Use of magnetic beads versus guanidium thiocyanate-phenol-chloroform RNA extraction followed by polymerase chain reaction for the rapid, sensitive detection of enterovirus RNA

The current study compares the sensitivity of RNA extraction using magnetic beads versus that of a standard extraction method. Streptavadin-coated magnetic beads were labelled with a biotinylated, enterovirus-specific oligonucleotide. RNA was extracted using labelled beads or guanidium thiocyanate-phenol-chloroform from 1, 0.1 and 0.01 TCID50/100 microliters of stock coxsackievirus types A9 and B3, echovirus type 11, enterovirus type 70 and poliovirus type 1. Each strain was tested three times. RNA extraction using magnetic beads was > 50% faster than the standard method. The RNA was amplified using RT-PCR, and the products were detected using agarose gel electrophoresis; 6/15 and 7/15 samples at an initial concentration of 0.01 TCID50/100 microliters were detected using magnetic beads or standard extraction, respectively. Negative-stain electron microscopy was used to determine that 0.01 TCID50/100 microliters of coxsackievirus B3 contained approximately 3 genomes. Thus, use of magnetic beads labelled with an enterovirus-specific oligonucleotide was less toxic, more rapid and as sensitive as the current standard RNA extraction method.

A novel synthetic reversible inhibitor of sialidase efficiently blocks secondary but not primary influenza virus infection of MDCK cells in culture

The sodium salts of 2-difluoromethyl-phenyl-alpha-ketoside of N-acetyl-neuraminic acid (compound 1) and of 4-difluoromethyl-2-methoxy-phenyl-alpha-ketoside of N-acetylneuraminic acid (compound 2) were designed as potential mechanism-based inhibitors of sialidase. In vitro both of these compounds competitively inhibited the sialidases of Clostridium perfringens and of influenza virus A/HK/1/68. Inhibition was irreversible with the sialidase of Clostridium perfringens whereas it was reversible with that of A/HK/1/68. Compound 2 did not inhibit the hemagglutinin of the virus but exhibited significant anti-influenza activity when added to the medium of Madin-Darby canine kidney (MDCK) cells infected by influenza virus. In non-infected MDCK cells no inhibition of cellular sialidase was observed. Compound 2 did not block primary infection, but inhibited the release of progeny virus from infected cells. Even after 8 passages in its presence, no resistant strains were detected. Because of its high Ki (8 x 10(-5) M) compared to the low Ki (1' x 1(-10) M) of 4 guanidino-Neu 5 Ac 2en and its reversible inhibition of viral sialidase, its development as an anti-influenza agent is no longer envisaged. Nevertheless, as a mechanism-based irreversible inhibitor of the bacterial enzyme, it could at least be useful for investigating the intrinsic role of sialidase in infections caused by this strain.

Aerosol administration of a recombinant adenovirus expressing CFTR to cystic fibrosis patients: a phase I clinical trial

Ad CFTR, a replication-deficient adenovirus expressing the human cystic fibrosis transmembrane conductance regulator (CFTR), was administered by aerosolization in a single escalating dose to three pairs (cohorts) of cystic fibrosis (CF) patients. Buffer only was administered to the nose and lungs 9-14 days before nasal instillation of virus followed the day after by aerosolization of Ad CFTR to the lung. Nasal doses (defined in terms of viral plaque forming units, pfu) were 10(5), 10(7), and 4 x 10(8), whereas aerosolized doses were 10(7), 10(8), 5.4 x 10(8) for each cohort, respectively. No acute toxic effects were observed in the first 4 weeks after virus treatment. Shedding of infectious Ad CFTR was never detected, whereas detection of vector DNA sequences and CFTR expression demonstrated DNA transfer to the nose and airways of patients. No significant deviations in immunological and inflammatory parameters were observed in serum and in bronchoalveolar lavage (BAL). Importantly, for all patients, the serum anti-adenovirus antibody levels did not change significantly from baseline and no antibodies against adenovirus were found in BAL.

Multicenter evaluating of a commercially available PCR assay for diagnosing enterovirus infection in a panel of cerebrospinal fluid specimens

Thirteen laboratories participated in blind tests of a panel of 20 coded cerebrospinal fluid specimens (7 uninfected samples, 3 samples infected with 1 50% tissue culture infective dose [TCID50]/0.1 ml [nonenterovirus strains], and 10 samples infected with 10, 1, or 0.1 TCID50/0.1 ml [three different enterovirus serotypes]) on the Amplicor enterovirus PCR assay (Roche Diagnostic Systems). The panel was also evaluated by in-house PCR (two nested-PCR and three one-step PCR assay) or tissue culture (eight laboratories). The viral load was shown to influence greatly the sensitivity of the assay. The average sensitivity of the Amplicor test ranged from 67 to 98% for viral titers of 1 to 10 TCID50/0.1 ml, respectively; titers of 0.1 TCID50/0.1 ml resulted in a sensitivity of only 16%. The overall specificity of the Amplicor test was 98%. The Amplicor assay compared favorably to the five in-house PCR tests (no significant difference in either sensitivity or specificity) and was much more sensitive than tissue culture (P < 0.001), even for high viral loads. It was easy to perform, rapid (about 6 h), well-standardized, and appeared to be suitable for the diagnosis of enterovirus meningitis on a routine basis in laboratories trained in molecular biology techniques.

Surveillance of community-acquired viral infections due to respiratory viruses in Rhone-Alpes (France) during winter 1994 to 1995

Nasal swab from patients with acute flu-like illness were evaluated for the presence of respiratory viruses in the Rhone-Alpes region of France from 1 October 1994 through 2 May 1995. The relative frequencies and seasonal distributions of the specific viruses were assessed. In addition, virus type was correlated with specific clinical signs and symptoms. During the study, 962 samples were collected by 75 medical practitioners participating in the Groupe Regional d'Observation de la Grippe surveillance network. One or more viruses were detected from 348 samples (36.1%), including 108 respiratory syncytial virus (RSV), 64 influenza virus A type H3N2, 47 influenza virus B, 64 coronavirus, 35 rhinovirus, 22 adenovirus, 5 enterovirus, and 3 parainfluenza-fluenza strains. There were 16 mixed infections. RSV infections peaked in the early winter, and influenza viruses A and B infections peaked during the late winter and early spring. There were two peaks of coronavirus infections (late fall and late winter). Other viruses were detected at lower levels throughout the study period. Patients from whom adenovirus was isolated were significantly more likely to have a fever of > 39.5 degrees C than were patients with other detectable viruses (P < 0.001). Furthermore, there was a significant correlation between influenza and cough (P < 0.01) and RSV and bronchiolitis (P < .001). Thus, the current study defined the overall and relative frequencies of respiratory virus detection from nasal swab specimens in patients with an acute flu-like illness in the Rhone-Alpes region of France during a 7-month period. Correlation with clinical signs and symptoms and provisional conclusions regarding seasonality were also determined.

Evaluation and comparison of PCR and hybridization methods for rapid detection of cytomegalovirus in clinical samples

Rapid diagnosis of cytomegalovirus (CMV) infection may be obtained by molecular techniques, such as the polymerase chain reaction (PCR) and hybridization assays. The optimal technique to detect CMV in clinical samples was assessed. Two different PCR assays were used, targeting either the major immediate early 1 (MIE 1) or the HXLF 4 gene. The PCR products were detected by gel electrophoresis, dot blotting and an easy to use, rapid, solid phase hybridization assay, DNA enzyme immunoassay (DEIA). Standard tissue culture was also used. Cerebrospinal fluids (18), liver biopsies (9) from hepatic transplant recipients, amniotic fluids (7) from mothers with suspected peripartum infection, and samples (6) of miscellaneous origin (brain and fundus biopsy, pericardial and pleural fluid) were tested. Among the 40 samples, CMV was detected in 19 cases. Three were positive by both molecular techniques and tissue culture, 14 by molecular methods and 2 by culture. 16/19 or 9/19 CMV-positive samples were detected by PCR amplification of the HXLF 4 or MIE 1 gene, respectively and 14/16 HXLF 4-positive samples were detected using either dot-blot or DEIA, compared to 9/16 using gel electrophoresis. Thus, the most sensitive assays for the detection of CMV in clinical samples using the methods compared in the current study were PCR amplification of the HXLF 4 gene followed by dot-blot or DEIA hybridization.

Evidence of presence of poliovirus genomic sequences in cerebrospinal fluid from patients with postpolio syndrome

The postpolio syndrome (PPS) is characterized by new neuromuscular symptoms occurring 30 to 40 years after the acute episode of poliomyelitis paralysis. The presence of the poliovirus RNA genome in the cerebrospinal fluid from 10 patients with PPS and from 23 control patients was sought by using reverse transcription and a PCR specific for polioviruses and/or other enteroviruses. Poliovirus-specific genomic sequences in the 5' untranslated region and in the capsid region (VP1) were detected by reverse transcription PCR in 5 of 10 patients with PPS but in none of the control patients. Sequencing confirmed the presence of mutated poliovirus sequences. This finding suggests persistent viral infection in the central nervous system related to the presence of poliovirus genomes.

Simultaneous purification of influenza haemagglutinin and neuraminidase proteins by immunochromatography

A new and rapid method for co-purification of haemagglutinin (HA) and neuraminidase (NA) proteins from influenza A/H3N2 viruses is described. Surface glycoproteins were first solubilized using a non-ionic detergent under high ionic strength conditions, then they were separated by chromatography on sepharose previously bound to monoclonal antibodies (MAbs) directed either against HA (IaH-chromatography) or against NA (IaN-chromatography). Depending on the protein specificity of the MAb immobilized on the column, HA or NA was bound to sepharose and the counterpart protein was free in the flow-through volume. IaH-chromatography and IaN-chromatography proved equally efficient in term of recoveries (> 75%) and purity (> or = 99%) of both HA and NA but differences appeared when considering functional and antigenic properties of pure proteins. Those properties were highly retained in IaH- and IaN-derived HA as well as in IaH-derived NA while IaN-NA was partially degraded. IaH-chromatography allowed the co-purification of HA and NA proteins in heterologous antigen-antibody system with a 50% rate of cross reactivity. IaH-HA and IaH-NA may be suitable for immunity studies, standardization of influenza vaccine and for diagnostic purposes.

Exposure to enteroviruses and hepatitis A virus among divers in environmental waters in France, first biological and serological survey of a controlled cohort

An epidemiological study of hepatitis A and enteroviruses was conducted in a military diving training school, by evaluating the viral contamination of water using an ultrafiltration concentration technique, and assessing seroconversion and the presence of virus in stool specimens obtained from 109 divers and 48 controls. Three of 29 water specimens were positive for enterovirus by cell culture and 9 by molecular hybridization. There was little or no risk of virus infection during the training course (49 h exposure) because there was no significant difference between divers and controls for both viral isolation and seroconversion. However, a higher percentage of coxsackievirus B4 and B5 seropositive divers suggests that these were more exposed during previous water training. No hepatitis A virus (HAV) detection and no seroconversion to HAV was observed. The rate of HAV seropositive subjects was 17% in this 24.5-year-old population.

Acute, chronic and persistent enterovirus and poliovirus infections: detection of viral genome by seminested PCR amplification in culture-negative samples

Enteroviral and polioviral infections are potentially serious in humans causing a variety of acute, chronic and probably persistent infections. A seminested polymerase chain reaction is described which allows the detection of 1 fg of enterovirus and poliovirus RNA by using specific primers located both in the 5' non-coding and the VPI region. The technique is applied in a variety of important clinical situations: meningitis and encephalitis cases occurring in immunocompetent or immunocompromised patients; acute cardiomyopathies; poliovirus induced pathologies. Our results demonstrate the usefulness of PCR in diagnosing enteroviral infections during culture-negative intervals in acute and/or persistent infections. Our PCR test will be a valuable tool in determining the predictive value of the presence of the viral genome in the aggravation of chronic and persistent enterovirus-induced pathologies.

Isolation of two H1N2 influenza viruses from swine in France

Samples collected in 1987 and 1988 in Brittany from influenza-infected swine made it possible to isolate and antigenically characterize two H1N2 recombinant viruses (Sw/France/5027/87 and Sw/France/5550/88). The former virus was cloned and reinoculated to swine to allow reproduction of the disease and reisolation of a strain similar to the original one. The serodiagnostic tests carried out on both the original sera and those from the experimentally infected animals confirmed that the virus was actually type Sw/H1N2.

Identification of pandemic viral strains. Role of the national reference centre

The identification of a pandemic viral strain will be performed by the National Reference Centres. The well established sentinels network collecting respiratory samples is able to work not only during the winter season but also a part from it and to allow the early detection of new variants. It also supplies pertinent clinical and epidemiological data in order to correlate a new strain with authentic pathogenic and epidemiologic potential. Based on the previous pandemics experiences, and on the current circulating Influenza strains in humans and animals, a limited number of H and N antigens could be expected as component of a new pandemic strain. The recent rapid tests for the detection and the isolation of influenza viruses permit the diagnosis of a new strain within a few days or weeks. Rapid exchanges of data, strains and reagents under the WHO authority would help in a rapid prediction of a pandemic risk.

Role of the French drug licensing authority in the prevention of influenza pandemics

The French Drug Agency is responsible for the control and delivery of batch release certificates. In the case of an influenza pandemic, the use of inactivated vaccines, produced according to well-established procedures and controlled according to the European Pharmacopea and FDA requirements, will be strictly dependent on the necessary delays for production and controls. Mutual recognition between the National Control Laboratories in Europe might help in shortening the delays. If new, inactivated vaccines are produced either on cell cultures or by using genetically modified organisms, and if live attenuated vaccines are needed, it would be suitable to organize ad hoc working groups and international collaborative studies in fields of both research and regulation.

Epidemiology of viral infections and evaluation of the potential benefit of OM-85 BV on the virologic status of children attending day-care centers

Viral investigations were performed during 4 winter seasons (88/89, 89/90, 92/93, 93/94) in children attending day-care centers (DCCs) in the Rhône Département in eastern France. Over the total observation period of 4 winter seasons, 780 children were screened with a nasal swab for the presence of viruses. Of those, 230 (29.5%) had a positive viral culture. The viruses identified were respiratory syncytial virus (RSV), influenza A and B virus, parainfluenza virus, coronavirus, rhinovirus, adenovirus and enterovirus. During that time, 83 epidemic events in 47 DCC were recorded. A particular virus was judged to be causally related to an epidemic if the identical virus was isolated in > or = 3 children during the same outbreak of respiratory diseases. Thus, in 51 cases (61.4%) of all epidemics, the following viruses were responsible for an epidemic: RSV (n = 23), coronavirus (n = 10) (only during the season of 1993-1994), influenza A virus (n = 6), rhinovirus (n = 4), enterovirus (n = 4), adenovirus (n = 3) and parainfluenza virus (n = 1). Except for the somewhat surprising accumulation of coronavirus epidemics during the winter of 1993-1994, there were only minor seasonal variations from one year to another. As expected, RSV accounted for about one third of all respiratory tract infections in children attending DCCs and was therefore the most important single causative agent. These results are compared with data from children who did not attend a DCC and were cared for in a private practice.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of the polymerase chain reaction with a murine model of picornavirus-induced myocarditis

Enteroviruses are common pathogens responsible for a wide spectrum of systemic infections. Conventional diagnosis of these infections relies on the isolation of viruses in cell culture and their identification by seroneutralization with polyclonal or monoclonal antibodies. Among enteroviruses, coxsackieviruses B have been involved as causative agents for viral myocarditis. Most of the time, in the case of cardiac pathologies, viral isolation is negative. Molecular biology techniques appear to be an alternative to conventional diagnosis and could supply evidence for the direct implication of enteroviruses in these severe pathologies. In this paper, we describe a murine experimental model of infection with the presumed highly cardiopathogenic coxsackie-virus B type 3. A kinetics of infection was observed for a period of 31 days, and the classical virological markers (viral isolation from feces and heart biopsies, seroconversion) were monitored and compared by means of molecular techniques (molecular hybridization, polymerase chain reaction [PCR]). In this 31-day period, the detection of coxsackievirus B type 3 RNA in the heart was possible only by using two successive seminested PCRs. After 9 to 11 days of active viral replication, when all other virological markers were negative, positive PCR signals were obtained, which supports the hypothesis of a shift to persistent enteroviral infection.

Susceptibilities to rimantadine of influenza A/H1N1 and A/H3N2 viruses isolated during the epidemics of 1988 to 1989 and 1989 to 1990

Clinical isolates of influenza A viruses identified during outbreaks in two winters were tested for their rimantadine susceptibilities by an enzyme-linked immunosorbent assay modified from that described previously by Belshe et al. (R. B. Belshe, B. Burk, F. Newman, R. L. Cerruti, and I. S. Sim, J. Virol. 62:1508-1512, 1988). The infectivity titer and the 50% inhibitory concentration of rimantadine were calculated for each virus. Of 105 influenza virus A isolates tested, 28 influenza A/H1N1 isolates from the 1988 and 1989 outbreak and 77 influenza A/H3N2 isolates from the outbreak in following year, were susceptible to the antiviral action of rimantadine.

Is there a relationship between malnutrition, inflammation, and post-vaccinal antibody response to influenza viruses in the elderly?

This study was designed to explore the relationship between malnutrition, inflammation, and the specific antibody response after influenza vaccination in the elderly. Eighty-two aged subjects, immunized annually against influenza with a trivalent inactivated vaccine, were evaluated for 9 protein markers (albumin, thyroxin-binding prealbumin, transferrin, immunoglobulins (Ig) G, M, and A, orosomucoid, haptoglobin, and C reactive protein) and for their antibody response to influenza viruses in comparison to 29 younger adults who received the same vaccine and 21 unvaccinated adults. IgM and nutritional markers were significantly reduced in the aged as compared to controls, while the opposite pattern was seen for IgA and inflammatory markers. No difference was observed between the elderly and the controls with regard to the antibody response to influenza virus after vaccination. Reciprocally, influenza immunization had no influence on the levels of the protein variables. These results suggest that the protein status does not play an important role in the antibody response to influenza vaccination in the elderly, a fact which could be related to the slight involvement of cellular immunity in the defense against influenza reinfection.

Use of cRNA digoxigenin-labelled probes for detection of enteroviruses in humans and in the environment

A dot blot hybridization test for enteroviruses is described using non-radioactive digoxigenin-labelled probes and a chemiluminescent detection. The use of a 5' non-coding riboprobe which detects all enteroviruses and a VP1 probe that detects the three serotypes of polioviruses allows the rapid detection of polioviruses and non-polio enteroviruses in human specimens or environmental water samples. The assay is strictly enterovirus specific and sensitive (800 fg RNA) and offers several advantages over conventional diagnosis or radioactive probes.

Cytomegalovirus infection--an etiological factor for rejection? A prospective study in 242 renal transplant patients

The study aimed at analyzing the role of CMV infection as a risk factor for rejection occurring after CMV infection because of the clinical consequences of the prevention of CMV infection that might lead to the decrease in rejection episodes. Two hundred forty-two consecutive renal transplant patients were prospectively checked for the occurrence of CMV infection. CMV infection was defined virologically by a positive viremia or/and a positive viruria or/and a seroconversion or/and a significant rise of the anti-CMV antibody titers. Viremia, viruria, and serology were performed weekly for the first month and then at day 90, day 180, and every 6 months, and moreover if clinical symptoms related to a viral infection occurred. Rejection episode was defined by a creatininemia rise of 25%, after cyclosporine nephrotoxicity and urological complications had been discarded, and by the response to the antirejection therapy, steroids, or OKT3 in case of steroid-resistant rejection. The outcome factor was rejection episode occurring from day 4 after the diagnosis of CMV infection. A patient undergoing "a rejection episode after CMV infection" could also be exposed to other potential confounding factors that can be considered as risk factors of rejection among our patients. Rejection occurring before CMV infection was the main factor because it was linked both to CMV infection itself and to "rejection after." Thus infected and noninfected patients were randomly paired off. To the noninfected patient of the pair was attributed the date of a fictitious CMV infection that was the date of the CMV infection of the infected member of the pair. Therefore, "rejection after" and "rejection before" were defined in infected and noninfected patients of the pair according to the time of onset of CMV infection of the infected member of the pair. The incidence of CMV infection was 65%, 157 of the 242 patients were infected, and 85 not infected. Thus 85 pairs of infected-noninfected patients were studied. The incidence of "rejection after" the diagnosis of CMV infection was significantly higher in the group of patients with CMV infection: 45% among infected (38/85) versus 10.60% among noninfected (9/85) (P < 0.0001). Among the 85 pairs, 48 pairs were concordant in which patient of the pair evinced the same outcome factor: 43 showed no rejection after, and 5 showed one.(ABSTRACT TRUNCATED AT 400 WORDS)

Cross-resistances to antiviral drugs of IUdR-resistant HSV1 in rabbit keratitis and in vitro

The emergence of cross-resistance to various antiviral drugs was investigated both in vivo and in vitro for herpes simplex virus type 1 (HSV1) resistant to idoxuridine (IUdR 0.24%) obtained by seven successive passages (from P0 to P7) in rabbit keratitis treated by IUdR. The viral population obtained at the seventh IUdR passage (P7) showed an activity of the thymidine kinase (TK) reduced to 5.6% of the parental strain (PO); moreover, most of the clones of P7 showed an altered TK phenotype determined by the [125I]iododeoxycytidine (IDC) procedure. In rabbit keratitis, IUdR-resistant viral population P7 showed cross-resistance to bromovinyl desoxyuridine (BVDU) (0.5%) and to acyclovir (ACV) (3%). Under trifluorothymidine (1%) treatment, P7 showed an intermediate sensitivity. HSV1 at P7 remained sensitive to adenine arabinoside (Ara A) (3%) and to dihydroxy-propoxymethylguanine used at high concentration (3%). The in vitro sensitivity determination to various antiviral drugs was investigated by dye-uptake assay for the initial viral population PO and for HSV1 collected under IUdR treatment at the third (P3) and the seventh (P7) passages. Cross-resistance to TK-dependent drugs, such as IDC, BVDU, and ACV were found at P7. P7 remained sensitive to Ara A and to phosphonoformic acids antiviral drugs known not to be dependent on viral TK.

Role of influenza vaccination in the elderly during an epidemic of A/H1N1 virus in 1988-1989: clinical and serological data

During a winter epidemic of A/H1N1 influenza virus, we evaluated the protection conferred by vaccination of 285 residents of a nursing home. Fifteen of 204 members of the nursing staff were also vaccinated. Serological determinations were performed before and after vaccination using radial hemolysis (RH) and neuraminidase inhibition (NI) tests. In the outbreak period, only one influenza case was noted in the vaccinated elderly and none among the vaccinated nursing staff. On the other hand, 38 cases (20%) occurred in the unvaccinated hospital personnel. Twenty-one percent of the elderly people exhibited seroconversion to the vaccinal strain by RH and NI while 27 and 20% of the vaccinated nursing staff seroconverted by the same tests, respectively. Thus, the clinical protection conferred by influenza vaccination was excellent and much greater than expected from serological results.

Rapid diagnosis of influenza A. Comparison with ELISA immunocapture and culture

The Directigen Flu-A is an enzyme immunoassay for detecting in 15 min the influenza A nucleoproteinic antigen directly from specimens after passive adsorption on a cellulose membrane. The test was assessed using 160 frozen (-20 degrees C) specimens collected during the 1988-1989 A/H1N1 influenza epidemic and the 1989-1990 A/H3N2 epidemic. Compared to the ELISA immunocapture test, the sensitivity of the commercial test was 87.8% and the specificity was 97.6%. When compared to isolation of viruses on LLCMK2 cells and/or chicken embryo, the sensitivity was 84%. No cross-reaction was found with other respiratory disease viruses. The feasibility, practicability and rapidity of the test make it a test of choice for rapid diagnosis of influenza A.

Cytomegalovirus (CMV) excretion as a factor in the severity of CMV disease in kidney and simultaneous kidney and pancreas transplantation

The aim of the study was to evaluate the virological parameters associated with the severity of cytomegalovirus (CMV) disease in renal and simultaneous renal and pancreatic transplantation. The association of the viral profile and the severity of the viral disease was analysed taking into account different confounding variables susceptible to linkage with the severity of the CMV infection and the viral parameters. All the patients transplanted between 1 January 1989 and 31 December 1990, a total of 242, were prospectively followed by viral cultures in blood and urine and by serological methods using the detection of CMV-specific IgM and the complement fixation (CF) test. The samples were taken systematically each week for the first month and then at day 90, 180 and every 6 months and also in cases of clinical manifestations related to viral disease. CMV infection was diagnosed virologically by the presence of viraemia, viruria, IgM, or a significant rise in CMV antibody titre in CF. CMV disease was classified as asymptomatic, mild (fever and/or leukopenia), moderate (fever, leukopenia and liver abnormalities), severe (CMV pneumopathy and/or gastrointestinal disease) or fatal. The incidence of CMV infection was 65% (157/242): 32% asymptomatic, 36% mild, 30% moderate and 2% severe. The presence of IgM was associated with the severity of CMV disease: 51.4% of moderate and severe CMV infections in the group with IgM versus only 16% in the group without IgM (P < 0.0001). The risk of having severe or moderate CMV disease was 3.28 times higher in patients with positive IgM. However the serological changes in CF were not significantly associated with the severity of the viral disease since 34.6% of the patients with CF changes had a severe form versus 20.8% in the group without CF modification. Viruria was significantly associated with moderate or severe infection: 43.6% of the patients with viruria had severe infection versus only 12.5% in the patients without viruria (P < 0.0002). The risk of having moderate or severe CMV disease was 3.48 times higher in the patients with viruria. Viraemia was also associated with more severe CMV infection: 48.6% of moderate or severe CMV infection in the group of patients with viraemia versus 19% in the group without viraemia (P < 0.0001). The risk of having severe or moderate CMV infection was 2.58 times higher in the patients with viraemia. Viraemia was not more associated with severe CMV infection than viruria. Using the maximum likelihood ratio method and the logistic regression model, CMV-specific IgM, viruria and viraemia were each shown to be associated with the severity of CMV disease and the addition of one parameter to the other(s), whatever the type (except the CF changes) and whatever the order of this addition, did not remove the link between the severity and IgM, viruria and viremia. The incidence of severe and moderate CMV disease increased with the number of positive viral parameters (PVP) from 2% of moderate and severe infections in the group with one PVP, to 28% in the group with two PVP, to 39% in the group with three PVP and 68% in the group with four PVP (trend, 35.95; P < 0.0001). Taking the absolute risk of the group of patients without IgM, viruria or viraemia as the basal level, the observed relative risk of severe CMV infection varied from 6.45 in the group with positive IgM without viruria or viraemia, to 10.74 in the group with positive IgM and viruria without viraemia and to 22.5 in the group with the three positive parameters IgM, viruria and viraemia. The different potential confounding factors (recipient and donor serology, renal or renal and pancreatic transplantation, DR compatibility, rejection before CMV infection) did not modify the link between the viral profile and the severity of CMV disease. This study suggests that the severity of CMV disease might be linked to the overspread of the virus as well as to the consequences of a CMV-specific humoral immune response.

Should hepatitits-C virus antibody-positive donors be excluded from kidney donation?

In organ transplantation, virus transmitted by the donor is associated with a higher risk of severe primary infection after transplantation in the seronegative recipient. In this study, the risk of hepatitis-C virus (HCV) transmission by the kidney was determined, and the morbidity in the recipient assessed. Serum samples from all kidney donors of our Transplantation Unit between 1983 and 1988 were screened for antibodies to anti-HCV by first enzyme-linked immunosorbent assay (Ortho ELISA) and positive samples were confirmed by a second-generation ELISA and the CHIRON RIBA HCV test. Of the 164 kidney donors whose sera were available, five were positive (3%) and all of them were positive with the RIBA test. Liver function was normal in the five donors. Seven recipients received a renal transplant from the anti-HCV-positive donors. Two patients had a follow-up too short to draw any conclusions. Two patients remained anti-HCV-negative up to 36 and 48 months, respectively, but one of them had chronic hepatitis. One patient was anti-HCV-positive before transplantation and remained positive over the 4-year follow-up. The two last patients seroconverted and acute hepatitis occurred at 16 and 101 days after transplantation, respectively. In both cases, no peroperative or postoperative transfusion was given and no other cause of hepatitis could be determined. A cirrhotic evolution was observed within 15 and 36 months in both cases. Thus HCV can be transmitted by a kidney transplant and cadaveric donors positive for anti-HCV antibodies should be excluded from kidney donation.

Occurrence and characterization of acyclovir-resistant herpes simplex virus isolates: report on a two-year sensitivity screening survey

For the past 2 years, a survey network was established for the screening of acyclovir (ACV)-resistant clinical isolates of herpes simplex virus (HSV). Among 889 strains tested for in vitro ACV sensitivity, 14 HSV-1 and 6 HSV-2 were resistant to ACV concentrations exceeding 3 micrograms/ml. These resistant isolates were most often obtained after prolonged ACV treatment of severely immunocompromised patients. For five patients, the emergence of ACV-resistant virus correlated with treatment failure. In particular, a decrease in the in vitro sensitivity to ACV was observed for eight successive HSV-1 isolates from one immunodeficient patient undergoing therapy. All ACV-resistant isolates were studied for their sensitivity to different antiherpetic compounds and showed various cross-sensitive and -resistant patterns. The examination of viral populations by plaque autoradiography procedures frequently revealed their heterogeneity in terms of thymidine kinase (TK) phenotype and allowed the detection of various proportions of TK-positive (TK+), TK-deficient (TKD), or TK-altered (TKA) viruses. Our data underline the importance of monitoring the emergence of drug-resistant virus during the course of antiviral therapy, and the need for the detection and characterization of TK mutants in clinical specimens. The routine examination of drug sensitivity of HSV isolates provides useful information to clinicians for the management of ACV treatment in the hope of preventing ACV-resistant mutants from becoming predominant in mixed viral populations.

Use of non-neutralizing monoclonal antibodies in an ELISA for intratypic differentiation of 28 echovirus type 25 clinical isolates

Three non-neutralizing monoclonal antibodies were produced and selected against echovirus type 25 JV-4 prototype strain. They were used in an ELISA to investigate the intratypic differentiation of 28 wild isolates. Clinical isolates fell into seven different groups according to their reactivity patterns in ELISA. Two of the non-neutralizing monoclonal antibodies, 9E4 and 6D3, were highly specific, while the third, 6C9, may recognize an epitope common to other types of echoviruses. In contrast, mouse polyclonal antiserum exhibited large cross-reactivities among echovirus serotypes. The reactivity patterns and the geographical origin of the isolates were generally not correlated and, in the same area, four major antigenic variants sometimes coexisted, especially in the south of France. Moreover, reactivity patterns found with ELISA were hardly ever correlated with those observed in a previous study when neutralization tests were used. These results again underline the non-correlation between structure and biological function in the Picornavirus family.

Influenza C virus infection in France

Little is known of the epidemiology of influenza C virus infections in western Europe and of the exact role of this agent in acute viral respiratory infections. Several tests may be used for detecting antibodies against this agent but the significance of their respective results is not clear. A total of 301 samples of serum was collected from persons aged from 4 months to 88 years living in France in 1988. The samples were tested for the presence of antibodies to influenza C virus by haemagglutination-inhibition (HI) tests and ELISA. The specificity of the results was checked by immunoblotting and by antibody absorption with staphylococcal protein A. Significant HI activity was found in 61% of the 301 samples tested, titres ranging from 20-320; 70% were positive by ELISA with titres ranging from 500 to 32,000. The population tested was divided into four age groups: 0-15 years; 16-30 years; 31-50 years and 51-88 years. The highest rates for positive samples were found in the 16-30 year group (76 and 79% by HI tests and ELISA respectively) as well as significant HI and ELISA geometric mean titres. Positive samples were less common in young children (46 and 50% by HI tests and ELISA respectively) and in the oldest group (44 and 54% respectively). The 31-50 years age group formed an intermediate class. The high prevalence of antibody as well as the significant titres indicate intense circulation of influenza C virus, especially among young adults.

[Influence of HLA compatibility on cytomegalovirus infection in kidney transplantation]

The influence of HLA A, B, DR on the incidence and symptoms of cytomegalovirus (CMV) infection was investigated in 143 patients who, between October 1st, 1987 and December 31st, 1989, received kidneys from cadaveric donors. Systematic virological monitoring was carried out weekly during the first hospitalization and thereafter at each new hospitalization or in the presence of clinical signs suggestive of viral infection. The diagnosis of CMV was based on positive isolation in blood or urine, or seroconversion, or 4-dilution rise in the anti-CMV antibodies titre. HLA grouping of all recipients was made in the same histocompatibility laboratory. Immunosuppression was obtained with a quadruple therapy consisting of corticosteroids (15 mg/kg before transplantation, then 1 mg/kg for 10 days, then gradually tapering off dosage), azathioprine (2 to 3 mg/day), cyclosporin A (2 mg/kg i.v. followed by an oral dose adjusted to the residual levels) and a randomized treatment with either monoclonal anti-CD3 antibody or anti-thymocyte globulins administered during the first 10 days. The incidence of CMV infection was 56 percent (80/143), with 25 percent of primary infection (20/80). The number of DR compatibilities was found to have a significant influence on the incidence of CMV infection, which rose from 22 to 50 and 65 percent respectively in the group of patients with 2.1 or 0 DR compatibility (P less than 0.02). The degree of B + DR compatibility was also associated with the occurrence of CMV infection, the incidence of which rose from 0 to 36, 59, 43.5 and 71 percent respectively in the group of patients with 4, 3, 2, 1, 0 B + DR compatibility (P less than 0.03). The incidence of primary CMV infection increased with the number of DR incompatibilities, rising from 0 to 29 and 52 percent respectively in the group of patients with 0, 1 or 2 DR incompatibilities. The symptoms and severity of CMV infection were significantly influenced by the degree of DR and B + DR compatibility. Despite a very strong association between graft rejection and CMV infection (P less than 0.000001), no influence of HLA, and particularly DR or B + DR compatibility on the incidence and number of graft rejections could be demonstrated. It is concluded that, under the above-described quadruple therapy, the HLA DR and B + DR compatibility exerts a predominant influence on the occurrence and severity of CMV infection, and that this effect is independent of any action on graft rejection.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison between three rapid methods for direct diagnosis of influenza and the conventional isolation procedure

Besides the rapid diagnostic tests based on influenza A and B antigens nucleoproteins detection, which are routinely used, the isolation of influenza strains is still required to obtain recent variant isolates for full antigenic characterization, in order to up-date the influenza vaccine composition. To increase the rapidity and the efficacy of the virus growth, we implemented a culture test in 24-well plates by centrifugation of samples on to LLCMK2 cells in the presence of trypsin. This test was routinely applied to 331 nasopharyngeal swabs collected during the influenza A outbreak in the winters 1988-1989 and to 962 in 1989-1990. The centrifugation culture assay has been compared with the direct detection of NP antigens in the clinical samples by immunofluorescence and capture ELISA tests and with the conventional virus isolation by inoculation of the samples to embryonated eggs and to LLCMK2 cell cultures. Compared with the NP antigen detection tests, the centrifugation culture assay closely correlated (r = 0.95) and the sensitivity and specificity were also excellent, 93.4% and 99.6%, respectively. Compared with the conventional culture assays, the centrifugation culture markedly increased the performance (five times) and rapidity (2 days) of influenza virus isolation and identification.

Heterogeneity of capsid proteins of echovirus type 25 wild-type strain and prototype strain, studied by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting were used to compare the capsid proteins of 19 antigenic variants of echovirus type 25 wild-type strains isolated in France between 1976 and 1987 with those of the prototype JV-4 reference strain isolated in 1957. Immunoblots were developed by using polyclonal sera from rabbits and mice immunized with the reference strain. Immunoblotting patterns revealed reactivity only against viral protein VP1 for sera from both animals. Comparative immunoblotting patterns showed differences in the electrophoretic mobilities of viral protein VP1, especially for the Montpellier 76.1262 wild-type strain. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of [35S]methioinine-labeled viral polypeptides revealed that the two variant strains, Montpellier 76.1262 and Thionville 86.222, exhibited significant and reproducible shifts in the relative mobilities of VP1 and VP3 and, to a lesser extent, in those of VP0 and VP2. The relative mobility of VP4 seemed very similar for the JV-4 reference strain and the two variants. Interestingly, the structural differences in VP1 and VP3 of Montpellier 76.1262 were not correlated with the pattern of neutralization by monoclonal antibodies, unlike in our previous study, in which this strain differed from the prototype strain in only two epitopes. We concluded that, in addition to the heterogeneity of their biological and antigenic properties that we observed previously, echovirus type 25 wild-type strains may exhibit differences in their structural proteins.

Epidemiology of measles in the Cameroons between 1984 and 1986: comparison of the effectiveness of different serological methods in rural regions

Epidemiological studies were carried out in Yaoundé and in Ngaoundéré from 1984 to 1986, in an attempt to develop adequate methods of collecting blood from small children and of diagnosing measles appropriate to conditions in the field. Alternative methods were necessary since classical methods used in modern laboratories are unsuitable in rural regions. Each study was carried out on a representative sample of 6- to 36-months-old infected children seen at consultation. This group was chosen because it suffers the highest mortality rate. The blood was obtained by digital puncture on blotting paper because venepuncture required sterile equipment and also the establishment of a cold chain for transporting the samples to the laboratory. The first criteria examined were the relative titers of sera taken by finger prick. Four serological techniques were used: indirect immunofluorescence (IIF), indirect immunoperoxidase (IIP), hemagglutination inhibition (HAI) and ELISA. Antimeasles antibodies were detected in 12% of infected children using IIF and in 18% using IIP. When sera were examined by HAI the percentage of positives was 54% and by ELISA 75%. These results clearly indicate that ELISA is the most effective and practical technique for diagnosing measles under field conditions.

Characterization of immune complexes containing cytomegalovirus-specific IgM antibodies following a kidney graft

In order to demonstrate the viral specificity of IgM-containing immune complexes (IgM-CIC) detected by a C1q assay in renal allograft recipients developing a CMV infection, a technique is described allowing: 1) the dissociation of IgM-CIC by action of an acid buffer, and 2) the characterization of the viral specificity of IgM antibodies released by this treatment. This step was performed by ELISA and Western Blot. When technique was applied to the follow-up of a renal allograft recipient developing a recurrent CMV infection within 2 months post-graft, it was found that the IgM-CIC detected on the day of the graft were not CMV-specific, whereas the IgM-CIC detected during the second month after transplantation contained CMV-specific IgM antibodies. These CMV-specific IgM-CIC were detected as early as the urinary viral excretion. It was shown by Western Blot analysis that these IgM antibodies reacted with a 45-47 kDa viral polypeptide which is a viral target for specific humoral response at the early phase of CMV infection.

Emergence of cross-resistant herpes simplex virus following topical drug therapy in rabbit keratitis

The acquisition of drug resistance in vivo was investigated by 7 serial passages (from P0 to P7) of herpes simplex virus (HSV-1) in rabbit cornea treated with either IUdR (idoxuridine), IDC (idoxycytidine), ACV (acyclovir), TFT (trifluridine), or Ara A (adenine arabinoside). Therapeutic failure was acquired gradually: at P3 for IUdR, at P4 for ACV and at P5 for TFT. At P7, viral thymidine kinase (TK) activity was reduced to 5.6% of the parental strain for IUdR, to 7.5% for ACV and to 4.6% for TFT treatment. No signs of clinical unresponsiveness occurred with IDC or Ara A. The in vitro determination of antiviral drug sensitivity performed by the dye-uptake assay on HSV isolates at each passage showed a correlation between the increase in the 50% effective dose (ED50) and the increase of ulcer area grade at each passage under antiviral drug (p less than 0.1). Both IUdR- and TFT-resistant HSV1 developed cross-resistances to TK dependent drugs. However ACV-resistant HSV1 did not show cross-resistance to other antiviral TK dependent drugs. The acquisition of the cross-resistances is discussed, and the practical implications in case of therapeutic failures are suggested.

Impact on routine diagnosis of echovirus infections of intratypic differentiation and antigenic variation in echovirus type 25 studied by using monoclonal antibodies

We studied the biological and antigenic properties of wild strains of echovirus type 25 isolated in France between 1982 and 1987 and compared them with the JV-4 prototype strains isolated in 1957. The wild strains differed from the prototype strain in their cellular tropism. The prototype strain grew readily in five cell lines (MRC5, MA 104, Vero, BGM, and HT 29-18), while for wild strains MRC5 and HT 29-18 cells were the most sensitive and supported growth to high titres (between 4.5 and 7.4 50% tissue culture infective doses per 0.05 ml). Plaques produced by wild strains were larger (6.05 +/- 0.94 mm in diameter [mean +/- standard deviation]) than those of the prototype strain (2.3 +/- 0.97 mm in diameter) and heterogeneous, even after cloning by three terminal dilution passages, which suggested heterogeneous virus populations. Virus neutralization with polyclonal monovalent sera showed that wild strains were significantly less neutralized by two reference immune sera than the prototype strain was. Monoclonal antibodies were raised against the echovirus type 25 JV-4 prototype strain. Nine clones with neutralizing activity were identified. Heterologous neutralizations of 14 clinical isolates revealed highly conserved, moderately conserved, and poorly conserved epitopes. The natural isolates differed from the prototype strain in two to four epitopes and can be classified into four different groups. We concluded that echovirus type 25, like coxsackie- and polioviruses, consists of heterogeneous viral populations with respect to biological and antigenic properties. In term of viral diagnosis, it may become increasingly difficult to identify recently isolated strains because of their antigenic variation.

Incidence of antibodies to human papillomavirus type 1 in patients with cutaneous and mucosal papillomas

A study of antibodies to human papillomavirus (HPV) 1 is reported in a series of sera from 126 patients with papilloma lesions of different clinical types (verruca plantaris, vulgaris, plana, condyloma acuminata, laryngeal papilloma) using a sensitive solid-phase enzyme-linked immunosorbent assay (ELISA). Our findings showed a significant prevalence of specific HPV 1 IgG antibodies in patients with plantar warts (65%). This incidence was considerably lower in patients with other papilloma lesions, in which positive sera may reflect a past infection with HPV 1. The ELISA test was evaluated as nearly 100 times more sensitive than the indirect immunofluorescence test, and IgG titers to HPV 1 in patients' sera were usually low. Serum samples taken at different times during the course of HPV infection in a few patients with refractory lesions did not show any significant change in their antibody titer.

Correlation between the reactivity patterns of monoclonal antibodies to distinct antigenic sites on HN glycoprotein and their protective abilities in Sendai (6/94) virus infection

The relative importance of the host immune response to various antigenic and functional sites on the HN glycoprotein of Sendai (6/94) virus for protection in vivo, was evaluated in mice passively immunized with monoclonal antibodies to HN and then intranasally challenged with infectious virus. Five neutralizing monoclonal antibodies reacting with distinct antigenic sites and exhibiting different reactivity patterns were selected. All of them were able to prevent entirely the growth of virus in the lungs of experimental animals injected with appropriate dilutions of monoclonal antibody. The calculation of correlation coefficients between the reduction of virus in the lungs of immunized mice and the amount of antibody, expressed in terms of hemagglutination inhibition, hemolysis inhibition or neutralizing units, showed a high degree of correlation (r = 0.89) with neutralization and a lack of correlation (r = 0.44) with hemagglutination inhibition. In parallel a minimum threshold value for protection equivalent to 2 x 10(3) neutralizing units per mouse was determined independently of the mechanism(s) by which monoclonal antibodies mediated the neutralization of the infectivity. On the HN glycoprotein of Sendai (6/94) virus we could not individualize a critical site for successful immune recognition by antibodies although the characteristics of an "ideal protective monoclonal antibody" have also been defined.

A rapid and simplified micromethod for subtyping varicella-zoster virus

A simplified and rapid micromethod based on restriction endonuclease analysis of radiolabelled varicella-zoster virus (VZV) DNA is described and applied to strains for comparison. This procedure is cheaper and less time consuming than that requiring viral nucleocapsid purification (macromethod). The micromethod is suitable for routine DNA analysis of VZV isolates, allows differentiation of vaccine strain from wild strains, and provides evidence for variability of wild strains.