Les contrôles nécessaires en immunohistochimie : de la recherche au diagnostic

Hippocampal Radial Glial Subtypes and Their Neurogenic Potential in Human Fetuses and Healthy and Alzheimer's Disease Adults

Neuropathological conditions might affect adult granulogenesis in the adult human dentate gyrus. However, radial glial cells (RGCs) have not been well characterized during human development and aging. We have previously described progenitor and neuronal layer establishment in the hippocampal pyramidal layer and dentate gyrus from embryonic life until mid-gestation. Here, we describe RGC subtypes in the hippocampus from 13 gestational weeks (GW) to mid-gestation and characterize their evolution and the dynamics of neurogenesis from mid-gestation to adulthood in normal and Alzheimer's disease (AD) subjects. In the pyramidal ventricular zone (VZ), RGC density declined with neurogenesis from mid-gestation until the perinatal period. In the dentate area, morphologic and antigenic differences among RGCs were observed from early ages of development to adulthood. Density and proliferative capacity of dentate RGCs as well as neurogenesis were strongly reduced during childhood until 5 years, few DCX+ cells are seen in adults. The dentate gyrus of both control and AD individuals showed Nestin+ and/or GFAPδ+ cells displaying different morphologies. In conclusion, pools of morphologically, antigenically, and topographically diverse neural progenitor cells are present in the human hippocampus from early developmental stages until adulthood, including in AD patients, while their neurogenic potential seems negligible in the adult.

Multimodal techniques failed to detect cytomegalovirus in human glioblastoma samples

The role of the human cytomegalovirus (HCMV) in gliomagenesis is largely debated. Contradictory data exist regarding the sensitivity and specificity of HCMV detection techniques, including immunohistochemistry (IHC), in situ hybridization (ISH), and RNA and DNA sequencing. The aim of this study is to detect HCMV in glioblastoma (GBM) tumor samples using IHC, ISH, and real-time PCR (qPCR), as well as to correlate the findings with serological status and HCMV DNA load in blood. Forty-seven patients with histopathological diagnosis of GBM and HCMV serological status were retrospectively reviewed. HCMV DNA quantification in whole blood was performed in 31 patients. The detection of HCMV in tumor samples was performed using IHC in 42 cases, ISH in 10 cases, and qPCR in 29 cases. All but two patients were taking high steroid doses at the time of biological testing. HCMV seroprevalence was 68%. Active infection with HCMV DNA detected in blood was diagnosed in 6 out of 21 (28%) seropositive patients. HCMV was not detected in GBM samples using IHC or ISH, while qPCR was positive in one case (also positive for blood HCMV DNA). These data do not support a crucial role of HCMV in GBM tumorigenesis. HCMV might be reactivated in GBM patients, due to steroid treatment.