Dengue virus (DENV) is an important mosquito borne-flavivirus that causes dengue fever and in some heterotypic secondary infections, haemorrhagic symptoms that might risk the lives of patients. These epidemiologic observations were made 50 years ago, suggest that the previous immune response to DENV could be involved in the pathology of the disease. Nowadays, it has been shown that the DENV specific antibodies are participating through a mechanism called antibody-dependent enhancement (ADE). The cellular bases of how these antibodies are generated in secondary lymphoid organs remain largely unexplored. In this issue, Marcial-Juárez et al., demonstrated massive B cell proliferation inside regional lymph node follicles after cutaneous DENV immunization in mice and, contrastingly, a very poor T cell response. The cover image shows a panoramic view of a lymph node, with intense recruitment of tingle-body macrophages (TBMs, green) inside DENV-induced germinal centers (IgD [red]-negative areas in the cortex) to remove the large number of apoptotic bodies present in regional lymph node follicles. Please see 575-587 pages for details.
Although norovirus, rotavirus, adenovirus and Astrovirus are considered the most important viral agents transmitted by food and water, in recent years other viruses, such as Aichi virus (AiV), have emerged as responsible for gastroenteritis outbreaks associated with different foods. AiV belongs to the genus Kobuvirus of the family Picornaviridae. It is a virus with icosahedral morphology that presents a single stranded RNA genome with positive sense (8280 nucleotides) and a poly (A) chain. AiV was first detected from clinical samples and in recent years has been involved in acute gastroenteritis outbreaks from different world regions. Furthermore, several studies conducted in Japan, Germany, France, Tunisia and Spain showed a high prevalence of AiV antibodies in adults (between 80% and 99%), which is indicative of a large exposure to this virus. The aim of this review is to bring together all the discovered information about the emerging pathogen human Aichi virus (AiV), discussing the possibles routes of transmission, new detection techniques and future research. Although AiV is responsible for a low percentage of gastroenteritis outbreaks, the high seroprevalence shown by human populations indicates an evident role as an enteric agent. The low percentage of AiV detection could be explained by the fact that the pathogen is more associated to subclinical infections. Further studies will be needed to clarify the real impact of AiV in human health and its importance as a causative gastroenteritis agent worldwide.
Hepatitis C virus (HCV) is still one of the main causes of liver disease worldwide. Metabolic disorders, including non-alcoholic fatty liver disease (NAFLD), induced by HCV have been shown to accelerate the progression of fibrosis to cirrhosis and to increase the risk of hepatocellular carcinoma. An optimal peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1A) activity is crucial to prevent NAFLD installation. The present study aims to investigate the associations between two common PPARGC1A polymorphisms (rs8192678 and rs12640088) and the outcomes of HCV infection in a North African context. A series of 592 consecutive Moroccan subjects, including 292 patients with chronic hepatitis C (CHC), 100 resolvers and 200 healthy controls were genotyped using a TaqMan allelic discrimination assay. PPARGC1A variations at rs8192678 and rs12640088 were not associated with spontaneous clearance of HCV infection (adjusted ORs = 0.76 and 0.79 respectively, P > 0.05, for both). Furthermore, multivariable logistic regression analysis showed that both SNPs were not associated with fibrosis progression (OR = 0.71; 95% CI 0.20–2.49; P = 0.739; OR = 1.28; 95% CI 0.25–6.54; P = 0.512, respectively). We conclude that, in the genetic context of South Mediterranean patients, rs8192678 and rs12640088 polymorphisms of PPARGC1A are neither associated with spontaneous clearance nor with disease progression in individuals infected with HCV.
Dengue is a global health problem without current specific treatment nor safe vaccines available. While severe dengue is related to pre-existing non-neutralizing dengue virus (DENV) antibodies, the role of T cells in protection or pathology is unclear. Using cutaneous DENV infection in immunocompetent mice we previously showed the generation of PNA+ germinal centers (GCs), now we assessed the activation and proliferation of B and T cells in draining lymph nodes (DLNs). We found a drastic remodelling of DLN compartments from 7 to 14 days post-infection (dpi) with greatly enlarged B cell follicles, occupying almost half of the DLN area compared to ~24% in naïve conditions. Enormous clusters of proliferating (Ki-67+) cells inside B follicles were found 14 dpi, representing ~33% of B cells in DLNs but only ~2% in non-infected mice. Inside GCs, we noticed an important recruitment of tingle body macrophages removing apoptotic cells. In contrast, the percentage of paracortex area and total T cells decreased by 14–16 dpi, compared to controls. Scattered randomly distributed Ki-67+ T cells were found, similar to non-infected mice. CD69 expression by CD4+ and CD8+ T cells was minor, while it was remarkable in B cells, representing 1764.7% of change from basal levels 3 dpi. The apparent lack of T cell responses cannot be attributed to apoptosis since no significant differences were observed compared to non-infected mice. This study shows massive B cell activation and proliferation in DLNs upon DENV infection. In contrast, we found very poor, almost absent CD4+ and CD8+ T cell responses.
由鸭甲型肝炎病毒(Duck hepatitis A virus,DHAV)引起的鸭肝炎是一种雏鸭的急性烈性传染病,呈全球性分布严重威胁养鸭业。本研究开发了一种SYBR Green I实时定量RT-PCR检测方法,使用1对引物扩增并通过扩增产物的熔解曲线分析可同时检测和区分1型和3型DHAV。特异性实验证实针对病毒5'非翻译区(UTR)的引物具有高度特异性,与其他常见鸭病毒病,如鸭星状病毒(DAstV),禽流感病毒(AIV),鸭呼肠孤病毒(DRV),鸭病毒肠炎病毒(DEV)和鸭细小病毒(DPV)均无交叉反应。灵敏性实验证实该方法对1型和3型DHAV的检测限均为100拷贝。使用40个临床样本对比测试发现该方法与常规RT-PCR具有100%的吻合度。结果表明,我们建立了一种针对DHAV的新型荧光定量检测方法,采用1对引物可同时鉴定和区分1型和3型DHAV的感染情况。