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The French Society of Clinical Biology (SFBC) set up a working group “Biochemical markers of Covid-19” whose main objective is to review, analyse and monitor biological prescriptions according to the patient’s care path. This study covers all public and private sectors of medical biology in metropolitan France and overseas and extends to the French-speaking world. We present a summary of feedbacks after 2 years of the pandemic. At the early stage of Covid-19, with regard to the regions surveyed, a common symptomatology with local zoonosis (dengue fever, zika, malaria, leptospirosis, etc.) complicates the diagnosis of Covid-19. At a more advanced stage, it is a question of managing an influx of patients suffering from acute respiratory distress syndrome. In this case, the biology is then simpler and delocalized medical biology devices have proven their effectiveness. As a result, ICU clinicians can better manage the frequent comorbidities encountered in these regions: obesity, diabetes, chronic renal failure, cardiovascular diseases.La Société française de biologie clinique (SFBC) a mis en place un groupe de travail « Marqueurs biochimiques de Covid-19 » dont l’objectif principal est de revoir, d’analyser et de suivre les prescriptions biologiques en fonction du parcours de soins du patient. Cette étude couvre tous les secteurs publics et privés de la biologie médicale en métropole et en Outre-mer et s’étend à la Francophonie. Nous présentons une synthèse des retours d’expériences après 2 ans de pandémie. Au stade précoce de la Covid-19, pour les régions interrogées, une symptomatologie commune avec des zoonoses locales (dengue, zika, paludisme, leptospirose…) complique le diagnostic de la Covid-19. À un stade plus avancé, il s’agit de gérer un afflux de patients atteints de syndrome de détresse respiratoire aiguë. La biologie est alors plus simple, et les dispositifs de biologie médicale délocalisée ont prouvé leur efficacité. De ce fait, les réanimateurs peuvent mieux gérer les comorbidités fréquentes rencontrées dans ces régions : obésité, diabète, insuffisance rénale chronique ou maladies cardiovasculaires.

BACKGROUND Among young consumers of cannabis, a brief psychotic disorder (BPD) can be either the clinical manifestation of acute cannabis psychosis (ACP) or an announcement of schizophrenia’s onset. Clinicians are faced with the difficulty of making a differential diagnosis between disorders of the schizophrenic field and disorders induced by cannabis. To date, no clinical or even less paraclinical criteria have made it possible to differentiate syndromes whose prognoses and management are different. OBJECTIVE We wanted to determine if these patients, cannabis users, suffering from BPD, present particular phenotypes of capillary cannabinoid concentrations (THC and CBD). In other words, it would be possible to make a first diagnosis just after the initial psychiatric evaluation, thus making it possible to overcome a significant delay (3–6 months), delaying the most appropriate care. Appropriate care and early therapeutic management are important if the pathology responsible for mental disorders is chronic psychosis. METHODS Since 2010, we measured delta-9 tetrahydrocannabinol (THC) and cannabidiol (CBD) concentrations in head hair among New Caledonian patients, all cannabis consumers (n = 256). At the time of initial psychiatric consultation, a sample of 3 cm proximal length of head hair was prepared for analysis, and THC and CBD were then assayed by Gas Chromatography coupled with Mass Spectrometry (Limit Of Quantitation: 0.05 ng/mg). At the end of the 6 months medico-psychologic follow-up from the initial evaluation, four groups of cannabis users were identified according to the final psychiatric diagnosis: control, acute cannabis psychosis (ACP), chronic psychosis (CP), and other personality disorders (OPD) groups. RESULTS In this study, a high hair level of THC detected (> 0.7 ng/mg) associated with a low hair CBD/THC ratio (< 0.26) are two parameters that taken together could be good markers of CP development. For OPD and ACP, hair CBD/THC ratios were higher in the ACP group (> 0.43) than in the OPD group (< 0.32). CONCLUSIONS This study highlights, once again, the protective role of CBD against the deleterious effects of THC. In association with clinical evaluation, this toxicological approach could be helpful for psychiatric diagnosis and would allow early management of BPD in cannabis consumers. For a consumer who does not present with a psychiatric disorder, it could give an information about the possibility of belonging to a group of patients at high risk of psychiatric decompensation. This provides an additional argument for efforts to control cannabis consumption by patients.

Among young consumers of cannabis, a brief psychotic disorder (BPD) can be either the clinical manifestation of acute cannabis psychosis (ACP) or an announcement of schizophrenia’s onset. Clinicians are faced with the difficulty of making a differential diagnosis between disorders of the schizophrenic field and disorders induced by cannabis. To date, no clinical or even less paraclinical criteria have made it possible to differentiate syndromes whose prognoses and management are different. Since 2010, we measured delta-9 tetrahydrocannabinol (THC) and cannabidiol (CBD) concentrations in head hair among New Caledonian patients, all cannabis consumers (n = 256). We wanted to determine if these patients, cannabis users, suffering from different mental pathologies, present particular phenotypes of capillary cannabinoid concentrations (THC and CBD). At the time of initial psychiatric consultation, a sample of 3 cm proximal length of head hair was prepared for analysis, and THC and CBD were then assayed by Gas Chromatography coupled with Mass Spectrometry (Limit Of Quantitation: 0.05 ng/mg). At the end of the 6 months medico-psychologic follow-up from the initial evaluation, four groups of cannabis users were identified according to the final psychiatric diagnosis: control, acute cannabis psychosis (ACP), chronic psychosis (CP), and other personality disorders (OPD) groups. In this study, a high hair level of THC detected (> 0.7 ng/mg) associated with a low hair CBD/THC ratio (< 0.26) are two parameters that taken together could be good markers of CP development. For OPD and ACP, hair CBD/THC ratios were higher in the ACP group (> 0.43) than in the OPD group (< 0.32). This study highlights, once again, the protective role of CBD against the deleterious effects of THC. In association with clinical evaluation, this toxicological approach could be helpful for psychiatric diagnosis and would allow early management of BPD in cannabis consumers. For a consumer who does not present with a psychiatric disorder, it could give an information about the possibility of belonging to a group of patients at high risk of psychiatric decompensation. This provides an additional argument for efforts to control cannabis consumption by patients.

The French society of clinical biology "Biochemical markers of COVID-19" has set up a working group with the primary aim of reviewing, analyzing and monitoring the evolution of biological prescriptions according to the patient's care path and to look for markers of progression and severity of the disease. This study covers all public and private sectors of medical biology located in metropolitan and overseas France and also extends to the French-speaking world. This article presents the testimonies and data obtained for the "Overseas and French-speaking countries" sub-working group made up of 45 volunteer correspondents, located in 20 regions of the world. In view of the delayed spread of the SARS-CoV-2 virus, the overseas regions and the French-speaking regions have benefited from feedback from the first territories confronted with COVID-19. Thus, the entry of the virus or its spread in epidemic form could be avoided, thanks to the rapid closure of borders. The overseas territories depend very strongly on air and/or sea links with the metropolis or with the neighboring continent. The isolation of these countries is responsible for reagent supply difficulties and has necessitated emergency orders and the establishment of stocks lasting several months, in order to avoid shortages and maintain adequate patient care. In addition, in countries located in tropical or intertropical zones, the diagnosis of COVID-19 is complicated by the presence of various zoonoses (dengue, Zika, malaria, leptospirosis, etc.).

Trehalose polyphleates (TPP) are high-molecular-weight, surface-exposed glycolipids present in a broad range of nontuberculous mycobacteria. These compounds consist of a trehalose core bearing polyunsaturated fatty acyl substituents (called phleic acids) and a straight-chain fatty acid residue and share a common basic structure with trehalose-based glycolipids produced byMycobacterium tuberculosis. TPP production starts in the cytosol with the formation of a diacyltrehalose intermediate. An acyltransferase, called PE, subsequently catalyzes the transfer of phleic acids onto diacyltrehalose to form TPP, and an MmpL transporter promotes the export of TPP or its precursor across the plasma membrane. PE is predicted to be an anchored membrane protein, but its topological organization is unknown, raising questions about the subcellular localization of the final stage of TPP biosynthesis and the chemical nature of the substrates that are translocated by the MmpL transporter. Here, using genetic, biochemical, and proteomic approaches, we established that PE ofMycobacterium smegmatisis exported to the cell envelope following cleavage of its signal peptide and that this process is required for TPP biosynthesis, indicating that the last step of TPP formation occurs in the outer layers of the mycobacterial cell envelope. These results provide detailed insights into the molecular mechanisms controlling TPP formation and transport to the cell surface, enabling us to propose an updated model of the TPP biosynthetic pathway. Because the molecular mechanisms of glycolipid production are conserved among mycobacteria, these findings obtained with PE fromM. smegmatismay offer clues to glycolipid formation inM. tuberculosis.