Search

Antibody-mediated rejection after kidney transplantation is a major limitation for long-term survival of donated kidneys within the recipient allograft. With the existing HLA cross-matching test only complement activating donor specific antibodies are evaluated. Other measurements are more sensitive, but cannot assert the clinical relevance of the donor specific antibodies. Thus, novel methods that address the more complex nature of cellular interactions with serum components are needed to improve antibody-mediated rejection prediction. Recent studies suggest, that the interaction of natural killer cells of the recipient with endothelial cells of the donor is of major interest. Here we present a microfluidic cell culture device and a corresponding assay to test for the relevance of natural killer cell activated antibody-mediated rejection in vitro. Therefore, a protocol to co-cultivate both cell types and track natural killer cell activated killing within a fluorescence-based assay was established. To automate this approach, the prototype of a well plate sized microfluidic device was developed, that enables staining of the two cell types and repeatable and timedependent co-cultivation of the cells with serum. This automated approach enables further evaluation of the clinical relevance of the established assay paving the way to additional information on HLA cross-matching that helps to quickly estimate the probability of Antibody-mediated rejection and the clinical relevance of donor specific antibodies.

BACKGROUND. Results of many randomized trials on COVID-19 convalescent plasma (CCP) have been reported, but information on long-term outcome after CCP treatment is limited. The objectives of this extended observation of the randomized CAPSID trial are to assess long-term outcome and disease burden in patients initially treated with or without CCP. METHODS. Of 105 randomized patients, 50 participated in the extended observation. Quality of life (QoL) was assessed by questionnaires and a structured interview. CCP donors (n = 113) with asymptomatic to moderate COVID-19 were included as a reference group. RESULTS. The median follow-up of patients was 396 days, and the estimated 1-year survival was 78.7% in the CCP group and 60.2% in the control (P = 0.08). The subgroup treated with a higher cumulative amount of neutralizing antibodies showed a better 1-year survival compared with the control group (91.5% versus 60.2%, P = 0.01). Medical events and QoL assessments showed a consistent trend for better results in the CCP group without reaching statistical significance. There was no difference in the increase in neutralizing antibodies after vaccination between the CCP and control groups. CONCLUSION. The trial demonstrated a trend toward better outcome in the CCP group without reaching statistical significance. A predefined subgroup analysis showed a significantly better outcome (long-term survival, time to discharge from ICU, and time to hospital discharge) among those who received a higher amount of neutralizing antibodies compared with the control group. A substantial long-term disease burden remains after severe COVID-19. TRIAL REGISTRATION. EudraCT 2020-001310-38 and ClinicalTrials.gov NCT04433910. FUNDING. Bundesministerium fur Gesundheit (German Federal Ministry of Health)., Introduction The use of COVID-19 convalescent plasma (CCP) from patients recovered from a SARS-CoV-2 infection was evaluated in many randomized trials during the pandemic (1-21). The trials were heterogeneous in [...]

Background: Autochthonous human West Nile virus (WNV) infections were notified in the infectious disease surveillance system in Germany in 2018 for the first time and every year since then. Since clinically apparent infections are infrequent, we conducted two studies to investigate subclinical infections of this emerging disease in Germany in 2019 to detect infections not visible to surveillance based on symptomatic infections: limited-scope blood donor testing and a serosurvey among employees at two Berlin zoos with a history of demonstrated WNV infections in animals. Methods: For the zoo study, employees of the two zoos in Berlin were invited to participate in the study in late 2019. Blood samples were drawn and tested for the presence of antibodies (immunoglobulin M [IgM] and immunoglobulin G [IgG]) against WNV, and two other flaviviruses present in Germany: Usutu virus and Tick-borne encephalitis virus (TBEV). For the study in blood donors, four blood establishments with collection sites in regions with documented WNV-infected animals in 2018 and 2019 participated in the study. All donations in these regions were tested for WNV genome from July to November 2019. Results: In the enzyme-linked immunosorbent assay, none of the 70 tested zoo employees were WNV IgM-positive, 8 were WNV IgG-positive, additional 2 participants had equivocal results. All 10 were negative in the virus neutralization test (VNT) for WNV, but positive in the VNT for TBEV. None of the 4273 samples from blood donors tested in areas with WNV-infected animals was positive for WNV-RNA. Conclusion: Our results indicate that WNV circulation in Germany, though clearly documented in animals in 2019, apparently affected very few humans. Still areas with WNV-positive animals remain risk areas for human infection as well. [ABSTRACT FROM AUTHOR]

COVID-19 disease, caused by the severe acute respiratory syndrome virus 2 (SARS-CoV-2), induces a broad spectrum of clinical symptoms ranging from asymptomatic cases to fatal outcomes. About 10–35% of all COVID-19 patients, even those with mild COVID-19 symptoms, continue to show symptoms, i. e., fatigue, shortness of breath, cough, and cognitive dysfunction, after initial recovery. Previously, we and others identified red blood cell precursors as a direct target of SARS-CoV-2 and suggested that SARS-CoV-2 induces dysregulation in hemoglobin- and iron-metabolism contributing to the severe systemic course of COVID-19. Here, we put particular emphasis on differences in parameters of clinical blood gas analysis and hematological parameters of more than 20 healthy and Long-COVID patients, respectively. Long-COVID patients showed impaired oxygen binding to hemoglobin with concomitant increase in carbon monoxide binding. Hand in hand with decreased plasma iron concentration and transferrin saturation, mean corpuscular hemoglobin was elevated in Long-COVID patients compared to healthy donors suggesting a potential compensatory mechanism. Although blood pH was within the physiological range in both groups, base excess- and bicarbonate values were significantly lower in Long-COVID patients. Furthermore, Long-COVID patients displayed reduced lymphocyte levels. The clinical relevance of these findings, e. g., as a cause of chronic immunodeficiency, remains to be investigated in future studies. In conclusion, our data suggest impaired erythrocyte functionality in Long-COVID patients, leading to diminished oxygen supply. This in turn could be an explanation for the CFS, dyspnea and anemia. Further investigations are necessary to identify the underlying pathomechanisms. [ABSTRACT FROM AUTHOR]

Background: In 2020/2021 in Germany, several non-pharmacological interventions were introduced to lower the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We investigated to what extent knowledge of prior infection with SARS-CoV-2 or vaccination status influenced the use of personal protection measures (PPM). Further, we were interested in the effect of compliance with PPM on SARS-CoV-2 serostatus. Methods: Data was based on a sequential, multilocal seroprevalence study (MuSPAD), carried out in eight locations from July 2020 to August 2021. We estimated the association between a known SARS-CoV-2 serostatus (reported positive PCR test or vaccination) and self-reported PPM behavior (hand hygiene, physical distancing, wearing face mask), just as the association of PPM compliance with seropositivity against nucleocapsid (NC), receptor-binding domain (RBD), and spike protein (S) antigens. We identified relevant variables and deduced adjustment sets with directed acyclic graphs (DAG), and applied mixed logistic regression. Results: Out of the 22,297 participants (median age: 54 years, 43% male), 781 were classified as SARS-CoV-2-infected and 3,877 had a vaccinated immune response. Vaccinated individuals were less likely to keep 1.5 m distance [OR = 0.74 (95% CI: 0.57–0.97)] and only partly physically distanced [OR = 0.71 (95% CI: 0.58–0.87)]. Participants with self-reported positive PCR test had a lower chance of adhering partly to physical distancing [OR = 0.70 (95% CI: 0.50–0.99)] in comparison to the reference group. Higher odds of additionally wearing a face mask was observed in vaccinated [OR = 1.28 (95% CI: 1.08–1.51)] even if it was not obligatory. Overall, among unvaccinated participants, we found little evidence of lower odds of seropositivity given mask wearing [OR: 0.91 (95% CI: 0.71–1.16)], physical distancing [OR: 0.84 (95% CI: 0.59–1.20)] and no evidence for completely adhering to hand cleaning [OR: 0.97 (95% CI: 0.29–3.22)]. Conclusions: A known confirmed prior infection and vaccination may have the potential to influence adherence to PPM. [ABSTRACT FROM AUTHOR]

Natural killer (NK) cells are attractive effectors for adoptive immunotherapy of cancer. Results from first-in-human studies using chimeric antigen receptor (CAR)-engineered primary NK cells and NK-92 cells are encouraging in terms of efficacy and safety. In order to further improve treatment strategies and to test the efficacy of CAR-NK cells in a personalized manner, preclinical screening assays using patient-derived tumor samples are needed. Zebrafish (Danio rerio) embryos and larvae represent an attractive xenograft model to study growth and dissemination of patient-derived tumor cells because of their superb live cell imaging properties. Injection into the organisms circulation allows investigation of metastasis, cancer cell-to-immune cell-interactions and studies of the tumor cell response to anti-cancer drugs. Here, we established a zebrafish larval xenograft model to test the efficacy of CAR-NK cells against metastatic breast cancer in vivo by injecting metastatic breast cancer cells followed by CAR-NK cell injection into the Duct of Cuvier (DoC). We validated the functionality of the system with two different CAR-NK cell lines specific for PD-L1 and ErbB2 (PDL1. CAR NK-92 and ErbB2.CAR NK-92 cells) against the PD-L1-expressing MDAMB- 231 and ErbB2-expressing MDA-MB-453 breast cancer cell lines. Injected cancer cells were viable and populated peripheral regions of the larvae, including the caudal hematopoietic tissue (CHT), simulating homing of cancer cells to blood forming sites. CAR-NK cells injected 2.5 hours later migrated to the CHT and rapidly eliminated individual cancer cells throughout the organism. Unmodified NK-92 also demonstrated minor in vivo cytotoxicity. Confocal live-cell imaging demonstrated intravascular migration and real-time [ABSTRACT FROM AUTHOR]

Hematopoietic stem cells (HSCs) remain mostly quiescent under steady-state conditions but switch to a proliferative state following hematopoietic stress, e.g., bone marrow (BM) injury, transplantation, or systemic infection and inflammation. The homeostatic balance between quiescence, self-renewal, and differentiation of HSCs is strongly dependent on their interactions with cells that constitute a specialized microanatomical environment in the BM known as the HSC niche. Here, we identified the secreted extracellular matrix protein Del-1 as a component and regulator of the HSC niche. Specifically, we found that Del-1 was expressed by several cellular components of the HSC niche, including arteriolar endothelial cells, CXCL12-abundant reticular (CAR) cells, and cells of the osteoblastic lineage. Del-1 promoted critical functions of the HSC niche, as it regulated long-term HSC (LT-HSC) proliferation and differentiation toward the myeloid lineage. Del-1 deficiency in mice resulted in reduced LT-HSC proliferation and infringed preferentially upon myelopoiesis under both steady-state and stressful conditions, such as hematopoietic cell transplantation and G-CSF- or inflammation-induced stress myelopoiesis. Del-1-induced HSC proliferation and myeloid lineage commitment were mediated by [beta] integrin on hematopoietic progenitors. This hitherto unknown Del-1 function in the HSC niche represents a juxtacrine homeostatic adaptation of the hematopoietic system in stress myelopoiesis., Introduction Hematopoietic stem cells (HSC) lie at the core of the hematopoietic and immune systems and have a unique capacity for self-renewal and differentiation to multipotent and lineage-committed hematopoietic progenitors, [...]