Breakthrough infections due to SARS-CoV-2 Delta variant: relation to humoral and cellular vaccine responses

IntroductionCOVID-19 vaccines are expected to provide effective protection. However, emerging strains can cause breakthrough infection in vaccinated individuals. The immune response of vaccinated individuals who have experienced breakthrough infection is still poorly understood.MethodsHere, we studied the humoral and cellular immune responses of fully vaccinated individuals who subsequently experienced breakthrough infection due to the Delta variant of SARS-CoV-2 and correlated them with the severity of the disease.ResultsIn this study, an effective humoral response alone was not sufficient to induce effective immune protection against severe breakthrough infection, which also required effective cell-mediated immunity to SARS-CoV-2. Patients who did not require oxygen had significantly higher specific (p=0.021) and nonspecific (p=0.004) cellular responses to SARS-CoV-2 at the onset of infection than those who progressed to a severe form.DiscussionKnowing both humoral and cellular immune response could allow to adapt preventive strategy, by better selecting patients who would benefit from additional vaccine boosters.Trial registration numbershttps://clinicaltrials.gov, identifier NCT04355351; https://clinicaltrials.gov, identifier NCT04429594

Hidroxicloroquina e azitromicina como tratamento do COVID-19: resultados de um ensaio clínico aberto não randomizado

Background Chloroquine and hydroxychloroquine have been found to be efficient on SARS-CoV-2, and reported to be efficient in Chinese COV-19 patients. We evaluate the role of hydroxychloroquine on respiratory viral loads. Patients and methods French Confirmed COVID-19 patients were included in a single arm protocol from early March to March 16th, to receive 600mg of hydroxychloroquine daily and their viral load in nasopharyngeal swabs was tested daily in a hospital setting. Depending on their clinical presentation, azithromycin was added to the treatment. Untreated patients from another center and cases refusing the protocol were included as negative controls. Presence and absence of virus at Day6-post inclusion was considered the end point. Results Six patients were asymptomatic, 22 had upper respiratory tract infection symptoms and eight had lower respiratory tract infection symptoms. Twenty cases were treated in this study and showed a significant reduction of the viral carriage at D6-post inclusion compared to controls, and much lower average carrying duration than reported of untreated patients in the literature. Azithromycin added to hydroxychloroquine was significantly more efficient for virus elimination. Conclusion Despite its small sample size our survey shows that hydroxychloroquine treatment is significantly associated with viral load reduction/disappearance in COVID-19 patients and its effect is reinforced by azithromycin.Contexto Verificou-se que a cloroquina e a hidroxicloroquina são eficientes no tratamento de SARS-CoV-2, e foram reportadas serem eficientes em pacientes chineses com COV-19. Nós avaliamos o papel da hidroxicloroquina na carga viral respiratória. Pacientes e Métodos Pacientes franceses com COVID-19 confirmada foram incluídos em um protocolo de braço único, do começo de março até 16 de março, para receber 600mg de hidroxicloroquina diariamente e as cargas virais em swabs de nasofaringe foram testadas diariamente no ambiente hospitalar. Dependendo da apresentação clínica, a azitromicina era adicionada ao tratamento. Pacientes não tratados de outros centros e casos que recusaram o protocolo foram incluídos como controles negativos. A presença ou a ausência do vírus no sexto dia pós inclusão foram consideradas os desfechos. Resultados Seis pacientes eram assintomáticos, vinte e dois tinham sintomas de infecção de trato respiratório superior e oito tinham sintomas de trato respiratório inferior. Vinte casos foram tratados neste estudo e mostraram uma redução significativa da carga viral no sexto dia após a inclusão em comparação com os controles, e uma duração da condição de portador muito menor do que a média reportada na literatura em pacientes não tratados. A azitromicina adicionada à hidroxicloroquina foi significantemente mais eficiente para a eliminação viral. Conclusão Apesar do tamanho pequeno da amostra, nossa pesquisa mostra que o tratamento com hidroxicloroquina é significantemente associada com redução/desaparecimento da carga viral em pacientes com COVID-19, e seu efeito é reforçado pela azitromicina

NLRP3 activation during S. aureus or E. coli bacteremia and in the course of SARS-CoV-2 infection

A la phase précoce d’une infection bactérienne ou virale l’immunité innée est capable de détecter certains motifs microbiens conservés (PAMP) reconnus par des récepteurs dédiés à ces motifs (PRR) permettant ainsi d’amorcer la réaction pro-inflammatoire via différentes voies de signalisation. Les inflammasomes représentent une catégorie de PRR capable de transformer la pro-IL-1β et la pro-IL-18 en cytokines pro-inflammatoires actives ainsi que d’induire une mort cellulaire pro-inflammatoire nommée pyroptose. NLRP3 est l’inflammasome le plus étudié. De nombreuses bactéries et de nombreux virus ont été décrits comme pouvant soit activer soit inhiber l’inflammasome NLRP3 mais l’implication clinique de cette activation ou inhibition, reste pour le moment indéterminée. L’objectif de ma thèse était d’étudier l’implication de l’inflammasome NLRP3 au cours de la bactériémie chez l’homme. L’apparition de l’épidémie de COVID-19 nous a permis d’élargir cette étude à l’infection par le SARS-CoV-2. Le protocole NLRP3-BACT nous a permis de mettre en œuvre un test cellulaire à partir du sang total afin d’évaluer le niveau d’activation de la Caspase-1 dans les monocytes et polynucléaires neutrophiles (PNN) ainsi que le potentiel d’activation de l’inflammasome NLRP3 dans ces cellules chez des patients présentant une bactériémie à S. aureus ou E. coli via une analyse par cytométrie en flux (signal FAM-FLICA).Le protocole CoVinnate avait pour objectif l’utilisation du test cellulaire précédemment mentionné afin de décrire l’activation d’une partie du système immunitaire inné dans les différentes cellules myéloïdes circulantes des patients COVID-19 ainsi que l’évaluation de ce test en tant qu’outil pronostique.Pour NLRP3-BACT 22 patients ont été inclus depuis le début de de l’étude, 16 ont bénéficié d’une analyse cytométrique. Dans cette première série de patients inclus nous avons mis en évidence que les monocytes présentent un potentiel d’activation de la Caspase-1 par Nigéricine+LPS plus important que les donneurs sains. Par ailleurs, l’activation basale de cette caspase dans les monocytes est plus importante chez les patients de réanimation et ceux infectés par E. coli. Enfin la multiplication de la MFI du signal FAM-FLICA induite par Nigéricine+LPS est plus important pour les patients de médecine comparativement aux patients de réanimation.Pour CoVinnate, 66 patients COVID-19 et 24 donneurs sains ont été inclus durant la période de l’étude. Dans les cellules CD66b+ CD16dim nous avons observé une diminution significative du signal de la sonde FAM-FLICA chez les patients les plus sévères comparativement aux témoins. Au sein des granulocytes, l’activation de la Caspase-1 induite par la Nigéricine était altérée dans les granulocytes CD66b+ CD16dim selon le degré de sévérité des patients. Nous avons enregistré une augmentation de l’activation de NLRP3 induite par la Nigéricine dans les monocytes non-classiques isolés chez les patients les plus graves, cet effet était inversement corrélé au nombre total de monocytes non-classiques. Chez les patients les plus sévères on notait une augmentation du nombre de cellules CD66b+CD16dimCD15+CD10- correspondant à des neutrophiles immatures. Nous avons utilisé la diminution des monocytes non-classiques et le défaut d’activation de NLRP3 par la Nigéricine des granulocytes CD66b+ CD16dim pour construire un score pronostique. Nous avons mis en évidence une corrélation entre ce score et le rapport SpO2 / FiO2 le jour de l’inclusion ainsi que 48 heures plus tard. Nous avons également constaté une association significative de ces deux marqueurs avec l’évolution finale des patients. Mon travail a permis de mieux comprendre l’implication de l’inflammasome NLRP3 chez l’homme au cours de la bactériémie et durant l’infection à SARS-CoV-2. Nous envisageons d’utiliser ces travaux pour caractériser la réponse des patients aux traitements immunomodulateurs utilisés dans la COVID-19 notamment les corticoïdes.At the early phase of bacterial or viral infections, innate immunity is able to detect some conserved microbial motifs (PAMP) recognized by receptors dedicated to these motifs (PRR), thus making it possible to initiate the pro-inflammatory reaction via different signaling pathways. Inflammasomes represent a family of PRR able to transform pro-IL-1β and pro-IL-18 into active pro-inflammatory cytokines as well as inducing a pro-inflammatory cell death called pyroptosis. NLRP3 is the most studied inflammasome. Many bacteria and viruses have been described as being able to either activate or inhibit the NLRP3 inflammasome, but the clinical implication of this activation or inhibition, under the control of a particular microorganism, remains undetermined at this time.The objective of my thesis was to study the involvement of the NLRP3 inflammasome during bacteremia in humans. The onset of the COVID-19 epidemic allowed us to expand this study to SARS-CoV-2 infection.The NLRP3-BACT protocol allowed us to implement a cellular test performed on whole blood to assess the level of Caspase-1 activation in monocytes and polymorphonuclear neutrophils (PMN) as well as the activation potential of the NLRP3 inflammasome in these cells in patients with S. aureus or E. coli bacteremia via flow cytometry (fluorescent inhibitor probe, FAM-FLICA).The objective of the CoVinnate protocol was to use the aforementioned cellular test to describe the activation of a part of the innate immune system in the various circulating myeloid cells of COVID-19 patients as well as the evaluation of this test as a prognostic tool.For NLRP3-BACT 22 patients have been included since the start of the study, 16 have undergone cytometric analysis. In this first series of patients included, we demonstrated that monocytes have a greater potential for Caspase-1 activation by Nigericin+LPS than healthy donors. In addition, basal activation of this caspase in monocytes is greater in intensive care patients and in those infected with E. coli compared to the ID ward and S. aureus respectively. Finally, the multiplication of the MFI of the FAM-FLICA signal induced by Nigericin + LPS is more important for medical patients compared to intensive care patients.For CoVinnate, 66 COVID-19 patients and 24 healthy donors were included during the study period. In CD66b+ CD16dim cells, we observed a significant decrease of the FAM-FLICA probe signal in the most severe patients compared to the controls. Within granulocytes, the activation of Caspase-1 induced by Nigericin was decreased in CD66b+ CD16dim cells according to the severity of the patients. We recorded an increase in Nigericin-induced activation of NLRP3 in non-classical monocytes isolated from the most severe patients, this effect was inversely correlated with the total number of non-classical monocytes. In the most severe patients there was an increase in the number of CD66b+CD16dimCD15+CD10- cells corresponding to immature neutrophils.We used the decreased number in non-classical monocytes and the failure of NLRP3 activation upon nigericin activation in CD66b + CD16dim granulocytes to build a prognostic score. We found a correlation between this score and the SpO2 / FiO2 ratio on the day of inclusion as well as 48 hours later. We also found a significant association of these two markers with the final outcome of the patients.My work has led to a better understanding of the involvement of the NLRP3 inflammasome in humans during bacteremia and during SARS-CoV-2 infection. We plan to use this work to characterize the response of patients to immunomodulatory treatments used in COVID-19, including corticosteroids

Activation de l’inflammasome NLRP3 au cours des bactériémies à E. coli ou S. aureus et durant l’infection à SARS-CoV-2

At the early phase of bacterial or viral infections, innate immunity is able to detect some conserved microbial motifs (PAMP) recognized by receptors dedicated to these motifs (PRR), thus making it possible to initiate the pro-inflammatory reaction via different signaling pathways. Inflammasomes represent a family of PRR able to transform pro-IL-1β and pro-IL-18 into active pro-inflammatory cytokines as well as inducing a pro-inflammatory cell death called pyroptosis. NLRP3 is the most studied inflammasome. Many bacteria and viruses have been described as being able to either activate or inhibit the NLRP3 inflammasome, but the clinical implication of this activation or inhibition, under the control of a particular microorganism, remains undetermined at this time.The objective of my thesis was to study the involvement of the NLRP3 inflammasome during bacteremia in humans. The onset of the COVID-19 epidemic allowed us to expand this study to SARS-CoV-2 infection.The NLRP3-BACT protocol allowed us to implement a cellular test performed on whole blood to assess the level of Caspase-1 activation in monocytes and polymorphonuclear neutrophils (PMN) as well as the activation potential of the NLRP3 inflammasome in these cells in patients with S. aureus or E. coli bacteremia via flow cytometry (fluorescent inhibitor probe, FAM-FLICA).The objective of the CoVinnate protocol was to use the aforementioned cellular test to describe the activation of a part of the innate immune system in the various circulating myeloid cells of COVID-19 patients as well as the evaluation of this test as a prognostic tool.For NLRP3-BACT 22 patients have been included since the start of the study, 16 have undergone cytometric analysis. In this first series of patients included, we demonstrated that monocytes have a greater potential for Caspase-1 activation by Nigericin+LPS than healthy donors. In addition, basal activation of this caspase in monocytes is greater in intensive care patients and in those infected with E. coli compared to the ID ward and S. aureus respectively. Finally, the multiplication of the MFI of the FAM-FLICA signal induced by Nigericin + LPS is more important for medical patients compared to intensive care patients.For CoVinnate, 66 COVID-19 patients and 24 healthy donors were included during the study period. In CD66b+ CD16dim cells, we observed a significant decrease of the FAM-FLICA probe signal in the most severe patients compared to the controls. Within granulocytes, the activation of Caspase-1 induced by Nigericin was decreased in CD66b+ CD16dim cells according to the severity of the patients. We recorded an increase in Nigericin-induced activation of NLRP3 in non-classical monocytes isolated from the most severe patients, this effect was inversely correlated with the total number of non-classical monocytes. In the most severe patients there was an increase in the number of CD66b+CD16dimCD15+CD10- cells corresponding to immature neutrophils.We used the decreased number in non-classical monocytes and the failure of NLRP3 activation upon nigericin activation in CD66b + CD16dim granulocytes to build a prognostic score. We found a correlation between this score and the SpO2 / FiO2 ratio on the day of inclusion as well as 48 hours later. We also found a significant association of these two markers with the final outcome of the patients.My work has led to a better understanding of the involvement of the NLRP3 inflammasome in humans during bacteremia and during SARS-CoV-2 infection. We plan to use this work to characterize the response of patients to immunomodulatory treatments used in COVID-19, including corticosteroids.A la phase précoce d’une infection bactérienne ou virale l’immunité innée est capable de détecter certains motifs microbiens conservés (PAMP) reconnus par des récepteurs dédiés à ces motifs (PRR) permettant ainsi d’amorcer la réaction pro-inflammatoire via différentes voies de signalisation. Les inflammasomes représentent une catégorie de PRR capable de transformer la pro-IL-1β et la pro-IL-18 en cytokines pro-inflammatoires actives ainsi que d’induire une mort cellulaire pro-inflammatoire nommée pyroptose. NLRP3 est l’inflammasome le plus étudié. De nombreuses bactéries et de nombreux virus ont été décrits comme pouvant soit activer soit inhiber l’inflammasome NLRP3 mais l’implication clinique de cette activation ou inhibition, reste pour le moment indéterminée. L’objectif de ma thèse était d’étudier l’implication de l’inflammasome NLRP3 au cours de la bactériémie chez l’homme. L’apparition de l’épidémie de COVID-19 nous a permis d’élargir cette étude à l’infection par le SARS-CoV-2. Le protocole NLRP3-BACT nous a permis de mettre en œuvre un test cellulaire à partir du sang total afin d’évaluer le niveau d’activation de la Caspase-1 dans les monocytes et polynucléaires neutrophiles (PNN) ainsi que le potentiel d’activation de l’inflammasome NLRP3 dans ces cellules chez des patients présentant une bactériémie à S. aureus ou E. coli via une analyse par cytométrie en flux (signal FAM-FLICA).Le protocole CoVinnate avait pour objectif l’utilisation du test cellulaire précédemment mentionné afin de décrire l’activation d’une partie du système immunitaire inné dans les différentes cellules myéloïdes circulantes des patients COVID-19 ainsi que l’évaluation de ce test en tant qu’outil pronostique.Pour NLRP3-BACT 22 patients ont été inclus depuis le début de de l’étude, 16 ont bénéficié d’une analyse cytométrique. Dans cette première série de patients inclus nous avons mis en évidence que les monocytes présentent un potentiel d’activation de la Caspase-1 par Nigéricine+LPS plus important que les donneurs sains. Par ailleurs, l’activation basale de cette caspase dans les monocytes est plus importante chez les patients de réanimation et ceux infectés par E. coli. Enfin la multiplication de la MFI du signal FAM-FLICA induite par Nigéricine+LPS est plus important pour les patients de médecine comparativement aux patients de réanimation.Pour CoVinnate, 66 patients COVID-19 et 24 donneurs sains ont été inclus durant la période de l’étude. Dans les cellules CD66b+ CD16dim nous avons observé une diminution significative du signal de la sonde FAM-FLICA chez les patients les plus sévères comparativement aux témoins. Au sein des granulocytes, l’activation de la Caspase-1 induite par la Nigéricine était altérée dans les granulocytes CD66b+ CD16dim selon le degré de sévérité des patients. Nous avons enregistré une augmentation de l’activation de NLRP3 induite par la Nigéricine dans les monocytes non-classiques isolés chez les patients les plus graves, cet effet était inversement corrélé au nombre total de monocytes non-classiques. Chez les patients les plus sévères on notait une augmentation du nombre de cellules CD66b+CD16dimCD15+CD10- correspondant à des neutrophiles immatures. Nous avons utilisé la diminution des monocytes non-classiques et le défaut d’activation de NLRP3 par la Nigéricine des granulocytes CD66b+ CD16dim pour construire un score pronostique. Nous avons mis en évidence une corrélation entre ce score et le rapport SpO2 / FiO2 le jour de l’inclusion ainsi que 48 heures plus tard. Nous avons également constaté une association significative de ces deux marqueurs avec l’évolution finale des patients. Mon travail a permis de mieux comprendre l’implication de l’inflammasome NLRP3 chez l’homme au cours de la bactériémie et durant l’infection à SARS-CoV-2. Nous envisageons d’utiliser ces travaux pour caractériser la réponse des patients aux traitements immunomodulateurs utilisés dans la COVID-19 notamment les corticoïdes

Bacterial infections in solid organ transplant recipients

Purpose of review: Bacteria are the leading cause of infections in solid organ transplant (SOT) recipients, significantly impacting patient outcome. Recently detailed and comprehensive epidemiological data have been published. Recent finding: This literature review aims to provide an overview of bacterial infections affecting different types of SOT recipients, emphasizing underlying risk factors and pathophysiological mechanisms. Summary: Lung transplantation connects two microbiotas: one derived from the donor's lower respiratory tract with one from the recipient's upper respiratory tract. Similarly, liver transplantation involves a connection to the digestive tract and its microbiota through the bile ducts. For heart transplant recipients, specific factors are related to the management strategies for end-stage heart failure based with different circulatory support tools. Kidney and kidney-pancreas transplant recipients commonly experience asymptomatic bacteriuria, but recent studies have suggested the absence of benefice of routine treatment. Bloodstream infections (BSI) are frequent and affect all SOT recipients. Nonorgan-related risk factors as age, comorbidity index score, and leukopenia contribute to BSI development. Bacterial opportunistic infections have become rare in the presence of efficient prophylaxis. Understanding the epidemiology, risk factors, and pathophysiology of bacterial infections in SOT recipients is crucial for effective management and improved patient outcomes.</p

Clinical Aspects of Syphilis Reinfection in HIV-Infected Patients

&lt;b&gt;&lt;i&gt;Background:&lt;/i&gt;&lt;/b&gt; The incidence of HIV-syphilis co-infection has risen since 2000, especially among men having sex with men (MSM). Syphilis reinfection can occur, but the clinical features of such events remain poorly characterized. &lt;b&gt;&lt;i&gt;Objective:&lt;/i&gt;&lt;/b&gt; To compare the cutaneous lesions seen with syphilis reinfections with those of first episodes in HIV-infected patients. &lt;b&gt;&lt;i&gt;Methods:&lt;/i&gt;&lt;/b&gt; In a cohort of HIV-infected patients, syphilis reinfection was established both clinically and biologically by evaluating changes in Venereal Disease Research Laboratory titers. Photographs and medical records were studied in order to determine the type of skin lesions and their quantification. &lt;b&gt;&lt;i&gt;Results:&lt;/i&gt;&lt;/b&gt; Among 533 HIV-infected patients, 42 (8%) experienced a first syphilis infection. Thirteen episodes of reinfection occurred in 12/42 (28%) patients, all MSM. In 78% of cases, reinfections were less symptomatic than first episodes. All patients presented classical syphilis lesions. &lt;b&gt;&lt;i&gt;Conclusions:&lt;/i&gt;&lt;/b&gt; We observed a high rate of reinfection, but with less severe skin manifestations during reinfection episodes.</jats:p