Transfusion Medicine and Hemotherapy最新文献

Introduction: Immune checkpoint inhibitors (ICIs) have revolutionized classical treatment approaches of various cancer entities, but are also associated with a number of side effects. One of these may be life-threatening clotting disorders with the risk of thrombotic or hemorrhagic complications, the mechanisms of which are still poorly understood. In the present study, we analyzed the direct effects of pembrolizumab, nivolumab, and ipilimumab on platelet aggregation as well as plasma coagulation followed by fibrinolysis in an ex vivo model.

Methods: Microplate spectrometry was used to analyze aggregation, coagulation, and fibrinolysis in platelet-free (PFP) and platelet-rich (PRP) healthy donor plasma samples treated with pembrolizumab, nivolumab, ipilimumab, and appropriate isotype controls. Aggregation was induced by TRAP-6. Clotting of PFP and PRP followed by lysis was initiated with a tissue factor in a mixture of phosphatidylserine:phosphatidylcholine and the addition of t-PA. Among other parameters, the area under the curve (AUC) was used to compare the effect of ICIs on aggregation, coagulation, and fibrinolysis.

Results: Upon direct contact with platelets, pembrolizumab stimulated platelet aggregation in PRP, while nivolumab and ipilimumab promoted disaggregation with corresponding changes in the AUC. Pembrolizumab and nivolumab, both PD-1 receptor inhibitors, had no effect on the plasma coagulation cascade. Ipilimumab, a CTLA-4 receptor inhibitor, significantly increased the rate of PRP clotting. When clotting was followed by lysis, all ICIs were found to prolong the growth of the PRP-derived fibrin clot and delay its elimination. This was manifested by an increase in AUC relative to control PRP.

Conclusion: This study characterizes the potential impact of pembrolizumab, nivolumab, and ipilimumab on hemostasis. Nivolumab and ipilimumab are able to reduce aggregation and increase the procoagulant properties of platelets, which can cause side effects associated with hemostatic imbalance leading to thrombosis or bleeding. The observed ICI-specific effects may contribute to our understanding of the mechanisms by which ICI affects platelets and suggest how, in a clinical setting, to reduce coagulation disorders during ICI treatment in the future.

Background: Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by intravascular hemolysis (IVH) due to diminished or absent inhibition of the complement system because of deficient expression of cell-anchored complement regulating surface proteins. IVH leads to heterogeneous symptoms such as anemia, abdominal pain, dyspnea, fatigue and increased rates of thrombophilia. Inhibitors of the terminal Complement cascade can reverse IVH leading to a significant reduction of disease burden such as thrombembolic events and also mortality.

Summary: Therapeutic inhibitors of the terminal complement cascade such as eculizumab or ravulizumab significantly improve overall survival through IVH-inhibition. However, not all patients experience complete disease control with normalization of hemoglobin levels and absolute reticulocyte counts (ARC) under terminal complement inhibition as a significant part of patients develop extravascular hemolysis (EVH). EVH can be clinically relevant causing persistent anemia and fatigue. New proximal complement inhibitors (CI) mainly targeting complement component C3 or factors of the amplification pathway such as pegcetacoplan, danicopan, and iptacopan became available and are meanwhile approved for marketing. Additional complement-inhibiting strategies are under clinical development. A switch from terminal to proximal CI in patients with significant EVH can achieve hemoglobin and ARC normalization and significant improvement in quality of life (QoL). Additional approvals of proximal CI agents for the treatment of hemolytic PNH in the first line are available for pegcetacoplan and iptacopan. So far, no evidence-based algorithm is available for decision-making in first-line treatment of which type of drug should be used for individual patients.

Key messages: Terminal CIs in hemolytic PNH patients can block IVH and have led to a dramatically improved survival. Proximal CIs ameliorate anemia and improve QoL in patients with relevant EVH. However, more (real-world) data are needed to demonstrate long-term improvement in all patients with hemolytic PNH, especially those under first-line treatment with proximal CI.

[This corrects the article DOI: 10.1159/000532049.].

Background: Sickle cell disease (SCD) is among the most frequent hereditary disorders globally and its prevalence in Europe is increasing due to migration movements.

Summary: The basic pathophysiological event of SCD is polymerization of deoxygenated sickle hemoglobin, resulting in hemolysis, vasoocclusion, and multiorgan damage. While the pathophysiological cascade offers numerous targets for treatment, currently only two disease-modifying drugs have been approved in Europe and transfusion remains a mainstay of both preventing and treating severe complications of SCD. Allogeneic stem cell transplantation and gene therapy offer a curative option but are restricted to few patients due to costs and limited availability of donors.

Key message: Further efforts are needed to grant patients access to approved treatments, to explore drug combinations and to establish new treatment options.

[This corrects the article DOI: 10.1159/000533624.].

Background: Telomeres are the end-capping structures of all eukaryotic chromosomes thereby protecting the genome from damage and degradation. During the aging process, telomeres shorten continuously with each cell division until critically short telomeres prevent further proliferation whereby cells undergo terminal differentiation, senescence, or apoptosis. Premature aging due to critically short telomere length (TL) can also result from pathogenic germline variants in the telomerase complex or related genes that typically counteract replicative telomere shortening in germline and certain somatic cell populations, e.g., hematopoetic stem cells. Inherited diseases that result in altered telomere maintenance are summarized under the term telomere biology disorder (TBD).

Summary: Since TL both reflects but more importantly restricts the replicative capacity of various human tissues, a sufficient telomere reserve is particularly important in cells with high proliferative activity (e.g., hematopoiesis, immune cells, intestinal cells, liver, lung, and skin). Consequently, altered telomere maintenance as observed in TBDs typically results in premature replicative cellular exhaustion in the respective organ systems eventually leading to life-threatening complications such as bone marrow failure (BMF), pulmonary fibrosis, and liver cirrhosis.

Key messages: The recognition of a potential congenital origin in approximately 10% of adult patients with clinical BMF is of utmost importance for the proper diagnosis, appropriate patient and family counseling, to prevent the use of inefficient treatment and to avoid therapy-related toxicities including appropriate donor selection when patients have to undergo stem cell transplantation from related donors. This review summarizes the current state of knowledge about TBDs with particular focus on the clinical manifestation patterns in children (termed early onset TBD) compared to adults (late-onset TBD) including typical treatment- and disease course-related complications as well as their prognosis and adequate therapy. Thereby, it aims to raise awareness for a disease group that is currently still highly underdiagnosed particularly when it first manifests itself in adulthood.

Background: The Lewis (Le) blood group system, unlike most other blood groups, is not defined by antigens produced internally to the erythrocytes and their precursors but rather by glycan antigens adsorbed on to the erythrocyte membrane from the plasma. These oligosaccharides are synthesized by the two fucosyltransferases FUT2 and FUT3 mainly in epithelial cells of the digestive tract and transferred to the plasma. At their place of synthesis, some Lewis blood group carbohydrate antigen variants also seem to be involved in various gastrointestinal malignancies. However, relatively little is known about the transcriptional regulation of FUT2 and FUT3.

Summary: To address this question, we screened existing literature and additionally used in silico prediction tools to identify novel candidate regulators for FUT2 and FUT3 and combine these findings with already known data on their regulation. With this approach, we were able to describe a variety of transcription factors, RNA binding proteins and microRNAs, which increase FUT2 and FUT3 transcription and translation upon interaction.

Key messages: Understanding the regulation of FUT2 and FUT3 is crucial to fully understand the blood group system Lewis (ISBT 007 LE) phenotypes, to shed light on the role of the different Lewis antigens in various pathologies, and to identify potential new diagnostic targets for these diseases.

Introduction: A_el is known to be one of the weakest A subgroups and can be identified through either the adsorption-elution technique or molecular analysis. Single nucleotide variation in the ABO gene can potentially disrupt the function of ABO glycosyltransferase, resulting in decreased ABO antigen expression.

Case presentation: We reported 1 case of the missense SNV c.1024A>C in the ABO*A1.02 allele was associated with an A_el phenotype. The proband was a 19-year-old male Chinese Han blood donor who was initially stereotyped as type B. Based on the findings from absorption elution, genotype tests, and a family investigation, both the proband and his mother were classified as the A_elB phenotype. An uncommon allele was detected in both the proband and his mother, differing by a single nucleotide at position 1,024 from A to C (c.1024A>C) when compared to the ABO*A1.02 allele. The c.1024A>C SNV induces an amino acid substitution, specifically p.Thr342Pro, which consequently leads to the loss of two sheets (p214-p216, p340-p344) in the wild-type A glycosyltransferase (GTA) 3D structure. The removal of these two sheets, situated at the protein's core, implies the occurrence of an interaction within this domain that affects the stability of the protein structure.

Conclusion: A_elB is prone to misidentification as type B, and the accurate determination of blood type can be achieved through the integration of the adsorption-elution technique and molecular analysis.