Background and ObjectivesRed blood cell (RBC) transfusions pose a risk of alloantibody development in patients. For patients with increased alloimmunization risk, extended preventive matching is... Show moreBackground and ObjectivesRed blood cell (RBC) transfusions pose a risk of alloantibody development in patients. For patients with increased alloimmunization risk, extended preventive matching is advised, encompassing not only the ABO-D blood groups but also the most clinically relevant minor antigens: C, c, E, e, K, Fya, Fyb, Jka, Jkb, S and s. This study incorporates patient-specific data and the clinical consequences of mismatching into the allocation process.Materials and MethodsWe have redefined the MINimize Relative Alloimmunization Risks (MINRAR) model to include patient group preferences in selecting RBC units from a finite supply. A linear optimization approach was employed, considering both antigen immunogenicity and the clinical impact of mismatches for specific patient groups. We also explore the advantages of informing the blood bank about scheduled transfusions, allowing for a more strategic blood distribution. The model is evaluated using historical data from two Dutch hospitals, measuring shortages and minor antigen mismatches.ResultsThe updated model, emphasizing patient group-specific considerations, achieves a similar number of mismatches as the original, yet shifts mismatches among patient groups and antigens, reducing expected alloimmunization consequences. Simultaneous matching for multiple hospitals at the distribution centre level, considering scheduled demands, led to a 30% decrease in mismatches and a 92% reduction in shortages.ConclusionThe reduction of expected alloimmunization consequences by incorporating patient group preferences demonstrates our strategy's effectiveness for patient health. Substantial reductions in mismatches and shortages with multi-hospital collaboration highlights the importance of sharing information in the blood supply chain. Show less
Graaf, E.L. de; Larsen, M.D.; Bolt, N. van der; Visser, R.; Verhagen, O.J.H.M.; Ederveen, A.L.H.; ... ; Vidarsson, G. 2023
The type and strength of effector functions mediated by immunoglobulin G (IgG) antibodies rely on the subclass and the composition of the N297 glycan. Glycosylation analysis of both bulk and... Show moreThe type and strength of effector functions mediated by immunoglobulin G (IgG) antibodies rely on the subclass and the composition of the N297 glycan. Glycosylation analysis of both bulk and antigen-specific human IgG has revealed a marked diversity of the glycosylation signatures, including highly dynamic patterns as well as long-term stability of profiles, yet information on how individual B cell clones would contribute to this diversity has hitherto been lacking. Here, we assessed whether clonally related B cells share N297 glycosylation patterns of their secreted IgG. We differentiated single antigen-specific peripheral IgG+ memory B cells into antibody-secreting cells and analysed Fc glycosylation of secreted IgG. Furthermore, we sequenced the variable region of their heavy chain, which allowed the grouping of the clones into clonotypes. We found highly diverse glycosylation patterns of culture-derived IgG, which, to some degree, mimicked the glycosylation of plasma IgG. Each B cell clone secreted IgG with a mixture of different Fc glycosylation patterns. The majority of clones produced fully fucosylated IgG. B cells producing afucosylated IgG were scattered across different clonotypes. In contrast, the remaining glycosylation traits were, in general, more uniform. These results indicate IgG-Fc fucosylation to be regulated at the single-clone level, whereas the regulation of other glycosylation traits most likely occurs at a clonotypic or systemic level. The discrepancies between plasma IgG and culture-derived IgG, could be caused by the origin of the B cells analysed, clonal dominance or factors from the culture system, which need to be addressed in future studies. Show less
Fetal and neonatal alloimmune thrombocytopenia (FNAIT) can occur due to maternal IgG antibodies targeting platelet antigens, causing life-threatening bleeding in the neonate. However, the disease... Show moreFetal and neonatal alloimmune thrombocytopenia (FNAIT) can occur due to maternal IgG antibodies targeting platelet antigens, causing life-threatening bleeding in the neonate. However, the disease manifests itself in only a fraction of pregnancies, most commonly with anti-HPA-1a antibodies. We found that in particular, the core fucosylation in the IgG-Fc tail is highly variable in anti-HPA-1a IgG, which strongly influences the binding to leukocyte IgG-Fc receptors IIIa/b (FcγRIIIa/b). Currently, gold-standard IgG-glycoanalytics rely on complicated methods (e.g., mass spectrometry (MS)) that are not suited for diagnostic purposes. Our aim was to provide a simplified method to quantify the biological activity of IgG antibodies targeting cells. We developed a cellular surface plasmon resonance imaging (cSPRi) technique based on FcγRIII-binding to IgG-opsonized cells and compared the results with MS. The strength of platelet binding to FcγR was monitored under flow using both WT FcγRIIIa (sensitive to Fc glycosylation status) and mutant FcγRIIIa-N162A (insensitive to Fc glycosylation status). The quality of the anti-HPA-1a glycosylation was monitored as the ratio of binding signals from the WT versus FcγRIIIa-N162A, using glycoengineered recombinant anti-platelet HPA-1a as a standard. The method was validated with 143 plasma samples with anti-HPA-1a antibodies analyzed by MS with known clinical outcomes and tested for validation of the method. The ratio of patient signal from the WT versus FcγRIIIa-N162A correlated with the fucosylation of the HPA-1a antibodies measured by MS (r=-0.52). Significantly, FNAIT disease severity based on Buchanan bleeding score was similarly discriminated against by MS and cSPRi. In conclusion, the use of IgG receptors, in this case, FcγRIIIa, on SPR chips can yield quantitative and qualitative information on platelet-bound anti-HPA-1a antibodies. Using opsonized cells in this manner circumvents the need for purification of specific antibodies and laborious MS analysis to obtain qualitative antibody traits such as IgG fucosylation, for which no clinical test is currently available. Show less
Coillie, J. van; Pongracz, T.; Sustic, T.; Wang, W.J.; Nouta, J.; Gars, M. le; ... ; COUGH1 Study Grp 2023
IgG antibodies are important mediators of vaccine-induced immunity through complement- and Fc receptor-dependent effector functions. Both are influenced by the composition of the conserved N-linke... Show moreIgG antibodies are important mediators of vaccine-induced immunity through complement- and Fc receptor-dependent effector functions. Both are influenced by the composition of the conserved N-linked glycan located in the IgG Fc domain. Here, we compared the anti-Spike (S) IgG1 Fc glycosylation profiles in response to mRNA, adenoviral, and protein-based COVID-19 vaccines by mass spectrometry (MS). All vaccines induced a transient increase of antigen-specific IgG1 Fc galactosylation and sialylation. An initial, transient increase of afucosylated IgG was induced by membrane-encoding S protein formulations. A fucose-sensitive ELISA for antigen-specific IgG (FEASI) exploiting FcγRIIIa affinity for afucosylated IgG was used as an orthogonal method to confirm the LC-MS-based afucosylation readout. Our data suggest that vaccine-induced anti-S IgG glycosylation is dynamic, and although variation is seen between different vaccine platforms and individuals, the evolution of glycosylation patterns display marked overlaps. Show less
Vos, T.W. de; Zagten, M. van; Haas, M. de; Oepkes, D.; Tan, R.N.G.B.; Schoot, C.E. van der; ... ; Klink, J.M.M. van 2023
ObjectiveTo evaluate the neurodevelopmental outcome at school age in children newly diagnosed with fetal and neonatal alloimmune thrombocytopenia (FNAIT).Study designThis observational cohort study... Show moreObjectiveTo evaluate the neurodevelopmental outcome at school age in children newly diagnosed with fetal and neonatal alloimmune thrombocytopenia (FNAIT).Study designThis observational cohort study included children diagnosed with FNAIT between 2002 and 2014. Children were invited for cognitive and neurological testing. Behavioral questionnaires and school performance results were obtained. A composite outcome of neurodevelopmental impairment (NDI) was used, defined, and subdivided into mild-to-moderate and severe NDI. Primary outcome was severe NDI, defined as IQ <70, cerebral palsy with Gross Motor Functioning Classification System level ≥ III, or severe visual/hearing impairment. Mild-to-moderate NDI was defined as IQ 70-85, minor neurological dysfunction or cerebral palsy with Gross Motor Functioning Classification System level ≤ II, or mild visual/hearing impairment.ResultsIn total, 44 children were included at a median age of 12 years (range: 6-17 years). Neuroimaging at diagnosis was available in 82% (36/44) of children. High-grade intracranial hemorrhage (ICH) was detected in 14% (5/36). Severe NDI was detected in 7% (3/44); two children had high-grade ICH, and one had low-grade ICH and perinatal asphyxia. Mild-to-moderate NDI was detected in 25% (11/44); one child had high-grade ICH, and eight children were without ICH, yet for two children, neuroimaging was not performed. Adverse outcome (perinatal death or NDI) was 39% (19/49). Four children (9%) attended special needs education, three of whom had severe NDI and one had mild-to-moderate NDI. Total behavioral problems within the clinical range were reported in 12%, which is comparable with 10% in the general Dutch population.ConclusionChildren who are newly diagnosed with FNAIT are at increased risk for long-term neurodevelopmental problems, even those without ICH. Show less
Gharbharan, A.; Jordans, C.; Zwaginga, L.; Papageorgiou, G.; Geloven, N. van; Wijngaarden, P. van; ... ; CoV-Early study grp 2023
Objectives: The potential benefit of convalescent plasma (CP) therapy for coronavirus disease 2019 (COVID-19) is highest when administered early after symptom onset. Our objective was to determine... Show moreObjectives: The potential benefit of convalescent plasma (CP) therapy for coronavirus disease 2019 (COVID-19) is highest when administered early after symptom onset. Our objective was to determine the effectiveness of CP therapy in improving the disease course of COVID-19 among high-risk outpatients. Methods: A multicentre, double-blind randomized trial was conducted comparing 300 mL of CP with non-CP. Patients were >= 50 years, were symptomatic for <8 days, had confirmed RT-PCR or antigen test result for COVID-19 and had at least one risk factor for severe COVID-19. The primary endpoint was the highest score on a 5-point ordinal scale ranging from fully recovered (score = 1) or not (score = 2) on day 7, over hospital admission (score = 3), intensive care unit admission (score = 4) and death (score = 5) in the 28 days following randomization. Secondary endpoints were hospital admission, symptom duration and viral RNA excretion. Results: After the enrolment of 421 patients and the transfusion in 416 patients, recruitment was dis-continued when the countrywide vaccination uptake in those aged >50 years was 80%. Patients had a median age of 60 years, symptoms for 5 days, and 207 of 416 patients received CP therapy. During the 28 day follow-up, 28 patients were hospitalized and two died. The OR for an improved disease severity score with CP was 0.86 (95% credible interval, 0.59-1.22). The OR was 0.58 (95% CI, 0.33-1.02) for patients with <5 days of symptoms. The hazard ratio for hospital admission was 0.61 (95% CI, 0.28-1.34). No difference was found in viral RNA excretion or in the duration of symptoms. Conclusions: In patients with early COVID-19, CP therapy did not improve the 5-point disease severity score. Arvind Gharbharan, Clin Microbiol Infect 2023;29:208 (c) 2022 The Authors. Published by Elsevier Ltd on behalf of European Society of Clinical Microbiology and Infectious Diseases. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/). Show less
Coillie, J. van; Pongracz, T.; Rahmoller, J.; Chen, H.J.; Geyer, C.E.; Vught, L.A. van; ... ; UMC COVID-19 S HCW Study Grp 2022
Background: Afucosylated IgG1 responses have only been found against membrane-embedded epitopes, including anti-S in SARS-CoV-2 infections. These responses, intrinsically protective through... Show moreBackground: Afucosylated IgG1 responses have only been found against membrane-embedded epitopes, including anti-S in SARS-CoV-2 infections. These responses, intrinsically protective through enhanced Fc gamma RIIIa binding, can also trigger exacerbated pro-inflammatory responses in severe COVID-19. We investigated if the BNT162b2 SARS-CoV-2 mRNA also induced afucosylated IgG responses. Methods: Blood from vaccinees during the first vaccination wave was collected. Liquid chromatography-Mass spectrometry (LC-MS) was used to study anti-S IgG1 Fc glycoprofiles. Responsiveness of alveolar-like macrophages to produce proinflammatory cytokines in presence of sera and antigen was tested. Antigen-specific B cells were characterized and glycosyltransferase levels were investigated by Fluorescence-Activated Cell Sorting (FACS). Findings: Initial transient afucosylated anti-S IgG1 responses were found in naive vaccinees, but not in antigen -experienced ones. All vaccinees had increased galactosylated and sialylated anti-S IgG1. Both naive and antigen -experienced vaccinees showed relatively low macrophage activation potential, as expected, due to the low antibody levels for naive individuals with afucosylated IgG1, and low afucosylation levels for antigen-experienced individuals with high levels of anti-S. Afucosylation levels correlated with FUT8 expression in antigen-specific plasma cells in naive individuals. Interestingly, low fucosylation of anti-S IgG1 upon seroconversion correlated with high anti-S IgG levels after the second dose. Interpretation: Here, we show that BNT162b2 mRNA vaccination induces transient afucosylated anti-S IgG1 responses in naive individuals. This observation warrants further studies to elucidate the clinical context in which potent afucosylated responses would be preferred. Copyright (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Show less
Vos, T.W. de; Winkelhorst, D.; Arnadottir, V.; Bom, J.G. van der; Suris, C.C.; Caram-Deelder, C.; ... ; Lopriore, E. 2022
Background Children affected by fetal and neonatal alloimmune thrombocytopenia (FNAIT) are at risk of severe intracranial haemorrhage. Management in the postnatal period is based on sparse evidence... Show moreBackground Children affected by fetal and neonatal alloimmune thrombocytopenia (FNAIT) are at risk of severe intracranial haemorrhage. Management in the postnatal period is based on sparse evidence. We aimed to describe the contemporary management and outcomes of patients with FNAIT in high-income countries.Methods In this multicentre, retrospective, cohort study, we set up a web-based registry for the collection of deidentified data on the management and course of neonates with FNAIT. Eight centres from seven countries (Australia, Norway, Slovenia, Spain, Sweden, the Netherlands, and the USA) participated. Eligibility criteria comprised neonates with FNAIT being liveborn between Jan 1, 2010, and Jan 1, 2020; anti-human platelet antigen (HPA) alloantibodies in maternal serum; confirmed maternal and fetal HPA incompatibility; and bleeding detected at antenatal ultrasound, neonatal thrombocytopenia (<150 x 10(9) platelets per L), or both in the current or previous pregnancy. Clinical data were retrieved from local medical records of the first neonatal admission and entered in the registry. The key outcome was the type of postnatal treatment given to neonates with FNAIT. Other outcomes were daily median platelet counts in the first week of life, median platelet count increment after first unmatched versus first matched transfusions, and the proportion of neonates with mild or severe bleeding.Findings 408 liveborn neonates with FNAIT were entered into the FNAIT registry, of whom 389 from Australia (n=74), Norway (n=56), Slovenia (n=19), Spain (n=55), Sweden (n=31), the Netherlands (n=138), and the USA (n=16) were included in our analyses. The median follow-up was 5 days (IQR 2-9). More neonates were male (241 [64%] of 379) than female (138 [36%]). Severe thrombocytopenia (platelet count <50 x 10(9) platelets per L) was reported in 283 (74%) of 380 neonates, and extreme thrombo-cytopenia (<10 x 10(9) platelets per L) was reported in 92 (24%) neonates. Postnatal platelet count nadir was higher in the no-treatment group than in all other groups. 163 (42%) of 389 neonates with FNAIT received no postnatal treatment. 207 (53%) neonates received platelet transfusions, which were either HPA-unmatched (88 [43%] of 207), HPA-matched (84 [41%]), or a combination of both (35 [17%]). The proportion of neonates who received HPA-matched platelet transfusions varied between countries, ranging from 0% (Slovenia) to 63% (35 of 56 neonates; Norway). Postnatal intravenous immunoglobulin treatment was given to 110 (28%) of 389 neonates (alone [n=19] or in combination with platelet transfusions [n=91]), with the proportion receiving it ranging from 12% (17 of 138 neonates; the Netherlands) to 63% (ten of 16 neonates; the USA) across countries. The median platelet increment was 59 x 10(9) platelets per L (IQR 35-94) after HPA-unmatched platelet transfusions and 98 x 10(9) platelets per L (67-134) after HPA-matched platelet transfusions (p<0 center dot 0001). Severe bleeding was diagnosed in 23 (6%) of 389 liveborn neonates, with one having a severe pulmonary haemorrhage and 22 having severe intracranial haemorrhages. Mild bleeding was diagnosed in 186 (48%) neonates.Interpretation Postnatal management of FNAIT varies greatly between international centres, highlighting the absence of consensus on optimal treatments. Our data suggest that HPA-matched transfusions lead to a larger median platelet count increment than HPA-unmatched transfusions, but whether HPA matching is also associated with a reduced risk of bleeding remains unknown. Copyright (c) 2022 Published by Elsevier Ltd. All rights reserved. Show less
Background The formation of alloantibodies directed against class I human leukocyte antigens (HLA) continues to be a clinically challenging complication after platelet transfusions, which can lead... Show moreBackground The formation of alloantibodies directed against class I human leukocyte antigens (HLA) continues to be a clinically challenging complication after platelet transfusions, which can lead to platelet refractoriness (PR) and occurs in approximately 5%-15% of patients with chronic platelet support. Interestingly, anti-HLA IgG levels in alloimmunized patients do not seem to predict PR, suggesting functional or qualitative differences among anti-HLA IgG. The binding of these alloantibodies to donor platelets can result in rapid clearance after transfusion, presumably via Fc gamma R-mediated phagocytosis and/or complement activation, which both are affected by the IgG-Fc glycosylation. Objectives To characterize the Fc glycosylation profile of anti-HLA class I antibodies formed after platelet transfusion and to investigate its effect on clinical outcome. Patients/Methods We screened and captured anti-HLA class I antibodies (anti-HLA A2, anti-HLA A24, and anti-HLA B7) developed after platelet transfusions in hemato-oncology patients, who were included in the PREPAReS Trial. Using liquid chromatography-mass spectrometry, we analyzed the glycosylation profiles of total and anti-HLA IgG1 developed over time. Subsequently, the glycosylation data was linked to the patients' clinical information and posttransfusion increments. Results The glycosylation profile of anti-HLA antibodies was highly variable between patients. In general, Fc galactosylation and sialylation levels were elevated compared to total plasma IgG, which correlated negatively with the platelet count increment. Furthermore, high levels of afucosylation were observed for two patients. Conclusions These differences in composition of anti-HLA Fc-glycosylation profiles could potentially explain the variation in clinical severity between patients. Show less
Vos, T.W. de; Haas, M. de; Oepkes, D.; Tan, R.N.G.B.; Schoot, C.E. van der; Steggerda, S.J.; ... ; Klink, J.M.M. van 2022
BACKGROUND: Children with fetal and neonatal alloimmune throm-bocytopenia face increased risk of intracranial hemorrhage potentially leading to developmental impairment. To prevent intracranial... Show moreBACKGROUND: Children with fetal and neonatal alloimmune throm-bocytopenia face increased risk of intracranial hemorrhage potentially leading to developmental impairment. To prevent intracranial hemorrhage, pregnant women with alloantibodies against fetal platelets are often treated with intravenous immunoglobulin. Intravenous immunoglobulin seems effective in vastly reducing the risk of fetal or neonatal bleeding complications. However, information on long-term neurodevelopment of these children is lacking. OBJECTIVE: This study aimed to evaluate long-term neurodevelopmental outcome in children with fetal and neonatal alloimmune thrombocytopenia who were treated with intravenous immunoglobulin antenatally. STUDY DESIGN: An observational cohort study was performed, including children of mothers treated with intravenous immunoglobulin during pregnancy because a previous child was diagnosed with fetal and neonatal alloimmune thrombocytopenia. Children were invited for a follow-up assessment including standardized cognitive and neurologic tests. The parents were asked to complete a behavioral questionnaire and school performance reports. The primary outcome was severe neurodevelopmental impairment, defined as severe cognitive impairment (intelligence quotient <70), cerebral palsy with Gross Motor Function Classification System Level >= 3, bilateral blindness, and/or bilateral deafness (requiring amplification). The secondary outcome was mild to moderate neurodevelopmental impairment, defined as either mild to moderate cognitive impairment (intelligence quotient <85), cerebral palsy with Gross Motor Function Classification System Level <= 2, minor neurologic dysfunction, vision loss, and/or hearing loss.RESULTS: Between 2003 and 2017, 51 children were live-born after antenatal intravenous immunoglobulin treatment. One family moved abroad and was therefore not eligible for inclusion. In total, 82% (41/50) of the eligible cases were included for neurodevelopmental assessment at a median age of 9 years and 8 months. Severe neurodevelopmental impairment was not detected. The incidence of mild to moderate neurodevelopmental impairment was 14% (6/41; 95% confidence interval, 6% -29%). The children's mean cognitive score, behavioral scores, and academic achievement were not different from those observed in the Dutch norm groups. Neuroimaging was performed in 90% (37/41) of cases. Severe intracranial hemorrhage was diagnosed in 2 cases (5%), one antenatally before the start of intravenous immunoglobulin and the other case 1 day after birth. Both cases had a normal neurodevelopmental outcome. CONCLUSION: The risk of neurodevelopmental impairment in children whose mothers were treated for fetal and neonatal alloimmune thrombocytopenia with antenatal intravenous immunoglobulin is comparable to that reported in the general population. Show less
Sustic, T.; Coillie, J. van; Larsen, M.D.; Derksen, N.I.L.; Szittner, Z.; Nouta, J.; ... ; Vidarsson, G. 2022
Background: Immunoglobulin G (IgG) antibodies serve a crucial immuno-protective function mediated by IgG Fc receptors (Fc gamma R). Absence of fucose on the highly conserved N-linked glycan in the... Show moreBackground: Immunoglobulin G (IgG) antibodies serve a crucial immuno-protective function mediated by IgG Fc receptors (Fc gamma R). Absence of fucose on the highly conserved N-linked glycan in the IgG Fc domain strongly enhances IgG binding and activation of myeloid and natural killer (NK) cell Fc gamma Rs. Although afucosylated IgG can provide increased protection (malaria and HIV), it also boosts immunopathologies in alloimmune diseases, COVID-19 and dengue fever. Quantifying IgG fucosylation currently requires sophisticated methods such as liquid chromatography-mass spectrometry (LC-MS) and extensive analytical skills reserved to highly specialized laboratories. Methods: Here, we introduce the Fucose-sensitive Enzyme-linked immunosorbent assay (ELISA) for Antigen-Specific IgG (FEASI), an immunoassay capable of simultaneously quantitating and qualitatively determining IgG responses. FEASI is a two-tier immunoassay; the first assay is used to quantify antigen-specific IgG (IgG ELISA), while the second gives Fc gamma RIIIa binding-dependent readout which is highly sensitive to both the IgG quantity and the IgG Fc fucosylation (Fc gamma R-IgG ELISA). Findings: IgG Fc fucosylation levels, independently determined by LC-MS and FEASI, in COVID-19 responses to the spike (S) antigen, correlated very strongly by simple linear regression (R-2=0.93, p < 0.0001). The FEASI method was then used to quantify IgG levels and fucosylation in COVID-19 convalescent plasma which was independently validated by LC-MS. Interpretation: FEASI can be reliably implemented to measure relative and absolute IgG Fc fucosylation and quantify binding of antigen-specific IgG to Fc gamma R in a high-throughput manner accessible to all diagnostic and research laboratories. Copyright (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Show less
Luken, J.S.; Ritsema, S.P.; Wal, M.M. van der; Schoot, C.E. van der; Rouwette, E.A.J.A.; Haas, M. de; Janssen, M.P. 2022
Background and objectives: Current genotyping techniques allow typing of all relevant red cell, human leukocyte and platelet antigens in a single analysis. Even genetic markers related to donor... Show moreBackground and objectives: Current genotyping techniques allow typing of all relevant red cell, human leukocyte and platelet antigens in a single analysis. Even genetic markers related to donor health can be added. Implementation of this technology will affect various stakeholders within the transfusion chain. This study aims to systematically map the anticipated advantages and disadvantages of a national rollout of blood group genotyping of donors, which will affect the availability of rare donors and the implementation of an extensively typed blood transfusion policy. Materials and methods: Two focus-group sessions were held with a wide representation of stakeholders, including representatives of donor and patient organisations. A dedicated software tool was used to collect the reflections of participants on genotyping for blood group antigens and extensive matching. Additionally, stakeholders and experts discussed various prepared propositions. All information collected was categorised. Results: From 162 statements collected, 59 statements (36%) were labelled as 'hopes' and 77 (48%) as 'fears'. Twenty-six (16%) statements remained unlabelled. The statements were divided in 18 categories under seven main themes: patient health, genotyping, privacy issues and ethical aspects, donor management, inventory management and logistics, hospital and transfusion laboratory and general aspects. The discussion on the propositions was analysed and summarised. Conclusion: Stakeholders believe that a genotyped donor pool can result in a reduction of alloimmunization and higher availability of typed blood products. There are concerns regarding logistics, costs, consent for extended typing, data sharing, privacy issues and donor management. These concerns need to be carefully addressed before further implementation. Show less
Vos, T.W.; Porcelijn, L.; Hofstede-van Egmond, S.; Pajkrt, E.; Oepkes, D.; Lopriore, E.; ... ; Haas, M. de 2022
Many studies already reported on the association between patient characteristics on the severity of COVID-19 disease outcome, but the relation with SARS-CoV-2 antibody levels is less clear. To... Show moreMany studies already reported on the association between patient characteristics on the severity of COVID-19 disease outcome, but the relation with SARS-CoV-2 antibody levels is less clear. To investigate this in more detail, we performed a retrospective observational study in which we used the IgG antibody response from 11,118 longitudinal antibody measurements of 2,082 unique COVID convalescent plasma donors. COVID-19 symptoms and donor characteristics were obtained by a questionnaire. Antibody responses were modelled using a linear mixed-effects model. Our study confirms that the SARS-CoV-2 antibody response is associated with patient characteristics like body mass index and age. Antibody decay was faster in male than in female donors (average half-life of 62 versus 72 days). Most interestingly, we also found that three symptoms (headache, anosmia, nasal cold) were associated with lower peak IgG, while six other symptoms (dry cough, fatigue, diarrhoea, fever, dyspnoea, muscle weakness) were associated with higher IgG concentrations. Show less
Wojcik, I.; Schmidt, D.E.; Neef, L.A. de; Rab, M.A.E.; Meek, B.; Weerdt, O. de; ... ; Vidarsson, G. 2021
As a lymphoid organ, the spleen hosts a wide range of immune cell populations, which not only remove blood-borne antigens, but also generate and regulate antigen-specific immune responses. In... Show moreAs a lymphoid organ, the spleen hosts a wide range of immune cell populations, which not only remove blood-borne antigens, but also generate and regulate antigen-specific immune responses. In particular, the splenic microenvironment has been demonstrated to play a prominent role in adaptive immune responses to enveloped viral infections and alloantigens. During both types of immunizations, antigen-specific immunoglobulins G (IgGs) have been characterized by the reduced amount of fucose present on N-linked glycans of the fragment crystallizable (Fc) region. These glycans are essential for mediating the induction of immune effector functions. Therefore, we hypothesized that a spleen may modulate humoral responses and serve as a preferential site for afucosylated IgG responses, which potentially play a role in immune thrombocytopenia (ITP) pathogenesis. To determine the role of the spleen in IgG-Fc glycosylation, we performed IgG subclass-specific liquid chromatography-mass spectrometry (LC-MS) analysis of Fc glycosylation in a large cohort of individuals splenectomized due to trauma, due to ITP, or spherocytosis. IgG-Fc fucosylation was consistently increased after splenectomy, while no effects for IgG-Fc galactosylation and sialylation were observed. An increase in IgG1- and IgG2/3-Fc fucosylation level upon splenectomy has been reported here for the first time, suggesting that immune responses occurring in the spleen may be particularly prone to generate afucosylated IgG responses. Surprisingly, the level of total IgG-Fc fucosylation was decreased in ITP patients compared to healthy controls. Overall, our results suggest a yet unrecognized role of the spleen in either the induction or maintenance of afucosylated IgG responses by B cells. Show less
Lak, N.S.M.; Voormanns, T.L.; Zappeij-Kannegieter, L.; Zogchel, L.M.J. van; Fiocco, M.; Noesel, M.M. van; ... ; Stutterheim, J. 2021
Purpose: Survival of children with rhabdomyosarcoma that suffer from recurrent or progressive disease is poor. Identifying these patients upfront remains challenging, indicating a need for... Show morePurpose: Survival of children with rhabdomyosarcoma that suffer from recurrent or progressive disease is poor. Identifying these patients upfront remains challenging, indicating a need for improvement of risk stratification. Detection of tumor-derived mRNA in bone marrow (BM) and peripheral blood (PB) using reverse-transcriptase qPCR (RT-qPCR) is a more sensitive method to detect disseminated disease. We identified a panel of genes to optimize risk stratification by RT-qPCR.Experimental Design: Candidate genes were selected using gene expression data from rhabdomyosarcoma and healthy hematologic tissues, and a multiplexed RT-qPCR was developed. Significance of molecular disease was determined in a cohort of 99 Dutch patients with rhabdomyosarcoma (72 localized and 27 metastasized) treated according to the European pediatric Soft tissue sarcoma Study Group (EpSSG) RMS2005 protocol.Results: We identified the following 11 rhabdomyosarcoma markers: ZIC1, ACTC1, MEGF10, PDLIM3, SNAI2, CDH11, TMEM47, MYOD1, MYOG, and PAX3/7-FOXO1. RT-qPCR was performed for this 11-marker panel on BM and PB samples from the patient cohort. Five-year event-free survival (EFS) was 35.5% [95% confidence interval (CI), 17.5%-53.5%] for the 33/99 RNA positive patients, versus 88.0% (95% CI, 78.9%-97.2%) for the 66/ 99 RNA-negative patients ( P < 0.0001). Five-year overall survival (OS) was 54.8% (95% CI, 36.2%-73.4%) and 93.7% (95% CI, 86.6%-100.0%), respectively (P < 0.0001). RNA panel positivity was negatively associated with EFS (Hazard Ratio = 9.52; 95% CI, 3.23-28.02), whereas the RMS2005 risk group stratification was not, in the multivariate Cox regression model.Conclusions: This study shows a strong association between PCR-based detection of disseminated disease at diagnosis with clinical outcome in pediatric patients with rhabdomyosarcoma, also compared with conventional risk stratification. This warrants further validation in prospective trials as additional technique for risk stratification. Show less
Larsen, M.D.; Lopez-Perez, M.; Dickson, E.K.; Ampomah, P.; Ndam, N.T.; Nouta, J.; ... ; Vidarsson, G. 2021
Here, Larsen et al. describe differences in Fc fucosylation of P. falciparum PfEMP1-specific IgG produced in response to natural infection versus VAR2CSA-type subunit vaccination, which leads to... Show moreHere, Larsen et al. describe differences in Fc fucosylation of P. falciparum PfEMP1-specific IgG produced in response to natural infection versus VAR2CSA-type subunit vaccination, which leads to differences in the ability to induce Fc gamma RIIIa-dependent natural killer cell degranulation.Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family members mediate receptor- and tissue-specific sequestration of infected erythrocytes (IEs) in malaria. Antibody responses are a central component of naturally acquired malaria immunity. PfEMP1-specific IgG likely protects by inhibiting IE sequestration and through IgG-Fc Receptor (Fc gamma R) mediated phagocytosis and killing of antibody-opsonized IEs. The affinity of afucosylated IgG to Fc gamma RIIIa is up to 40-fold higher than fucosylated IgG, resulting in enhanced antibody-dependent cellular cytotoxicity. Most IgG in plasma is fully fucosylated, but afucosylated IgG is elicited in response to enveloped viruses and to paternal alloantigens during pregnancy. Here we show that naturally acquired PfEMP1-specific IgG is strongly afucosylated in a stable and exposure-dependent manner, and efficiently induces Fc gamma RIIIa-dependent natural killer (NK) cell degranulation. In contrast, immunization with a subunit PfEMP1 (VAR2CSA) vaccine results in fully fucosylated specific IgG. These results have implications for understanding protective natural- and vaccine-induced immunity to malaria. Show less
Osch, T.L.J. van; Nouta, J.; Derksen, N.I.L.; Mierlo, G. van; Schoot, C.E. van der; Wuhrer, M.; ... ; Vidarsson, G. 2021
Human IgG contains one evolutionarily conserved N-linked glycan in its Fc region at position 297. This glycan is crucial for Fc-mediated functions, including its induction of the classical... Show moreHuman IgG contains one evolutionarily conserved N-linked glycan in its Fc region at position 297. This glycan is crucial for Fc-mediated functions, including its induction of the classical complement cascade. This is induced after target recognition through the IgG-Fab regions, allowing neighboring IgG-Fc tails to associate through Fc:Fc interaction, ultimately leading to hexamer formation. This hexamerization seems crucial for IgG to enable efficient interaction with the globular heads of the first complement component C1q and subsequent complement activation. In this study, we show that galactose incorporated in the IgG1-Fc enhances C1q binding, C4, C3 deposition, and complement-dependent cellular cytotoxicity in human erythrocytes and Raji cells. IgG1-Fc sialylation slightly enhanced binding of C1q, but had little effect on downstream complement activation. Using various mutations that decrease or increase hexamerization capacity of IgG1, we show that IgG1-Fc galactosylation has no intrinsic effect on C1q binding to IgG1, but enhances IgG1 hexamerization potential and, thereby, complement activation. These data suggest that the therapeutic potential of Abs can be amplified without introducing immunogenic mutations, by relatively simple glycoengineering. Show less
Vos, T.W. de; Porcelijn, L.; Hofstede-van Egmond, S.; Pajkrt, E.; Oepkes, D.; Lopriore, E.; ... ; Haas, M. de 2021
Fetal neonatal alloimmune thrombocytopenia (FNAIT) is caused by maternal alloantibodies directed against the human platelet antigens (mostly HPA-1a or HPA-5b) of the (unborn) child and can lead to... Show moreFetal neonatal alloimmune thrombocytopenia (FNAIT) is caused by maternal alloantibodies directed against the human platelet antigens (mostly HPA-1a or HPA-5b) of the (unborn) child and can lead to severe bleeding. Anti-HPA-1a-mediated FNAIT shows a severe clinical outcome more often than anti-HPA-5b-mediated FNAIT. Given the relatively high prevalence of anti-HPA-5b in pregnant women, the detection of anti-HPA-5b in FNAIT-suspected cases may in some cases be an incidental finding. Therefore we investigated the frequency of anti-HPA-5b-associated severe bleeding in FNAIT. We performed a retrospective nationwide cohort study in cases with clinical suspicion of FNAIT. HPA antibody screening was performed using monoclonal antibody-specific immobilisation of platelet antigens. Parents and neonates were typed for the cognate antigen. Clinical data were collected by a structured questionnaire. In 1 864 suspected FNAIT cases, 161 cases (8 center dot 6%) had anti-HPA-1a and 60 (3 center dot 2%) had anti-HPA-5b. The proportion of cases with severe bleeding did not differ between the cases with anti-HPA-1a (14/129; 11%) and anti-HPA-5b (4/40; 10%). In multigravida pregnant women with a FNAIT-suspected child, 100% (81/81) of anti-HPA-1a cases and 79% (38/48) of anti-HPA-5b cases were HPA-incompatible, whereas 86% and 52% respectively were expected, based on the HPA allele distribution. We conclude that anti-HPA-5b can be associated with severe neonatal bleeding symptoms. A prospective study is needed for true assessment of the natural history of anti-HPA-5b mediated FNAIT. Show less
Jolink, A.T.C.; Nelson, V.S.; Schipperus, M.R.; Amini, S.N.; Vidarsson, G.; Schoot, C.E. van der; ... ; Kapur, R. 2021
