[Viral encephalitis: update]

Suspicion of viral encephalitis should always be considered as a medical emergency and the prognosis depend on both the immune status of the host and the virulence of the virus. Among them, the herpes simplex virus is by far the most important one since it can be associated with severe encephalitis in immunocompetent host, and because a good response to acyclovir can be expected when rapidly initiated. Nevertheless, confirmation of the diagnosis requires exclusion of both metabolic or toxic encephalopathy and inflammatory encephalitis of non-infectious origin. In addition, other germs than viruses can mimic viral encephalitis and must be taken into consideration. The purpose of this review is to update the investigation that should be performed in clinical practice for any patient with suspicion of acute viral encephalitis.

Thymoma, immunodeficiency, and herpes simplex virus infections

Hypogammaglobulinemia develops in 3 to 6% of patients with thymoma and this association is commonly referred to as thymoma with immunodeficiency (formerly Good syndrome). Recurrent infections with encapsulated bacteria and opportunistic infections associated with disorders of both humoral and cell mediated immunity frequently occur in this rare primary, adult-onset immunodeficiency. We report a case of thymoma with immunodeficiency complicated by disseminated herpes simplex virus (HSV) infection and review five additional cases of HSV-related infections reported since 1966 in patients presenting with thymoma with immunodeficiency. Patients presented with epiglottitis, keratitis, recurrent genital herpes, ulcerative dermatitis, and acute hepatitis. Four of the six cases had a fatal outcome, two of which were directly attributable to HSV infection. Since the risk of invasive opportunistic infections is high and the presentation atypical, lymphocyte count and total serum immunoglobulin should be measured regularly in all patients presenting with thymoma with immunodeficiency.

Case report: human herpesvirus 6 reactivation associated with colitis in a lung transplant recipient

Whereas human herpesvirus 6 (HHV-6) reactivation is frequent in solid organ transplant recipients, symptomatic disease is rare. A case of colitis associated with HHV-6B reactivation was observed in a lung transplant recipient. This case report suggests that symptomatic HHV-6 infection may occur in the absence of detectable viremia.

[Varicella pneumonia]

The seroprevalence of chickenpox in countries with temperate climate is very high among young people. Only 4% of the infections occur in adults but the clinical course is usually more severe than in children. In adults, The mortality is approximately 40 times higher and the complication rate 25 times higher than in children. Pneumonia is the most frequent complication in adults and may be extremely severe in immunocompromised patients and in pregnant women. Pneumonia must be promptly treated with intravenous aciclovir. Vaccination is indicated in young seronegative patients with supplemental risk factors for severe complications. It is also effective post exposure, preventing or modifying the illness course in up to 90% of exposed people if given within 3 days. Immunoglobulins may be effective as late as 96 hours after exposure. They are frequently used for exposed people at high risk of severe disease, when varicella vaccine is contraindicated.

[First case of nephropathia epidemica acquired in Switzerland]

A 43 year healthy old man complains of fever with abdominal pain, vomiting, diarrhoea, followed by the development of thrombocytopenia and acute renal failure. The laboratory tests show the presence of Hantavirus specific IgM and IgG which is confirmed by a specific test revealing Puumala serotype as responsible. The patient received a symptomatic treatment with a favourable evolution allowing discharge about ten days after the beginning of symptoms. Hantavirus are transmitted by rodents, and this patient has certainly been infected in Switzerland in the absence of travel abroad during the incubation period. This means that when confronted in Switzerland with an acute nephritis of unknown origin, a diagnosis of nephropathia epidemica must be taken into account.

[Tick-borne encephalitis in the North part of the canton de Vaud]

Tick-borne encephalitis (TBE) is described in Switzerland since 1969. More than 200 cases are reported every year to the Federal office of public health (FOPH) and new sites of endemic disease have been documented recently, in particular in the North part of the canton de Vaud. The aim of this article is to review the clinical pictures of 11 patients hospitalised in Yverdon-les-Bains with a diagnosis of TBE between 2003 and August 2007. The occurrence of 5 new cases exposed in the North part of the canton de Vaud over these last 18 months confirms the presence of endemic foci in this area and should prompt the vaccination against the MEVE which is recommended by the FOPH in endemic zones. The sequels of MEVE being observed mainly in the elderly, vaccination should be afforded also to this group of patients.

Swiss recommendations for the management of varicella zoster virus infections

Infections with varicella zoster virus (VZV) are common viral infections associated with significant morbidity. Diagnosis and management are complex, particularly in immunocompromised patients and during pregnancy. The present recommendations have been established by a multidisciplinary panel of specialists and endorsed by numerous Swiss medical societies involved in the medical care of such patients (Appendix). The aim was to improve the care of affected patients and to reduce complications.

[Swiss recommendations for the management of varicella-zoster virus infections]

Infections with varicella zoster virus (VZV) are common viral infections associated with significant morbidity. Diagnosis and management are complex, particularly in immunocompromised patients and during pregnancy. The present recommendations have been established by a multidisciplinary panel of specialists and endorsed by numerous Swiss medical societies involved in the medical care of such patients (Appendix). The aim is to improve the care of affected patients and to reduce complications.

Determination of aciclovir and ganciclovir in human plasma by liquid chromatography–spectrofluorimetric detection and stability studies in blood samples

A sensitive HPLC method has been developed for the assay of aciclovir and ganciclovir in human plasma, by HPLC coupled with spectrofluorimetric detection. Plasma (1000 microl), with 9-ethyl-guanine added as internal standard, is submitted to protein precipitation with trichloroacetic acid solution 20%. The supernatant, evaporated to dryness at 37 degrees C, is reconstituted in 100 microl of a solution of sodium heptanosulfonate 0.4% adjusted with acetic acid to pH 2.60 and a 30 microl volume is then injected onto a Nucleosil 100-5 microm C18 column. Aciclovir and ganciclovir are analysed by spectrofluorimetric detection set at 260 nm (excitation) and 380 nm (emission) using a gradient elution program with solvents constituted of acetonitrile and a solution of sodium heptanosulfonate 0.4% adjusted to pH 2.60. The calibration curves are linear between 0.1 and 10 microg/ml. The mean absolute recovery of aciclovir and ganciclovir are 99.2+/-2.5 and 100.3+/-2.5%, respectively. The method is precise (with mean inter-day C.V.s within 1.0-1.6% for aciclovir and 1.2-3.5% for ganciclovir), and accurate (range of inter-day deviations -1.6 to +1.6% for aciclovir and -0.4 to -1.4% for ganciclovir). The method has been applied in stability studies of ganciclovir in patients' blood samples, demonstrating its good stability in plasma at -20 degrees C and at room temperature. The distribution of ganciclovir and aciclovir in plasma and red blood cells was also investigated in vitro in spiking experiments with whole blood, which showed an initial drop of ganciclovir and aciclovir levels in plasma (about -25%) due to the cellular uptake of aciclovir and ganciclovir by red blood cells. The method has been validated and is currently applied in a clinical study assessing the ganciclovir plasma concentration variability after administration of valganciclovir in a population of solid organ transplant patients.

Swiss recommendations for the management of varicella zoster virus infections

Infections with varicella zoster virus (VZV) are common viral infections associated with significant morbidity. Diagnosis and management are complex, particularly in immunocompromised patients and during pregnancy. The present recommendations have been established by a multidisciplinary panel of specialists and endorsed by numerous Swiss medical societies involved in the medical care of such patients (Appendix). The aim was to improve the care of affected patients and to reduce complications.

[Evidence of new foci of tick-borne encephalitis in the French speaking part of Switzerland]

The incidence of tick-borne encephalitis (TBE) has more than doubled in Switzerland in recent years. In the French part of Switzerland several patients seem to have acquired the infection outside of known endemic foci. Thirty patients with TBE living or having acquired the infection in the French speaking part of Switzerland between 2000 and 2005 were identified. For one patient it wasn't possible to obtain precise information about the place of acquisition of the infection and 16 patients were infected in known endemic foci. Among the 13 remaining patients, 6 were infected on the southern shores of the lake of Neuchâtel and 7 in the plaine of Orbe. We conclude that there are new foci of TBE in the northern regions of the canton of Vaud. Vaccination should be proposed to the population at risk of these regions. In addition it is important that persons with outdoor activities in this regions respect the preventive

[Swiss recommendations for the management of gential herpers and herpes simplex virus infection of the neonate]

Genital herpes is being recognised as a medical problem of increasing importance. Diagnosis and management are complex. The present recommendations have been established by a multidisciplinary panel of specialists and endorsed by all Swiss medical societies involved in the medical care of such patients. The aim is to improve the care of affected patients, to reduce horizontal and vertical transmission and to diminish the psychosocial burden.

Resistance to nucleoside analog reverse transcriptase inhibitors mediated by human immunodeficiency virus type 1 p6 protein

Resistance of human immunodeficiency virus type 1 (HIV-1) to antiretroviral agents results from target gene mutation within the pol gene, which encodes the viral protease, reverse transcriptase (RT), and integrase. We speculated that mutations in genes other that the drug target could lead to drug resistance. For this purpose, the p1-p6(gag)-p6(pol) region of HIV-1, placed immediately upstream of pol, was analyzed. This region has the potential to alter Pol through frameshift regulation (p1), through improved packaging of viral enzymes (p6(Gag)), or by changes in activation of the viral protease (p6(Pol)). Duplication of the proline-rich p6(Gag) PTAP motif, necessary for late viral cycle activities, was identified in plasma virus from 47 of 222 (21.2%) patients treated with nucleoside analog RT inhibitor (NRTI) antiretroviral therapy but was identified very rarely from drug-naïve individuals. Molecular clones carrying a 3-amino-acid duplication, APPAPP (transframe duplication SPTSPT in p6(Pol)), displayed a delay in protein maturation; however, they packaged a 34% excess of RT and exhibited a marked competitive growth advantage in the presence of NRTIs. This phenotype is reminiscent of the inoculum effect described in bacteriology, where a larger input, or a greater infectivity of an organism with a wild-type antimicrobial target, leads to escape from drug pressure and a higher MIC in vitro. Though the mechanism by which the PTAP region participates in viral maturation is not known, duplication of this proline-rich motif could improve assembly and packaging at membrane locations, resulting in the observed phenotype of increased infectivity and drug resistance.

Individual contributions of mutant protease and reverse transcriptase to viral infectivity, replication, and protein maturation of antiretroviral drug-resistant human immunodeficiency virus type 1

Human immunodeficiency virus type 1 (HIV-1) variants resistant to protease (PR) and reverse transcriptase (RT) inhibitors may display impaired infectivity and replication capacity. The individual contributions of mutated HIV-1 PR and RT to infectivity, replication, RT activity, and protein maturation (herein referred to as "fitness") in recombinant viruses were investigated by separately cloning PR, RT, and PR-RT cassettes from drug-resistant mutant viral isolates into the wild-type NL4-3 background. Both mutant PR and RT contributed to measurable deficits in fitness of viral constructs. In peripheral blood mononuclear cells, replication rates (means +/- standard deviations) of RT recombinants were 72.5% +/- 27.3% and replication rates of PR recombinants were 60.5% +/- 33.6% of the rates of NL4-3. PR mutant deficits were enhanced in CEM T cells, with relative replication rates of PR recombinants decreasing to 15.8% +/- 23.5% of NL4-3 replication rates. Cloning of the cognate RT improved fitness of some PR mutant clones. For a multidrug-resistant virus transmitted through sexual contact, RT constructs displayed a marked infectivity and replication deficit and diminished packaging of Pol proteins (RT content in virions diminished by 56.3% +/- 10.7%, and integrase content diminished by 23.3% +/- 18.4%), a novel mechanism for a decreased-fitness phenotype. Despite the identified impairment of recombinant clones, fitness of two of the three drug-resistant isolates was comparable to that of wild-type, susceptible viruses, suggestive of extensive compensation by genomic regions away from PR and RT. Only limited reversion of mutated positions to wild-type amino acids was observed for the native isolates over 100 viral replication cycles in the absence of drug selective pressure. These data underscore the complex relationship between PR and RT adaptive changes and viral evolution in antiretroviral drug-resistant HIV-1.

Immunological and virological responses in HIV-1-infected adults at early stage of established infection treated with highly active antiretroviral therapy

OBJECTIVE

To evaluate the immunological and virological responses to highly active antiretroviral therapy (HAART) in blood and lymphoid compartments of HIV-1-infected patients at an early stage of infection.

DESIGN

An open-label, observational, non-randomized, prospective trial of outpatients attending the Centre of Clinical Investigation in Infectious Diseases, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Switzerland.

SUBJECTS

Forty-one antiretroviral-naive HIV-1-infected adults with 400 CD4 T cells/microl or greater and 5000 plasma HIV-1-RNA copies/ml or greater were enrolled, and 32 finished the study. Forty-nine HIV-negative individuals were included as controls. All subjects gave written informed consent.

INTERVENTIONS

All patients received abacavir 300 mg by mouth every 12 h and amprenavir 1200 mg by mouth every 12 h for 72 weeks.

MAIN OUTCOME MEASURES

The extent of immune reconstitution in blood and lymph nodes after 72 weeks of HAART was evaluated, and compared with immunological measures of 49 HIV-negative subjects.

RESULTS

Virus replication was effectively suppressed (-3.5 log10 at week 72). Substantial increments of CD4 T cell count in blood and percentage in lymph nodes were observed over time, and these measures were comparable to HIV-negative subjects by week 24 in blood and by week 48 in lymph nodes. The increase was equally distributed between naive and memory CD4 T cells. Recovery of HIV-specific CD4 responses occurred in 40% of patients.

CONCLUSION

The initiation of HAART at an early stage of established HIV infection induces systemic quantitative normalization of CD4 T cells, a partial recovery of HIV-specific CD4 cell responses, and effective and durable suppression of virus replication.

Virological and immunological characteristics of HIV treatment failure

BACKGROUND

Resistance to antiretroviral treatment is prevalent. There is limited knowledge of the determinants of disease evolution in subjects infected with multidrug-resistant HIV (MDR-HIV).

METHODS

Infectivity, replication, chemokine receptor usage, and env, gag, protease and reverse transcriptase sequence analysis was performed for MDR-HIV isolates from 14 HIV-infected individuals and compared to wild-type HIV isolates from individuals naive to antiretroviral treatment. Expression of CD45RO/RA, Ki67 and interferon-gamma and CD4 proliferative response to various antigens was determined for individuals infected with MDR-HIV and compared to that in individuals with optimal suppression of viral replication.

RESULTS

Infectivity and replication are diminished for various MDR-HIV isolates, usually in the context of an increase in CD4 and CD4+CD45RA+ T-cell counts. However, a number of MDR-HIV isolates are associated with high in vivo viraemia and pronounced immunosuppression, and display in vitro levels of infectivity and replication comparable to those of wild-type strains. No specific genetic sequence or chemokine receptor usage predicted the fitness of an MDR isolate.

CONCLUSIONS

Despite the biological diversity of resistant viruses and the range of host responses observed, our descriptive analysis indicates that viral factors play a role in determining the degree of immune damage observed in the context of MDR-HIV infection.

Nef enhances human immunodeficiency virus replication and responsiveness to interleukin-2 in human lymphoid tissue ex vivo

The nef gene is important for the pathogenicity associated with simian immunodeficiency virus infection in rhesus monkeys and with human immunodeficiency virus type 1 (HIV-1) infection in humans. The mechanisms by which nef contributes to pathogenesis in vivo remain unclear. We investigated the contribution of nef to HIV-1 replication in human lymphoid tissue ex vivo by studying infection with parental HIV-1 strain NL4-3 and with a nef mutant (DeltanefNL4-3). In human tonsillar histocultures, NL4-3 replicated to higher levels than DeltanefNL4-3 did. Increased virus production with NL4-3 infection was associated with increased numbers of productively infected cells and greater loss of CD4(+) T cells over time. While the numbers of productively infected T cells were increased in the presence of nef, the levels of viral expression and production per infected T cell were similar whether the nef gene was present or not. Exogenous interleukin-2 (IL-2) increased HIV-1 production in NL4-3-infected tissue in a dose-dependent manner. In contrast, DeltanefNL4-3 production was enhanced only marginally by IL-2. Thus, Nef can facilitate HIV-1 replication in human lymphoid tissue ex vivo by increasing the numbers of productively infected cells and by increasing the responsiveness to IL-2 stimulation.

Limited CD4+ T-cell renewal in early HIV-1 infection: effect of highly active antiretroviral therapy

We show that the fraction of proliferating CD4+ lymphocytes is similar in HIV-infected subjects in the early stage of disease and in HIV-negative subjects, whereas the fraction of proliferating CD8+ lymphocytes is increased 6.8-fold in HIV-infected subjects. After initiation of antiviral therapy, there is a late increase in proliferating CD4+ T cells associated with the restoration of CD4+ T-cell counts. These results provide strong support for the idea of limited CD4+ T-cell renewal in the early stage of HIV infection and indicate that after effective suppression of virus replication, the mechanisms of CD4+ T-cell production are still functional in early HIV infection.

Tests of turtle phylogeny: molecular, morphological, and paleontological approaches

We present phylogenetic analyses of both molecular and morphological data for the 23 major lineages of living turtles and seven key fossil taxa. Nearly 1 kilobase of cytochrome b sequence, 325 base pairs of 12S ribosomal DNA, and 115 morphological characters contained similar phylogenetic information, although each provided unique information on different nodes of chelonian history. A character-based combinability test (implemented in PAUP*) and a non-parametric test of taxonomic congruence indicated no strong evidence for heterogeneity among data sets, and we used a combined approach to estimate a final phylogeny of the major lineages of living turtles. This approach resulted in a very well-resolved tree, with only a few of the deep branches within the Cryptodira left as an unresolved polytomy. The addition of six relatively complete fossils chosen to help resolve this basal polytomy provided little added resolution to the tree and resulted in a sharp decline in bootstrap proportions for nodes near the fossils. Branch-length analysis and independent dates from the fossil record suggest that these unresolved nodes may represent a rapid radiation of the major cryptodiran lineages 90-120 million years ago.