC classification, by using an enzyme amplified sensitivity immunoassay. We measured the level of GM-CSF and TNF alpha in supernatant of phytohemagglutinin-activated peripheral blood mononuclear cells from patients and healthy individuals. In one out of 10 stage II patients and 4 out of 14 stage IV patients, we obtained higher levels of GM-CSF than the mean + 2 S.D. of controls, but in 3 stage IV patients with very low CD4+ T lymphocyte counts (< 50/mm-3) compared to other patients, the GM-CSF values were very low. High levels of TNF alpha were detected in 3 out of 10 stage II and 6 out of 11 stage IV patients. The high values of TNF alpha were associated with high values of GM-CSF in stage II and in most of AIDS patients except those with very low CD4+ T cell counts, who produced low levels of GM-CSF. Plasma levels of cytokines were evaluated in 10 stage II, 22 stage IV patients and 20 controls. Increased levels of GM-CSF (more than 9 pg/ml) were observed in the plasma from 8 out of 10 stage II patients and 17 out of 22 stage IV patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Analytical study of the Abbott and Ortho tests for screening and confirmation of anti-HCV antibodies. Le groupe de Travail "Hépatites virales" de la Société Française de Transfusion Sanguine]. / Etude analytique des trousses de dépistage et de confirmation des anticorps anti-VHC Abbott et Ortho.Le groupe de Travail "Hépatites Virales" de la Société Française de Transfusion Sanguine.

Anti-HCV systematic screening on blood donation was mandatory in France since first of March 1991. Two laboratories (Ortho-Chiron and Abbott) have introduced in Europe successively two kinds of hepatitis C positive diagnosis with 1st and 2nd generation ELISA screening and confirmatory assays. The aim of this multicentric study was to evaluated the sensibility and specificity of these tests. For that, they used 10,090 blood sera. As a result we have seen that the new "second generation" screening assays have a higher sensitivity without less of specificity for the confirmatory tests.

[Serological diagnosis of anti-HCV antibodies. Tests for screening and confirmation: analytical study. Le groupe "Hépatites virales" de la Société Française de Transfusion Sanguine]. / Le diagnostic sérologique des anticorps anti-VHC. Les trousses de dépistage et de confirmation: étude analytique. Groupe "Hépatites virales" de la SFTS.

Four screening and five confirmatory ELISA 2nd generation tests for anti-HCV serological diagnostic purpose are detailed herein. All studied assays were indirect ELISA procedures. Solid phase are coated with viral antigens (synthetic peptides or recombinant proteins) corresponding to structural and non structural HCV genes. Solid phase antigenic adsorbent, assay procedures and interpretations of results are analysed.

[Hepatitis C virus and transfusion: policy regarding the donation and the donor. Groupe "Hépatites Virales" de la Société Nationale de Transfusion Sanguine]. / Virus de l'hépatite C et transfusion: attitude vis-à-vis du don et du donneur. Groupe "Hépatites Virales" de la Société Nationale de Transfusion Sanguine.

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.

[Evaluation of the quality of the principal kits to identify HBs antigen used in French blood transfusion centers. "Viral hepatitis" group of the SNTS]. / Evaluation de la qualité des principales trousses de dépistage de l'antigène HBs utilisées dans les centres français de transfusion sanguine. Groupe "Hépatites Virales" de la SNTS.

The aim of this study is the evaluation of the main kits used for the HBs Ag screening in French blood donors. Eight ELISA or RIA kits were evaluated. The specificity was assessed by testing samples from unselected blood donors. Repeatedly reactive sera were confirmed by a neutralisation test using an anti-HBs polyclonal antibody. The specificity expressed by the false positive reactions was lower than 0.1% for the ELISA and RIA kits. Sensitivity was assessed by the study of a panel of 16 HBs Ag specimens (ad and ay subtypes) with titres ranging from 0.05 to 1.80 ng/ml; all were tested in duplicate. Differences in sensitivity were observed according to the kits and procedures used. Some kits have a better sensitivity than RIA which is no longer the most sensitive technique. Such a study and a permanent control of each lot of HBs Ag commercial kit allow an improvement of reagents quality.

[Serological markers of hepatitis B virus in hospitalized patients (Gastroenterology and Internal Medicine Service of the University Hospital Center of Brazzaville - Congo )]. / Etude de marqueurs serologiques du virus de l'hepatite B chez des patients hospitalisés (Service de Gastro-Entérologie et de Médecine Interne du Centre Hospitalier Universitaire de Brazzaville - Congo.

The prevalence of serum markers of the hepatitis B virus was studied in 139 patients, 88 men and 51 women, at the Gastroenterology and Internal Medicine Department at the University Hospital in Brazzaville (Congo). The findings show that 125 individuals (89%), 79 men and 46 women, show signs of infection. Only 14 patients, 9 men and 5 women, show no hepatitis B virus markers. 64 individuals (46%) are carriers of Ag HBS, and among these, 23 (35.9%) are carriers of Ag HBe. Ac anti HBC was found 116 times (83.4%): 12 times by itself, and 16 times in association with Ac anti HBS. 43 individuals (30.9 %) are carriers of Ac anti HBS. Such high frequency of Ac anti HBS, whether or not accompanied by Ac anti HBC, argues in favor of the age of the infection. The study points out the high frequency of hepatitis B virus markers (89.8 %) compared with blood donors (7 to 9 %). This should incite government officials to set up some preventive procedures.

[Guillain-Barré syndrome with favorable outcome in a case of recent human immunodeficiency virus infection]. / Syndrome de Guillain et Barré d'evolution favorable dans un cas d'infection récente par le virus de l'immunodéficience humaine.

An acute polyradiculoneuropathy occurred in a 30 years homosexual male. E.L.I.S.A. test and Western Blot showed recent infection by H.I.V. Besides, endogenous reinfestation by cytomegalovirus was found: high concentrations of specific IgG antibodies and presence of the virus in the blood. T4 helper cells were severely reduced, without any other sign of cellular immunity failure. None of the two viruses was found in the nervous biopsy. This Guillain-Barre syndrome with a subsequent cellular reaction in the CSF, is probably to be related to an immunoallergic mechanism. Brief increase of antibodies specific for HBsAg and Borrelia Burgdorferri and the beneficial effect of plasmapheresis, supported this view. Two months later, the patient showed superficial lymph nodes hyperplasia, without any other symptom of pre-Acquired Immuno-Depression Syndrome.

[Preparation of a specific anti-cytomegalovirus immunoglobulin for intravenous injection]. / Préparation d'une immunoglobuline spécifique anti-cytomégalovirus injectable par voie intraveineuse.

In the industrialised countries of Europe about 60-70% of adults possess antibodies against cytomegalovirus. Primary infections or exacerbations of a latent infection are in most cases clinically asymptomatic in healthy patients. By way of contrast, attenuations in the immunological defence system: prematureness, pregnancy, the presence of malignant disease, immunosuppressive therapy, as well as massive transfusions of blood, are the commonest causes of a raised incidence of CMV infections often combined with severe clinical overt illness. Because a critical level of antibody is needed to prevent infection and disseminating, we have produced cytomegalovirus hyperimmune globulin for intravenous administration. They are prepared from plasmas of healthy blood donors on the basis of a high antibody level against cytomegalovirus. About 6% are selected by an ELISA procedure. Immunoglobulins, treated to ensure excellent intravenous acceptability, are lyophilized. The final product is found to have an anti-CMV antibody titer of 25 600, by the ELISA test, at a protein concentration of 5%. This CMV-immunoglobulin I.V. has 8 fold higher antibody content than do conventional immunoglobulin preparations. The first trials of prophylaxis and treatment of clinically apparent CMV infections are under study.