A human postnatal lymphoid progenitor capable of circulating and seeding the thymus

Identification of a thymus-seeding progenitor originating from human bone marrow (BM) constitutes a key milestone in understanding the mechanisms of T cell development and provides new potential for correcting T cell deficiencies. We report the characterization of a novel lymphoid-restricted subset, which is part of the lineage-negative CD34+CD10+ progenitor population and which is distinct from B cell–committed precursors (in view of the absence of CD24 expression). We demonstrate that these Lin−CD34+CD10+CD24− progenitors have a very low myeloid potential but can generate B, T, and natural killer lymphocytes and coexpress recombination activating gene 1, terminal deoxynucleotide transferase, PAX5, interleukin 7 receptor α, and CD3ε. These progenitors are present in the cord blood and in the BM but can also be found in the blood throughout life. Moreover, they belong to the most immature thymocyte population. Collectively, these findings unravel the existence of a postnatal lymphoid-polarized population that is capable of migrating from the BM to the thymus

Herpes simplex virus, early neuroimaging markers and incidence of Alzheimer's disease

While previous studies suggest the implication of herpes simplex virus (HSV) in the onset of Alzheimer's disease (AD), no study has investigated its association with early neuroimaging markers of AD. In the Three-City and the AMI cohorts, the associations between HSV infection and (i) hippocampal volume (n = 349), (ii) white matter alterations in the parahippocampal cingulum and fornix using diffusion tensor imaging (n = 260), and (iii) incidence of AD (n = 1599) were assessed according to APOE4 status. Regardless of APOE4 status, infected subjects presented (i) significantly more microstructural alterations of the parahippocampal cingulum and fornix, (ii) lower hippocampal volumes only when their anti-HSV IgG level was in the highest tercile-reflecting possibly more frequent reactivations of the virus (p = 0.03 for subjects with a high anti-HSV IgG level while there was no association for all infected subjects, p = 0.19), and (iii) had no increased risk of developing AD. Nevertheless, among APOE4 carriers, infected subjects presented lower hippocampal volumes, although not significant (p = 0.09), and a two or three times higher risk of developing AD (adjusted Hazard ratio (aHR) = 2.72 [1.07-6.91] p = 0.04 for infected subjects and aHR = 3.87 [1.45-10.28] p = 0.007 for infected subjects with an anti-HSV IgG level in the highest tercile) while no association was found among APOE4 noncarriers. Our findings support an association between HSV infection and AD and a potential interaction between HSV status and APOE4. This reinforces the need to further investigate the infectious hypothesis of AD, especially the associated susceptibility factors and the possibility of preventive treatments

Antiherpetic drugs: a potential way to prevent Alzheimer's disease?

BACKGROUND: Considering the growing body of evidence suggesting a potential implication of herpesviruses in the development of dementia, several authors have questioned a protective effect of antiherpetic drugs (AHDs) which may represent a new means of prevention, well tolerated and easily accessible. Subsequently, several epidemiological studies have shown a reduction in the risk of dementia in subjects treated with AHDs, but the biological plausibility of this association and the impact of potential methodological biases need to be discussed in more depth. METHODS: Using a French medico-administrative database, we assessed the association between the intake of systemic AHDs and the incidence of (i) dementia, (ii) Alzheimer's disease (AD), and (iii) vascular dementia in 68,291 subjects over 65 who were followed between 2009 and 2017. Regarding potential methodological biases, Cox models were adjusted for numerous potential confounding factors (including proxies of sociodemographic status, comorbidities, and use of healthcare) and sensitivity analyses were performed in an attempt to limit the risk of indication and reverse causality biases. RESULTS: 9.7% of subjects (n=6642) had at least one intake of systemic AHD, and 8883 incident cases of dementia were identified. Intake of at least one systemic AHD during follow-up was significantly associated with a decreased risk of AD (aHR 0.85 95% confidence interval [0.75-0.96], p=0.009) and, to a lesser extent with respect to p values, to both dementia from any cause and vascular dementia. The association with AD remained significant in sensitivity analyses. The number of subjects with a regular intake was low and prevented us from studying its association with dementia. CONCLUSIONS: Taking at least one systemic AHD during follow-up was significantly associated with a 15% reduced risk of developing AD, even after taking into account several potential methodological biases. Nevertheless, the low frequency of subjects with a regular intake questions the biological plausibility of this association and highlights the limits of epidemiological data to evaluate a potential protective effect of a regular treatment by systemic AHDs on the incidence of dementia

Covichem: A biochemical severity risk score of COVID-19 upon hospital admission

Clinical and laboratory predictors of COVID-19 severity are now well described and combined to propose mortality or severity scores. However, they all necessitate saturable equipment such as scanners, or procedures difficult to implement such as blood gas measures. To provide an easy and fast COVID-19 severity risk score upon hospital admission, and keeping in mind the above limits, we sought for a scoring system needing limited invasive data such as a simple blood test and co-morbidity assessment by anamnesis. A retrospective study of 303 patients (203 from Bordeaux University hospital and an external independent cohort of 100 patients from Paris Pitié-Salpêtrière hospital) collected clinical and biochemical parameters at admission. Using stepwise model selection by Akaike Information Criterion (AIC), we built the severity score Covichem. Among 26 tested variables, 7: obesity, cardiovascular conditions, plasma sodium, albumin, ferritin, LDH and CK were the independent predictors of severity used in Covichem (accuracy 0.87, AUROC 0.91). Accuracy was 0.92 in the external validation cohort (89% sensitivity and 95% specificity). Covichem score could be useful as a rapid, costless and easy to implement severity assessment tool during acute COVID-19 pandemic waves

Seropositivity to Herpes Simplex Virus Antibodies and Risk of Alzheimer's Disease: A Population-Based Cohort Study

International audienceBACKGROUND: Herpes Simplex Virus (HSV) infection has been proposed as a possible risk factor of Alzheimer's Disease (AD) notably because it is neurotropic, ubiquitous in the general population and able to establish lifelong latency in the host. The fact that HSV was present in elderly subjects with AD suggests that the virus could be a co-factor of the disease. We investigated the risk of developing AD in anti-HSV immunoglobulin G (IgG) positive subjects (indicator of a lifelong infection to HSV) and IgM-positive subjects (indicator of primary infection or reactivation of the virus) in a longitudinal population-based cohort of elderly subjects living in the community. METHODS: Cox proportional hazard models were used to study the risk of developing AD according to the presence or not of anti-HSV IgG and IgM antibodies, assessed in the sera of 512 elderly initially free of dementia followed for 14 years. RESULTS: During the follow-up, 77 incident AD cases were diagnosed. Controlled for age, gender, educational level and Apolipoprotein E4 (APOE4) status, IgM-positive subjects showed a significant higher risk of developing AD (HR = 2.55; 95% CI [1.38-4.72]), although no significant increased risk was observed in IgG-positive subjects (HR = 1.67; 95%CI [0.75-3.73]). No modification effect with APOE4 status was found. CONCLUSION: Reactivation of HSV seropositivity is highly correlated with incident AD. HSV chronic infection may therefore be contributive to the progressive brain damage characteristic of AD

Ex vivo T-lymphopoiesis assays assisting corrective treatment choice for genetically undefined T-lymphocytopaenia

Persistent selective T-lymphocytopenia is found both in SCID and congenital athymia. Without molecular diagnosis, it is challenging to determine whether HCT or thymus transplantation ought to be performed. Ex vivo T-lymphopoiesis assays have been proposed to assist clinical decision-making for genetically undefined patients. We investigated 20 T-lymphocytopenic patients, including 13 patients awaiting first-line treatment and 7 patients with failed immune reconstitution after previous HCT or thymus transplantation. Whilst developmental blocks in ex vivo T-lymphopoiesis indicated hematopoietic cell-intrinsic defects, successful T-lymphocyte differentiation required careful interpretation, in conjunction with clinical status, immunophenotyping, and genetic investigations. Of the 20 patients, 13 proceeded to treatment, with successful immune reconstitution observed in 4 of the 6 patients post-HCT and 4 of the 7 patients after thymus transplantation, the latter including two patients who had previously undergone HCT. Whilst further validation and standardization are required, we conclude that assessing ex vivo T-lymphopoiesis during the diagnostic pathway for genetically undefined T-lymphocytopenia improves patient outcomes by facilitating corrective treatment choice

Diagnostic prénatal de l infection congénitale à CMV au CHU de Bordeaux (validation d une nouvelle méthode de PCR en temps réel dans le liquide amniotique)

Le Cytomégalovirus (CMV) est l agent étiologique le plus fréquent des infections congénitales, avec une prévalence estimée de 0,5 à 1 % des nouveau-nés. Ce virus est la principale cause de retard mental et de déficit auditif lié aux infections congénitales. Bien que le dépistage ne soit pas recommandé en France, plusieurs circonstances peuvent conduire au diagnostic prénatal (DPN) de l infection. La recherche directe du virus dans le liquide amniotique par Polymerase Chain Reaction (PCR) est un outil de choix. Notre travail a porté sur la validation d une nouvelle méthode de PCR CMV en temps réel dans le liquide amniotique, selon les exigences de la norme NF EN ISO 15189 relative aux Laboratoires de Biologie Médicale concernant la qualité et les compétences. Les différentes étapes de la méthode (extraction, amplification et quantification) ont démontré initialement des performances tout à fait satisfaisantes en termes de spécificité et sensibilité analytique. La validation continue sera assurée par les éléments de suivi des performances mis en place. L interprétation et la validation des résultats est sous la responsabilité du Biologiste Médical autorisé au DPN, et conditionne la suite de la prise en charge de la femme enceinte. Ce travail mené sur plusieurs mois a permis au CHU de Bordeaux de déposer en 2014 auprès de l Agence Régionale de la Santé un dossier de demande d autorisation de DPN de l infection congénitale à CMV par PCR CMV dans le liquide amniotique.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF

Existe-t-il une association entre une ADNémie CMV plasmatique positive et le risque de cancer parmi des patients infectés par le VIH ? (étude cas-témoins nichée au sein de la cohorte Aquitaine ANRS-CO3)

BORDEAUX2-BU Santé (330632101) / SudocSudocFranceF

Variabilité du gèné viral immunomodulateur UL40 parmi les souches cliniques des patients transplantés rénaux

BORDEAUX2-BU Santé (330632101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

[Prevention and screening of cervical cancer].

International audienceCervical cancer may be prevented by human papillomavirus (HPV) vaccination and the treatment of intraepithelial lesions diagnosed using cervical pap smears. HPV vaccines are effective for the prevention of CIN2/3 related to HPV 16, 18 and some other oncogenic HPV subtypes in HPV-naïve women. They are very well tolerated and to date, no increase in the incidence of auto-immune diseases has been reported. HPV vaccines primarily target girls aged 11-14 years old and catch-up programs include girls aged 15-19 years old. Vaccination coverage is below 40% in France, which is insufficient to induce herd immunity. Screening via pap smears is performed every three years in women between 25 and 65 years old, after two normal annual smears. However, screening is an individualised decision and is only performed in 57% of women. Abnormal smears require subsequent diagnostic investigations. Apart from high grade intra-epithelial lesions which generally require treatment, these abnormalities may be observed as they often undergo spontaneous regression due to viral clearance