The rapid evolution of new SARS-CoV-2 variants poses a continuing threat to human health. Vaccination has become the primary therapeutic intervention. The goal of the current work was the construction of immunogenic virus-like particles (VLPs). Here, we describe a human cell line for cost-efficient and scalable production of immunogenic SARS-CoV-2 VLPs. The modular design of the VLP-production platform facilitates rapid adaptation to new variants. Methods: The N, M-, and E-protein genes were integrated into the genome of Expi293 cells (ExpiVLP_MEN). Subsequently, this cell line was further modified for the constitutive expression of the SARS-CoV-2 spike protein. The resulting cell line (ExpiVLP_SMEN) released SARS-CoV-2 VLP upon exposure to doxycycline. ExpiVLP_SMEN cells were readily adapted for VLP production in a 5 L bioreactor. Purified VLPs were quantified by Western blot, ELISA, and nanoparticle tracking analysis and visualized by electron microscopy. Immunogenicity was tested in mice. Results: The generated VLPs contained all four structural proteins, are within the size range of authentic SARS-CoV-2 virus particles, and reacted strongly and specifically with immunoserum from naturally infected individuals. The VLPs were stable in suspension at 4 °C for at least 10 weeks. Mice immunized with VLPs developed neutralizing antibodies against lentiviruses pseudotyped with the SARS-CoV-2 spike protein. The flexibility of the VLP-production platform was demonstrated by the rapid switch of the spike protein to a new variant of concern (BA.1/Omicron). The present study describes an efficient, scalable, and adaptable production method of immunogenic SARS-CoV-2 VLPs with therapeutic potential.

Background:Macrophages play a key role in all environmental conditions surrounding pregnancy. Coating of autologous red blood cells (RBCs) with polyclonal antibodies to Rh(D) antigen may result in an immunomodulation and improved outcome in Rh(D) positive women with recurrent pregnancy loss (RPL).Methods:A total of 60 Rh(D) positive women (age 23 to 45 years) with a history of RPL and ineffective treatment with low molecular weight heparin (LMWH) and/or aspirin were included in this retrospective study. In addition to this treatment, Anti-D (300 μg) was given subcutaneously to each woman either prior to pregnancy and/or two times within 12 weeks of gestation.Results:Treatment with Anti-D in non-responders to heparin/aspirin resulted in successful pregnancies in 67% of all cases. The remaining women had only aborts (23%) or did not become pregnant (10%). None of the treated women has developed anemia due to this treatment or any other significant adverse reaction. The rate of successful pregnancies does not appear to be influenced by the administration of: Anti-D prior to pregnancy, age, thrombophilia or previous alive births.Conclusion:The improved outcome following the administration of Anti-D in women with RPL might be explained by immune modulations induced by different immune reactions including polarization of decidual macrophages. The results obtained in this study clearly indicate that Anti-D is safe and highly effective in treatment of Rh(D) positive women with RPL. However, further studies are required to support our results and to find out the optimal dose and timing of Anti-D administration.

A key in controlling the SARS-CoV-2 pandemic is the assessment of the immune status of the population. We explored the utility of SARS-CoV-2 virus-like particles (VLPs) as antigens to detect specific humoral immune reactions in an enzyme-linked immunosorbent assay (ELISA). For this purpose, SARS-CoV-2 VLPs were produced from an engineered cell line and characterized by Western blot, ELISA, and nanoparticle tracking analysis. Subsequently, we collected 42 serum samples from before the pandemic (2014), 89 samples from healthy subjects, and 38 samples from vaccinated subjects. Seventeen samples were collected less than three weeks after infection, and forty-four samples more than three weeks after infection. All serum samples were characterized for their reactivity with VLPs and the SARS-CoV-2 N- and S-protein. Finally, we compared the performance of the VLP-based ELISA with a certified in vitro diagnostic device (IVD). In the applied set of samples, we determined a sensitivity of 95.5% and a specificity of 100% for the certified IVD. There were seven samples with an uncertain outcome. Our VLP-ELISA demonstrated a superior performance, with a sensitivity of 97.5%, a specificity of 100%, and only three uncertain outcomes. This result warrants further research to develop a certified IVD based on SARS-CoV-2 VLPs as an antigen.

BACKGROUND:We describe here the first patient with recurrent hemolysis related to disinfectant containing silver nanoparticles (AgNps).METHODS:A 58-year-old chemist repeatedly experienced DAT-negative (Coombs-negative) hemolysis during the last 5 years. He was treated with a number of immunosuppressive drugs including 18 times rituximab. The attempt to treat him with cyclosporine A served only to increase the rate of hemolysis. Only by chance, we revealed that the patient regularly used a hand disinfectant containing AgNps. Serological testing was performed using standard techniques. Eryptosis was measured by binding annexin to exposed phosphatidylserine (PS) of the circulating red blood cells (RBCs).RESULTS:Antiglobulin tests remained negative, and PS exposing RBCs were detected two times during the last hemolytic episodes. Hemolysis completely disappeared following discontinuation of AgNp containing products.CONCLUSION:AgNps are increasingly being used in a large variety of products. Recently, it was reported that they induce in vitro prohemolytic and procoagulant effects via oxidative stress and eryptosis. The clinical findings imply the hemolysis was provoked by the patient's regular use of cleansing products containing AgNps. Our finding might help to explain the etiology of hemolytical disorders that may remain obscure in many cases.

Introduction: Uncrossmatched ABO-compatible red blood cells (RBCs) are generally recommended in patients with life-threatening massive bleeding. There is little data regarding RBC transfusion when patients are transfused against clinically significant alloantibodies because compatible RBCs are not immediately available. Methods/Patients: All patients reviewed in this study (n = 6,109) required emergency blood transfusion and were treated at the Charité – Universitätsmedizin Berlin between 2001 and 2015. Primary uncrossmatched O Rh(D)-positive or -negative RBC units were immediately transfused prior to complete regulatory serological testing including determination of ABO group, Rhesus antigens, antibody screening, and crossmatching. Results: Without any significant change in the protocol of emergency transfusion of RBCs, a total of 63,373 RBC units were transfused in 6,109 patients. Antibody screening was positive in 413 patients (6.8%), and 19 of these patients received RBC units against clinically significant alloantibodies. None of these patients appeared to have developed significant hemolysis, and only one patient with anti-D seems to have developed signs of insignificant hemolysis following the transfusion of three Rh(D)-positive units. One patient who had anti-Jka received unselected units and did not develop a hemolytic transfusion reaction. Conclusion: Transfusion of uncrossmatched ABO-compatible RBCs against alloantibodies is highly safe in patients with life-threatening hemorrhage.

6078 Background: PARP inhibitors (PARPi) have been established as a targeted therapeutic approach not only in patients with high-grade serous ovarian cancer (HGSOC) that have genetic loss of function of BRCA1/2-associated DNA repair. However, treatment efficacy varies and neither BRCA mutation, nor homolog recombination deficiency (HRD) status seem to be optimal predictors. Moreover, mechanisms of treatment resistance are poorly understood and novel approaches are urgently required. Methods: Here we created gene expression data of HGSOC patients (n = 52) before PARPi treatment to elucidate key signaling pathways of resistance to increase their efficacy in combinatorial therapeutic strategies. We performed a comprehensive bioinformatics analysis of the differentially expressed genes between the 25% extreme responders (n = 26; 13 each group), including gene set enrichment analysis (GSEA) and causal inference analysis with the CARNIVAL pipeline to elucidate the underlying molecular and regulatory mechanisms governing treatment efficacy and resistance. Results: In accordance with recent publications, we found higher levels of MYC activity in non-responders and deregulation of the Wnt/ß-catenin signaling pathway resulting in PARPi treatment resistance. The pathway enrichment analysis also revealed specific pathways especially PDGFR, FGFR, PI3K/mTOR and MAPK signaling pathway associated with resistant phenotype. Furthermore, we have identified key kinases, particularly JAK1/2 and SRC that might mediate resistance to PARP inhibition. In addition, differential gene expression analysis revealed folate receptor 1 (FOLR1) to be significantly higher expressed in non-responders (logFC = 2.66; p < 0.0026) with the potential as a serum-based biomarker not only for ovarian cancer, as it correlates closely with CA125, but also PARPi treatment efficacy. Conclusions: In conclusion, these findings define a network of pathways, that are crucial to mediate mechanism of PARPi resistance and identified key signaling kinases as therapeutic targets in ovarian cancer.

With regard to relapse and survival, early-stage high-grade serous ovarian (HGSOC) patients comprise a heterogeneous group and there is no clear consensus on first-line treatment. Currently, no prognostic markers are available for risk assessment by standard targeted immunohistochemistry and novel approaches are urgently required. Here, we applied MALDI-imaging mass spectrometry (MALDI-IMS), a new method to identify distinct mass profiles including protein signatures on paraffin-embedded tissue sections. In search of prognostic biomarker candidates, we compared proteomic profiles of primary tumor sections from early-stage HGSOC patients with either recurrent (RD) or non-recurrent disease (N = 4; each group) as a proof of concept study. In total, MALDI-IMS analysis resulted in 7537 spectra from the malignant tumor areas. Using receiver operating characteristic (ROC) analysis, 151 peptides were able to discriminate between patients with RD and non-RD (AUC > 0.6 or < 0.4; p < 0.01), and 13 of them could be annotated to proteins. Strongest expression levels of specific peptides linked to Keratin type1 and Collagen alpha-2(I) were observed and associated with poor prognosis (AUC > 0.7). These results confirm that in using IMS, we could identify new candidates to predict clinical outcome and treatment extent for patients with early-stage HGSOC.

e17091 Background: Previously four molecular subtypes of high grade serous ovarian cancer (HGSOC) with distinct biological features and clinical outcome have been described: C1 (mesenchymal), C2 (immunoreactive), C4 (differentiated), and C5 (proliferative). Using Nanostring technique and a minimal signature of 39 classifier genes could reproduce the subtypes identified by microarray gene expression profiling (Leong HS et al. Australian Ovarian Cancer Study. J Pathol. 2015). Methods: We characterized paraffin embedded tissue samples from 279 HGSOC patients for molecular subtypes, utilizing the 39 classifier signature and 9 control genes by Nanostring nCounter Analysis System. From 16 patients paired primary and relapsed samples were available. Only chemonaive primary HGSOC patients were included in the study. FFPEs and clinical data were provided by TOC ( www.toc-network.de ). For each sample, probability scores for the four molecular subtypes (C1, C2, C4, and C5) were calculated. The highest calculated score determined the most likely subtype of the tumor. Results: Of all analyzed primary tumor samples, 88 (31.5%) were classified as C1, 83 (29.8%), 53 (19.0%) and 55 (19.7%) as subtypes C2, C4 and C5, respectively. Our results confirmed data by the AOCS study, which described the distribution of HGSOC with 40.2% (C1), 22.5% (C2), 20.1% (C4) and 17.2% (C5), respectively. Within the paired samples, for 12 of the 16 patients dynamic changes in the molecular subtypes between primary and relapse occurred, while in the remaining 4 patients the phenotype was stable. Conclusions: Molecular subtypes of HGSOC using Nanostring technology with a small panel of classifier genes can be confirmed. Furthermore, the data showed that a change of the established molecular subtype might occur during the evolution of the disease, and therefore translate in a different clinical outcome.

The thrombopoietin receptor agonists (TPO-RAs), romiplostim and eltrombopag, stimulate megakaryopoiesis and thereby increase platelet counts. Both drugs are increasingly used in the treatment of immune thrombocytopenic purpura (ITP). To assess the effect of TPO-RAs on trilineage haematopoiesis, colony-forming cell (CFC) assays were performed on peripheral blood mononuclear cells of 8 healthy donors and 52 ITP patients. Additionally, we revaluated the regular and complete blood counts (CBCs) performed during romiplostim therapy in 45 patients and the CBCs performed in 9 patients during eltrombopag therapy. The clonogenic capacity of PBMCs was significantly increased in patients treated with TPO-RAs compared with healthy donors and untreated patients [BFU-E, 69 ± 47; CFU-GM, 61 ± 48; CFU-GEMM, 16 ± 11; CFU-total, 145 ± 94; P values < 0.05)]. Relative leukocytosis was observed in routine blood counts in 12 of 45 (26%) patients treated with romiplostim. The regular CBCs, performed time dependent within the first 5 days, revealed a maximum increase of leukocytes on days 2 and 3 following romiplostim administration. There were no significant changes in red blood cell parameters. None of the affected patients did recognise any significant symptom, which may be related to leukocytosis. Similarly, we observed a statistically significant increase of leukocyte count in a small cohort of ITP patients (n = 9) in whom CBCs were controlled following treatment initiation (P = 0.044). Our results indicate that TPO-RAs may also mobilize haematopoietic stem and progenitor cells (HSPCs) in peripheral blood and the occurrence of such relative leukocytosis may signalize an early symptom of myelofibrosis due to treatment with TPO-RAs.

Background: Eltrombopag and romiplostim are thrombopoietin receptor agonists (TPOs) that have been increasingly used for the treatment of immune thrombocytopenia (ITP). Based on our experience, the incidence of abortive treatment with these drugs and the occurrence of adverse reactions that lead to therapy break-off despite response are higher than has been previously suggested. Methods: During the last 8 years, a total of 65 patients were treated with eltrombopag and/or romiplostim at our institute. Results: 36 of a total of 58 patients responded well to eltrombopag. In 12 patients that responded, treatment with eltrombopag was discontinued due to the development of adverse reactions. Eltrombopag was replaced by romiplostim in 23 cases (14 non-responders, 9 patients with adverse reactions). Of these patients, 83% responded to romiplostim. Among all patients treated with romiplostim (n = 32), 75% initially responded; however, 8 of these patients developed adverse reactions. Romiplostim was replaced by eltrombopag in 5 cases (4 due to adverse reactions, 1 non-responsive patient), and only 3 (60%) of these patients were observed to respond to eltrombopag. Conclusion: TPOs often remain ineffective in ITP or result in adverse reactions, which lead to treatment stop or to drug switch. Therefore, alternative treatment options are required.

by undertaking a retrospective longitudinal study in CML patients in BC. We identified CML patients in BC from our previous study for whom we had 5 or more serial samples in total prior to and/or following progression to the blastic disease phase [1] . The 5 CML patients (2 female, 3 male) had a median age of 62 years (range 46–76), and 4 were treated with one or more of the tyrosine kinase inhibitors (TKIs) ( table 1 ). The other had undergone stem cell transplant (SCT). The study was performed using previously described standard molecular biology methods [1] . The MSI2 expression in 4 of the 5 patients appeared to mirror the BCR-ABL1 kinetics ( fig. 1 ). With the exception of the post-SCT samples of patient 5, the MSI2 expressions were lower than the BCR-ABL1 transcript numbers. BCR-ABL1 was undetectable in the post-SCT samples. The notion that regular and close monitoring of MSI2 mRNA levels in serial samples might identify patients at risk of progressing to BC was not supported by this study. Moreover, the data presented here show that an increase in MSI2 transcripts does not precede an increase in BCRABL1 mRNA levels. More importantly, this raises the question as to whether increased MSI2 expression in BC is the cause or effect. The early identification of chronic myeloid leukemia (CML) patients in the chronic phase (CP) who are at risk of progression to blast crisis (BC) would enhance the clinical management of these individuals. Recently, we verified reported data showing increased levels of Musashi 2 (MSI2) transcripts in CML patients in BC compared to those in CP, implying a role for MSI2 in CML transformation [1–3] . MSI2 , a posttranscriptional regulator, is reported to control hematopoietic stem cell self-renewal and differentiation [2, 3] . MSI2 achieves this control by binding to mRNA and thereby impeding translation of the target RNA [2, 3] . Interestingly, we found the MSI2 transcript numbers were significantly lower (p < 0.0001) in CML patients in CP at diagnosis than normal adult blood control samples [1] . Based on these observations and knowing that MSI2 expression is restricted to early hematopoietic progenitors, we reasoned that regular close monitoring of its mRNA levels might identify patients at risk of transformation prior to detecting increasing levels of BCR-ABL1 . If confirmed, it would provide a window in which to intervene early with alternative therapy with a view to reversing the progression, before the patient becomes refractory to further treatment. We addressed this notion Received: January 14, 2016 Accepted: March 1, 2016 Published online: May 10, 2016

The pathological mechanisms underlying the development of immune thrombocytopenia (ITP) are unclear and its diagnosis remains a process of exclusion. Currently, there are no known specific biomarkers for ITP to support differential diagnosis and treatment decisions. Profiling of serum proteins may be valuable for identifying such biomarkers. Sera from 46 patients with primary chronic ITP and 34 healthy blood donors were analysed using a microarray of 755 antibodies. We identified 161 differentially expressed proteins. In addition to oncoproteins and tumour-suppressor proteins, including apoptosis regulator BCL2, breast cancer type 1 susceptibility protein (BRCA1), Fanconi anaemia complementation group C (FANCC) and vascular endothelial growth factor A (VEGFA), we detected six anti-nuclear autoantibodies in a subset of ITP patients: anti-PCNA, anti-SmD, anti-Ro/SSA60, anti-Ro/SSA52, anti-La/SSB and anti-RNPC antibodies. This finding may provide a rational explanation for the association of ITP with malignancies and other autoimmune diseases. While RUNX1mRNA expression in the peripheral blood mononuclear cells (PBMC) of patients was significantly downregulated, an accumulation of RUNX1 protein was observed in the platelets of ITP patients. This may indicate dysregulation of RUNX1 expression in PBMC and megakaryocytes and may lead to an imbalanced immune response and impaired thrombopoiesis. In conclusion, we provide novel insights into the pathogenic mechanisms of ITP that warrant further exploration.

DISCLAIMER: The ideas and opinions expressed in the journal’s Just Accepted articles do not necessarily reflect those of Informa Healthcare (the Publisher), the Editors or the journal. The Publisher does not assume any responsibility for any injury and/or damage to persons or property arising from or related to any use of the material contained in these articles. The reader is advised to check the appropriate medical literature and the product information currently provided by the manufacturer of each drug to be administered to verify the dosages, the method and duration of administration, and contraindications. It is the responsibility of the treating physician or other health care professional, relying on his or her independent experience and knowledge of the patient, to determine drug dosages and the best treatment for the patient. Just Accepted articles have undergone full scientific review but none of the additional editorial preparation, such as copyediting, typesetting, and proofreading, as have articles published in the traditional manner. There may, therefore, be errors in Just Accepted articles that will be corrected in the final print and final online version of the article. Any use of the Just Accepted articles is subject to the express understanding that the papers have not yet gone through the full quality control process prior to publication. Just Accepted by Leukemia & Lymphoma

Data show 40% of chronic myeloid leukemia (CML) patients maintain complete molecular remission (CMR), i.e. failure to detect BCR-ABL1, consenting to termination of Imatinib mesylate (IM) therapy, following undetectable disease for ≥2 years by quantitative PCR (Q-PCR). These findings suggest majority of the patients experience molecular relapse. Furthermore, majority relapse in the first 6 months, implying Q-PCR assay sensitivity is suboptimum, to confidently identify patients for discontinuation of IM. Droplet digital PCR (ddPCR) is suggested to have sensitivity that is one log greater than the Taqman (Q-PCR) assay. If verified, ddPCR would enhance safe withdrawal of IM therapy from CML patients. Here we present data comparing ddPCR with Q-PCR.

A better understanding of events triggering chronic myeloid leukemia progression is critical for optimized clinical management of chronic myeloid leukemia (CML). We sought to validate that increased expression of Musashi 2 (MSI2), a post-transcription regulator, is associated with progression and prognosis. Screening of 152 patients with CML showed that MSI2 was significantly decreased among patients with CML in chronic phase (CP) at diagnosis (p < 0.0001), but found no significant difference between the normal control group and treated patients with CML in CP. Moreover MSI2 was significantly increased (p < 0.0001) in patients with advance disease (AD) CML. Furthermore, our human hematopoietic cell line data imply that MSI2 and BCR-ABL1 mRNA expression are correlated. However, these data cast a doubt on earlier reports that MSI2 effects HES1 expression via NUMB-NOTCH signaling.

Musashi 2 (also known as MSI2), a mRNA binding protein, is reported to control critical stem cell fate decisions by binding to the 3’untranslated region of target mRNAs, thereby inhibiting translation. MSI2 is preferentially expressed in hematopoietic tissue and in particular in early myeloid progenitors. Furthermore, investigators have shown MSI2 expression is upregulated by HOXA9 resulting in dysfunction of the regulatory pathway, leading to hematopoietic stem cell proliferation, impaired myeloid differentiation and is associated with worse prognosis in chronic myeloid leukemia (CML) and acute myeloid leukemia (Kharas, et al. Nat Med 2010; 16:903; Ito, et al. Nature 2010; 466:765). We verified MSI2 levels are significantly increased in CML patients in blast crisis compared with those in chronic phase, irrespective of lymphoid or myeloid transformation (Kaeda, et al. Blood. 2011;118;supplement). Given these observations we sought to assess MSI2 and HOXA9 expression in BCR-ABL1negative myeloproliferative neoplasm (MPN) patients.

Janus kinases are critical components of signaling pathways that regulate hematopoiesis. Mutations of the non-receptor tyrosine kinase JAK2 are found in many BCR-ABL-negative myeloproliferative neoplasms. Preclinical results support that JAK2 inhibitors could show efficacy in treating chronic myeloproliferative neoplasms. JAK2 has also been postulated to play a role in BCR-ABL signal transduction. Therefore, inhibitors of JAK2 kinases are turning into therapeutic strategies for treatment of chronic myelogenous leukemia (CML). In this study, the effects of two novel JAK2 inhibitors, NVP-BSK805 and NVP-BVB808, have been investigated in cell lines expressing either BCR-ABL or mutant JAK2. Possible synergies between NVP-BSK805/NVP-BVB808 and the kinase inhibitors imatinib and nilotinib were assessed. Proliferation and apoptosis tests with both substances showed response in the following cell lines: CHRF-288-11, SET-2 and UKE-1. All BCR-ABL-positive cell lines showed some reduction in proliferation, but with half-maximal growth-inhibitory values >1 µM. Combination of the JAK2 inhibitors with imatinib and nilotinib showed no significant additive or synergistic effects, although all BCR-ABL-positive cell lines responded well to both CML therapeutic agents. Interestingly, it seemed that the combination of imatinib with NVP-BSK805 had a protective effect on the cells. Combination treatment with nilotinib did not show this effect.

Musashi 2 (also known as MSI2), a mRNA binding protein is reported to control critical stem cell fate decisions by binding to the 3’untranslated region of target mRNAs, thereby inhibiting translation. MSI2 is preferentially expressed in hematopoietic tissue, in particular early myeloid progenitors. Moreover, investigators suggest upregulated MSI2 disrupts regulatory pathway/s leading to hematopoietic stem cell proliferation, impaired myeloid differentiation and worse clinical prognosis in CML and AML (Kharas et al. Nat Med. 2010; 16:903; Ito et al. Nature. 2010; 466:765). Indeed we have confirmed increased MSI2 levels in CML patients in blast crisis (BC) compared with those in chronic phase (CP), irrespective of lymphoid or myeloid transformation. Furthermore, we have shown MSI2 and BCR-ABL1 expressions correlate. Here we report data implying MSI2 functions viaTGFβ1 signalling pathway.

Despite the unprecedented success of tyrosine kinase inhibitors (TKIs), the clinical management of 20–30% of patients with chronic myeloid leukemia (CML) experiencing primary or secondary resistanc...

To date no single molecular biomarker, with proven clinical utility, that is predictive and identifies patients with more aggressive chronic myeloid leukaemia (CML) at diagnosis, has been reported. Such a molecular biomarker would enable stratification of patients according to aggressiveness of the malignancy and therefore at greater risk of progressing to blast crisis (BC). If these patients could be identified a more potent TKI could be prescribed at presentation or be considered for stem cell transplant up front. Recently a common polymorphic variant of growth factor independent 1 (GFI1), a zinc finger DNA binding transcriptional repressor, whereby serine is substituted by asparagine at residue 36 (S36N), was reported (Khandanpour et al. Blood. 2010; 115:22462) to be associated with a 1.6 fold increased risk of developing acute myeloid leukemia (AML). In addition, investigators reported a frequency of 11% of the S36N GFI1 allele among AML patients, compared with 3-7% among the European populations. Reports suggest S36N GFI1 variant fails to repress the target genes, including HOXA9, and as a consequence their expression levels are elevated. These observations are consistent with a critical role for GFI1 in myeloid differentiation. In view of these findings we hypothesized that the GFI1 S36N allele might influence CML progression, via up-regulation of HOXA9, from a relatively indolent chronic phase (CP) to invariably fatal BC, characterized by presence of leukaemic stem cells, resistant to tyrosine kinase inhibitors in peripheral blood. Therefore, we assessed if S36N allele frequency was increased in CML and quantified GFI1expression.