L'infection rubéolique maternofœtale : apport de la biologie moléculaire

AIM OF THE STUDY

To assess the diagnostic value of RT-PCR on amniotic fluid (AF) for prenatal diagnosis of congenital rubella infection.

MATERIAL AND METHODS

RT-PCR on AF was compared to specific IgM antibody detection in foetuses and/or newborns in 45 pregnant women with confirmed primary infection.

RESULTS

specificity of RT-PCR was 100% and sensitivity ranged between 83 and 95%.

CONCLUSION

RT PCR may be considered as a valuable tool for prenatal diagnosis of foetal rubella infection.

Prévalence des infections sexuellement transmissibles asymptomatiques chez des sujets à haut risque consultant dans un centre de dépistage anonyme et gratuit du SIDA

INTRODUCTION

The aim of this study was to assess the prevalence of sexually transmitted infections among patients attending an anonymous HIV Screening Center.

PATIENTS AND METHODS

This prospective study was performed in the HIV Screening Center of University hospital in Reims (France) from May 1997 to December 1997. The inclusion criteria were the asymptomatic clinical presentation and the presence of risk factors for sexually transmitted infections referring to WHO criteria. The methods included clinical examination after application of acetic acid and urethral and endocervical swabs to identify:Neisseria gonorrhoeae, Chlamydia trachomatis, Ureaplasma urealyticum, Mycoplasma hominis, Gardnerella vaginalis, Trichomonas vaginalis in specific culture. Treponema pallidum and HIV-1 infection were both detected by Enzym Linked Immuno Sorbent Assay (ELISA).

RESULTS

One hundred and one patients (62 men and 39 women) were included in the study. Their mean age was 27 +/- 4 Years. Risk factors for sexually transmitted infections were: multiple sexual partners 81 p. 100; homo or bisexuality 16 p. 100; intravenous drug use 3 p. 100. The sexually transmitted infections were: HIV-1 infection 1 p. 100;Ureaplasma urealyticum 25 p. 100; genital warts 5 p. 100;Chlamydia trachomatis 3 p. 100; Gardnerella vaginalis 3 p. 100; Mycoplasma hominis 2 p. 100; Treponema pallidum 0 p. 100; Neisseria gonorrhoeae 0 p. 100; Trichomonas vaginalis 0 p. 100. The prevalence of sexually transmitted infections was significantly higher among women (p<0.05).

DISCUSSION

Classical sexually transmitted infections and HIV infection were rarely detected in this study; but prevalence of other sexually transmitted infections (genital warts, Chlamydia trachomatis, Mycoplasma hominis, Ureaplasma urealyticum) was high. Ureaplasma urealyticum is considered as a possible pathogenic agent in pregnant women (preterm delivery, decrease of birth weight, chorioamniotitis). These results suggest that other than sexually transmitted infections in high risk patients attending a HIV Screening Center other sexually transmitted infections should also be systematically screened for.

Preferential and persistent depletion of CCR5+ T-helper lymphocytes with nonlymphoid homing potential despite early treatment of primary HIV infection

Strains of human immunodeficiency virus (HIV) transmitted between individuals use the CCR5 coreceptor, but no preferential depletion of particular Th-lymphocyte subpopulations has been reported during primary HIV infection (PHI). In contrast, gut-associated Th lymphocytes are preferentially depleted in macaques recently infected by simian immunodeficiency virus. The expression of CCR5 and the intestinal homing receptor integrin alpha4beta7 on subpopulations of Th lymphocytes was studied in 12 patients with PHI. There was a profound decrease of circulating alpha4beta7+ Th lymphocytes and CCR5+ memory Th lymphocytes with nonlymphoid homing potential (CD62L-CD45RO+). Unlike other Th lymphocytes, this cell population remained depleted despite early control of viral replication under antiretroviral treatment. Therefore, HIV preferentially targets a specific CCR5+ subpopulation of Th lymphocytes early during infection, inducing its persistent depletion despite treatment. Protective immunity in vivo depends on Th lymphocytes carrying homing capacity to nonlymphoid tissue, and therefore these data may explain the persistent abnormalities of immune functions in patients infected with HIV.

Virological and histological responses to one year alpha-interferon-2a in hemodialyzed patients with chronic hepatitis C

BACKGROUND

alpha-Interferon-2a (IFNalpha) alone is a therapy of limited proven benefit for non-uremic patients with chronic hepatitis C virus (HCV) infection. In dialyzed patients, such an effect is suggested on small short-term studies without sufficient clinical and virologic follow-up to document any sustained effect.

PROTOCOL

Twelve chronically hemodialyzed patients with chronic hepatitis C and waiting for renal transplantation were included in a prospective open study of treatment with IFNalpha. We used, as did others, doses of 3 million units (MU), three times a week, but for a longer period of treatment of 12 months. Follow-up was continued for 6 months after the end of IFNalpha in order to document any sustained biochemical, virological and histological responses.

RESULTS

Aminotransferase levels returned to the normal range within 1-2 months of treatment in all patients in whom they had been elevated at baseline. At 1 month of treatment, serum HCV-RNA was not detected in 5 (41%) patients and in 9 (75%) at 12 months. A sustained virological response was documented in 4 (33%) patients 6 months after the end of treatment. Relapse occurred in 5 patients within 2 months after IFNalpha withdrawal. HCV genotype was not predictive of any sustained response. At inclusion, using the histologic Metavir scoring system, half of the patients had low-grade cytolytic activity and none had cirrhosis. After IFNalpha, liver biopsy specimens were available from 9 patients and showed histologic improvement in 3. IFNalpha tolerance was poor, inducing a 5% mean weight loss and the acute rejection of two nonfunctioning kidney grafts.

CONCLUSION

This study documents that administration of IFNalpha at 3 MU three times a week, for 12 months, in hemodialysis patients with chronic hepatitis C was efficient for clearing the serum of HCV-RNA in 75% of the patients. A sustained response was maintained in one third of these patients after cessation of IFNalpha, and was predicted by the early serum clearance of the virus within the first 2 months of treatment. We confirm that a 12-month treatment period carries a higher sustained response rate than shorter treatment periods. These encouraging results call for larger studies in uremic patients, using IFNalpha alone or in association with new antiviral drugs.

[Sarcoidosis and progressive multifocal leukoencephalopathy]

A 70-year-old woman treated for sarcoidosis complained of progressive cognitive impairment and gait disability. Magnetic resonance imaging of the brain revealed a nonenhancing lesion in T1-weighted imaging in the left parieto-occipital region and sarcoidosis of the central nervous system was evoked. However, she rapidly deteriorated with posterior and cerebellar extension of the lesions, suggesting of progressive multifocal leukoencephalopathy (PML). DNA of the JC virus (JCV) was detected in the cerebrospinal fluid (CSF) by a polymerase chain reaction. Despite antiviral therapy, she died nine months after the first neurological signs. This case illustrates the possible association between sarcoidosis and PML, and underlines the interest to detect the presence of JCV in the CSF when the diagnosis of neurosarcoidosis appeared uncertain.

JC virus genotypes in France: molecular epidemiology and potential significance for progressive multifocal leukoencephalopathy

JC virus (JCV) induces progressive multifocal leukoencephalopathy (PML), especially in human immunodeficiency virus (HIV)-infected patients. Although JCV genotypes have primarily been associated with geographic patterns, a distinctive neuropathogenicity was recently attributed to genotype 2. A multicenter study was conducted to describe the distribution of JCV genotypes in France and to investigate correlations between genotypes and PML. Genotypes were determined by sequencing 494 bp in the VP1 capsid gene. Peripheral JCV was studied in 65 urine samples from 43 HIV-infected patients and from 22 control subjects. Genotypes 1, 4, 2, and 3 were detected in 52.3%, 30.8%, 12.3%, and 4.6% of the samples, respectively. In 56 brain or cerebrospinal fluid samples, PML-associated JCV of genotypes 1, 2, 4, and 3 was found in 66%, 19.7%, 8.9%, and 5.4%, respectively. Infection with JCV genotypes 1 or 2 was correlated with PML (odds ratio, 3.29). On the other hand, infection with JCV genotype 4 could represent a lower risk for PML.

Isolation of an unusual Mycobacterium species from an AIDS patient with acute lymphadenitis

A nonchromogenic Mycobacterium species was isolated from an AIDS patient with acute lymphadenitis. On the basis of the results of conventional tests, the strain appeared to be an atypical nonphotochromogenic Mycobacterium kansasii strain. Sequencing of the 16S rRNA gene revealed a unique nucleic acid sequence, suggesting that the isolate represents an undescribed pathogenic species.

[Anti-herpes chemotherapy]

With the increasing number of immunocompromised patients over the last two decades, disease pattern caused by Herpesviridae has changed. More virulent, more severe, herpesvirus diseases are more frequently treated and consequently the drug-resistant herpesvirus mutants have arisen in the clinic. All these events justify to explore future directions in drug development and herpesviral research as antisens strategy or immunotherapy.

Prevalence of JC virus viraemia in HIV-infected patients with or without neurological disorders: a prospective study

Progressive Multifocal Leukoencephalopathy (PML) is a severe demyelinating disease, which is rapidly fatal and is due to JC virus (JCV) infection, which especially occurs in HIV-infected patients. To investigate JCV pathophysiology and to evaluate the predictive value of JCV detection in blood, we looked for JCV DNA in leukocytes and plasma of 96 patients without any neurological symptoms and 109 patients with neurological diseases, among whom 19 were suffering from PML. JCV genome was detected in about 18% of all patients, i.e. 15.6% of patients with central nervous system disorders except PML, 13.5% of patients without neurological symptoms and significantly more often in PML patients (47.6%). Both leukocytes and plasma were tested; in plasma, JCV DNA was found in 36.1% of positive patients and in cells in 80.5%. Surprisingly in seven instances only the plasma contained JCV genome. One-year follow-up of these patients showed that the absence of JCV DNA in blood was associated with a very low probability of developing PML (negative predictive value=0.99).

[Progressive multifocal leukoencephalopathy: virological and neuropathological aspects]

Progressive multifocal leukoencephalopathy is a subacute demyelinating disease of the central nervous system due to an opportunistic infection by a polyomavirus, most often JC virus, which predominantly infects oligodendrocytes. Progressive multifocal leukoencephalopathy used to be a rare condition, usually complicating lymphoproliferative diseases. Since the onset of the AIDS epidemic, its incidence has considerably increased and HIV infection has become, by far, the main risk factor for the disease. In AIDS patients, progressive leukoencephalopathy frequently shows atypical clinical and pathological features. The development of malignant glial tumors, within demyelinating regions, in patients with progressive multifocal leukoencephalopathy, has been reported in exceptional cases. The course of progressive multifocal leukoencephalopathy is invariably fatal. The diagnosis can only be made with certainty by histopathological examination of the brain, on cerebral biopsy or at postmortem. However, neuroradiological features may be extremely suggestive in many cases and PCR seems to be a reliable technique for demonstrating viral genome in the CSF. A few antiviral treatments have been proposed, however their efficacy is difficult to assess due to the low prevalence of the disease and the occurrence of rare cases with spontaneously prolonged survival.

Safety and efficacy of lamivudine-zidovudine combination therapy in antiretroviral-naive patients. A randomized controlled comparison with zidovudine monotherapy. Lamivudine European HIV Working Group

OBJECTIVE

To compare safety and efficacy of lamivudine-zidovudine combination therapy with zidovudine monotherapy in treating human immunodeficiency virus type 1 (HIV-1)-infected, antiretroviral therapy-naive patients.

DESIGN

Double-blind, randomized, multicenter, comparative trial of 129 patients throughout 24 weeks followed by 24 weeks of open-label lamivudine in combination with zidovudine.

SETTING

Outpatients from 14 hospitals in Belgium, France, Germany, Spain, and the United Kingdom were enrolled within 6 months.

PATIENTS

HIV-1-positive, antiretroviral-naive ( < or = 4 weeks prior zidovudine use) patients aged atleast 18 years with CD4+ cell counts between 0.10 x 10(9)/L and 0.40 x 10(9)/L (100-400/microL).

INTERVENTION

Patients received either 300 mg of lamivudine every 12 hours in combination with 200 mg of zidovudine every 8 hours for 24 weeks or zidovudine monotherapy for 24 weeks. All patients were then allowed to receive zidovudine in combination with open-label lamivudine (300 mg every 12 hours).

MAIN OUTCOME MEASURES

Efficacy was assessed by changes in CD4+ cell counts beta 2-microglobulin, neopterin, HIV-1 immune-complex dissociated (ICD) p24 antigenemia, and HIV-1 viral load. Safety was assessed by incidence of adverse clinical events and defined laboratory-measured toxic effects.

RESULTS

Combination therapy showed superior treatment effects compared with monotherapy during the first 24 weeks as documented by changes in CD4+ cell counts (increase of 0.08 x 10(9)/L vs 0.02 x 10(9)/L; P < .001), ICDp24 (-88% vs -49%; P = .04), cellular viremia (-1.27 vs -0.20 log10 median tissue-culture infected dose [TCID50] per 10(6) peripheral blood mononuclear cells; P = .001), and viral load measured by HIV-1 RNA polymerase chain reaction using a Roche method (-1.33 vs -0.57 log10 copies/mL; P = .001) or an immune-capture method (-0.6 vs -0.14log10 copies/mL; P = .008). Observed changes were sustained to 48 weeks for patients continuing to receive combination therapy. Patients switching to receive combination therapy at week 24 showed improvements in CD4+ cell count and viral load to week 48. Mutation results suggested that mutations associated with zidovudine resistance may have developed more slowly over the first 24 weeks in patients receiving combination therapy. In contrast, mutations associated with lamivudine resistance appeared to develop rapidly, despite sustained antiviral treatment effect. However, the number of patients evaluated for genotypic changes was small, and confirmation of these results is needed in larger studies. No statistically significant differences in incidence or severity of clinically manifested or laboratory-measured toxic effects were noted between treatment groups.

CONCLUSIONS

The combination of lamivudine and zidovudine results in a potent and sustained antiviral effect in antiretroviral-naive patients that is superior to that observed with zidovudine monotherapy.

Photodynamic inactivation of cell-free HIV strains by a red-absorbing chlorin-type photosensitizer

We have investigated the photodynamic activity of a new chlorin-type photosensitizer on a reference human immunodeficiency virus type 1 (HIV-1) strain, two wild-type HIV-1 isolates and two drug-resistant HIV-1 isolates. This chlorin was highly effective for the inactivation of free viruses, as assessed by two different quantitative cell culture assays. In the absence of blood components, all the HIV strains, including wild-type and drug-resistant mutant isolates, were totally inactivated using 30 micrograms ml-1 of chlorin and 0.75 J cm-2 of 661 nm light. Successful killing of HIV-1 strains in either plasma or whole blood was also obtained by increasing the chlorin concentration moderately. Our results demonstrate the antiviral efficiency of this chlorin, suggesting the potential application of dye-sensitized photoirradiation to decontaminate blood products.

Phase I/II study of 3TC (lamivudine) in HIV-positive, asymptomatic or mild AIDS-related complex patients: sustained reduction in viral markers. The Lamivudine European HIV Working Group

OBJECTIVE

To evaluate the efficacy of 3TC (lamivudine), a synthetic nucleoside analogue that inhibits HIV reverse transcriptase in vitro, as treatment for HIV-positive, asymptomatic or mild AIDS-related complex patients.

DESIGN

Open-label, multinational and multicentre, non-comparative, escalating dose study.

METHODS

Patients who meet the selection criteria (n = 104) were enrolled in three European countries. Ten to 15 patients were included at each of the six dose levels of 3TC (0.5, 1.0, 2.0, 4.0, 8.0, 12.0 and 20.0 mg/kg daily in two divided doses every 12 h). Virological parameters--immune-complex dissociation (ICD) assay for HIV p24 antigenaemia, plasma HIV RNA load, whole blood assay and cellular viraemia--were evaluated at weeks 0, 4, 12 and 24.

RESULTS

Sustained reductions in HIV RNA load and in ICD p24 antigen levels were observed and maintained over the 12-week assessment period. Greater reductions were noted at higher doses but this trend did not reach statistical significance. In 38 patients, reductions of cell viraemia were significantly greater at 4 weeks for patients treated at higher doses of 3TC.

CONCLUSION

These virological data show that 3TC is a potent inhibitor of HIV replication in HIV-positive, asymptomatic or mild ARC patients as assessed by ICD p24 antigenaemia, plasma HIV RNA load and cell viraemia.

Evaluation of safety and efficacy of 3TC (lamivudine) in patients with asymptomatic or mildly symptomatic human immunodeficiency virus infection: a phase I/II study

In a phase I/II study, 7 levels of 3TC therapy (from 0.5 to 20.0 mg/kg/day) were studied in 104 asymptomatic and mildly symptomatic human immunodeficiency virus-infected patients with CD4 cell counts < or = 400 x 10(6)/L. Mild and transient episodes of diarrhea, headache, fatigue, nausea, and abdominal pain were the most frequent events reported. No dose-limiting toxicities were observed. Small and transient increases in CD4 cell counts were detected during the first 4 weeks of treatment. These were followed by progressive declines during prolonged therapy. Sustained decreases in beta 2-microglobulin, neopterin, and p24 antigen levels were seen over the 52-week study. There was no consistent dose-response correlation for any surrogate marker. Penetration of 3TC into cerebrospinal fluid (CSF) was in the same range as reported for ddC and ddI; the mean CSF-to-serum ratio was 0.06. These findings indicate that 3TC exhibits an excellent safety profile and has antiretroviral activity at the dosages studied.

HIV-1/HIV-2 seronegativity in HIV-1 subtype O infected patients

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.

Simultaneous progressive multifocal leukoencephalopathy, Epstein-Barr virus (EBV) latent infection and cerebral parenchymal infiltration during chronic lymphocytic leukemia

We report a non-HIV patient who had B chronic lymphocytic leukemia (CLL) with progressive multifocal leukoencephalopathy (PML) and diffuse cerebral leukemic parenchymal infiltration in the presence of JC virus and Epstein-Barr virus (EBV) cerebral co-infection. Multiple subcortical hypodensities lining the cortico-subcortical junction were present within the white matter on computerized tomography (CT) scan, with large areas of high signal intensity on T2-weighted sequences on magnetic resonance imaging (MRI). JCV DNA was identified in peripheral blood nuclear cells and cerebrospinal fluid polymerase chain reaction (PCR) DNA/DNA hybridization plus Southern blot analysis. Frontal stereotactic biopsy confirmed the diagnosis of PML by immunocytochemistry, in situ hybridization (ISH) with JC Enzo probe and electron microscopy. Leukemic B cells with the same phenotype as leukemic blood cells were disseminated in the demyelinated areas. They were labeled by anti-latent membrane protein and by BamHl W EBV probe after ISH. Adhesion and activation molecules were positive for CD23. Autopsy showed diffuse visceral leukemic infiltration without acutization. EBV-transformed B lymphocytes would favour JCV penetration and/or intracerebral reactivation of previously latent JCV infection with further development of simultaneous PML and cerebral CLL infiltration in an immunosuppressed patient.

Virological diagnosis of progressive multifocal leukoencephalopathy: detection of JC virus DNA in cerebrospinal fluid and brain tissue of AIDS patients

Cerebrospinal fluid (CSF) from 12 AIDS patients with clinical signs consistent with progressive multifocal leukoencephalopathy (PML) was examined by the polymerase chain reaction (PCR) for the presence of JC virus (JCV). A specific JCV target sequence was amplified in the CSF from 9 of the 12 patients and also in brain tissue from all nine JCV-positive patients. The clinical course, neuroimaging features, and, in four cases, histopathology of brain tissue proved that the nine patients had PML. In the other three patients with central nervous system disorders, the JCV genome was undetectable by PCR and Southern blot analysis in CSF and brain tissue. The clinical course and neuroimaging features ruled out PML in these three patients. Five CSF samples and five brain tissue specimens from 10 PML-free AIDS patients with central nervous system disorders were all negative for the JCV genome by PCR and Southern blot analysis. These results show that detection of JCV in CSF by PCR is a good alternative to brain tissue studies for the virological diagnosis of PML in AIDS patients.

Inhibition of viral growth by an alpha-oligonucleotide directed to the splice junction of herpes simplex virus type-1 immediate-early pre-mRNA species 22 and 47

A 13-residue alpha-anomeric oligonucleotide [alpha-5'-d(GGGCGTCCTCCTT)3'], 5'-substituted with a psoralen derivative, Pso-alpha-13 psoralen linked to the 5' end of an alpha-anomeric n-residue oligonucleotide, was targeted to the acceptor splice junction of Herpes simplex virus type-1 immediate-early pre-mRNA species 22 and 47. Inhibition of viral growth was observed upon irradiation of Vero cells infected with Herpes simplex virus type-1 and treatment with Pso-alpha-13. The virus titer was decreased by 80% at an oligonucleotide concentration of 0.5 microM and at a multiplicity of infection of 0.1 plaque-forming units/cell. The 13-residue oligonucleotide did not induce any cytotoxic effect after irradiation and the inhibition of viral growth was clearly sequence specific. A non-specific 5' Pso-alpha-15 did not inhibit Herpes simplex virus type-1 growth. The 5' Pso-alpha-13 targeted to the acceptor splice junction of Herpes simplex virus type 1, contained five mismatches with respect to the corresponding sequence of Herpes simplex virus type 2, and did not exhibit any inhibitory effects on Herpes simplex virus type-2 growth. These results show that alpha-oligonucleotides can exhibit a sequence-specific antiviral effect and suggest that they may inhibit splicing reactions and be useful in targeting specific nucleic acid sequences within the cell nucleus.

HIV-1 sensitivity to zidovudine: a consensus culture technique validated by genotypic analysis of the reverse transcriptase

In order to select and standardize a reliable assay for the analysis of sensitivity of HIV isolates to AZT, we have compared two culture methods. The first assay (Cell-Associated Isolate Sensitivity Assay: CAISA) quantified AZT-resistant HIV isolates by end-point dilution cultures of peripheral blood mononuclear cells (PBMCs) in the presence of various concentrations of AZT. In the second assay (Cell-Free Isolate Sensitivity Assay: CFISA), following a conventional isolation of HIV, dilutions of infected cell-free supernatants were cultivated with fresh normal donor PBMCs in the presence of increasing concentrations of AZT. Samples from 64 untreated and AZT-treated patients were studied by CAISA (41), CFISA (43) or both assays (20). The CFISA, which allows the determination of titration parameters with respect to various kinetics patterns of viral replication was selected, and some of the CFISA phenotypically characterized isolates were further studied by nucleotide sequence analysis of the reverse transcriptase gene. CFISA showed that isolates from untreated patients were susceptible to AZT while the frequency of resistance increased with the duration of therapy. Genotypic analysis of CFISA-resistant isolates exhibited mutations at crucial positions, particularly at residue 215. We consider CFISA as a consensus culture technique for longitudinal studies of isolates from patients receiving AZT or other analogs of nucleosides.

Susceptibility of HIV-1 isolates to zidovudine: correlation between widely applicable culture test and PCR analysis

Thirteen isolates of human immunodeficiency virus type 1 (HIV-1) obtained in coculture with peripheral blood lymphocytes were tested for in vitro susceptibility to zidovudine (ZDV). Seven isolates were obtained from patients who had never been treated with ZDV and six from patients receiving the drug. The seven isolates from untreated patients and four of six from treated patients were susceptible to ZDV. The two isolates from the patients treated for the longest periods were resistant to the drug. The presence of mutations at critical positions of the reverse transcriptase gene was investigated by direct sequencing of polymerase chain reaction (PCR)-amplified DNA and four isolates were found to be mutants. An isolate from an untreated patient showed a change at residue 70 of the reverse transcriptase and an isolate from a patient treated for 4 months showed a change at residue 67. A change at residue 215 was found only for the two drug-resistant isolates, which correlated with the results obtained by Larder et al. using isolates from MT-2 cell cocultures. These results suggest that any HIV isolate provided by conventional coculture could be confidently tested for ZDV susceptibility in order to study the emergence of resistance during long-term therapy.

Several groups among human herpesvirus 6 strains can be distinguished by Southern blotting and polymerase chain reaction

Eight human herpesvirus 6 (HHV-6) strains were studied by Southern blot and polymerase chain reaction. DNA from infected cells was digested by a panel of restriction enzymes and hybridized with cloned BamHI fragments corresponding to about 30% of the HHV-6 strain SIE genome. In parallel, this DNA was amplified by polymerase chain reaction using pairs of primers derived from the strain SIE nucleotide sequence. Subsequently, amplification products were analyzed by hybridization, digestion with restriction endonucleases, and partial nucleotide sequencing. Overall results indicated that all strains were closely related to one another. However, concordant differences in restriction patterns allowed at least two groups to be distinguished, typified by strains SIE and HST, respectively. Differences between the two groups were found to reflect a limited number of punctual changes in nucleotide sequences. These results strengthen the idea of a unique HHV-6 species with genetic polymorphism. In addition, this study provides useful markers for the diagnosis and molecular epidemiology of HHV-6 infections.

[Virologic diagnosis of ocular infections]

Viral infections of the anterior part of the eye are easy to diagnose as a rule: the inoculation of cell cultures with specimens collected on readily accessible and virus-rich lesions facilitates the isolation of adenoviridae, picornaviridae and herpesviridae responsible for these lesions. Viral infections of the posterior part of the eye are a different matter, and they require more complex and also more invasive investigation techniques. Yet an aetiological research is necessary: since effective antiviral agents with a highly specific mode of action are available, the virus to be eradicated must be identified with great accuracy.

Detection of antibodies to human herpesvirus-6 using immunofluorescence assay

A serological study of human herpesvirus-6 (HHV-6) infection was performed by means of immunofluorescence assay on fixed HHV-6-infected cells. Comparison between indirect immunofluorescence assay (IFA) and anticomplement immunofluorescence assay (ACIF) showed that the latter test was the most appropriate for HHV-6 serology, although both methods exhibited identical sensitivity. ACIF, which was performed on HSB2 cells infected with the HBLV strain (provided by S.Z. Salahuddin), was then used to determine the titre of HHV-6 antibodies in serum by end-point dilution. The sera from 115 healthy subjects and 99 patients with presumed viral infection were tested. A similar distribution of HHV-6 titres was evidenced in both cases and the rate of individuals exhibiting a positive titre of 20 and above was about 30% of the whole population studied. No serological cross-reactivity was observed between HHV-6 and other herpesviruses, suggesting that the HHV-6 ACIF test was quite specific.

Perspectives in antiviral chemotherapy

The current progress in antiviral therapy is related to our better understanding of the viral multiplication, with potential targets for specific antiviral action at each step of the multiplication cycle inside the infected cell. Amantadine and Rimantadine are anti-influenza A drugs interfering with the penetration and the release of the virus. Most of the other antiviral drugs which are clinically available have the same target in common, namely the viral DNA polymerase. This holds true for modified nucleosides such as Acycloguanosine (Acyclovir), DHPG, Adenine-Arabinoside, Azidothymidine as well as pyrophosphate derivatives such as phosphonoformic acid. Unfortunately the antiviral chemotherapy must confront 3 obstacles: 1) a possible interference with the normal cellular metabolism, leading to residual cytotoxic side effects; 2) the genetic variability of the viruses, producing drug-resistant mutants and 3) the inability of any antiviral chemotherapeutic agent known to date to eradicate latent viral infection. A new approach of the control of latent infection is suggested with anti sense oligonucleotides of hybridons.

Simplified test for detecting the resistance of herpes simplex virus to acyclovir

The detection of herpes simplex virus (HSV) antigen by means of an enzyme amplified ELISA was investigated for rapid screening of acyclovir (ACV) resistance. Vero cell monolayers were inoculated in the presence of different concentrations of ACV. When cytopathic effect was present, the culture supernatants were tested by ELISA. The absorbance values were found to correlate with the results of virus yield and plaque reduction assays. The comparison between absorbance values obtained in the presence of 10 microM ACV and in the absence of drug provided the basis for a simplified sensitivity test. The use of a single ACV concentration allowed discrimination between ACV-resistant and ACV-sensitive reference strains, the detection of ACV-resistant virus mixed in the proportion of 10% with ACV-sensitive virus, and a study of the emergence of an ACV-resistant virus population in serial samples taken from experimental rabbit keratitis. The simplified susceptibility assay is a sensitive and convenient method for rapid screening of HSV resistance to ACV.

In vitro sensitivity of human herpesvirus-6 to antiviral drugs

We studied the sensitivity of human herpesvirus-6 (HHV-6) to 4 antiviral drugs known to be effective in the treatment of infections with other human herpesviruses and human immunodeficiency virus. HHV-6 was grown in peripheral blood lymphocytes, and virus multiplication was quantified by evaluation of the cytopathic effect by molecular hybridization and indirect immunofluorescence assay. The 50% and 90% inhibitory concentrations (IC50 and IC90) were determined for each drug. The results obtained by the 3 different quantification techniques were found to correlate, and enabled us to conclude that HHV-6 replication was readily inhibited by foscarnet or ganciclovir. In contrast, inhibition of HHV-6 replication was observed only at high concentrations of acyclovir, and was not detected at the tested concentrations of zidovudine.

Evaluation of three assays on alveolar lavage fluid in the diagnosis of cytomegalovirus pneumonitis after bone marrow transplantation

Cytologic examination, immunofluorescence assays, and cultures for virus were compared prospectively in the detection of cytomegalovirus (CMV) in cells obtained by 41 bronchoalveolar lavages (BALs) from 30 bone marrow transplant recipients with pneumonia. No evidence of CMV was found in 21 BALs. Viral inclusions, positive immunologic assays, and positive cultures were found in 14, 15, and 18 BALs, respectively. Cytological and immunologic results were closely related except in one BAL. In five BALs, a positive culture for virus was the sole criterion noted for diagnosis of CMV. The patients with both cytologically and immunologically positive results were more likely to die with or from respiratory failure (P less than .05), diffuse interstitial patterns (P less than .01), and severe acute graft-vs.-host disease (P less than .02) than were the patients without any criterion for diagnosis of CMV. The discrepancies with the previously reported data, the interpretation of the three diagnostic procedures, and the ability of BAL to diagnose CMV pneumonia are discussed.

Eczema herpeticum of the child. An unusual manifestation of herpes simplex virus infection

Two children aged 7 months with eczema herpeticum received treatment consisting of intravenous acyclovir and human plasma with a high titer of herpes simplex virus antibodies. One recovered following two recurrences, but the other died rapidly, suffering both septicemia due to Pseudomonas aeruginosa and herpetic encephalitis. In both cases, the virus involved was a herpes simplex virus type 1 (HSV 1). The various isolates obtained before, during and after treatment remained equally sensitive to acyclovir. These observations highlight three points: the unpredictable and sometimes dramatic development of eczema herpeticum in the young child; the urgency of early diagnosis and treatment; the role of environment in viral contamination.

A one-year virological survey of acute intussusception in childhood

A prospective study was carried out during 1 year in order to correlate intussusceptions in childhood with a viral infection. A virus was incriminated in 50% of the 64 patients in this survey. Adenovirus infections remain predominant as compared to rotavirus infections.

Antiviral activity in sera of patients with influenza infection

An interferon like activity was investigated in the sera of patients, very early during an Influenza A or B infection. A such substance was significantly more frequent among the patients who shed a Myxovirus Influenza than among the patients without virus isolation in the nasopharynx. The following relations are discussed : either is the interferon production merely associated without effect on the virus level? Or, on the other hand, in some cases is the rate or virus multiplication strictly directed by this interferon production? This study don't allowed to choose one of these hypothesis.