The Fc region of HIV-1 Env-specific broadly neutralizing antibodies (bNAbs) is required for suppressing viraemia, through mechanisms which remain poorly understood. Here, we identify bNAbs that exert ...antibody-dependent cellular cytotoxicity (ADCC) in cell culture and kill HIV-1-infected lymphocytes through natural killer (NK) engagement. These antibodies target the CD4-binding site, the glycans/V3 and V1/V2 loops on gp120, or the gp41 moiety. The landscape of Env epitope exposure at the surface and the sensitivity of infected cells to ADCC vary considerably between viral strains. Efficient ADCC requires sustained cell surface binding of bNAbs to Env, and combining bNAbs allows a potent killing activity. Furthermore, reactivated infected cells from HIV-positive individuals expose heterogeneous Env epitope patterns, with levels that are often but not always sufficient to trigger killing by bNAbs. Our study delineates the parameters controlling ADCC activity of bNAbs, and supports the use of the most potent antibodies to clear the viral reservoir.
Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening disorder characterized by an uncontrolled, persistent, hyperimmune response. It can be triggered by an infectious, neoplastic, or ...autoimmune event. The involvement of cytomegalovirus (CMV) in the onset of HLH is subject to debate, and the epidemiology of CMV-associated HLH (HLH-CMV) remains poorly characterized. We identified 5 cases of HLH-CMV in our hospital, systematically searched the PubMed database for publications on HLH-CMV, and reviewed 57 publications with a total of 67 cases of HLH-CMV. Only 48 patients (71.6%) were immunodeficient, suggesting that HLH-CMV can occur in immunocompetent patients. The major cause of underlying immunodepression (51%) was inflammatory bowel disease (mainly treated with azathioprine). CMV infection was nearly always symptomatic, and lung involvement was frequent (31 cases). Fifty-five patients recovered. Nineteen patients were treated for CMV infection only and had a good outcome, suggesting that antiviral drugs might be the cornerstone of HLH-CMV treatment.
Prolonged Covid‐19 is an emerging issue for patients with lymphoma or immune deficiency. We aimed to examine prolonged length of in‐hospital stay (LOS) due to Covid‐19 among patients with lymphoma ...and assess its determinants and outcomes. Adult patients with lymphoma admitted for Covid‐19 to 16 French hospitals in March and April, 2020 were included. Length of in‐hospital stay was analyzed as a competitor vs death. The study included 111 patients. The median age was 65 years (range, 19–92). Ninety‐four patients (85%) had B‐cell non‐Hodgkin lymphoma. Within the 12 months prior to hospitalization for Covid‐19, 79 patients (71%) were treated for their lymphoma. Among them, 63 (57%) received an anti‐CD20 therapy. Fourteen patients (12%) had relapsed/refractory disease. The median LOS was 14 days (range, 1–235). After a median follow‐up of 191 days (3–260), the 6‐month overall survival was 69%. In multivariable analyses, recent administration of anti‐CD20 therapy was associated with prolonged LOS (subdistribution hazard ratio 2.26, 95% confidence interval 1.42–3.6, p < 0.001) and higher risk of death (hazard ratio 2.17, 95% confidence interval 1.04–4.52, p = 0.039). An age ≥ 70 years and relapsed/refractory lymphoma were also associated with prolonged LOS and decreased overall survival. In conclusion, an age ≥ 70 years, a relapsed/refractory lymphoma and recent administration of anti‐CD20 therapy are risk factors for prolonged LOS and death for lymphoma patients hospitalized for Covid‐19. These findings may contribute to guide the management of lymphoma during the pandemic, support evaluating specific therapeutic approaches, and raise questions on the efficacy and timing of vaccination of this particular population.
Anti-human immunodeficiency virus type 1 (HIV-1) nonneutralizing antibodies (nnAbs) capable of antibody-dependent cellular cytotoxicity (ADCC) have been identified as a protective immune correlate in ...the RV144 vaccine efficacy trial. Broadly neutralizing antibodies (bNAbs) also mediate ADCC in cell culture and rely on their Fc region for optimal efficacy in animal models. Here, we selected 9 monoclonal nnAbs and 5 potent bNAbs targeting various epitopes and conformations of the gp120/41 complex and analyzed the potency of the two types of antibodies to bind and eliminate HIV-1-infected cells in culture. Regardless of their neutralizing activity, most of the selected antibodies recognized and killed cells infected with two laboratory-adapted HIV-1 strains. Some nnAbs also bound bystander cells that may have captured viral proteins. However, in contrast to the bNAbs, the nnAbs bound poorly to reactivated infected cells from 8 HIV-positive individuals and did not mediate effective ADCC against these cells. The nnAbs also inefficiently recognize cells infected with 8 different transmitted-founder (T/F) isolates. The addition of a synthetic CD4 mimetic enhanced the binding and killing efficacy of some of the nnAbs in an epitope-dependent manner without reaching the levels achieved by the most potent bNAbs. Overall, our data reveal important qualitative and quantitative differences between nnAbs and bNAbs in their ADCC capacity and strongly suggest that the breadth of recognition of HIV-1 by nnAbs is narrow.
Most of the anti-HIV antibodies generated by infected individuals do not display potent neutralizing activities. These nonneutralizing antibodies (nnAbs) with antibody-dependent cellular cytotoxicity (ADCC) have been identified as a protective immune correlate in the RV144 vaccine efficacy trial. However, in primate models, the nnAbs do not protect against simian-human immunodeficiency virus (SHIV) acquisition. Thus, the role of nnAbs with ADCC activity in protection from infection remains debatable. In contrast, broadly neutralizing antibodies (bNAbs) neutralize a large array of viral strains and mediate ADCC in cell culture. We analyzed the capacities of 9 nnAbs and 5 bNAbs to eliminate infected cells. We selected 18 HIV-1 strains, including virus reactivated from the reservoir of HIV-positive individuals and transmitted-founder isolates. We report that the nnAbs bind poorly to cells infected with primary HIV-1 strains and do not mediate potent ADCC. Overall, our data show that the breadth of recognition of HIV-1 by nnAbs is narrow.
Background. Although prognosis of Chronic Granulomatous Disease (CGD) has greatly improved, few studies have focused on its long-term outcome. We studied the clinical course and sequelae of CGD ...patients diagnosed before age 16, at various adult time points. Method. Cross-sectional French nationwide retrospective study of patients screened through the National Reference Center for Primary Immunodeficiencies (CEREDIH) registry. Results. Eighty CGD patients (71 males 88.7%, 59 X-linked 73.7%, median age 23.9 years minimum, 16.6; maximum, 59.9) were included, Median ages at diagnosis and last follow-up were 2.52 and 23.9 years, respectively. Seven patients underwent hematopoietic stem cell transplantation. A total of 553 infections requiring hospitalization occurred in 2017 patient-years. The most common site of infection was pulmonary (31%). Aspergillus spp. (17%) and Staphylococcus aureus (10.7%) were the commonest pathogens. A total of 224 inflammatory episodes occurred in 71 patients, mainly digestive (50%). Their characteristics as well as their annual frequency did not vary before and after age 16. Main sequelae were a small adult height and weight and mild chronic restrictive respiratory failure. At age 16, only 53% of patients were in high school. After age 30 years, 9/13 patients were working. Ten patients died during adulthood. Conclusions. Adult CGD patients displayed similar characteristics and rates of severe infections and inflammatory episodes that those of childhood. The high rate of handicap has become a matter of medical and social consideration. Careful follow-up in centers of expertise is strongly recommended and an extended indication of curative treatment by HSCT should be considered.
A chemical devulcanization process of waste tires was investigated using different peroxide derivatives as devulcanizing agents. This radical process afforded the recovery of functionalized ...elastomers with a well-defined architecture, in up to 60% yields, directly from ground tire waste and simultaneously afforded the functionalization of the residual vulcanized waste. Kinetic studies provided a better insight into the radical reaction behavior in such complex materials. This mild process constituted a facile route to recover the elastomers contained in waste tires and more generally in sulfur-cross-linked rubbers.
As the COVID-19 pandemic is still ongoing, and considering the lack of efficacy of antiviral strategies to this date, and the reactive hyperinflammation leading to tissue lesions and pneumonia, ...effective treatments targeting the dysregulated immune response are more than ever required. Immunomodulatory and immunosuppressive drugs have been repurposed in severe COVID-19 with contrasting results. The heterogeneity in the timing of treatments administrations could be accountable for these discrepancies. Indeed, many studies included patients at different timepoints of infection, potentially hiding the beneficial effects of a time-adapted intervention. We aim to review the available data on the kinetics of the immune response in beta-coronaviruses infections, from animal models and longitudinal human studies, and propose a four-step model of severe COVID-19 timeline. Then, we discuss the results of the clinical trials of immune interventions with regards to the timing of administration, and finally suggest a time frame in order to delineate the best timepoint for each treatment.
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