Impaired antibody memory to varicella zoster virus in HIV-infected children: low antibody levels and avidity*.

OBJECTIVE: HIV-infected children have impaired antibody responses after exposure to certain antigens. Our aim was to determine whether HIV-infected children had lower varicella zoster virus (VZV) antibody levels compared with HIV-infected adults or healthy children and, if so, whether this was attributable to an impaired primary response, accelerated antibody loss, or failure to reactivate the memory VZV response. METHODS: In a prospective, cross-sectional and retrospective longitudinal study, we compared antibody responses, measured by enzyme-linked immunosorbent assay (ELISA), elicited by VZV infection in 97 HIV-infected children and 78 HIV-infected adults treated with antiretroviral therapy, followed over 10 years, and 97 age-matched healthy children. We also tested antibody avidity in HIV-infected and healthy children. RESULTS: Median anti-VZV immunoglobulin G (IgG) levels were lower in HIV-infected children than in adults (264 vs. 1535 IU/L; P<0.001) and levels became more frequently unprotective over time in the children [odds ratio (OR) 17.74; 95% confidence interval (CI) 4.36-72.25; P<0.001]. High HIV viral load was predictive of VZV antibody waning in HIV-infected children. Anti-VZV antibodies did not decline more rapidly in HIV-infected children than in adults. Antibody levels increased with age in healthy (P=0.004) but not in HIV-infected children. Thus, antibody levels were lower in HIV-infected than in healthy children (median 1151 IU/L; P<0.001). Antibody avidity was lower in HIV-infected than healthy children (P<0.001). A direct correlation between anti-VZV IgG level and avidity was present in HIV-infected children (P=0.001), but not in healthy children. CONCLUSION: Failure to maintain anti-VZV IgG levels in HIV-infected children results from failure to reactivate memory responses. Further studies are required to investigate long-term protection and the potential benefits of immunization.

Cognitive dysfunction in HIV patients despite long-standing suppression of viremia.

OBJECTIVE:: To determine the prevalence of cognitive complaints and HIV-associated neurocognitive disorders (HANDs) in a cohort of aviremic HIV-positive patients. To evaluate the relevance of the HIV dementia scale to detect HANDs. DESIGN:: Assessment of HANDs with neuropsychological tests. METHODS:: Two hundred HIV-infected patients with undetectable HIV-1 RNA concentrations in the plasma, no history of major opportunistic infection of the central nervous system in the past 3 years, no current use of intravenous drugs, and no major depression answered a questionnaire designed to elicit cognitive complaints. Cognitive functions of 50 complaining and 50 noncomplaining HIV-positive patients were assessed. RESULTS:: Patients had undetectable HIV-1 RNA concentrations for a median time of 48 months (range 3.2-136.6). The prevalence of cognitive complaints was 27%. The prevalence of HANDs was 84% among patients with cognitive complaints (asymptomatic neurocognitive impairment 24%, mild neurocognitive disorders 52%, and HIV-associated dementia 8%) and 64% among noncomplainers (asymptomatic neurocognitive impairment 60%, mild neurocognitive disorders 4%, and HIV-associated dementia 0%; P < 0.001). A score of 14 points or less on the HIV dementia scale yielded a positive predictive value of HANDs of 92% in complainers and 82% in noncomplainers. CONCLUSION:: The prevalence of HANDs is high even in long-standing aviremic HIV-positive patients. However, HANDs without functional repercussion in daily life (asymptomatic neurocognitive impairment) is the most frequent subtype observed. In this population, the HIV dementia scale with a cutoff of 14 points or less seems to provide a useful tool to screen for the presence of HANDs.

Simultaneous co-expression of memory- and effector-related genes by individual human CD8 T cells depends on antigen specificity and differentiation

Purpose/Objective: Phenotypic and functional T cell properties are usually analyzed at the level of defined cell populations. However, large differences between individual T cells may have important functional consequences. To answer this issue, we performed highly sensitive single-cell gene expression profiling, which allows the direct ex vivo characterization of individual virus- and tumor-specific T cells from healthy donors and melanoma patients. Materials and methods: HLA-A*0201-positive patients with stage III/ IV metastatic melanoma were included in a phase I clinical trial (LUD- 00-018). Patients received monthly low-dose of the Melan-AMART- 1 26_35 unmodified natural (EAAGIGILTV) or the analog A27L (ELAGIGILTV) peptides, mixed CPG and IFA. Individual effector memory CD28+ (EM28+) and EM28- tetramer-specific CD8pos T cells were sorted by flow cytometer. Following direct cell lysis and reverse transcription, the resulting cDNA was precipitated and globally amplified. Semi-quantitative PCR was used for gene expression and TCR BV repertoire analyses. Results: We have previously shown that vaccination with the natural Melan-A peptide induced T cells with superior effector functions as compared to the analog peptide optimized for enhanced HLA binding. Here we found that natural peptide vaccination induced EM28+ T cells with frequent co-expression of both memory/homing-associated genes (CD27, IL7R, EOMES, CXCR3 and CCR5) and effector-related genes (IFNG, KLRD1, PRF1 and GZMB), comparable to protective EBV- and CMV-specific T cells. In contrast, memory/homing- and effectorassociated genes were less frequently co-expressed after vaccination with the analog peptide. Conclusions: These findings reveal a previously unknown level of gene expression diversity among vaccine- and virus-specific T cells with the simultaneous co-expression of multiple memory/homing- and effector- related genes by the same cell. Such broad functional gene expression signatures within antigen-specific T cells may be critical for mounting efficient responses to pathogens or tumors. In summary, direct ex vivo high-resolution molecular characterization of individual T cells provides key insights into the processes shaping the functional properties of tumor- and virus-specific T cells.

Tools in pharmacovigilance in psychiatry: therapeutic drug monitoring, pharmacogenetic tests and drug-drug interactions databases

SUMMARYIn order to increase drug safety we must better understand how medication interacts with the body of our patients and this knowledge should be made easily available for the clinicians prescribing the medication. This thesis contributes to how the knowledge of some drug properties can increase and how to make information readily accessible for the medical professionals. Furthermore it investigates the use of Therapeutic drug monitoring, drug interaction databases and pharmacogenetic tests in pharmacovigilance.Two pharmacogenetic studies in the naturalistic setting of psychiatric in-patients clinics have been performed; one with the antidepressant mirtazapine, the other with the antipsychotic clozapine. Forty-five depressed patients have been treated with mirtazapine and were followed for 8 weeks. The therapeutic effect was as seen in other previous studies. Enantioselective analyses could confirm an influence of age, gender and smoking in the pharmacokinetics of mirtazapine; it showed a significant influence of the CYP2D6 genotype on the antidepressant effective S-enantiomer, and for the first time an influence of the CYP2B6 genotype on the plasma concentrations of the 8-OH metabolite was found. The CYP2B6*/*6 genotype was associated to better treatment response. A detailed hypothesis of the metabolic pathways of mirtazapine is proposed. In the second pharmacogenetic study, analyses of 75 schizophrenic patients treated with clozapine showed the influence of CYP450 and ABCB1 genotypes on its pharmacokinetics. For the first time we could demonstrate an in vivo effect of the CYP2C19 genotype and an influence of P-glycoprotein on the plasma concentrations of clozapine. Further we confirmed in vivo the prominent role of CYP1A2 in the metabolism of clozapine.Identifying risk factors for the occurrence of serious adverse drug reactions (SADR) would allow a more individualized and safer drug therapy. SADR are rare events and therefore difficult to study. We tested the feasibility of a nested matched case-control study to examine the influence of high drug plasma levels and CYP2D6 genotypes on the risk to experience an SADR. In our sample we compared 62 SADR cases with 82 controls; both groups were psychiatric patients from the in-patient clinic Königsfelden. Drug plasma levels of >120% of the upper recommended references could be identified as a risk factor with a statistically significant odds ratio of 3.5, a similar trend could be seen for CYP2D6 poor metaboliser. Although a matched case-control design seems a valid method, 100% matching is not easy to perform in a relative small cohort of one in-patient clinic. However, a nested case-control study is feasible.On the base of the experience gained in the AMSP+ study and the fact that we have today only sparse data indicating that routine drug plasma concentration monitoring and/or pharmacogenetic testing in psychiatry are justified to minimize the risk for ADR, we developed a test algorithm named "TDM plus" (TDM plus interaction checks plus pharmacogenetic testing).Pharmacovigilance programs such as the AMSP project (AMSP = Arzneimittelsicherheit in der Psychiatrie) survey psychiatric in-patients in order to collect SADR and to detect new safety signals. Case reports of such SADR are, although anecdotal, valuable to illustrate rare clinical events and sometimes confirm theoretical assumptions of e.g. drug interactions. Seven pharmacovigilance case reports are summarized in this thesis.To provide clinicians with meaningful information on the risk of drug combinations, during the course of this thesis the internet based drug interaction program mediQ.ch (in German) has been developed. Risk estimation is based on published clinical and pharmacological information of single drugs and alimentary products, including adverse drug reaction profiles. Information on risk factors such as renal and hepatic insufficiency and specific genotypes are given. More than 20'000 drug pairs have been described in detail. Over 2000 substances with their metabolic and transport pathways are included and all information is referenced with links to the published scientific literature or other information sources. Medical professionals of more than 100 hospitals and 300 individual practitioners do consult mediQ.ch regularly. Validations with comparisons to other drug interaction programs show good results.Finally, therapeutic drug monitoring, drug interaction programs and pharmacogenetic tests are helpful tools in pharmacovigilance and should, in absence of sufficient routine tests supporting data, be used as proposed in our TDM plus algorithm.RESUMEPour améliorer la sécurité d'emploi des médicaments il est important de mieux comprendre leurs interactions dans le corps des patients. Ensuite le clinicien qui prescrit une pharmacothérapie doit avoir un accès simple à ces informations. Entre autres, cette thèse contribue à mieux connaître les caractéristiques pharmacocinétiques de deux médicaments. Elle examine aussi l'utilisation de trois outils en pharmacovigilance : le monitorage thérapeutique des taux plasmatiques des médicaments (« therapeutic drug monitoring »), un programme informatisé d'estimation du risque de combinaisons médicamenteuses, et enfin des tests pharmacogénétiques.Deux études cliniques pharmacogénétiques ont été conduites dans le cadre habituel de clinique psychiatrique : l'une avec la mirtazapine (antidépresseur), l'autre avec la clozapine (antipsychotique). On a traité 45 patients dépressifs avec de la mirtazapine pendant 8 semaines. L'effet thérapeutique était semblable à celui des études précédentes. Nous avons confirmé l'influence de l'âge et du sexe sur la pharmacocinétique de la mirtazapine et la différence dans les concentrations plasmatiques entre fumeurs et non-fumeurs. Au moyen d'analyses énantiomères sélectives, nous avons pu montrer une influence significative du génotype CYP2D6 sur l'énantiomère S+, principalement responsable de l'effet antidépresseur. Pour la première fois, nous avons trouvé une influence du génotype CYP2B6 sur les taux plasmatiques de la 8-OH-mirtazapine. Par ailleurs, le génotype CYP2B6*6/*6 était associé à une meilleure réponse thérapeutique. Une hypothèse sur les voies métaboliques détaillées de la mirtazapine est proposée. Dans la deuxième étude, 75 patients schizophrènes traités avec de la clozapine ont été examinés pour étudier l'influence des génotypes des iso-enzymes CYP450 et de la protéine de transport ABCB1 sur la pharmacocinétique de cet antipsychotique. Pour la première fois, on a montré in vivo un effet des génotypes CYP2C19 et ABCB1 sur les taux plasmatiques de la clozapine. L'importance du CYP1A2 dans le métabolisme de la clozapine a été confirmée.L'identification de facteurs de risques dans la survenue d'effets secondaire graves permettrait une thérapie plus individualisée et plus sûre. Les effets secondaires graves sont rares. Dans une étude de faisabilité (« nested matched case-control design » = étude avec appariement) nous avons comparé des patients avec effets secondaires graves à des patients-contrôles prenant le même type de médicaments mais sans effets secondaires graves. Des taux plasmatiques supérieurs à 120% de la valeur de référence haute sont associés à un risque avec « odds ratio » significatif de 3.5. Une tendance similaire est apparue pour le génotype du CYP2D6. Le « nested matched case-control design » semble une méthode valide qui présente cependant une difficulté : trouver des patients-contrôles dans le cadre d'une seule clinique psychiatrique. Par contre la conduite d'une « nested case-control study » sans appariement est recommandable.Sur la base de notre expérience de l'étude AMSP+ et le fait que nous disposons que de peux de données justifiant des monitorings de taux plasmatiques et/ou de tests pharmacogénétiques de routine, nous avons développé un test algorithme nommé « TDMplus » (TDM + vérification d'interactions médicamenteuses + tests pharmacogénétique).Des programmes de pharmacovigilances comme celui de l'AMSP (Arzneimittelsicherheit in der Psychiatrie = pharmacovigilance en psychiatrie) collectent les effets secondaires graves chez les patients psychiatriques hospitalisés pour identifier des signaux d'alertes. La publication de certains de ces cas même anecdotiques est précieuse. Elle décrit des événements rares et quelques fois une hypothèse sur le potentiel d'une interaction médicamenteuse peut ainsi être confirmée. Sept publications de cas sont résumées ici.Dans le cadre de cette thèse, on a développé un programme informatisé sur internet (en allemand) - mediQ.ch - pour estimer le potentiel de risques d'une interaction médicamenteuse afin d'offrir en ligne ces informations utiles aux cliniciens. Les estimations de risques sont fondées sur des informations cliniques (y compris les profils d'effets secondaires) et pharmacologiques pour chaque médicament ou substance combinés. Le programme donne aussi des informations sur les facteurs de risques comme l'insuffisance rénale et hépatique et certains génotypes. Actuellement il décrit en détail les interactions potentielles de plus de 20'000 paires de médicaments, et celles de 2000 substances actives avec leurs voies de métabolisation et de transport. Chaque information mentionne sa source d'origine; un lien hypertexte permet d'y accéder. Le programme mediQ.ch est régulièrement consulté par les cliniciens de 100 hôpitaux et par 300 praticiens indépendants. Les premières validations et comparaisons avec d'autres programmes sur les interactions médicamenteuses montrent de bons résultats.En conclusion : le monitorage thérapeutique des médicaments, les programmes informatisés contenant l'information sur le potentiel d'interaction médicamenteuse et les tests pharmacogénétiques sont de précieux outils en pharmacovigilance. Nous proposons de les utiliser en respectant l'algorithme « TDM plus » que nous avons développé.

On the significance of CD8 alpha alpha expression for T cell memory.

Longitudinal studies on the kinetics of viral antigen specific CD8 T cell responses have led to a model whereby a relatively small subset of the primary effector CD8 T cells expanding after the first week of acute viral infection initiate a program of cell survival and differentiation into long lived memory T cells. These T cells are then critical for maintaining protective immunity to subsequent viral infection. Recent observations, using fluorescent tetramers of the MHC class Ib molecule TL, link transient expression of CD8alphaalpha homodimers on expanding primary effector CD8 T cells to the generation of memory cells. At present it is controversial what the role of CD8alphaalpha is in the generation of memory CD8 T cells. The involvement of the high affinity CD8alphaalpha ligand, the TL molecule, is not understood either. However, evidence from two viral infection models in mice, including one paper in this issue of the European Journal of Immunology, suggest a role for CD8alphaalpha in this process and call for additional research focus into these issues.

Chronic deep brain stimulation in mesial temporal lobe epilepsy.

The objective of this study was to evaluate the efficiency and the effects of changes in parameters of chronic amygdala-hippocampal deep brain stimulation (AH-DBS) in mesial temporal lobe epilepsy (TLE). Eight pharmacoresistant patients, not candidates for ablative surgery, received chronic AH-DBS (130 Hz, follow-up 12-24 months): two patients with hippocampal sclerosis (HS) and six patients with non-lesional mesial TLE (NLES). The effects of stepwise increases in intensity (0-Off to 2 V) and stimulation configuration (quadripolar and bipolar), on seizure frequency and neuropsychological performance were studied. The two HS patients obtained a significant decrease (65-75%) in seizure frequency with high voltage bipolar DBS (≥1 V) or with quadripolar stimulation. Two out of six NLES patients became seizure-free, one of them without stimulation, suggesting a microlesional effect. Two NLES patients experienced reductions of seizure frequency (65-70%), whereas the remaining two showed no significant seizure reduction. Neuropsychological evaluations showed reversible memory impairments in two patients under strong stimulation only. AH-DBS showed long-term efficiency in most of the TLE patients. It is a valuable treatment option for patients who suffer from drug resistant epilepsy and who are not candidates for resective surgery. The effects of changes in the stimulation parameters suggest that a large zone of stimulation would be required in HS patients, while a limited zone of stimulation or even a microlesional effect could be sufficient in NLES patients, for whom the importance of the proximity of the electrode to the epileptogenic zone remains to be studied. Further studies are required to ascertain these latter observations.

Increased numbers of circulating polyfunctional Th17 memory cells in patients with seronegative spondylarthritides

OBJECTIVE: A distinct subset of proinflammatory CD4+ T cells that produce interleukin-17 was recently identified. These cells are implicated in different autoimmune disease models, such as experimental autoimmune encephalomyelitis and collagen-induced arthritis, but their involvement in human autoimmune disease has not yet been clearly established. The purpose of this study was to assess the frequency and functional properties of Th17 cells in healthy donors and in patients with different autoimmune diseases. METHODS: Peripheral blood was obtained from 10 psoriatic arthritis (PsA), 10 ankylosing spondylitis (AS), 10 rheumatoid arthritis (RA), and 5 vitiligo patients, as well as from 25 healthy donors. Synovial tissue samples from a separate group of patients were also evaluated (obtained as paraffin-embedded sections). Peripheral blood cells were analyzed by multiparameter flow cytometry and immunohistochemistry. Cytokine production was examined by enzyme-linked immunosorbent assay and intracellular cytokine staining using specific monoclonal antibodies. Synovial tissue was examined for infiltrating T cells by immunohistochemical analysis. RESULTS: We found increased numbers of circulating Th17 cells in the peripheral blood of patients with seronegative spondylarthritides (PsA and AS), but not in patients with RA or vitiligo. In addition, Th17 cells from the spondylarthritis patients showed advanced differentiation and were polyfunctional in terms of T cell receptor-driven cytokine production. CONCLUSION: These observations suggest a role of Th17 cells in the pathogenesis of certain human autoimmune disorders, in particular the seronegative spondylarthritides.

Pédiatrie. 3. Le score de McIsaac: une aide à l'indication des tests de diagnostic rapide dans tes angines à streptocoques A [Pediatrics. Using the McIsaac score for the indication of rapid diagnostic testing in children with streptococcal pharyngitis].

The McIsaac scoring system is a tool designed to predict the probability of streptococcal pharyngitis in children aged 3 to 17 years with a sore throat. Although it does not allow the physician to make the diagnosis of streptococcal pharyngitis, it enables to identify those children with a sore throat in whom rapid antigen detection tests have a good predictive value.

Les tests génétiques peuvent-ils être utiles pour la prévention cardiovasculaire? [Are genetic tests useful for cardiovascular prevention?].

Recent progresses in genetics have opened new avenues to further our understanding of the pathophysiological mechanisms underlying cardiovascular disease, raising, new expectations in the field of personalized medicine. Genetic tests may have a high predictive value for rare monogenic diseases. The situation is very different for common polygenic diseases, such as myocardial infarction, type 2 diabetes or stroke. The results from recent genome-wide association studies have provided useful information for research, but have not yet been proven to be clinically useful. It is therefore currently not recommended to conducted genetic testing to guide cardiovascular prevention neither in clinical nor in public health settings.

Sex differences: From mental rotation to object location memory, an ERP study

Sex differences in cognition have been largely investigated. The most consistent sex differences favoring females are observed in object location memory involving the left hemisphere whereas the most consistent sex differences favoring males are observed in tasks that require mental rotation involving the right hemisphere. Here we used a task involving these two abilities to see the impact of mental rotation on object location memory. To that end we used a combination of behavioral and event-related potential (ERP) electroencephalography (EEG) measures.A computer screen displayed a square frame of 4 pairs of images (a "teddy" bear, a shoe, an umbrella and a lamp) randomly arranged around a central fixation cross. After a 10-second interval for memorization, images disappeared and were replaced by a test frame with no image but a random pair of two locations marked in black. In addition, this test frame was randomly displayed either in the original orientation (0° rotation) or in the rotated one (90° clockwise - CW - or 90° counterclockwise - CCW). Preceding the test frame, an arrow indicating the presence or the absence of rotation of the frame was displayed on the screen. The task of the participants (15 females and 15 males) was to determine if two marked locations corresponded or not to a pair of identical images. Each response was followed by feedback.Findings showed no significant sex differences in the performance of the original orientation. In comparison with this position, the rotation of the frame produced an equal decrease of male and female performance. In addition, this decrease was significantly higher when the rotation of the frame was in a CCW direction. We further assessed the ERP when the arrow indicated the direction of rotation as stimulus-onset, during four time windows representing major components C1, P1, N1 and N2. Although no sex differences were observed in performance, brain activities differed according to sex. Enhanced amplitudes were found for the CCW compared to CW rotation over the right posterior areas for the P1, N1 and N2 components for men as well as for women. Major topographical differences related to sex were measured for the CW rotation condition as marked lateralized amplitude: left-hemisphere amplitude larger than right one was measured during P1 time range for men. These similar patterns prolonged from P1 to N1 for women. Early distinctions were found in interaction with sex between CCW and CW waveform amplitudes, expressing over anterior electrode sites during C1 time range (0-50 ms post-stimulus).In conclusion (i) women do not outperform men in object location memory in this study (absence of rotation condition); (ii) mental rotation, in particular the direction of rotation, influences performance on object location memory; (iii) CCW rotation is associated with activity in the right parietal hemisphere whereas the CW rotation involves the left parietal hemisphere; (iv) this last effect is less pronounced in males, which could explain why greater involvement of right parietal areas in men and of bilateral posterior areas in women is generally reported in mental rotation tasks; and (v) the early distinctions between both directions of rotation located over anterior sites could be related to sex differences in their respective involvement of control mechanisms.

Substantial advantage of a combined Bayesian and genotyping approach in testosterone doping tests.

Testosterone abuse is conventionally assessed by the urinary testosterone/epitestosterone (T/E) ratio, levels above 4.0 being considered suspicious. A deletion polymorphism in the gene coding for UGT2B17 is strongly associated with reduced testosterone glucuronide (TG) levels in urine. Many of the individuals devoid of the gene would not reach a T/E ratio of 4.0 after testosterone intake. Future test programs will most likely shift from population based- to individual-based T/E cut-off ratios using Bayesian inference. A longitudinal analysis is dependent on an individual's true negative baseline T/E ratio. The aim was to investigate whether it is possible to increase the sensitivity and specificity of the T/E test by addition of UGT2B17 genotype information in a Bayesian framework. A single intramuscular dose of 500mg testosterone enanthate was given to 55 healthy male volunteers with either two, one or no allele (ins/ins, ins/del or del/del) of the UGT2B17 gene. Urinary excretion of TG and the T/E ratio was measured during 15 days. The Bayesian analysis was conducted to calculate the individual T/E cut-off ratio. When adding the genotype information, the program returned lower individual cut-off ratios in all del/del subjects increasing the sensitivity of the test considerably. It will be difficult, if not impossible, to discriminate between a true negative baseline T/E value and a false negative one without knowledge of the UGT2B17 genotype. UGT2B17 genotype information is crucial, both to decide which initial cut-off ratio to use for an individual, and for increasing the sensitivity of the Bayesian analysis.