Receptor transfer between immune cells by autoantibody-enhanced, CD32-driven trogocytosis is hijacked by HIV-1 to infect resting CD4 T cells.

Immune cell phenotyping frequently detects lineage-unrelated receptors. Here, we report that surface receptors can be transferred from primary macrophages to CD4 T cells and identify the Fcγ receptor CD32 as driver and cargo of this trogocytotic transfer. Filamentous CD32+ nanoprotrusions deposit distinct plasma membrane patches onto target T cells. Transferred receptors confer cell migration and adhesion properties, and macrophage-derived membrane patches render resting CD4 T cells susceptible to infection by serving as hotspots for HIV-1 binding. Antibodies that recognize T cell epitopes enhance CD32-mediated trogocytosis. Such autoreactive anti-HIV-1 envelope antibodies can be found in the blood of HIV-1 patients and, consistently, the percentage of CD32+ CD4 T cells is increased in their blood. This CD32-mediated, antigen-independent cell communication mode transiently expands the receptor repertoire and functionality of immune cells. HIV-1 hijacks this mechanism by triggering the generation of trogocytosis-promoting autoantibodies to gain access to immune cells critical to its persistence.

Are enterococcal bloodstream infections an independent risk factor for a poorer 5-year survival or just a marker for severity of illness?-The Munich multicentric enterococci cohort.

IMPORTANCE: The present study provides a substantial contribution to literature, showing that patients with enterococcal bloodstream infections (BSI) have a lower survival rate than those with Escherichia coli (E. coli) bloodstream infections after adjusting for 17 limiting prognostic factors and excluding patients with a limited life expectancy [metastatic tumor disease, Charlson Comorbidity Index (CCI) (greater than or equal to) 5]. This difference in the 5-year long-term survival was mainly driven by Enterococcus faecium (ECFM) bloodstream infections, with vancomycin resistance not being a significant contributing factor. Our findings imply that E. faecium bloodstream infections seem to be an independent risk factor for poor long-term outcomes. As such, future research should confirm this relationship and prioritize investigating its causality through prospective studies.

Evaluation of Self-Collected Versus Health Care Professional (HCP)-Performed Sampling and the Potential Impact on the Diagnostic Results of Asymptomatic Sexually Transmitted Infections (STIs) in High-Risk Individuals.

Sexually transmitted infections (STIs) are increasing among men who have sex with men (MSM). Screening can improve the detection and outcome of asymptomatic STIs in high-risk populations. Self-sampling may be a resource-optimized strategy; however, its diagnostic reliability compared to testing by healthcare professionals (HCPs) requires further investigation. In this prospective, multicenter cohort study in a high-income country, asymptomatic MSM with a sexual risk profile for STIs were included. Sequential swabs for STI nucleic acid-based diagnosis of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) were performed after randomization, either through self-sampling or HCP-performed sampling. Baseline demographic information, sexual risk behavior, and acceptance and feedback on self-sampling were recorded using an electronic questionnaire. Out of 236 asymptomatic MSM, 47 individuals (19.9%) tested positive for CT and/or NG through self- or HCP-performed sampling. For CT, the sensitivity was 93.3% for both sampling methods, while for NG, it was 90.0% for self-sampling and 95.0% for HCP-performed sampling. Our study demonstrates that self-sampling for asymptomatic STIs has a comparable diagnostic outcome to HCP-performed sampling, with high acceptance in high-risk MSM.

[Measures and Recommendations for Ensuring Adequate Inpatient Care Capacities for Pandemic Management within a Region: Results of a Hybrid Delphi Method]. / Maßnahmen und Empfehlungen für die Sicherstellung adäquater stationärer Versorgungskapazitäten für das Pandemiemanagement innerhalb einer Region ­ Ergebnisse eines hybriden Delphi-Verfahrens.

INTRODUCTION: Since the beginning of the pandemic in spring 2020, inpatient healthcare has been under enormous burden, which is reflected especially in overworked staff, imprecise bed planning and/or data transfer. According to the recommendation of the Science Council, university clinics should play a controlling role in regional healthcare and act in conjunction with surrounding hospitals and practices. METHODS: In September 2021, 31 representatives from 18 university hospitals were invited to a hybrid Delphi study with a total of 4 survey rounds to discuss criteria for effective inpatient care in a pandemic situation, which were extracted from previous expert interviews. Criteria that were classified as very important/relevant by≥75% of the participants in the first round of the survey (consensus definition) were then further summarized in 4 different small groups. In a third Delphi round, all participants came together again to discuss the results of the small group discussions. Subsequently, these were prioritized as Optional ("can"), Desirable ("should") or Necessary ("must") recommendations. RESULTS: Of the invited clinical experts, 21 (67.7%) participated in at least one Delphi round. In an online survey (1st Delphi round), 233 criteria were agreed upon and reduced to 84 criteria for future pandemic management in four thematic small group discussions (2nd Delphi round) and divided into the small groups as follows: "Crisis Management and Crisis Plans" (n=20), "Human Resources Management and Internal Communication" (n=16), "Regional Integration and External Communication" (n=24) and "Capacity Management and Case & Care" (n=24). In the following group discussion (3rd Delphi round), the criteria were further modified and agreed upon by the experts, so that in the end result, there were 23 essential requirements and recommendations for effective inpatient care in a pandemic situation. CONCLUSION: The results draw attention to key demands of clinical representatives, for example, comprehensive digitization, standardization of processes and better (supra) regional networking in order to be able to guarantee needs-based care even under pandemic conditions. The present consensus recommendations can serve as guidelines for future pandemic management in the inpatient care sector.

T-Cell-Dominated Immune Response Resolves Protracted SARS-CoV-2 Infection in the Absence of Neutralizing Antibodies in an Immunocompromised Individual.

Immunocompromised individuals are at higher risk of developing protracted and severe COVID-19, and understanding individual disease courses and SARS-CoV-2 immune responses in these individuals is of the utmost importance. For more than two years, we followed an immunocompromised individual with a protracted SARS-CoV-2 infection that was eventually cleared in the absence of a humoral neutralizing SARS-CoV-2 antibody response. By conducting an in-depth examination of this individual's immune response and comparing it to a large cohort of convalescents who spontaneously cleared a SARS-CoV-2 infection, we shed light on the interplay between B- and T-cell immunity and how they interact in clearing SARS-CoV-2 infection.

Differentiation of Spontaneous Bacterial Peritonitis from Secondary Peritonitis in Patients with Liver Cirrhosis: Retrospective Multicentre Study.

Ascitic fluid infection is a serious complication of liver cirrhosis. The distinction between the more common spontaneous bacterial peritonitis (SBP) and the less common secondary peritonitis in patients with liver cirrhosis is crucial due to the varying treatment approaches. This retrospective multicentre study was conducted in three German hospitals and analysed 532 SBP episodes and 37 secondary peritonitis episodes. Overall, >30 clinical, microbiological, and laboratory parameters were evaluated to identify key differentiation criteria. Microbiological characteristics in ascites followed by severity of illness and clinicopathological parameters in ascites were the most important predictors identified by a random forest model to distinguish between SBP and secondary peritonitis. To establish a point-score model, a least absolute shrinkage and selection operator (LASSO) regression model selected the ten most promising discriminatory features. By aiming at a sensitivity of 95% either to rule out or rule in SBP episodes, two cut-off scores were defined, dividing patients with infected ascites into a low-risk (score ≥ 45) and high-risk group (score < 25) for secondary peritonitis. Overall, the discrimination of secondary peritonitis from SBP remains challenging. Our univariable analyses, random forest model, and LASSO point score may help clinicians with the crucial differentiation between SBP and secondary peritonitis.

Use and effectiveness of remdesivir for the treatment of patients with covid-19 using data from the Lean European Open Survey on SARS-CoV-2 infected patients (LEOSS): a multicentre cohort study.

OBJECTIVES: The use of remdesivir (RDV) as the first drug approved for coronavirus disease 2019 (COVID-19) remains controversial. Based on the Lean European Open Survey on severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infected patients (LEOSS), we aim to contribute timing-focused complementary real-world insights to its evaluation. METHODS: SARS-CoV-2 infected patients between January 2020 and December 2021 treated with RDV were matched 1:1 to controls considering sociodemographics, comorbidities and clinical status. Multiple imputations were used to account for missing data. Effects on fatal outcome were estimated using uni- and multivariable Cox regression models. RESULTS: We included 9,687 patients. For those starting RDV administration in the complicated phase, Cox regression for fatal outcome showed an adjusted hazard ratio (aHR) of 0.59 (95%CI 0.41-0.83). Positive trends could be obtained for further scenarios: an aHR of 0.51 (95%CI 0.16-1.68) when RDV was initiated in uncomplicated and of 0.76 (95% CI 0.55-1.04) in a critical phase of disease. Patients receiving RDV with concomitant steroids exhibited a further reduction in aHR in both, the complicated (aHR 0.50, 95%CI 0.29-0.88) and critical phase (aHR 0.63, 95%CI 0.39-1.02). CONCLUSION: Our study results elucidate that RDV use, in particular when initiated in the complicated phase and accompanied by steroids is associated with improved mortality. However, given the limitations of non-randomized trials in estimating the magnitude of the benefit of an intervention, further randomized trials focusing on the timing of therapy initiation seem warranted.

Disease severity in hospitalized COVID-19 patients: comparing routine surveillance with cohort data from the LEOSS study in 2020 in Germany.

INTRODUCTION: Studies investigating risk factors for severe COVID-19 often lack information on the representativeness of the study population. Here, we investigate factors associated with severe COVID-19 and compare the representativeness of the dataset to the general population. METHODS: We used data from the Lean European Open Survey on SARS-CoV-2 infected patients (LEOSS) of hospitalized COVID-19 patients diagnosed in 2020 in Germany to identify associated factors for severe COVID-19, defined as progressing to a critical disease stage or death. To assess the representativeness, we compared the LEOSS cohort to cases of hospitalized patients in the German statutory notification data of the same time period. Descriptive methods and Poisson regression models were used. RESULTS: Overall, 6672 hospitalized patients from LEOSS and 132,943 hospitalized cases from the German statutory notification data were included. In LEOSS, patients above 76 years were less likely represented (34.3% vs. 44.1%). Moreover, mortality was lower (14.3% vs. 21.5%) especially among age groups above 66 years. Factors associated with a severe COVID-19 disease course in LEOSS included increasing age, male sex (adjusted risk ratio (aRR) 1.69, 95% confidence interval (CI) 1.53-1.86), prior stem cell transplantation (aRR 2.27, 95% CI 1.53-3.38), and an elevated C-reactive protein at day of diagnosis (aRR 2.30, 95% CI 2.03-2.62). CONCLUSION: We identified a broad range of factors associated with severe COVID-19 progression. However, the results may be less applicable for persons above 66 years since they experienced lower mortality in the LEOSS dataset compared to the statutory notification data.

[Development and validation of potential structure indicators for clinical infectious disease (ID) care in German hospitals during the COVID-19 pandemic]. / Entwicklung und Validierung potenzieller Strukturindikatoren zur Evaluierung des klinisch-infektiologischen Versorgungsangebots in deutschen Krankenhäusern während der COVID-19-Pandemie.

INTRODUCTION: This study describes the development and validation of structure indicators for clinical infectious disease (ID) care in German hospitals, which is important to adequately face the future challenges in ID medicine. METHODS: A team of experts developed the structure indicators in a three-stage, multicriteria decision-making process: (1) identification of potential structure indicators based on a literature review, (2) written assessment process, and (3) face-to-face discussion to reach consensus and final selection of appropriate structure indicators. A field study was conducted to assess the developed structure indicators. A score based on the structure indicators was determined for each hospital and validated via receiver operator characteristic (ROC) curves using externally validated ID expertise (German Society of ID (DGI) Centre). RESULTS: Based on a list of 45 potential structure indicators, 18 suitable indicators were developed for clinical ID care structures in German hospitals. Out of these, ten key indicators were defined for the general and coronavirus disease 2019- (COVID-19-) specific clinical ID care structures. In the field survey of clinical ID care provision for COVID-19 patients in 40 German hospitals, the participating facilities achieved 0 to 9 points (median 4) in the determined score. The area under the ROC curve was 0.893 (95% CI: 0.797, 0.988; p < 0.001). DISCUSSION/CONCLUSION: The structure indicators developed within the framework of a transparent and established development process can be used in the future to both capture the current state and future developments of ID care quality in Germany and enable comparisons.

Sofosbuvir plus velpatasvir for 8 weeks in patients with acute hepatitis C: The HepNet acute HCV-V study.

Background & Aims: EASL guidelines recommend 8 weeks of treatment with sofosbuvir plus velpatasvir (SOF/VEL) for the treatment of acute or recently acquired HCV infection, but only 6- and 12-week data are available. Therefore, the aim of this study was to evaluate the safety and efficacy of a shortened 8-week SOF/VEL treatment for acute HCV monoinfection. Methods: In this investigator-initiated, prospective, multicentre, single-arm study, we recruited 20 adult patients with acute HCV monoinfection from nine centers in Germany. Patients received SOF/VEL (400/100 mg) as a fixed-dose combination tablet once daily for 8 weeks. The primary efficacy endpoint was the proportion of patients with sustained virological response 12 weeks after the end of treatment (SVR12). Results: The median HCV RNA viral load at baseline was 104,307 IU/ml; the distribution of HCV genotypes was as follows: GT1a/1b/2/3/4: n = 12/1/1/3/3. Thirteen (65%) of the 20 patients were taking medication for HIV pre-exposure prophylaxis. SVR12 was achieved in all patients who complied with the study protocol (n = 18/18 [100%], per protocol analysis), but the primary endpoint was not met in the intention-to-treat analysis (n = 18/20 [90%]) because two patients were lost to follow-up. One serious adverse event (unrelated to study drug) occurred during 12 weeks of post-treatment follow-up. Conclusions: The 8-week treatment with SOF/VEL was well tolerated and highly effective in all adherent patients with acute HCV monoinfection. Early treatment of hepatitis C might effectively prevent the spread of HCV in high-risk groups. Clinical Trial Number: NCT03818308. Impact and implications: The HepNet acute HCV-V study (NCT03818308), an investigator-initiated, single-arm, multicenter pilot study, demonstrates the efficacy and safety of 8 weeks of daily treatment with the fixed-dose combination sofosbuvir/velpatasvir (400/100 mg) in patients with acute hepatitis C virus (HCV) infection. All patients who completed therapy and were followed-up achieved sustained virologic response. Thus, early treatment with SOF/VEL which might effectively prevent the spread of HCV in high-risk groups can be recommended for patients with acute HCV monoinfection.

Clinical and virological features of first human monkeypox cases in Germany.

BACKGROUND: Monkeypox is a zoonotic orthopoxvirus infection endemic in central and western Africa. In May 2022, human monkeypox infections including human-to-human transmission were reported in a multi-country outbreak in Europe and North America. CASE PRESENTATIONS: Here we present the first two cases of monkeypox infection in humans diagnosed in Germany. We present clinical and virological findings, including the detection of monkeypox virus DNA in blood and semen. The clinical presentation and medical history of our patients suggest close physical contact during sexual interactions as the route of infection. CONCLUSION: Monkeypox requires rapid diagnosis and prompt public health response. The disease should be considered in the current situation especially the differential diagnosis of vesicular or pustular rash, particularly in patients with frequent sexual contacts. Most importantly, it is essential to raise awareness among all health professionals for the rapid and correct recognition and diagnosis of this disease, which is probably still underreported in Europe (Adler et al. in Lancet Infect Dis https://doi.org/10.1016/s1473-3099(22)00228-6 , 2022).

Clinical characteristics of monkeypox virus infections among men with and without HIV: A large outbreak cohort in Germany.

BACKGROUND: Since May 2022, increasing numbers of monkeypox virus (MPXV) infections have been reported from across Europe and North America. Studies, mainly from Africa, have suggested a higher risk for severe MPXV cases in people living with HIV. METHODS: This was a retrospective study of all confirmed MPXV infections observed in the participating centres since 19 May 2022. We conducted a chart review to evaluate clinical characteristics, comorbidities, and coinfections, including HIV, viral hepatitis, and sexually transmitted infections (STIs). RESULTS: By 30 June 2022, a total of 546 MPXV infections were reported from 42 German centres. All patients were men who have sex with men (MSM), of whom 256 (46.9%) were living with HIV, mostly with a preserved immune system and with viral suppression. In total, 232 (42.5%) MSM were also taking HIV pre-exposure prophylaxis (PrEP) and 58 (10.6%) MSM had no known HIV infection or PrEP use. The median age was 39 years (range 20-67), and comorbidities were rare. However, 52.4% and 29.4% of all patients had been diagnosed with at least one STI within the last 6 months or within the last 4 weeks, respectively. The most frequent localizations of MPXV infection were genital (49.9%) and anal (47.9%), whereas fever (53.2%) and lymphadenopathy (42.6%) were the most frequent general symptoms. The hospitalization rate was low (4.0%), and no fatal course was observed. The clinical picture showed no apparent differences between MSM with or without HIV. CONCLUSIONS: In this preliminary cohort analysis from a current large outbreak among MSM in Germany, the clinical picture of MPXV infection did not differ between MSM with and without HIV infection. Severe courses were rare and hospitalization rates were low. However, most patients were relatively healthy, and only a few people living with HIV were viremic or severely immunosuppressed.

Low Spontaneous Clearance Rates of Recently Acquired Hepatitis C Virus in Human Immunodeficiency Virus-Positive Men Who Have Sex With Men (PROBE-C Study).

BACKGROUND: Using direct-acting antivirals (DAAs) for recently acquired hepatitis C virus (RAHCV) infections, particularly in human immunodeficiency virus (HIV)-positive men who have sex with men (MSM), dramatically reduced the incidence of hepatitis C. However, implementation into clinical practice is challenging. The aim of this study was to analyze spontaneous clearance (SC) rates of RAHCV and to identify predictors of SC. METHODS: The PROBE-C study is an observational European cohort on RAHCV infections in HIV-positive MSM. Between 2007 and 2017, RAHCV infections were documented with ≥12 months of follow-up. Fisher exact, χ2, and Mann-Whitney U tests were used for statistical analysis. RESULTS: A total of 464 RAHCV infections were documented; 457 of 464 patients (98%) were male, and the median age (interquartile range [IQR]) was 41 (38-46) years. The main risk group for hepatitis C virus (HCV) transmission was MSM (98.9%). Most participants were infected with HCV genotype 1 (78.3%). The median baseline HCV RNA level (IQR) was 230 000 (135 000-474 432) IU/mL, and the median CD4+ T-cell count was 574/µL (547-604/µL. Of all cases, 92% received combination antiretroviral therapy, with 91% showing suppressed HIV RNA levels (<200 copies/mL). The median maximum alanine aminotransferase level (IQR) was 445 (402-522) U/L. SC of RAHCV infection occurred in 55 of 464 cases (11.9%). A >2-log decline in HCV RNA levels 4 weeks after diagnosis of RAHCV infection was the strongest predictor of SC (P < .001; sensitivity, 96.4%; specificity, 97.5%; positive predictive value, 84.1%; negative predictive value, 99.5%). CONCLUSIONS: SC of RAHCV in HIV-positive MSM is found in only 11.9% of cases and a <2-log drop in HCV RNA level at week 4 after diagnosis should prompt early DAA-based treatment. However, immediate DAA treatment for RAHCV infection may also be favored in patients with ongoing transmission risk behavior.

A Novel Machine Learning-Based Point-Score Model as a Non-Invasive Decision-Making Tool for Identifying Infected Ascites in Patients with Hydropic Decompensated Liver Cirrhosis: A Retrospective Multicentre Study.

This study is aimed at assessing the distinctive features of patients with infected ascites and liver cirrhosis and developing a scoring system to allow for the accurate identification of patients not requiring abdominocentesis to rule out infected ascites. A total of 700 episodes of patients with decompensated liver cirrhosis undergoing abdominocentesis between 2006 and 2020 were included. Overall, 34 clinical, drug, and laboratory features were evaluated using machine learning to identify key differentiation criteria and integrate them into a point-score model. In total, 11 discriminatory features were selected using a Lasso regression model to establish a point-score model. Considering pre-test probabilities for infected ascites of 10%, 15%, and 25%, the negative and positive predictive values of the point-score model for infected ascites were 98.1%, 97.0%, 94.6% and 14.9%, 21.8%, and 34.5%, respectively. Besides the main model, a simplified model was generated, containing only features that are fast to collect, which revealed similar predictive values. Our point-score model appears to be a promising non-invasive approach to rule out infected ascites in clinical routine with high negative predictive values in patients with hydropic decompensated liver cirrhosis, but further external validation in a prospective study is needed.

Invasiveness of Ventilation Therapy Is Associated to Prevalence of Secondary Bacterial and Fungal Infections in Critically Ill COVID-19 Patients.

Superinfections are a fundamental critical care problem, and their significance in severe COVID-19 cases needs to be determined. This study analyzed data from the Lean European Open Survey on SARS-CoV-2-Infected Patients (LEOSS) cohort focusing on intensive care patients. A retrospective analysis of patient data from 840 cases of COVID-19 with critical courses demonstrated that co-infections were frequently present and were primarily of nosocomial origin. Furthermore, our analysis showed that invasive therapy procedures accompanied an increased risk for healthcare-associated infections. Non-ventilated ICU patients were rarely affected by secondary infections. The risk of infection, however, increased even when non-invasive ventilation was used. A further, significant increase in infection rates was seen with the use of invasive ventilation and even more so with extracorporeal membrane oxygenation (ECMO) therapy. The marked differences among ICU techniques used for the treatment of COVID-19-induced respiratory failure in terms of secondary infection risk profile should be taken into account for the optimal management of critically ill COVID-19 patients, as well as for adequate antimicrobial therapy.

Efficacy, safety, and immunogenicity of a booster regimen of Ad26.COV2.S vaccine against COVID-19 (ENSEMBLE2): results of a randomised, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: Despite the availability of effective vaccines against COVID-19, booster vaccinations are needed to maintain vaccine-induced protection against variant strains and breakthrough infections. This study aimed to investigate the efficacy, safety, and immunogenicity of the Ad26.COV2.S vaccine (Janssen) as primary vaccination plus a booster dose. METHODS: ENSEMBLE2 is a randomised, double-blind, placebo-controlled, phase 3 trial including crossover vaccination after emergency authorisation of COVID-19 vaccines. Adults aged at least 18 years without previous COVID-19 vaccination at public and private medical practices and hospitals in Belgium, Brazil, Colombia, France, Germany, the Philippines, South Africa, Spain, the UK, and the USA were randomly assigned 1:1 via a computer algorithm to receive intramuscularly administered Ad26.COV2.S as a primary dose plus a booster dose at 2 months or two placebo injections 2 months apart. The primary endpoint was vaccine efficacy against the first occurrence of molecularly confirmed moderate to severe-critical COVID-19 with onset at least 14 days after booster vaccination, which was assessed in participants who received two doses of vaccine or placebo, were negative for SARS-CoV-2 by PCR at baseline and on serology at baseline and day 71, had no major protocol deviations, and were at risk of COVID-19 (ie, had no PCR-positive result or discontinued the study before day 71). Safety was assessed in all participants; reactogenicity, in terms of solicited local and systemic adverse events, was assessed as a secondary endpoint in a safety subset (approximately 6000 randomly selected participants). The trial is registered with ClinicalTrials.gov, NCT04614948, and is ongoing. FINDINGS: Enrolment began on Nov 16, 2020, and the primary analysis data cutoff was June 25, 2021. From 34 571 participants screened, the double-blind phase enrolled 31 300 participants, 14 492 of whom received two doses (7484 in the Ad26.COV2.S group and 7008 in the placebo group) and 11 639 of whom were eligible for inclusion in the assessment of the primary endpoint (6024 in the Ad26.COV2.S group and 5615 in the placebo group). The median (IQR) follow-up post-booster vaccination was 36·0 (15·0-62·0) days. Vaccine efficacy was 75·2% (adjusted 95% CI 54·6-87·3) against moderate to severe-critical COVID-19 (14 cases in the Ad26.COV2.S group and 52 cases in the placebo group). Most cases were due to the variants alpha (B.1.1.7) and mu (B.1.621); endpoints for the primary analysis accrued from Nov 16, 2020, to June 25, 2021, before the global dominance of delta (B.1.617.2) or omicron (B.1.1.529). The booster vaccine exhibited an acceptable safety profile. The overall frequencies of solicited local and systemic adverse events (evaluated in the safety subset, n=6067) were higher among vaccine recipients than placebo recipients after the primary and booster doses. The frequency of solicited adverse events in the Ad26.COV2.S group were similar following the primary and booster vaccinations (local adverse events, 1676 [55·6%] of 3015 vs 896 [57·5%] of 1559, respectively; systemic adverse events, 1764 [58·5%] of 3015 vs 821 [52·7%] of 1559, respectively). Solicited adverse events were transient and mostly grade 1-2 in severity. INTERPRETATION: A homologous Ad26.COV2.S booster administered 2 months after primary single-dose vaccination in adults had an acceptable safety profile and was efficacious against moderate to severe-critical COVID-19. Studies assessing efficacy against newer variants and with longer follow-up are needed. FUNDING: Janssen Research & Development.

Host KIR/HLA-C Genotypes Determine HIV-Mediated Changes of the NK Cell Repertoire and Are Associated With Vpu Sequence Variations Impacting Downmodulation of HLA-C.

NK cells play a pivotal role in viral immunity, utilizing a large array of activating and inhibitory receptors to identify and eliminate virus-infected cells. Killer-cell immunoglobulin-like receptors (KIRs) represent a highly polymorphic receptor family, regulating NK cell activity and determining the ability to recognize target cells. Human leukocyte antigen (HLA) class I molecules serve as the primary ligand for KIRs. Herein, HLA-C stands out as being the dominant ligand for the majority of KIRs. Accumulating evidence indicated that interactions between HLA-C and its inhibitory KIR2DL receptors (KIR2DL1/L2/L3) can drive HIV-1-mediated immune evasion and thus may contribute to the intrinsic control of HIV-1 infection. Of particular interest in this context is the recent observation that HIV-1 is able to adapt to host HLA-C genotypes through Vpu-mediated downmodulation of HLA-C. However, our understanding of the complex interplay between KIR/HLA immunogenetics, NK cell-mediated immune pressure and HIV-1 immune escape is still limited. Therefore, we investigated the impact of specific KIR/HLA-C combinations on the NK cell receptor repertoire and HIV-1 Vpu protein sequence variations of 122 viremic, untreated HIV-1+ individuals. Compared to 60 HIV-1- controls, HIV-1 infection was associated with significant changes within the NK cell receptor repertoire, including reduced percentages of NK cells expressing NKG2A, CD8, and KIR2DS4. In contrast, the NKG2C+ and KIR3DL2+ NK cell sub-populations from HIV-1+ individuals was enlarged compared to HIV-1- controls. Stratification along KIR/HLA-C genotypes revealed a genotype-dependent expansion of KIR2DL1+ NK cells that was ultimately associated with increased binding affinities between KIR2DL1 and HLA-C allotypes. Lastly, our data hinted to a preferential selection of Vpu sequence variants that were associated with HLA-C downmodulation in individuals with high KIR2DL/HLA-C binding affinities. Altogether, our study provides evidence that HIV-1-associated changes in the KIR repertoire of NK cells are to some extent predetermined by host KIR2DL/HLA-C genotypes. Furthermore, analysis of Vpu sequence polymorphisms indicates that differential KIR2DL/HLA-C binding affinities may serve as an additional mechanism how host genetics impact immune evasion by HIV-1.