Polyclonal Anti-D Antibodies Significantly Reduce the Rate of Miscarriages in Rh(D) positive Women with Recurrent Pregnancy loss.

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.

Silvernanoparticle-induced hemolysis confounded with direct antiglobulin test-negative autoimmune hemolytic anemias diagnosis.

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.

Safety of Uncrossmatched ABO-Compatible RBCs in Alloimmunized Patients with Bleeding: Data from Two Decades: Results of a Systematic Analysis in 6,109 Patients.

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.

A fluorometric erythrophagocytosis assay using differentiated monocytic THP-1 cells to assess the clinical significance of antibodies to red blood cells.

BACKGROUND AND OBJECTIVES: The significance of antibodies to red blood cells (RBCs) is variable and cannot be predicted solely by serological testing. A flow cytometry-based erythrophagocytosis assay was established using phorbol 12-myristate 13-acetate (PMA)-treated THP-1 cells and RBCs labelled with PKH26 to assess allo- and autoantibodies to RBCs. MATERIALS AND METHODS: THP-1 cells were differentiated into macrophage-like cells by treatment with PMA. RBC samples coated with alloantibodies or autoantibodies were obtained from 16 patients with autoimmune haemolytic anaemia of warm type (wAIHA) as well as from five pregnant women with warm autoantibodies. RBCs from healthy blood donors were used as controls. RBCs were labelled with the red lipophilic fluorescent dye PKH26 and incubated with PMA-treated THP-1 cells. After removal of nonadherent RBCs by washing and haemolysis of adherent RBCs, erythrophagocytosis was quantified by flow cytometry. RESULTS: We observed significant phagocytosis of RBCs coated with clinically relevant alloantibodies (i.e. anti-D and anti-K) or autoantibodies from patients with active wAIHA, but not of those coated with alloantibodies (anti-Ch) or autoantibodies from patients and pregnant women without haemolysis. CONCLUSION: The flow cytometry-based erythrophagocytosis test described here is quantitative, highly reliable, and may be helpful for the assessment of the clinical significance of antibodies to RBCs.

Risk of piperacillin-induced hemolytic anemia in patients with cystic fibrosis and antipseudomonal treatment: a prospective observational study.

BACKGROUND: Drug-induced immune hemolytic anemia (DIIHA) is a rare but severe side effect caused by numerous drugs. Case reports and case series suggest that piperacillin-related DIIHA may be more common among patients with cystic fibrosis (CF). However, the prevalence is speculative. The aim of this prospective, observational study was determine the prevalence of DIIHA in such affected patients. METHODS AND MATERIALS: Patients with CF hospitalized for parenteral antibiotic therapy at Charité Universitätsmedizin Berlin, who had previously been exposed to IV antibiotics, were enrolled. Blood samples were collected on Days 3 and 12 of antibiotic treatment courses. Serological studies were performed using standard techniques with gel cards. Screening for drug-dependent antibodies (ddab) was performed in the presence of the drugs and their urinary metabolites. RESULTS: A total of 52 parenteral antibiotic cycles in 43 patients were investigated. Ddab against piperacillin were detected in two patients (4.7%). The direct AHG was positive with anti-IgG only in both patients. However only one of these patients developed mild immune hemolytic anemia. Both patients had been repeatedly treated with piperacillin without any evident hemolysis. There was no correlation between the exposure to piperacillin and the prevalence of ddab. CONCLUSION: Our prospective study indicates that piperacillin-induced ddab occur more frequently in patients with CF than previously suggested. The question related to the significance of piperacillin-dependent antibodies may reflect new aspects in this field.

Sublytic Terminal Complement Components Induce Eryptosis in Autoimmune Haemolytic Anaemia Related to IgM Autoantibodies.

BACKGROUND/AIMS: Eryptosis, the suicidal death of red blood cells (RBCs), is characterized by phosphatidylserine (PS) exposure at the cell surface. It can be catalysed by a variety of abnormal conditions and diseases. Until now, the many questions surrounding the physiology and pathophysiology of eryptosis have not been sufficiently answered. Recently, we demonstrated IgM and IgA autoantibodies (aab) to induce PS exposure on circulating RBCs of patients with autoimmune haemolytic anaemia (AIHA). However, it remained unclear how these aab lead to eryptosis. METHODS: Serum and plasma samples from patients with clinically relevant AIHA of cold type were used to induce eryptosis in O RBCs. Serum containing fresh complement from healthy donors, antibodies to complement component, and complement factor depleted sera were added to examine the influence of the complement on PS-exposure. RBC bound annexin V PE were analysed by flow cytometry. RESULTS: Eryptosis related to IgM aab was found to be dependent on complement activation and could be effectively inhibited by EDTA, serum heat inactivation and anti-C5. PS exposure increased with sequential activation of the sublytic terminal complement components C5b6, C5b-7 and was most significant at the C5b-8 stage. A decrease was observed following the formation of the lytic membrane attack complex C5b-9, either because of lysis of eryptotic RBCs or because of inhibition of eryptosis by C9. CONCLUSION: Our findings reflect new aspects on RBC destruction in AIHA as well the impact of the terminal complement complexes on the RBC membrane. The striking differences to nucleated cell apoptosis may even have physiological meaning of RBC acting as a buffer of the complement system.

Changes in health-related quality of life with long-term eltrombopag treatment in adults with persistent/chronic immune thrombocytopenia: Findings from the EXTEND study.

Patients with persistent/chronic immune thrombocytopenia (cITP) have low platelet counts, increased risk of bleeding and bruising, and often suffer from reduced health-related quality of life (HRQoL). cITP treatments may either improve HRQoL by increasing platelet counts or decrease it because of side effects. The open-label EXTEND study (June 2006 to July 2015) evaluated long-term safety, tolerability, and efficacy of eltrombopag (an oral thrombopoietin-receptor-agonist) in adults with cITP who completed a previous eltrombopag ITP trial. The final results of EXTEND were published and used to assess changes in patient-reported HRQoL over time and association between HRQoL and platelet response. Four validated HRQoL instruments were administered: SF-36v2 including physical component summary (PCS) and Mental Component Summary; Motivation and Energy Inventory Short Form (MEI-SF); Fatigue Subscale of FACIT (FACIT-Fatigue); and FACT-Thrombocytopenia Subscale Six-Item Extract (FACT-Th6). For the 302 patients enrolled, median duration of eltrombopag treatment was 2.37 years. All 4 HRQoL instruments demonstrated positive mean changes from baseline over time adjusted for patient baseline characteristics and rescue therapy use, and had positive association with platelet response (platelet count ≥30 × 109 /L; ≥50 × 109 /L; and ≥50 × 109 /L and >2 times baseline). Improvements from baseline started within 3 months and persisted through 5 years of treatment for FACIT-Fatigue and FACT-Th6 (P <.05 for nearly all time points); through 2.5 years for SF-36v2 PCS and less consistently for the MEI-SF. In conclusion, in addition to eltrombopag increasing platelet counts and reducing bleeding/bruising, it also alleviated fatigue, concerns about bleeding and bruising, and improved physical function in many patients, especially responders.

Efficacy of Antenatal Intravenous Immunoglobulin Treatment in Pregnancies at High Risk due to Alloimmunization to Red Blood Cells.

BACKGROUND: Alloimmunization to red blood cells (RBCs) may result in fetal anemia prior to 20 weeks gestation. The question as to whether early commencement of antenatal treatment with high-dose intravenous immunoglobulins (IVIG) may prevent or at least delay the development of fetal anemia in the presence of alloantibodies to RBCs is highly relevant. PATIENTS AND RESULTS: Here we describe a patient with high-titer anti-K and two other severely affected pregnant women with a history of recurrent pregnancy loss due to high-titer anti-D or anti-D plus anti-C. Early commencement of treatment with IVIG (1 g/kg/week) resulted in prevention of intrauterine transfusion (IUT) in the former two cases, and in a significant delay of development of fetal anemia in the remaining case (26 weeks gestation). CONCLUSION: Based on our findings and of previously published cases, early initiation of treatment of severely alloimmunized women with IVIG (1 g/kg/week) could potentially improve the outcome of fetuses at risk.

Efficacy and tolerability of old and new drugs used in the treatment of immune thrombocytopenia: Results from a long-term observation in clinical practice.

BACKGROUND: Many patients with immune thrombocytopenia (ITP) may require special attention and long-term treatment. Little is known on the efficacy and tolerability of the drugs used in practice. MATERIAL AND METHODS: We retrospectively reviewed the results of therapy of 400 patients with chronic ITP. All Patients were treated at our institution between 1996-2016 under consideration of guidelines, general recommendations, and individual aspects, including gender, age, weight, comorbidity, patient's medical history and bleeding risk. RESULTS: Treatment was not required in 25% of patients (n = 100) during observation. In treated patients (n = 300), the rate of patients that responded and tolerated treatment with prednisolone was 59% (52/88), with azathioprine 32% (29/90), with eltrombopag 49% (31/63), with romiplostim 59% 27/45, with IVIG (intravenous immunoglobulines) 75% (94/126), with anti-D 37% (19/52) and with dexamethasone 60% (25/42) patients. Eighteen treated patients (6%) entered sustained remission after treatment with various drugs. Twenty-six patients underwent splenectomy (Splx) resulting in sustained remission in 15 cases (60%). Only two patients remained refractory to Splx and to all used drugs. DISCUSSION: None of the currently available drugs used in the treatment of ITP are invariably safe and effective. Responses, the duration of response, intolerability, and the course of disease are unpredictable. Although the treatment of ITP has considerably improved in the recent years, the currently available drugs may rarely cure affected patients. The need for safe and effective therapy in ITP is evident. Optimal treatment decisions for each patient remains a challenge in many cases.

Efficacy and Safety of IQYMUNE®, a Ten Percent Intravenous Immunoglobulin in Adult Patients With Chronic, Primary Immune Thrombocytopenia.

BACKGROUND: Intravenous immunoglobulin (IVIG) IQYMUNE® is a highly purified 10% IVIG that was assessed using the new stringent definition of response described in the revised guideline on the clinical investigation of IVIG. The efficacy and the safety of IQYMUNE® were investigated in adult patients with chronic primary immune thrombocytopenia (ITP). METHODS: In this phase III multinational, multicentre, prospective, uncontrolled, open-label, single-arm study, adult patients with a baseline platelet count < 30 × 109/L were treated with IVIG 10% at a dose of 2 g/kg body weight administered over 2 consecutive days. The primary endpoint was Response over the study period and was defined according to the recent and most stringent European Medicines Agency guidelines (platelet count ≥ 30 × 109/L and a ≥ 2-fold increase from baseline, no new bleeding, and no concomitant treatment with drugs that affect platelet count and/or induce bleeding cessation). RESULTS: Thirty-eight patients were enrolled; 73 infusions were administered (38 on Day 1 and 35 on Day 2). Response was reached by 24 patients corresponding to 63.2% of patients in the full analysis set (95% CI: 46.0; 78.2) and 68.6% of patients in the per-protocol set (95% CI: 50.7; 83.1). The median time to Response was 1 day. The median duration of Response was 13.5 days. Reasons for non-response were failure to reach the required platelet count (n = 12), a new bleeding event (n = 1), and forbidden medication use (n = 1). Among the 23 patients with a baseline platelet count ≤ 20 × 109/L, 19 patients (82.6%) achieved a platelet count ≥ 50 × 109/L at least once before Day 5 (previous European Medicines Agency definition of response). Treatment was well tolerated even in patients with a high flow rate (≥ 6 mL/kg/h in 40% of patients). Headache (34.2%), pyrexia (15.8%), and creatinine renal clearance decrease, including one case of decrease in glomerular filtration rate (10.5%) were the most frequently reported drug-related adverse events. CONCLUSIONS: Administration of IQYMUNE® for 2 consecutive days at a dose of 2 g/kg was safe and efficacious. These results support the treatment of adult patients with chronic ITP with IQYMUNE®.

Eryptosis in autoimmune haemolytic anaemia.

OBJECTIVE: Haemolysis and anaemia related to autoimmune haemolytic anaemia (AIHA) of warm type (wAIHA) and of cold type (cAIHA) are believed to be solely due to antibody and/or complement-mediated destruction and clearance of red blood cells (RBCs). There is evidence that RBCs of affected patients may also undergo eryptosis, the suicidal death of RBCs. METHOD: RBCs from 24 patients with wAIHA, 7 patients with chronic cAIHA and one patient with AIHA of mixed type were analysed for exposed phosphatidylserine (PS) by treatment with phycoerythrin-labelled Annexin V, and cell-associated fluorescence was measured using a MACSQuant flow cytometer. RESULTS: PS-exposing RBCs were detected in 7 of 13 patients with clinically significant wAIHA. Haemolysis was mostly related to IgM or IgA autoantibodies (aab) in those patients. In contrast, PS exposure in 11 patients with wAIHA in complete remission was comparable to that in healthy blood donors. All patients with chronic cAIHA and the patient with AIHA of mixed type showed haemolytic activity and high numbers of PS-exposing RBCs. Patients with decompensated AIHA appear to respond to treatment with erythropoietin, which is a known inhibitor of eryptosis. CONCLUSION: Eryptosis may frequently occur in AIHA related to IgM or IgA aab. Inhibition of eryptosis with erythropoietin may represent a new therapeutic option in the treatment of AIHA.

Bidirectional inefficacy or intolerability of thrombopoietin receptor agonists: new data and a concise review.

BACKGROUND: There is evidence that the thrombopoietin-receptor agonists romiplostim and eltrombopag may have different therapeutic values and adverse reaction profiles. Here we present new data and provide a review of all studies dealing with switching between these two drugs. MATERIALS AND METHODS: A total of 89 patients (38 males and 51 females, aged between 14-87 years) were treated with eltrombopag and/or romiplostim between 2007 and 2016 at our institution. Eltrombopag was switched to romiplostim or vice versa in 32 patients. In addition, all published data concerning patients treated sequentially with different thrombopoietin-receptor agonists were identified via a computer-assisted search and summarised in this article. RESULTS: Thirty-two of 89 patients treated with a thrombopoietin-receptor agonist in our institution were given both eltrombopag and romiplostim sequentially. Therapy was switched to the alternate thrombopoietin-receptor agonist 36 times, due to inefficacy (n=21), adverse reactions (n=14), and a patient's preference (n=1). In addition, data from 126 patients who have been treated with both agonists have been published by other groups. In total eltrombopag was replaced by romiplostim in 56 cases due to poor or no response or to adverse reactions. Forty-five patients responded to treatment with romiplostim, 11 patients shared cross-resistance and nine had adverse reactions to romiplostim. In contrast, romiplostim was replaced by eltrombopag in 106 cases. Seventy-eight patients responded to eltrombopag, 27 shared cross-resistance and 19 had adverse reactions to eltrombopag. DISCUSSION: Eltrombopag and romiplostim often share bidirectional cross-resistance and/or adverse reactions. Both drugs appear to cause more adverse reactions than have been previously reported.

Effect of glucocorticoid treatment on BAFF and APRIL expression in patients with immune thrombocytopenia (ITP).

Immune thrombocytopenic purpura (ITP) is an idiopathic bleeding disorder. B cell activating factor (BAFF) and 'A proliferation-inducing ligand' (APRIL) have regulatory effects on B and T cells and may represent relevant factors in the pathogenesis of ITP. Serum levels and gene expression were investigated in ITP patients. Both BAFF and APRIL serum levels were significantly elevated in active ITP. However, gene expression analysis revealed both factors to have a tendency toward downregulation. Glucocorticoid treatment significantly reduced BAFF but not APRIL serum levels, which may be mediated by differences in transcription factor binding sites. The glucocorticoid receptor binding site is present in the BAFF promotor region, but not in the APRIL promotor region. Prednisolone in combination with vitamin D3 may be effective in reducing APRIL serum levels. In conclusion, glucocorticoid treatment exerts different regulatory effects on both BAFF and APRIL, whereas antioxidant supplementation may also be beneficial in reducing serum levels.

Effect of thrombopoietin receptor agonists on leukocyte and haematopoietic stem and progenitor cells in the peripheral blood of patients with immune thrombocytopenic purpura.

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.

Safety and efficacy of long-term treatment of chronic/persistent ITP with eltrombopag: final results of the EXTEND study.

In phase 2/3 trials, eltrombopag treatment of 6 months or less in patients with chronic/persistent immune thrombocytopenia (ITP) increased platelet counts and reduced bleeding. The open-label EXTEND study evaluated long-term safety and efficacy of eltrombopag in adults with ITP who had completed a previous eltrombopag study. For the 302 patients enrolled, median duration of eltrombopag treatment was 2.37 years (2 days-8.76 years). Median platelet counts increased to 50 × 109/L or more by week 2 and were sustained throughout the treatment period. Overall, 259 patients (85.8%) achieved a response (platelet count ≥50 × 109/L at least once in the absence of rescue), and 133 (52%) of 257 patients achieved a continuous response of 25 weeks or longer. Responses in patients with platelet counts lower than 15 × 109/L, more previous therapies, and/or splenectomy were somewhat lower. Thirty-four (34%) of 101 patients receiving concomitant ITP medication discontinued 1 or more medication. In patients with assessments, bleeding symptoms (World Health Organization grades 1-4) decreased from 57% at baseline to 16% at 1 year. Forty-one patients (14%) withdrew because of adverse events. Hepatobiliary adverse events (n = 7), cataracts (n = 4), deep vein thrombosis (n = 3), cerebral infarction (n = 2), headache (n = 2), and myelofibrosis (n = 2) occurred in more than 1 patient; the remaining adverse events occurred only once. Rates of thromboembolic events (6%) and hepatobiliary adverse events (15%) did not increase with treatment duration past 1 year. EXTEND demonstrated that long-term use of eltrombopag was effective in maintaining platelet counts of 50 × 109/L or more and reducing bleeding in most patients with ITP of more than 6 months' duration. Important adverse events (eg, thrombosis, hepatobiliary, and bone marrow fibrosis) were infrequent. (ClinicalTrials.gov:NCT00351468).

Successful treatment of bleeding with tranexamic acid in a series of 12 patients with immune thrombocytopenia.

BACKGROUND AND OBJECTIVES: The clinical significance of immune thrombocytopenia (ITP) is mainly reflected by bleeding and/or bleeding risks, which, in some cases, cannot be adequately controlled by standard therapy. Tranexamic acid (TA) is increasingly used in preventing and reducing bleeding in several medical settings. There is little information on whether TA may also be useful in the management of ITP. MATERIALS AND METHODS: Twelve patients with ITP were treated with TA (0·5-3 g/day) due to recognizable bleeding. Ten of the 12 patients were under regular treatment for ITP. The remaining two patients did not require additional therapy. RESULTS: Cessation or, at least, significant improvement of bleeding was achieved shortly after the initiation of TA in all cases. TA was well tolerated and discontinued after cessation of bleeding. CONCLUSIONS: We recommend the use of TA in ITP patients with bleeding and/or an increased bleeding risk. Ultimately, cessation of bleeding plays a key role in the management of such affected patients. However, future studies are required to optimize dose and administration routes (intravenous or oral).

Hemolysis related to intravenous immunoglobulins is dependent on the presence of anti-blood group A and B antibodies and individual susceptibility.

BACKGROUND: Patients treated with intravenous immunoglobulins (IVIG) rarely experience symptomatic hemolysis. Although anti-A and anti-B isoagglutinins from the product are involved in most cases, the actual mechanisms triggering hemolysis are unclear. STUDY DESIGN AND METHODS: A prospective, open-label, multicenter, single-arm clinical trial in 57 patients with immune thrombocytopenia treated with IVIG (Privigen, CSL Behring) was conducted. RESULTS: Twenty-one patients received one infusion (1 g/kg) and 36 received two infusions (2 × 1 g/kg) of IVIG. After a study duration of more than 2 years, no cases of clinically significant hemolysis as defined in the protocol were identified. Data of patients with mild hematologic and biochemical changes were analyzed in more detail. Twelve cases (10/23 patients with blood group A1 and 2/11 patients with blood group B, all having received 2 g/kg IVIG) were adjudicated as mild hemolysis (median hemoglobin [Hb] decrease, -3.0 g/dL); Hb decreases were transient, with partial or full recovery achieved by last visit. Eighteen patients (31.6%), all with non-O blood group, of whom 16 (88.9%) received 2 g/kg IVIG, fulfilled post hoc criteria for hemolytic laboratory reactions. Red blood cell (RBC) eluates of all direct antiglobulin test-positive samples were negative for non-ABO blood group antibodies. Blood groups A and B antigen density on RBCs appeared to be a risk factor for hemolytic laboratory reactions. Platelet response to treatment was observed in 42 patients (74%); eight of 12 patients with complete response had blood group A1. CONCLUSION: Isoagglutinins are involved in clinically nonsignificant hemolysis after treatment with IVIG, but individual susceptibility varies greatly.

Immobilization and high platelet count are associated with thromboembolic complications in heparin-induced thrombocytopenia.

PURPOSE: Immune-mediated heparin-induced thrombocytopenia (HIT type II, HIT) is a potentially serious adverse drug reaction characterized by an increased risk of venous and arterial thrombosis. This study aimed to identify risk factors associated with the development of these complications. METHODS: Our study cohort included patients with HIT assembled in our pharmacovigilance center by reports from 51 collaborating hospitals in Berlin, Germany. To identify risk factors for thromboembolic complications, patients with thromboembolic events (cases) were compared to those without thromboembolic events (controls) in a case-control design. We applied univariable and multivariable logistic regression analysis to estimate odds ratios (OR) and corresponding 95% confidence intervals (CI) for potential risk factors of thromboembolic complications. RESULTS: Our cohort comprised 209 HIT patients. Of those, 53 developed thromboembolic complications. Most HIT patients received heparin for medical indications (42.1%) or in the context of cardiovascular surgery (40.2%). Of the 78 thromboembolic complications, 49 (63%) and 29 (37%) were observed in the venous and arterial vascular bed, respectively. The main locations were deep vein thrombosis (39.7%), pulmonary embolism (16.7%), and limb artery thrombosis (16.7%). In multivariable analysis, immobilization prior to HIT (OR 4.6, 95% CI 1.2-18.0; P = .026) and higher platelet counts before initiation of heparin therapy (OR 1.004, 95% CI 1.000-1.008; P = .046) were independently associated with the occurrence of thromboembolic events. CONCLUSIONS: Immobilization and a high platelet count (with a low effect size) are additional risk factors of thromboembolic complications in the course of HIT.

Analysis of platelet-derived extracellular vesicles in plateletpheresis concentrates: a multicenter study.

BACKGROUND: Routine quantification of platelet-derived extracellular vesicles (PL-EVs) may be useful in the quality control (QC) of platelet concentrates (PCs). The aim of this multicenter study was to establish and validate a consensus protocol for the standardized PL-EV quantification using conventional flow cytometers. STUDY DESIGN AMD METHODS: Eighty-six PCs were investigated in five blood transfusion centers (A-E) on Days 0 and 5. The centers used different apheresis instruments: Trima Accel (n = 56) and/or Amicus (n = 30). PCs were prepared using standard methods (sd-PCs; n = 73; A-D) or with pathogen inactivation (PI [PI-PCs]; n = 13; E). Platelet (PLT) count was determined using conventional hematology analyzers. PLT degranulation (P-selectin expression in response to thrombin receptor PAR1 activation) and PL-EVs were analyzed by flow cytometry. RESULTS: During storage, PLT count remained stable in 58 PCs (A, C, E), whereas a decrease was observed in 12 PCs (B). PLT degranulation declined in all PCs (p < 0.001) and PL-EVs increased in 74 PCs (A, C-E; p < 0.001). Certain donor variables (e.g., plasma cholesterol, immature PLT fraction) were associated with lower PL-EVs. In Trima-produced PCs, PL-EVs were significantly lower (D) and PLT degranulation was superior compared to PCs prepared with the Amicus (A, D). PL-EVs were 10-fold lower in PI-PCs, compared to sd-PCs. However, similar QC trends were demonstrated for both PC groups during storage. CONCLUSION: PL-EV analysis in a QC program of PCs was successfully performed with results comparable among the different centers. PLT degranulation and vesiculation were primarily affected by preparation techniques.

Emerging drugs for immune thrombocytopenia (ITP).

INTRODUCTION: Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by autoantibody production against platelets, increased platelet destruction, and, in some cases, impaired thrombopoiesis. The majority of affected patients have significant bleeding risks due to low platelet counts and require treatment. The etiology of ITP is an immunological labyrinth. Currently available treatment options are usually not only nonspecific, but are also associated with some risks. Areas covered: Several useful drugs for the treatment of ITP are currently available. Furthermore, ongoing trials with new drugs and preclinical development of additional drugs may help to improve and determine their value. Expert opinion: ITP is a heterogeneous complex requiring individualized treatment. None of the available drugs are specific, nor are they invariably safe and effective. Thus, the need for specific therapy is evident.