Search

Human norovirus (HuNoV) infection is associated with an active FUT2 gene, which characterizes the secretor phenotype. However, nonsecretor individuals are also affected by HuNoV infection although in a lesser proportion. Here, we studied GII.3, GII.4, and GII.17 HuNoV interactions in nonsecretor individuals using virus-like particles (VLPs). Only GII.4 HuNoV specifically interacted with nonsecretor saliva. Competition experiments using histo-blood group antigen (HBGA)-specific monoclonal antibodies (MAbs) demonstrate that GII.4 VLPs recognized the Lewis a (Le(a)) antigen. We also analyzed HuNoV VLP interactions on duodenum tissue blocks from healthy nonsecretor individuals. VLP binding was observed for the three HuNoV genotypes in 10 of the 13 individuals, and competition experiments demonstrated that VLP recognition was driven by an interaction with the Le(a) antigen. In 3 individuals, binding was restricted to either GII.4 alone or GII.3 and GII.17. Finally, we performed a VLP binding assay on proximal and distal colon tissue blocks from a nonsecretor patient with Crohn’s disease. VLP binding to inflammatory tissues was genotype specific since GII.4 and GII.17 VLPs were able to interact with regenerative mucosa, whereas GII.3 VLP was not. The binding of GII.4 and GII.17 HuNoV VLPs was linked to Le(a) in regenerative mucosae from the proximal and distal colon. Overall, our data clearly showed that Le(a) has a pivotal role in the recognition of HuNoV in nonsecretors. We also showed that Le(a) is expressed in inflammatory/regenerative tissues and interacts with HuNoV in a nonsecretor individual. The physiological and immunological consequences of such interactions in nonsecretors have yet to be elucidated. IMPORTANCE Human norovirus (HuNoV) is the main etiological agent of viral gastroenteritis in all age classes. HuNoV infection affects mainly secretor individuals where ABO(H) and Lewis histo-blood group antigens (HBGAs) are present in the small intestine. Nonsecretor individuals, who only express Lewis (Le) antigens, are less susceptible to HuNoV infection. Here, we studied the interaction of common HuNoV genotypes (GII.3, GII.4, and GII.17) in nonsecretor individuals using synthetic viral particles. Saliva binding assays showed that only GII.4 interacted with nonsecretor saliva via the Lewis a (Le(a)) antigen Surprisingly, the three genotypes interacted with nonsecretor enterocytes via the Le(a) antigen on duodenal tissue blocks, which were more relevant for HuNoV/HBGA studies. The Le(a) antigen also played a pivotal role in the recognition of GII.4 and GII.17 particles by inflammatory colon tissue from a nonsecretor Crohn’s disease patient. The implications of HuNoV binding in nonsecretors remain to be elucidated in physiological and pathological conditions encountered in other intestinal diseases.

Resume Introduction Afin de valider notre strategie d’amelioration continue et chercher d’eventuelles nouvelles pistes pour une performance accrue, nous avons audite l’ensemble des processus du service en utilisant les principes du lean management. Materiel et methodes L’application de la methodologie Lean-6-sigma (Gemba Walk, Value Stream Mapping, diagramme spaghetti, atelier Kaizen et matrice de priorisation) a permis d’analyser les processus des secteurs conventionnels et moleculaires, de definir les goulets d’etranglement, d’evaluer les actions sans valeur ajoutee et de proposer des solutions. Resultats L’audit a identifie les principaux goulets d’etranglement qui interessaient les secteurs pre-analytique (enregistrement), analytique (cytologie, immunohistochimie, sequencage, pathologistes) et post-analytique (absence de secretaire et diffusion du courrier). Il a souligne une marche en avant insuffisante, l’impact important de l’augmentation de la charge de travail (8 %/an) sur la reception et la microscopie malgre l’externalisation et une maquette de postes techniques souvent critique qui ne permettait pas de realiser des taches sans valeur ajoutee (qualite, validation de methodes, protocoles) et parfois quotidiennes (coupes, immunohistochimie). Au terme des 72 tâches du plan d’action pour gerer la surproduction, l’amelioration des conditions de travail et le developpement de nouvelles activites, les delais de reponse sont partiellement maitrises et notre demarche d’automatisation bien avancee. Discussion et conclusion L’audit a valide notre strategie d’amelioration et mieux standardise nos conditions de travail. Meme s’il n’a permis qu’une maitrise partielle des delais de reponse, il a initie une dynamique medicale et technique positive vertueuse pour continuer a avancer vers les prochaines etapes de notre reorganisation (automatisation, agrandissement du service).

Human norovirus (HuNoV) infection is associated with active FUT2 status, which characterizes the secretor phenotype. However, non-secretor individuals are also affected by HuNoV infection although in a lesser proportion. Here, we study GII.3, GII.4 and GII.17 HuNoV interactions in non-secretor individuals using baculovirus-expressed virus-like particles (VLPs). Only GII.4 HuNoV specifically interacted with non-secretor saliva. Competition experiments using HBGA-specific mAbs demonstrate that GII.4 VLPs recognized the Lewis a antigen (Lea). We also analyzed HuNoV VLP interactions on duodenum tissue blocks from healthy non-secretor individuals. VLP binding was observed for the three HuNoV genotypes in 10 of the 13 individuals, and competition experiments demonstrated that VLP recognition was driven by interaction with the Lea antigen. In 3 individuals, binding was restricted to either GII.4 alone or GII.3 and GII.17. One patient did not display VLP binding for any of the three genotypes.Finally, we performed a VLP binding assay on proximal and distal colon tissue blocks from a non-secretor patient with Crohn’s disease. VLP binding to inflammatory tissues was genotype-specific since GII.4 and GII.17 VLPs were able to interact with regenerative mucosa whereas GII.3 VLP was not. Binding of GII.4 and GII.17 HuNoV VLPs was linked to Lea in regenerative mucosae from the proximal and distal colon. Overall, our data clearly showed that Lea has a pivotal role in the recognition of HuNoV in non-secretors. We also showed that Lea is expressed in inflammatory/regenerative tissues and that it can interact with HuNoV in secretor and non-secretor individuals. The physiological and immunological consequences of such interactions in non-secretors has yet to be elucidated.IMPORTANCEHuman norovirus (HuNoV) is the main etiological agent of viral gastroenteritis in all age classes. HuNoV infection mainly affects secretor individuals, who are characterized by the presence of the ABO(H) and Lewis histo-blood group antigens at the surface of the small intestine. Non-secretor individuals, who only express Lewis antigens (Le), are less susceptible to HuNoV infection. Here we study the interaction of three frequently encountered HuNoV genotypes (GII.3, GII.4 and GII.17) in non-secretor individual using baculovirus-expressed viral particles. Preliminary saliva binding assays showed that only GII.4 interacted with non-secretor saliva via the Lea antigen.Surprisingly, in the binding assays on duodenal tissue blocks, the three genotypes interacted with non-secretor enterocytes via Lea. This suggests that HBGA status in the saliva does not necessarily reflect interactions in the intestines and, secondly, that Lea plays a pivotal role in HuNoV attachment in non-secretors. Similarly, Lea was involved in the recognition of GII.4 and GII.17 HuNoV particles by inflammatory colon tissue from a non-secretor Crohn’s disease patient. The molecular implications of HuNoV binding in non-secretors remains to be elucidated in physiological and pathological conditions encountered in other intestinal diseases.

Background The recent COVID-19 pandemic has raised concerns about patient diagnosis and follow-up of chronically ill patients. Patients suffering from chronic illnesses, concomitantly infected by SARS-CoV-2, globally tend to have a worse prognosis and poor outcomes. Renal tropism and acute kidney injury following SARS-CoV-2 infection has recently been described in the literature, with elevated mortality rates. Furthermore, patients with pre-existing chronic kidney disease, infected by SARS-CoV-2, should be monitored carefully. Here, we report the case of a 69-year-old patient with splenic marginal zone lymphoma, suffering from longstanding chronic kidney disease following SARS-CoV-2 infection. Case presentation A 69-year-old male patient previously diagnosed with pulmonary embolism and splenic marginal zone lymphoma (Splenomegaly, Matutes 2/5, CD5 negative and CD23 positive), was admitted to the hospital with shortness of breath, fever and asthenia. A nasopharyngeal swab test was performed in addition to a CT-scan, which confirmed SARS-CoV-2 infection. Blood creatinine increased following SARS-CoV-2 infection at 130 μmol/l, with usual values at 95 μmol/l. The patient was discharged at home with rest and symptomatic medical treatment (paracetamol and hydration), then readmitted to the hospital in August 2020. A kidney biopsy was therefore conducted as blood creatinine levels were abnormally elevated. Immunodetection performed in a renal biopsy specimen confirmed co-localization of SARS-CoV2 nucleocapsid and protease 3C proteins with ACE2, Lewis x and sialyl-Lewis x antigens in proximal convoluted tubules and podocytes. Co-localization of structural and non-structural viral proteins clearly demonstrated viral replication in proximal convoluted tubules in this chronically ill patient. Additionally, we observed the co-localization of sialyl-Lewis x and ACE2 receptors in the same proximal convoluted tubules. Reverse Transcriptase-Polymerase Chain Reaction test performed on the kidney biopsy was negative, with very low Ct levels (above 40). The patient was finally readmitted to the haematology department for initiation of chemotherapy, including CHOP protocol and Rituximab. Conclusions Our case emphasizes on the importance of monitoring kidney function in immunosuppressed patients and patients suffering from cancer following SARS-CoV-2 infection, through histological screening. Further studies will be required to decipher the mechanisms underlying chronic kidney disease and the putative role of sialyl-Lewis x and HBGA during SARS-CoV-2 infection.

In order to validate our strategy of continuous improvement and to identify new ways to increase performance, an evaluation of all the procedures was conducted in our department using the principles of lean management.Lean-6-sigma methodology (Gemba Walk, Value StreamMapping, spaghetti diagram, Kaizen workshop and priorization matrix) was used to analyze the procedures of the conventional and molecular sectors, and to identify bottlenecks, actions without added value and solutions.The audit identified bottlenecks in pre-analytical (registration), analytical (cytology, immunohistochemistry, sequencing, pathologists) and post-analytical processes (absence of secretaries, delivery of reports by mail). It underlined a suboptimal flow of people and materials, the heavy impact of an increasing work load (8%/year) in reception and microscopy even though we had outsourced, and an often critical work place schedule for technicians which prevent them from achieving tasks without added value (quality control, validation of methods and protocols) or even daily tasks (cutting, immunohistochemistry). After completing the 72 actions aimed at managing overproduction, improving working conditions and developing new activities, turn-around time was partially under control and the automation process was well advanced.The audit validated our strategy of continuous improvement and advanced the standardization of our working conditions. Even if the turn-around time for reports was shortened, the audit initiated a positive medical and technical dynamic that should help us to implement the next steps of our reorganization (automation and extension of the department).