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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.