IL-13 determines specific IgE responses and SARS-CoV-2 immunity after mild COVID-19 and novel mRNA vaccination.

After recovery, mild and severe COVID-19 diseases are associated with long-term effects on the host immune system, such as prolonged T-cell activation or accumulation of autoantibodies. In this study, we show that mild SARS-CoV-2 infections, but not SARS-CoV-2 spike mRNA vaccinations, cause durable atopic risk factors such as a systemic Th2- and Th17-type environment as well as activation of B cells responsive of IgE against aeroallergens from house dust mite and mold. At an average of 100 days post mild SARS-CoV-2 infections, anti-mold responses were associated with low IL-13 levels and increased pro-inflammatory IL-6 titers. Acutely severely ill COVID-19 patients instead showed no evidence of atopic reactions. Considering convalescents of mild COVID-19 courses and mRNA-vaccinated individuals together, IL-13 was the predominant significantly upregulated factor, likely shaping SARS-CoV-2 immunity. Application of multiple regression analysis revealed that the IL-13 levels of both groups were determined by the Th17-type cytokines IL-17A and IL-22. Taken together, these results implicate a critical role for IL-13 in the aftermath of SARS-CoV-2 mild infections and mRNA vaccinations, conferring protection against airway directed, atopic side reactions that occur in mildly experienced COVID-19.

PD-1/PD-L1 Control of Antigen-Specifically Activated CD4 T-Cells of Neonates.

Newborns are highly susceptible to infections; however, the underlying mechanisms that regulate the anti-microbial T-helper cells shortly after birth remain incompletely understood. To address neonatal antigen-specific human T-cell responses against bacteria, Staphylococcus aureus (S. aureus) was used as a model pathogen and comparatively analyzed in terms of the polyclonal staphylococcal enterotoxin B (SEB) superantigen responses. Here, we report that neonatal CD4 T-cells perform activation-induced events upon S. aureus/APC-encounter including the expression of CD40L and PD-1, as well as the production of Th1 cytokines, concomitant to T-cell proliferation. The application of a multiple regression analysis revealed that the proliferation of neonatal T-helper cells was determined by sex, IL-2 receptor expression and the impact of the PD-1/PD-L1 blockade. Indeed, the treatment of S. aureus-activated neonatal T-helper cells with PD-1 and PD-L1 blocking antibodies revealed the specific regulation of the immediate neonatal T-cell responses with respect to the proliferation and frequencies of IFNγ producers, which resembled in part the response of adults' memory T-cells. Intriguingly, the generation of multifunctional T-helper cells was regulated by the PD-1/PD-L1 axis exclusively in the neonatal CD4 T-cell lineage. Together, albeit missing memory T-cells in neonates, their unexperienced CD4 T-cells are well adapted to mount immediate and strong anti-bacterial responses that are tightly controlled by the PD-1/PD-L1 axis, thereby resembling the regulation of recalled memory T-cells of adults.

Unique autoantibody prevalence in long-term recovered SARS-CoV-2-infected individuals.

The variability in resolution of SARS-CoV-2-infections between individuals neither is comprehended, nor are the long-term immunological consequences. To assess the long-term impact of a SARS-CoV-2-infection on the immune system, we conducted a prospective study of 80 acute and former SARS-CoV-2 infected individuals and 39 unexposed donors to evaluate autoantibody responses and immune composition. Autoantibody levels against cyclic citrullinated peptide (CCP), a specific predictor for rheumatoid arthritis (RA), were significantly (p = 0.035) elevated in convalescents only, whereas both acute COVID-19 patients and long-term convalescents showed critically increased levels of anti-tissue transglutaminase (TG), a specific predictor of celiac disease (CD) (p = 0.002). Both, anti-CCP and anti-TG antibody levels were still detectable after 4-8 months post infection. Anti-TG antibodies occurred predominantly in aged patients in a context of a post-SARS-CoV-2-specific immune composition (R2 = 0.31; p = 0.044). This study shows that increased anti-CCP and anti-TG autoantibody levels can remain long-term after recovering even from mildly experienced COVID-19. The inter-relationship of the lung as viral entry side and RA- and CD-associated autoimmunity indicates that a SARS-CoV-2-infection could be a relevant environmental factor in their pathogenesis.

A combined oro-nasopharyngeal swab is more sensitive than mouthwash in detecting SARS-CoV-2 by a high-throughput PCR assay.

OBJECTIVES: The optimal diagnostic specimen to detect SARS-CoV-2 by PCR in the upper respiratory tract is unclear. Mouthwash fluid has been reported as an alternative to nasopharyngeal and oropharyngeal swabs. We compared mouthwash fluid with a combined oro-nasopharyngeal swab regarding test performance. METHODS: In a large refugee facility, we retested individuals with a previous positive test for SARS-CoV-2 and their quarantined close contacts. All individuals were asymptomatic at the time of testing. First, a mouthwash (gargling for at least 5 s) with sterile water was performed. Then, with a single flocked swab the back of the throat and subsequently the nasopharynx were sampled. Samples were inactivated and analysed on a Roche cobas 6800® system with the Roche SARS-CoV-2 test. RESULTS: Of 76 individuals, 39 (51%) tested positive for SARS-CoV-2 by oro-nasopharyngeal swab. Mouthwash detected 13 of 76 (17%) infections, but did not detect any additional infection. Samples that were positive in both tests, had lower cycle threshold (Ct)-values for oro-nasopharyngeal samples, indicating a higher virus concentration, compared to samples only positive in oro-nasopharyngeal swabs. CONCLUSION: Mouthwash is not as sensitive as combined oro-nasopharyngeal swab in detecting upper respiratory tract infection.

High-intensity interval training in allogeneic adoptive T-cell immunotherapy - a big HIT?

BACKGROUND: Adoptive transfer of virus-specific T cells (VSTs) represents a prophylactic and curative approach for opportunistic viral infections and reactivations after transplantation. However, inadequate frequencies of circulating memory VSTs in the T-cell donor's peripheral blood often result in insufficient enrichment efficiency and purity of the final T-cell product, limiting the effectiveness of this approach. METHODS: This pilot study was designed as a cross-over trial and compared the effect of a single bout (30 min) of high-intensity interval training (HIT) with that of 30 min of continuous exercise (CONT) on the frequency and function of circulating donor VSTs. To this end, we used established immunoassays to examine the donors' cellular immune status, in particular, with respect to the frequency and specific characteristics of VSTs restricted against Cytomegalovirus (CMV)-, Epstein-Barr-Virus (EBV)- and Adenovirus (AdV)-derived antigens. T-cell function, phenotype, activation and proliferation were examined at different time points before and after exercise to identify the most suitable time for T-cell donation. The clinical applicability was determined by small-scale T-cell enrichment using interferon- (IFN-) γ cytokine secretion assay and virus-derived overlapping peptide pools. RESULTS: HIT proved to be the most effective exercise program with up to fivefold higher VST response. In general, donors with a moderate fitness level had higher starting and post-exercise frequencies of VSTs than highly fit donors, who showed significantly lower post-exercise increases in VST frequencies. Both exercise programs boosted the number of VSTs against less immunodominant antigens, specifically CMV (IE-1), EBV (EBNA-1) and AdV (Hexon, Penton), compared to VSTs against immunodominant antigens with higher memory T-cell frequencies. CONCLUSION: This study demonstrates that exercise before T-cell donation has a beneficial effect on the donor's cellular immunity with respect to the proportion of circulating functionally active VSTs. We conclude that a single bout of HIT exercise 24 h before T-cell donation can significantly improve manufacturing of clinically applicable VSTs. This simple and economical adjuvant treatment proved to be especially efficient in enhancing virus-specific memory T cells with low precursor frequencies.

Transfer of Hexon- and Penton-selected adenovirus-specific T cells for refractory adenovirus infection after haploidentical stem cell transplantation.

Adenovirus (HAdV) infections confer a high risk of morbidity and mortality for immunocompromised patients after stem cell transplantation (SCT). Treatment with standard antiviral drugs is of limited efficacy and associated with a high rate of adverse effects. HAdV-specific T cells are crucial for sustained viral elimination and the efficacy of adoptive T-cell therapy with donor-derived HAdV-specific T cells has been reported by several investigators. Here, we report our experience with the transfer of HAdV-specific T cells specific for penton, which was recently identified as an immunodominant target of T cells, and hexon in a 14-year-old boy after T-cell-depleted haploidentical SCT for myelodysplastic syndrome (MDS). He developed severe HAdV-associated enteritis complicated by acute graft-versus-host disease (GvHD). The patient received ten infusions of allogeneic HAdV-specific T cells manufactured from the haploidentical stem cell donor using the CliniMacs Interferon-γ (IFN-γ) cytokine capture and immunomagnetic selection. Initially, T cells were generated against the immunodominant target hexon and in subsequent transfers dual antigen-specific T cells against hexon and penton were applied. T-cell transfers were scheduled individually tailored to current immunosuppressive treatment. Each transfer was followed by reduction of HAdV load in peripheral blood and clinical improvement. Importantly, T-cell responses to both penton and hexon pools emerged in patient blood after repetitive transfers. Unfortunately, the patient experienced bacterial sepsis, and in this context, severe GvHD requiring intensive immunosuppression followed by secondary progression of HAdV infection. The patient succumbed to multiorgan failure 283 days after SCT. This case demonstrates the feasibility of HAdV-specific T-cell transfer even in the presence of immunosuppressive treatment. Targeting of multiple immunodominant viral proteins may prove valuable in patients with complicated HAdV infections.

Relation of α2-Antiplasmin Genotype and Genetic Determinants of Fibrinogen Synthesis and Fibrin Clot Formation with Vascular Endothelial Growth Factor Level in Axial Spondyloarthritis.

OBJECTIVE: Coagulation and fibrinolysis are interrelated with the expression of vascular endothelial growth factor (VEGF), which frequently is increased in axial spondyloarthritis (axSpA). We tested whether (i) α2-antiplasmin (A2AP) Arg6Trp, (ii) fibrinogen, factor XIII A-subunit or B-subunit genotypes are associated with VEGF levels and assessed whether the known association between elevated VEGF and radiographic spinal progression in axSpA depends on genetic background. METHODS: One hundred and eighty-six axSpA patients from the German Spondyloarthritis Inception Cohort were genotyped, characterized for VEGF levels, and statistically analyzed. The association between VEGF and radiographic spinal progression was assessed in dependence on genetic background in stratified analyses. RESULTS: A2AP 6Trp carriage was associated with VEGF elevation (OR: 2.37, 95% CI: 1.06-5.29) and VEGF levels (6Trp, 455 ± 334 pg/mL; 6Arg/Arg, 373 ± 293 pg/mL; p < 0.008). Association between elevated VEGF and radiographic spinal progression in axSpA (OR: 3.11, 95% CI: 1.02-8.82) depended remarkably on the fibrinogen (FGA) genotype. When considering axSpA patients with elevated VEGF, in FGA rs6050A>G wild types, 42.1% of patients (8 of 19) progressed, while in G-allele carriers, no radiographic progression happened (0 of 13) (p < 0.04). CONCLUSIONS: The A2AP Arg6Trp genotype seems to influence VEGF levels in axSpA. The predictive value of VEGF elevations in respect of radiographic spinal progression in axSpA depends on FGA genotypes.

Intracoronary autologous bone marrow cell transfer after myocardial infarction: the BOOST-2 randomised placebo-controlled clinical trial.

AIMS: Intracoronary infusion of autologous nucleated bone marrow cells (BMCs) enhanced the recovery of left ventricular ejection fraction (LVEF) after ST-segment elevation myocardial infarction (STEMI) in the randomised-controlled, open-label BOOST trial. We reassessed the therapeutic potential of nucleated BMCs in the randomised placebo-controlled, double-blind BOOST-2 trial conducted in 10 centres in Germany and Norway. METHODS AND RESULTS: Using a multiple arm design, we investigated the dose-response relationship and explored whether γ-irradiation which eliminates the clonogenic potential of stem and progenitor cells has an impact on BMC efficacy. Between 9 March 2006 and 16 July 2013, 153 patients with large STEMI were randomly assigned to receive a single intracoronary infusion of placebo (control group), high-dose (hi)BMCs, low-dose (lo)BMCs, irradiated hiBMCs, or irradiated loBMCs 8.1 ± 2.6 days after percutaneous coronary intervention (PCI) in addition to guideline-recommended medical treatment. Change in LVEF from baseline (before cell infusion) to 6 months as determined by MRI was the primary endpoint. The trial is registered at Current Controlled Trials (ISRCTN17457407). Baseline LVEF was 45.0 ± 8.5% in the overall population. At 6 months, LVEF had increased by 3.3 percentage points in the control group and 4.3 percentage points in the hiBMC group. The estimated treatment effect was 1.0 percentage points (95% confidence interval, -2.6 to 4.7; P = 0.57). The treatment effect of loBMCs was 0.5 percentage points (-3.0 to 4.1; P = 0.76). Likewise, irradiated BMCs did not have significant treatment effects. BMC transfer was safe and not associated with adverse clinical events. CONCLUSION: The BOOST-2 trial does not support the use of nucleated BMCs in patients with STEMI and moderately reduced LVEF treated according to current standards of early PCI and drug therapy.

Differentiation of induced pluripotent stem cell-derived neutrophil granulocytes from common marmoset monkey (Callithrix jacchus).

BACKGROUND: Inherited and acquired marrow failure syndromes most commonly lead to defect in myeloid and/or neutrophil differentiation and/or function. Besides this, neutropenia induced by cancer-adjusted chemotherapy is a frequent clinical problem. In both cases, cell replacement therapy is a well-established, but due to necessity of donors limited and perilous procedure. Therefore, autologous cell replacement from patients' own marrow-derived cells lowers risk and bares new possibilities for therapy. Since the immune system of the marmoset monkey is known to show high similarity to humans, preclinical studies with these animals bare high hopes for immunologic research and cell replacement therapy. STUDY DESIGN AND METHODS: Marmoset-induced pluripotent stem (iPS) cells (cj-iPSC) were first cultivated on mouse embryonic feeder cells in medium containing recombinant human vascular endothelial growth factor. After 13 days, CD34+/vascular endothelial growth factor receptor-2 (VEGFR2)- cells were sorted, treated with interleukin (IL-3), thrombopoietin, and stem cell factor for 20 days and further cultivated with granulocyte-colony-stimulating factor (G-CSF) and IL-3 for 10 days. RESULTS: CD34+/VEGFR2- cells could be generated in high amounts (39.65 ± 6.01%; 2.31 × 105 cells). Afterward, these hematopoietic progenitors could be successfully differentiated into mature cj-iPSC-derived neutrophils showing similar morphology, specific surface antigens, and neutrophil-specific gene products and in vitro phagocytic activity. CONCLUSION: cj-iPSC-derived neutrophils bare high hopes in hematologic cell replacement therapy. They exhibit high morphologic similarity to native neutrophils and present neutrophil-specific surface antigens, antimicrobial proteins, and gene products yielding an auspicious approach for continuative experiments including tests in living animals.

Donor Safety in Haemapheresis: Development of an Internet-Based Registry for Comprehensive Assessment of Adverse Events from Healthy Donors.

BACKGROUND: Currently, there is an extensive but highly inconsistent body of literature regarding donor adverse events (AEs) in haemapheresis. As the reports diverge with respect to types and grading of AEs, apheresis procedures and machines, the range of haemapheresis-related AEs varies widely from about 0.03% to 6.6%. METHODS: The German Society for Transfusion Medicine and Immunohaematology (DGTI) formed a 'Haemapheresis Vigilance Working Party' (Arbeitsgemeinschaft Hämapheresevigilanz; AGHV) to create an on-line registry for comprehensive and comparable AE assessment with all available apheresis devices in all types of preparative haemapheresis: plasmapheresis (PLS), plateletpheresis (PLT), red blood cell apheresis, all kind of leukaphereses (autologous/allogeneic blood stem cell apheresis, granulocyte apheresis, lymphocyte/monocyte apheresis) and all possible types of multi-component apheresis. To ensure the comparability of the data, the AGHV adopted the 'Standard for Surveillance of Complications Related to Blood Donation' from the International Society for Blood Transfusion in cooperation with the International Haemovigilance Network (IHN) and the American Association of Blood Banks for AE acquisition and automated evaluation. The registry is embedded in a prospective observational multi-centre study with a study period of 7 years. RESULTS: A preliminary evaluation encompassed the time period from January, 2012 to December, 2015. During this time, the system proved to be safe and stable. Out of approximately 345,000 haemaphereses 16,477 AEs were reported (4.9%) from 20 participating centres. The majority of AEs occurred in PLSs (63%), followed by PLT (34.5%) and SC (2.2%). Blood access injuries (BAI) accounted for about 55% of the supplied AEs, whereas citrate toxicity symptoms, vasovagal reactions and technical events (e.g. disposable leakages, software failures) rather equally affected haemaphereses at 8-15%. Out of 12,348 finalized AEs, 8,759 (70.1%) were associated with a procedure-related break-off, with BAI being the prevailing cause (5,463/8,759; 62.4%). An automated centre- and procedure-specific AE evaluation according to the latest IHN standard and AGHV pre-settings is available within a few minutes. CONCLUSIONS: An on-line electronic platform for comprehensive assessment and centre-specific automated evaluation of AEs in haemaphereses has been developed and proved to be stable and safe over a period of 4 years.

Rapid generation of clinical-grade antiviral T cells: selection of suitable T-cell donors and GMP-compliant manufacturing of antiviral T cells.

BACKGROUND: The adoptive transfer of allogeneic antiviral T lymphocytes derived from seropositive donors can safely and effectively reduce or prevent the clinical manifestation of viral infections or reactivations in immunocompromised recipients after hematopoietic stem cell (HSCT) or solid organ transplantation (SOT). Allogeneic third party T-cell donors offer an alternative option for patients receiving an allogeneic cord blood transplant or a transplant from a virus-seronegative donor and since donor blood is generally not available for solid organ recipients. Therefore we established a registry of potential third-party T-cell donors (allogeneic cell registry, alloCELL) providing detailed data on the assessment of a specific individual memory T-cell repertoire in response to antigens of cytomegalovirus (CMV), Epstein-Barr virus (EBV), adenovirus (ADV), and human herpesvirus (HHV) 6. METHODS: To obtain a manufacturing license according to the German Medicinal Products Act, the enrichment of clinical-grade CMV-specific T cells from three healthy CMV-seropositive donors was performed aseptically under GMP conditions using the CliniMACS cytokine capture system (CCS) after restimulation with an overlapping peptide pool of the immunodominant CMVpp65 antigen. Potential T-cell donors were selected from alloCELL and defined as eligible for clinical-grade antiviral T-cell generation if the peripheral fraction of IFN-γ(+) T cells exceeded 0.03% of CD3(+) lymphocytes as determined by IFN-γ cytokine secretion assay. RESULTS: Starting with low concentration of IFN-γ(+) T cells (0.07-1.11%) we achieved 81.2%, 19.2%, and 63.1% IFN-γ(+)CD3(+) T cells (1.42 × 10(6), 0.05 × 10(6), and 1.15 × 10(6)) after enrichment. Using the CMVpp65 peptide pool for restimulation resulted in the activation of more CMV-specific CD8(+) than CD4(+) memory T cells, both of which were effectively enriched to a total of 81.0% CD8(+)IFN-γ(+) and 38.4% CD4(+)IFN-γ(+) T cells. In addition to T cells and NKT cells, all preparations contained acceptably low percentages of contaminating B cells, granulocytes, monocytes, and NK cells. The enriched T-cell products were stable over 72 h with respect to viability and ratio of T lymphocytes. CONCLUSIONS: The generation of antiviral CD4(+) and CD8(+) T cells by CliniMACS CCS can be extended to a broad spectrum of common pathogen-derived peptide pools in single or multiple applications to facilitate and enhance the efficacy of adoptive T-cell immunotherapy.

Desmopressin (DDAVP) improves recruitment of activated platelets to collagen but simultaneously increases platelet endothelial interactions in vitro.

Platelet dysfunction can cause clinically relevant bleeding. Treatment with DDAVP is advocated for this condition. DDAVP increases von Willebrand factor (VWF) on endothelial cells (ECs) and in plasma. VWF could facilitate platelet deposition on subendothelial collagen. VWF also facilitates platelet/EC interactions. Therefore DDAVP could precipitate thromboembolic events. We used a flow chamber model to study in vitro and ex vivo if DDAVP alters recruitment of platelets to EC and collagen. Resting or TRAP-activated platelets and EC were treated individually or simultaneously with 0.4 ng/ml DDAVP. Fluorophor-labeled platelets (10(6)/ml) were resuspended in reconstituted blood and superfused across EC and collagen in an in vitro flow chamber model at arterial shear (320 s(-1)). Adhesion of platelets to the respective surface was recorded fluorescence microscopically and platelet covered area was assessed. TRAP significantly induced adhesiveness of platelets for collagen and EC. DDAVP pretreatment of platelets did not affect adhesiveness of resting or TRAP-activated platelets for collagen or EC. Adhesiveness of resting but not TRAP-activated platelets was induced on DDAVP-treated EC. DDAVP-conditioned EC supernatant contained vWF and significantly increased platelet deposition on collagen. Platelets from patients with clinically suspected platelet dysfunction undergoing aortic valve replacement exhibited decreased platelet deposition on collagen surfaces. In summary, our data confirm that DDAVP can induce release of platelet adhesion promoting factors from EC, which is most likely vWF. DDAVP has no direct effect on platelets. Blood samples from DDAVP-treated patients do not exhibit significantly augmented platelet deposition on collagen ex vivo. This influence of released promoting factors might cause an increase of undesirable interactions of platelets with EC.

Sociodemographic influences on private and professional contact behaviour during the COVID-19 pandemic in Germany: cross-sectional analysis based on a Regional Blood Donor Cohort.

OBJECTIVE: The COVID-19 pandemic has had significant health and socioeconomic impacts worldwide. Extensive measures, including contact restrictions, were implemented to control the spread of the virus. This study aims to examine the factors that influenced private and professional contact behaviour during the COVID-19 pandemic. RESULTS: We used baseline data (January-April 2021) from the SeMaCo study (Serologische Untersuchungen bei Blutspendern des Großraums Magdeburg auf Antikörper gegen SARS-CoV-2), a longitudinal, regional cohort study assessing COVID-19 seroprevalence in blood donors from Magdeburg and surrounding areas in Germany. In the blood donor cohort (n = 2,195), there was a general reduction in private contacts (by 78.9%) and professional contacts (by 54.4%) after March 18, 2020. Individuals with higher education reduced both private (by 84.1%) and professional (by 70.1%) contacts more than those with lower education levels (private contacts 59.5%; professional contacts 37%). Younger age groups (18-30 years) reduced private contacts more frequently (by 85.4%) than older individuals (61-83 years, by 68.6%) and demonstrated a higher likelihood of private contact reduction compared to older age groups (51-60 years: odds ratio (OR) 0.45 [95% [CI] 0.32-0.65]; 61-83 years: OR 0.33 [95% [CI] 0.22-0.48]).

CMV-, EBV- and ADV-specific T cell immunity: screening and monitoring of potential third-party donors to improve post-transplantation outcome.

Adoptive immunotherapy with virus-specific T lymphocytes can efficiently reconstitute antiviral immunity against cytomegalovirus (CMV), Epstein-Barr virus (EBV), and adenovirus (ADV) without causing acute toxicity or increasing the risk of graft-versus-host disease. To gain insight into antiviral T cell repertoires and to identify the most efficient antigens for immunotherapy, the frequencies of CMV-, EBV- and ADV-specific T cells in 204 HLA-typed healthy donors were assessed using viral peptides and peptide pools. Confirmatory testing for CMV serology by Western blot technique revealed 19 of 143 (13%) false-positive results. We observed highly significant individual and overall differences in T cell frequencies against CMV, EBV, and ADV antigens, whereas antigen-specific T cells were detected in 100% of CMV- seropositive donors, 73% of EBV- seropositive donors, and 73% of ADV-seropositive donors. At least 124 (61%) potential T cell donors were identified for each virus. Among the tested antigens, frequencies for CMVpp65 and EBVBZLF1 peptide pools were highest. Short-term in vitro peptide stimulation revealed that a donor response to a certain ADV- and EBV-derived peptide may not be determined without prior stimulation. A modified granzyme B ELISpot was used to detect T cell specificity and alloreactivity. Treatment with allogeneic virus-specific cytotoxic T lymphocytes from seropositive third-party donors may be a feasible therapeutic option for infections following cord-blood stem cell transplantation or hematopoietic stem cell transplantation from virus-seronegative donors.

Donor safety in triple plateletpheresis: results from the German and Austrian Plateletpheresis Study Group multicenter trial.

BACKGROUND: The objective was to investigate potential risks for apheresis donors associated with a triple-plateletpheresis (TP) program. STUDY DESIGN AND METHODS: Eleven hemapheresis centers randomly assigned 411 repeat donors (ratio, 1:1.2) to either double plateletpheresis (DP; 185 donors) or TP (226 donors) with a platelet (PLT) target content of at least 5.0×10(11) PLTs/DP and at least 7.5×10(11) PLTs/TP. The primary endpoint was procedure-related postapheresis PLT count of at least 150×10(9) /L (probability, ≥98%). Secondary endpoints were apheresis characteristics and donor adverse reactions. RESULTS: In 6 of 1133 DPs (0.5%) in 4 of 185 donors (2.2%) and in 20 of 1020 TPs (2.0%) in 14 of 226 donors (6.2%), postapheresis PLT counts were below 150×10(9) /L. There were marginal but significant differences in collection efficiency (DP, 69.2±9.1%; TP, 70.9±9.0%; p≤0.0001) and collection rate (DP, 10.4×10(9) ±2.3×10(9) PLTs/min; TP, 10.8×10(9) ±2.3×10(9) PLTs/min; p≤0.005). The PLT yields were 5.9×10(11) ±0.8×10(11) PLTs for DP and 8.3×10(11) ±0.9×10(11) PLT for TP (p≤0.0001) at processing times of 59±13 minutes (DP) versus 80±16 minutes (TP; p≤0.0001). Significant PLT recruitment (1.10±0.14 vs. 1.20±0.23; p<0.0001) was seen for both DP and TP. DP and TP did not differ with regard to venous access problems (VAPs) without discontinuation (3.8% for both), but DP induced fewer VAPs with discontinuation (1.1% vs. 3.0%; p<0.01). Mild citrate toxicity (1.7% vs. 3.9%; p<0.01) and circulatory reactions (0.4% vs. 2.2%; p<0.01) were more often noticed in TP, but caused no increase in discontinuations. CONCLUSIONS: TP results in an increase in mild donor reactions but does not significantly impair donor safety or product quality.

Window period donations during primary cytomegalovirus infection and risk of transfusion-transmitted infections.

BACKGROUND: Donors with short interdonation intervals (e.g., apheresis donors) have an increased risk of window period donations. The frequency of cytomegalovirus (CMV) window period donations is important information to decide whether selection of seronegative donors might be advantageous for patients at risk for transfusion-transmitted CMV infections (TT-CMV). STUDY DESIGN AND METHODS: CMV seroconversion in 93 donors with positive results in routine CMV antibody testing within at most 35 days after the last seronegative sample was evaluated by Western blot and/or a second antibody test. In donors with unconfirmed seroconversion, an additional later sample was tested. Concentration of CMV DNA was determined in pre- and postseroconversion samples. RESULTS: CMV seroconversion was confirmed in 12 donors (13%). Among these, the last seronegative sample was CMV DNA positive in three donors (25%, below 30 IU/mL). The first seropositive sample was CMV DNA positive in 10 donors (83%, maximum 1600 IU/mL). Both prevalence and median concentration of CMV DNA were higher in the first seropositive sample (p = 0.004 and p = 0.02), with maximum concentrations being reached about 2 weeks after seroconversion. No CMV DNA was detected in samples from donors with unconfirmed seroconversion. CONCLUSION: At least in donors with short interdonation intervals, most suspected CMV seroconversions are due to false-positive results of the screening test. As window period donations are rare and contain less CMV DNA than the first seropositive donation, avoidance of blood products from primarily seropositive donors is especially helpful to avoid TT-CMV if donors with short interdonation intervals are concerned.

Cohort profile: a longitudinal regional cohort study to assess COVID-19 seroprevalence in blood donors - baseline characteristics of the SeMaCo study participants.

PURPOSE: The SeMaCo study (Serologische Untersuchungen bei Blutspendern des Großraums Magdeburg auf Antikörper gegen SARS-CoV-2), a prospective, longitudinal cohort study with four survey phases spanning 3-5 months each over a period of 22 months, extends the spectrum of seroepidemiological studies in Germany. We present here a careful characterisation of the initial survey phase of the cohort to provide baseline data on infection incidence and obtained from questionnaires, focussing in particular on the attitude towards COVID-19 vaccinations, the vaccination success and the vaccination acceptance. PARTICIPANTS: A total of 2195 individual blood donors from the donor pool of the blood donation service of the University Hospital Magdeburg were enrolled in the initial survey phase from 20 January 2021 to 30 April 2021. 2138 participants gave sociodemographic/contact data (51.7% male, mean age 44 years) and 2082 participants answered the vaccination questionnaire. FINDINGS TO DATE: Out of 2195 participants with antibody results, 1909 (87.0%) were antibody negative. The remaining 286 subjects (13.0%) were either antibody-positive and vaccinated (160/286; 55.9%) or antibody-positive without vaccination information (17/286; 5.9%) or antibody-positive and unvaccinated (109/286; 38.1%). The latter result reflects the rate of true or highly probable SARS-CoV-2 infections in our initial study cohort. FUTURE PLANS: The study primarily aims to measure the prevalence and long-term kinetics of IgG-antibodies against SARS-CoV-2. Including the baseline, the study foresees four survey periods of 3-4 months each. At each visit, we will assess the blood donors' attitude towards vaccination, the antibody response following vaccination and/or infection, as well as undesired vaccination effects. We aim to test the same participants during the survey periods by repeated invitations for blood donation to ensure a long-term (follow-up) in as many study participants as possible. After the four survey phases, a longitudinal data set will be created that reflects the course of the antibody levels/frequencies as well as the infection and vaccination incidence. TRIAL REGISTRATION NUMBER: DRKS00023263.

Monitoring the SARS-CoV-2 Pandemic: Prevalence of Antibodies in a Large, Repetitive Cross-Sectional Study of Blood Donors in Germany-Results from the SeBluCo Study 2020-2022.

SARS-CoV-2 serosurveillance is important to adapt infection control measures and estimate the degree of underreporting. Blood donor samples can be used as a proxy for the healthy adult population. In a repeated cross-sectional study from April 2020 to April 2021, September 2021, and April/May 2022, 13 blood establishments collected 134,510 anonymised specimens from blood donors in 28 study regions across Germany. These were tested for antibodies against the SARS-CoV-2 spike protein and nucleocapsid, including neutralising capacity. Seroprevalence was adjusted for test performance and sampling and weighted for demographic differences between the sample and the general population. Seroprevalence estimates were compared to notified COVID-19 cases. The overall adjusted SARS-CoV-2 seroprevalence remained below 2% until December 2020 and increased to 18.1% in April 2021, 89.4% in September 2021, and to 100% in April/May 2022. Neutralising capacity was found in 74% of all positive specimens until April 2021 and in 98% in April/May 2022. Our serosurveillance allowed for repeated estimations of underreporting from the early stage of the pandemic onwards. Underreporting ranged between factors 5.1 and 1.1 in the first two waves of the pandemic and remained well below 2 afterwards, indicating an adequate test strategy and notification system in Germany.