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Lung ultrasound (LUS) has rapidly emerged in COVID-19 diagnosis and for the follow-up during the acute phase. LUS is not yet used routinely in lung damage follow-up after COVID-19 infection. We investigated the correlation between LUS score, and clinical and laboratory parameters of severity of SARS-COV-2 damage during hospitalization and at follow-up visit. Observational retrospective study including all the patients discharged from the COVID-19 wards, who attended the post-COVID outpatient clinic of the IRCCS Policlinico San Matteo in April-June 2020. 115 patients were enrolled. Follow-up visits with LUS score measurements were at a median of 38 days (IQR 28-48) after discharge. LUS scores were associated with the length of hospitalization (p 0.001), patients' age (p = 0.036), use of non-invasive ventilation (CPAP p 0.001 or HFNC p = 0.018), administration of corticosteroids therapy (p = 0.030), and laboratory parameters during the acute phase (WBC p 0.001, LDH p 0.001, CRP p 0.001, D-dimer p = 0.008, IL-6 p = 0.045), and inversely correlated with lymphocyte count (p = 0.007). We found correlation between LUS score and both LDH (p = 0.001) and the antibody anti-SARS-CoV-2 titers (p value = 0.008). Most of these finding were confirmed by dichothomizing the LUS score (≤ 9 or 9 points). We found a significantly higher LUS score at the follow-up in the patients with persistent dyspnea (7.00, IQR 3.00-11.00) when compared to eupnoeic patients (3.00, IQR 0-7.00 p 0.001). LUS score at follow-up visit correlates with more severe lung disease. These findings support the hypothesis that ultrasound could be a valid tool in the follow-up medium-term COVID-19 lung damage.

Chronic gastrointestinal disorders (including autoimmune gastritis, celiac disease, inflammatory bowel disease, and diverticular disease) are highly prevalent disorders, that may be associated with unpredictable, life-threatening complications, such as thromboembolic events. Venous thromboembolism (VTE) is one of the major causes of morbidity and mortality worldwide. Several conditions, including cancer, major trauma, surgery, prolonged immobilization, are well-established risk factors for VTE. Over the past decade, chronic inflammation has also been identified as an independent risk factor for VTE due to the prothrombotic effects of inflammatory cytokines and oxidative stress on the coagulation cascade. Other several mechanisms were shown to be associated with a higher incidence of VTE in patients with gastrointestinal disorders.We critically discuss the latest insights into the mechanisms responsible for thromboembolic manifestations in chronic gastrointestinal disorders, also focusing on the recognition of risk factors and treatment.The occurrence of thrombotic complications is underestimated in patients with chronic gastrointestinal disorders. Identifying potential risk factors and concomitant predisposing conditions and to prevent VTE and guide treatment require a multidisciplinary approach, and this is critically important for clinicians, in order to provide the best care for such patients.

GFI1B is a transcription factor essential for the regulation of erythropoiesis and megakaryopoiesis, and pathogenic variants have been associated with thrombocytopenia and bleeding. Analysing thrombocytopenic families by whole exome sequencing, we identified a novel GFI1B variant (c.648+5G>A), which causes exon 9 skipping and overexpression of a shorter p32 isoform. We report the clinical data of our patients and critically review the phenotype observed in individuals with different GFI1B variants leading to the same effect on the p32 expression. Since p32 is increased in acute and chronic leukemia cells, we tested the expression level of genes playing a role in various type of cancers, including hematological tumors and found that they are significantly dysregulated, suggesting a potential role for GFI1B in carcinogenesis regulation. Increasing the detection of individuals with GFI1B variants will allow us to better characterize this rare disease and determine whether it is associated with an increased risk of developing malignancies.

This study points out that combination therapy of hydroxychloroquine with azithromycin (HY+AZ) prolongs the QT interval in COVID-19 patients. Interestingly, patients who reached a QTc of at least 500 ms, a cut-off value known to increase the arrhythmic risk independently of comorbidity, among those treated with HY+AZ, have a significant prolonged QTc interval at the admission ECG compared with those who did not reach this QTc value despite the same treatment. This last finding suggests a potential higher arrhythmic risk in patients with QTc slightly prolonged at hospital admission who are treated with HY+AZ, stressing the need to perform careful ECG monitoring in these patients.

Autoimmune diseases (AID) are increasingly prevalent conditions which comprise more than 100 distinct clinical entities that are responsible for a great disease burden worldwide. The early recognition of these diseases is key for preventing their complications and for tailoring proper management. In most cases, autoantibodies, regardless of their potential pathogenetic role, can be detected in the serum of patients with AID, helping clinicians in making a definitive diagnosis and allowing screening strategies for early -and sometimes pre-clinical- diagnosis. Despite their undoubted crucial role, in a minority of cases, patients with AID may not show any autoantibody, a condition that is referred to as seronegative AID. Suboptimal accuracy of the available laboratory tests, antibody absorption, immunosuppressive therapy, immunodeficiencies, antigen exhaustion, and immunosenescence are the main possible determinants of seronegative AID. Indeed, in seronegative AID, the diagnosis is more challenging and must rely on clinical features and on other available tests, often including histopathological evaluation and radiological diagnostic tests. In this review, we critically dissect, in a narrative fashion, the possible causes of seronegativity, as well as the diagnostic and management implications, in several AID including autoimmune gastritis, celiac disease, autoimmune liver disease, rheumatoid arthritis, autoimmune encephalitis, myasthenia gravis, Sjögren's syndrome, antiphospholipid syndrome, and autoimmune thyroid diseases.

Pulmonary embolism (PE) is a frequent, life-threatening COVID-19 complication, whose diagnosis can be challenging because of its non-specific symptoms. There are no studies assessing the impact of diagnostic delay on COVID-19 related PE. The aim of our exploratory study was to assess the diagnostic delay of PE in COVID-19 patients, and to identify potential associations between patient- or physician-related variables and the delay. This is a single-center observational retrospective study that included 29 consecutive COVID-19 patients admitted to the San Matteo Hospital Foundation between February and May 2020, with a diagnosis of PE, and a control population of 23 non-COVID-19 patients admitted at our hospital during the same time lapse in 2019. We calculated the patient-related delay (i.e., the time between the onset of the symptoms and the first medical examination), and the physician-related delay (i.e., the time between the first medical examination and the diagnosis of PE). The overall diagnostic delay significantly correlated with the physician-related delay (p < 0.0001), with the tendency to a worse outcome in long physician-related diagnostic delay (p = 0.04). The delay was related to the presence of fever, respiratory symptoms and high levels of lactate dehydrogenase. It is important to rule out PE as soon as possible, in order to start the right therapy, to improve patient's outcome and to shorten the hospitalization.

The inherited thrombocytopenias (IT) are a heterogeneous group of diseases resulting from mutations in more than 30 different genes. Among them, ACTN1-related thrombocytopenia (ACTN1-RT; Online Mendelian Inheritance in Man: 615193) is one of the most recently identified forms. It has been described as a mild autosomal dominant macrothrombocytopenia caused by mutations in ACTN1, a gene encoding for one of the two non-muscle isoforms of alpha-actinin. We recently identified seven new unrelated families with ACTN1-RT caused by different mutations. Two of them are novel missense variants (p.Trp128Cys and p.Pro233Leu), whose pathogenic role has been confirmed by in vitro studies. Together with the 10 families we have previously described, our cohort of ACTN1-RT now consists of 49 individuals carrying ACTN1 mutations. This is the largest case series ever collected and enabled a critical evaluation of the clinical aspects of the disease. We concluded that ACTN1-RT is the fourth most frequent form of IT worldwide and it is characterized by platelet macrocytosis in all affected subjects and mild thrombocytopenia in less than 80% of cases. The risk of bleeding, either spontaneous or upon haemostatic challenge, is negligible and there are no other associated defects, either congenital or acquired. Therefore, ACTN1-RT is a benign form of IT, whose diagnosis provides affected individuals and their families with a good prognosis.

Impaired immune responses have been hypothesised to be a possible trigger of unfavourable outcomes in coronavirus disease 2019 (COVID-19). We aimed to characterise IgM memory B cells in patients with COVID-19 admitted to an internal medicine ward in Northern Italy. Overall, 66 COVID-19 patients (mean age 74 ± 16.6 years; 29 females) were enrolled. Three patients (4.5%; 1 female) had been splenectomised and were excluded from further analyses. Fifty-five patients (87.3%) had IgM memory B cell depletion, and 18 (28.6%) died during hospitalisation (cumulative incidence rate 9.26/100 person-week; 5.8–14.7 95% CI). All patients who died had IgM memory B cell depletion. A superimposed infection was found in 6 patients (9.5%), all of them having IgM memory B cell depletion (cumulative incidence rate 3.08/100 person-week; 1.3–6.8 95% CI). At bivariable analyses, older age, sex, number of comorbidities, and peripheral blood lymphocyte count

Major surgery is associated with an increased risk of venous thromboembolism, thus the application of mechanical or pharmacologic prophylaxis is recommended. The incidence of venous thromboembolism in patients with inherited platelet disorders undergoing surgical procedures is unknown and no information on the current use and safety of thromboprophylaxis, particularly of low-molecular-weight-heparin in these patients is available. Here we explored the approach to thromboprophylaxis and thrombotic outcomes in inherited platelet disorders patients undergoing surgery at venous thromboembolism-risk participating in the multicenter SPATA study. We evaluated 210 surgical procedures carried out in 155 patients with well-defined forms of inherited platelet disorders (venous thromboembolism-risk: 31% high, 28.6% intermediate, 25.2% low, 15.2% very low). The use of thromboprophylaxis was low (23.3% of procedures), with higher prevalence in orthopedic and gynecological surgeries, and was related to venous thromboembolism-risk. The most frequently employed thromboprophylaxis was mechanical and appeared to be effective, as no patients developed thrombosis, including patients belonging to the highest venous thromboembolism-risk classes. Low-molecular-weight-heparin use was low (10.5%) and it did not influence the incidence of post-surgical bleeding or of antihemorrhagic prohemostatic interventions. Two thromboembolic events were registered, both occurring after high venous thromboembolism-risk procedures in patients who did not receive thromboprophylaxis (4.7%). Our findings suggest that venous thromboembolism incidence is low in patients with inherited platelet disorders undergoing surgery at venous thromboembolism-risk and that it is predicted by the Caprini score. Mechanical thromboprophylaxis may be of benefit in patients with inherited platelet disorders undergoing invasive procedures at venous thromboembolism-risk and low-molecular-weight-heparin should be considered for major surgery. Fil: Paciullo, Francesco. Università di Perugia; Italia Fil: Bury, Loredana. Università di Perugia; Italia Fil: Noris, Patrizia. Universita Degli Studi Di Pavia; Italia Fil: Falcinelli, Emanuela. Università di Perugia; Italia Fil: Melazzini, Federica. Universita Degli Studi Di Pavia.; Italia Fil: Orsini, Sara. Università di Perugia; Italia Fil: Zaninetti, Carlo. Universita Degli Studi Di Pavia.; Italia Fil: Abdul Kadir, Rezan. Haemophilia Centre And Haemostasis Unit, Royal Free Fou; Reino Unido Fil: Obeng Tuudah, Deborah. Haemophilia Centre And Haemostasis Unit, Royal Free Fou; Reino Unido Fil: Heller, Paula Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina Fil: Glembotsky, Ana Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina Fil: Fabris, Fabrizio. Università di Padova; Italia Fil: Rivera, Jose. Universidad de Murcia; España Fil: Lozano, Maria Luisa. Universidad de Murcia; España Fil: Butta, Nora. Hospital Universitario la Paz; España Fil: Favier, Remi. French Reference Centre For Inherited Platelet Disorder; Francia Fil: Cid, Ana Rosa. Hospital Universitario y Politecnico la Fe; España Fil: Fouassier, Marc. French Reference Centre For Inherited Platelet Disorder; Francia Fil: Podda, Gian Marco. Università degli Studi di Milano; Italia Fil: Santoro, Cristina. Università degli studi di Roma "La Sapienza"; Italia Fil: Grandone, Elvira. Casa Sollievo Della Sofferenza,s.giovanni Rotondo; Italia Fil: Henskens, Yvonne. Maastricht University Medical Centre; Países Bajos Fil: Nurden, Paquita. French Reference Centre For Inherited Platelet Disorder; Francia Fil: Zieger, Barbara. Albert Ludwigs University of Freiburg; Alemania Fil: Cuker, Adam. University of Pennsylvania; Estados Unidos Fil: Devreese, Katrien. University of Ghent; Bélgica Fil: Tosetto, Alberto. Hospital San Bortolo; Italia Fil: De Candia, Erica. Istituto Nazionale di Ricovero e Cura a Carattere Scientifico "Saverio de Bellis"; Italia Fil: Dupuis, Arnaud. French Reference Centre For Inherited Platelet Disorder; Francia Fil: Miyazaki, Koji. Kitasato University School Of Medicine; Japón Fil: Othman, Maha. Queens University; Canadá Fil: Gresele, Paolo. Università di Perugia; Italia

Background: Careful assessment of bleeding history is the first step in the evaluation of patients with mild/moderate bleeding disorders, and the use of a bleeding assessment tool (BAT) is strongly encouraged. Although a few studies have assessed the utility of the ISTH-BAT in patients with inherited platelet function disorders (IPFD) none of them was sufficiently large to draw conclusions and/or included appropriate control groups. Objectives: The aim of the present study was to test the utility of the ISTH-BAT in a large cohort of patients with a well-defined diagnosis of inherited platelets disorder in comparison with two parallel cohorts, one of patients with type-1 von Willebrand disease (VWD-1) and one of healthy controls (HC). Patients/Methods: We enrolled 1098 subjects, 482 of whom had inherited platelet disorders (196 IPFD and 286 inherited platelet number disorders [IT]) from 17 countries. Results: IPFD patients had significantly higher bleeding score (BS; median 9) than VWD-1 patients (median 5), a higher number of hemorrhagic symptoms (4 versus 3), and higher percentage of patients with clinically relevant symptoms (score > 2). The ISTH-BAT showed excellent discrimination power between IPFD and HC (0.9

Several hundreds of studies recently investigated mean platelet volume (MPV) as measured by electronic cell counters in a wide variety of acquired diseases, and most of them found that platelet size was significantly increased with respect to healthy subjects. On this basis, it has been suggested that MPV can be used for diagnostic purposes. Moreover, investigation of subjects with arterial thrombosis not only revealed that their platelets were larger than those of controls, but also found that a high MPV predicted poor prognosis. Despite the large amount of available data, the pathogenesis of increased platelet size in these conditions is unclear. In particular, we do not know whether the increased platelet size is the cause or the consequence of thrombosis. Differences in MPV between patients and controls are usually very small and they reach the statistical significance because of the large number of investigated patients and the standardized methodology for MPV measurement. In real life, the wide variability of MPV possibly due to platelet count, sex, age, and ethnicity, as well as the very poor standardization of the methodologies used for MPV measurement, makes it impossible to decide whether an individual patient has normal or instead slightly increased MPV. So, MPV has presently no role in making diagnosis and defining prognosis in any acquired illness.

Congenital amegakaryocytic thrombocytopenia (CAMT) is an inherited disorder characterized at birth by thrombocytopenia with reduced megakaryocytes, which evolves into generalized bone marrow aplasia during childhood. Although CAMT is genetically heterogeneous, mutations of MPL , the gene encoding for the receptor of thrombopoietin (THPO), are the only known disease‐causing alterations. We identified a family with three children affected with CAMT caused by a homozygous mutation (p.R119C) of the THPO gene. Functional studies showed that p.R119C affects not only ability of the cytokine to stimulate MPL but also its release, which is consistent with the relatively low serum THPO levels measured in patients. In all the three affected children, treatment with the THPO‐mimetic romiplostim induced trilineage hematological responses, remission of bleeding and infections, and transfusion independence, which were maintained after up to 6.5 years of observation. Recognizing patients with THPO mutations among those with juvenile bone marrow failure is essential to provide them with appropriate substitutive therapy and prevent the use of invasive and unnecessary treatments, such as hematopoietic stem cell transplantation or immunosuppression.

Essentials Extramedullary hematopoiesis (EMH) represents a pathologic finding in adult life. We report a mass-like EMH in the presacral space in a patient with ANKRD26-related thrombocytopenia. We found possible correlation between EMH and conditions causing lifelong thrombocytopenia. EMH can cause masses of unknown origin in patients with inherited thrombocytopenias. Summary Most commonly located in the liver and spleen, extramedullary hematopoiesis (EMH) is the presence of hematopoietic tissue outside the bone marrow. MYH9-related thrombocytopenia (MYH9-RD) and ANKRD26-related thrombocytopenia (ANKRD26-RT) are two of the most frequent forms of inherited thrombocytopenia (IT). Until recently, EMH has been associated with neoplastic and non-neoplastic hematologic conditions in which ITs were not included. We describe a case of mass-like EMH in the presacral space in a patient affected with ANKRD26-RT, comparing it with another case of paravertebral EMH we recently described in a subject with MYH9-RD. The surprisingly similitude of such a finding in the context of a group of rare disorders induces us to speculate about the possible pathogenic relationship between EMH and conditions causing lifelong thrombocytopenia, particularly the entity of ITs. Finally, we suggest that EMH has to be taken into consideration in the diagnostic work-up of masses of unknown origin in subjects affected with ITs.

Thrombopoietin (THPO) is an essential regulator of haemopoiesis that is required for the maintenance of haemopoietic progenitors and their differentiation into megakaryocytes (Mks). Moreover, it modulates the events that drive Mk maturation and allows the release of platelets into bone marrow sinusoids. THPO plays these roles by binding the MPL receptor, which is expressed in bone marrow stem cells, Mks, platelets and many other human cells. Until recently, no inherited THPO defect was known to cause thrombocytopenia or bone marrow aplasia. However, it was recently shown that microdeletions encompassing the THPO gene in chromosome 3 result in a complex clinical picture, including mild congenital thrombocytopenia. Moreover, a Micronesian family carrying the homozygous c.112C>T (p.Arg38Cys or p.Arg17Cys in the mature protein) missense mutation in THPO presents inherited bone marrow aplasia. No THPO mutation associated with isolated thrombocytopenia has been reported to date, but the application of whole exome sequencing (WES) in a cohort of patients with inherited thrombocytopenias (ITs) of unknown origin revealed that monoallelic changes in this gene identify a new form of IT. In fact, WES identified two unrelated individuals carrying the heterozygous variant c.91C>T (p. Arg31*), which is expected to result in mutant protein degradation and THPO haploinsufficiency.

Bleeding diathesis has been considered for a long time the main clinical issue impacting the lives of patients affected by inherited thrombocytopaenias. However, the number of known inherited thrombocytopaenias greatly increased in recent years, and careful evaluation of hundreds of patients affected by these 'new' disorders revealed that most of them are at risk of developing additional life-threatening disorders during childhood or adult life. These additional disorders are usually more serious and dangerous than low platelet count. For instance, it is known that mutations in RUNX1, ANKRD26 and ETV6 cause congenital thrombocytopaenia, but we now know that they also predispose to haematological malignancies. Similarly, MYH9 mutations result in congenital thrombocytopaenia and increase the risk of developing kidney failure, cataracts and hearing loss at a later stage, while MPL mutations cause a congenital thrombocytopaenia that almost always evolves into deadly bone marrow failure. Thus, identification of patients with these disorders is essential for evaluation of their prognosis, enabling effective genetic counselling, personalizing follow-up and giving appropriate treatments in case of development of additional diseases. Careful clinical evaluation and peripheral blood film examination are extremely useful tools in guiding the diagnostic process and identifying the candidate genes to be sequenced.

Excessive bleeding at surgery is a feared complication in patients with inherited platelet disorders. However, very few studies have evaluated the frequency of surgical bleeding in these hemorrhagic disorders. We performed a worldwide, multicentric, retrospective study to assess the bleeding complications of surgery, the preventive and therapeutic approaches adopted, and their efficacy in patients with inherited platelet disorders: the Surgery in Platelet disorders And Therapeutic Approach (SPATA) study. We rated the outcome of 829 surgical procedures carried out in 423 patients with well-defined forms of inherited platelet disorders: 238 inherited platelet function disorders and 185 inherited platelet number disorders. Frequency of surgical bleeding was high in patients with inherited platelet disorders (19.7%), with a significantly higher bleeding incidence in inherited platelet function disorders (24.8%) than in inherited platelet number disorders (13.4%). The frequency of bleeding varied according to the type of inherited platelet disorder, with biallelic Bernard Soulier syndrome having the highest occurrence (44.4%). Frequency of bleeding was predicted by a pre-operative World Health Organization bleeding score of 2 or higher. Some types of surgery were associated with a higher bleeding incidence, like cardiovascular and urological surgery. The use of pre-operative pro-hemostatic treatments was associated with a lower bleeding frequency in patients with inherited platelet function disorders but not in inherited platelet number disorders. Desmopressin, alone or with antifibrinolytic agents, was the preventive treatment associated with the lowest bleedings. Platelet transfusions were used more frequently in patients at higher bleeding risk. Surgical bleeding risk in inherited platelet disorders is substantial, especially in inherited platelet function disorders, and bleeding history, type of disorder, type of surgery and female sex are associated with higher bleeding frequency. Prophylactic pre-operative pro-hemostatic treatments appear to be required and are associated with a lower bleeding incidence.

The reference range for any blood test is defined as the set of values which 95% of the normal population falls within. When the value of a parameter varies according to specific physiological characteristics of investigated individuals, a single reference range is not sufficient, and personalized

Since the beginning of the century, our knowledge of inherited thrombocytopenias greatly advanced, and we presently know 30 forms with well-defined genetic defects. This great advancement changed our view of these disorders, as we realized that most patients have only mild thrombocytopenia with inconspicuous bleeding or no bleeding tendency at all. However, better knowledge of inherited thrombocytopenias also revealed that some of the most prevalent forms expose to the risk of acquiring during infancy or adulthood additional disorders that endanger the life of patients much more than hemorrhages. Thus, inherited thrombocytopenias are complex disorders with quite different clinical features and prognosis. Identification of novel genes whose mutations result in low platelet count greatly advanced also our knowledge of the megakaryocyte biology and proved beyond any doubt that the defective proteins play an essential role in platelet biogenesis or survival in humans. Based on the study of inherited thrombocytopenias, we better understood the sequence of molecular events regulating megakaryocyte differentiation, maturation, and platelet release. Since nearly 50% of patients have as yet unidentified genetic or molecular mechanisms underlying their inherited thrombocytopenia, further studies are expected to reveal new clinical entities and new molecular mechanisms of platelet production.

ETV6-related thrombocytopenia is an autosomal dominant thrombocytopenia that has been recently identified in a few families and has been suspected to predispose to hematologic malignancies. To gain further information on this disorder, we searched for ETV6 mutations in the 130 families with inherited thrombocytopenia of unknown origin from our cohort of 274 consecutive pedigrees with familial thrombocytopenia. We identified 20 patients with ETV6-related thrombocytopenia from seven pedigrees. They have five different ETV6 variants, including three novel mutations affecting the highly conserved E26 transformation-specific domain. The relative frequency of ETV6-related thrombocytopenia was 2.6% in the whole case series and 4.6% among the families with known forms of inherited thrombocytopenia. The degree of thrombocytopenia and bleeding tendency of the patients with ETV6-related thrombocytopenia were mild, but four subjects developed B-cell acute lymphoblastic leukemia during childhood, resulting in a significantly higher incidence of this condition compared to that in the general population. Clinical and laboratory findings did not identify any particular defects that could lead to the suspicion of this disorder from the routine diagnostic workup. However, at variance with most inherited thrombocytopenias, platelets were not enlarged. In vitro studies revealed that the maturation of the patients' megakaryocytes was defective and that the patients have impaired proplatelet formation. Moreover, platelets from patients with ETV6-related thrombocytopenia have reduced ability to spread on fibrinogen. Since the dominant thrombocytopenias due to mutations in RUNX1 and ANKRD26 are also characterized by normal platelet size and predispose to hematologic malignancies, we suggest that screening for ETV6, RUNX1 and ANKRD26 mutations should be performed in all subjects with autosomal dominant thrombocytopenia and normal platelet size.

Platelet transfusion is currently the primary medical treatment for reducing thrombocytopenia in patients with inherited thrombocytopenias. To evaluate whether stimulating megakaryopoiesis could increase platelet count in these conditions, we treated patients with a severe thrombocytopenia induced by MYH9 mutations (MYH9-related disease) with a nonpeptide thrombopoietin receptor agonist, eltrombopag. Twelve adult patients with MYH9-RD and platelet counts of less than 50 × 109/L received 50 mg of eltrombopag orally per day for 3 weeks. Patients who achieved a platelet count higher than 150 × 109/L stopped therapy, those with 100 to 150 platelets × 109/L continued treatment at the same eltrombopag dose for 3 additional weeks, while those with less than 100 platelets × 109/L increased the eltrombopag dose to 75 mg for 3 weeks. Major responses (platelet count of at least 100 × 109/L or 3 times the baseline value) were obtained in 8 patients, minor responses (platelet counts at least twice the baseline value) in 3. One patient did not respond. Bleeding tendency disappeared in 8 of 10 patients with bleeding symptoms at baseline. Mild adverse events were reported in 2 patients. The availability of thrombopoietin mimetics opened new prospects in the treatment of inherited thrombocytopenias. This study is registered at www.clinicaltrials.gov as NCT01133860 (European Union Drug Regulating Authorities Clinical Trials number 2008-001903-42).

This study evaluated 65 pregnancies in 34 women with five different inherited platelet function disorders. Gestation was similar to that of the general population. Severe bleeds requiring blood transfusions were observed in 50% of deliveries in Glanzmann thrombasthenia (GT), but not in the patients with delta storage pool disease, Hermansky-Pudlak syndrome, P2Y12 defect or defect of thromboxane A2 receptor. Of note, severe haemorrhage also occurred in women with GT who had received prophylactic platelet transfusions, suggesting that better preventive treatments are required. Diagnosis and degree of spontaneous bleeding tendency before pregnancy were reliable parameters to predict the delivery-related bleeding risk.

Abnormalities of platelet size are one of the distinguishing features of inherited thrombocytopenias (ITs), and evaluation of blood films is recommended as an essential step for differential diagnosis of these disorders. Nevertheless, what we presently know about this subject is derived mainly from anecdotal evidence. To improve knowledge in this field, we evaluated platelet size on blood films obtained from 376 patients with all 19 forms of IT identified so far and found that these conditions differ not only in mean platelet diameter, but also in platelet diameter distribution width and the percentage of platelets with increased or reduced diameters. On the basis of these findings, we propose a new classification of ITs according to platelet size. It distinguishes forms with giant platelets, with large platelets, with normal or slightly increased platelet size, and with normal or slightly decreased platelet size. We also measured platelet diameters in 87 patients with immune thrombocytopenia and identified cutoff values for mean platelet diameter and the percentage of platelets with increased or reduced size that have good diagnostic accuracy in differentiating ITs with giant platelets and with normal or slightly decreased platelet size from immune thrombocytopenia and all other forms of IT. Fil: Noris, Patrizia. University of Pavia; Italia Fil: Biino, Ginevra. Consiglio Nazionale Delle Ricerche. Istituto di Genetica Molecolare; Italia Fil: Pecci, Alessandro. University of Pavia; Italia Fil: Civaschi, Elisa. University of Pavia; Italia Fil: Savoia, Anna. Università degli Studi di Trieste; Italia. Istituto Di Ricovero e Cura a Carattere Scientifico Burlo Garofolo; Italia Fil: Seri, Marco. Università di Bologna; Italia Fil: Melazzini, Federica. University of Pavia; Italia Fil: Loffreddo, Giuseppe. Pausilipon Hospital; Italia Fil: Russo, Giovana. Università degli Studi di Catania; Italia Fil: Bozzi, Valeria. University of Pavia; Italia Fil: Notarangelo, Lucia Dora. Spedali Civili. Ospedale dei Bambini; Italia Fil: Gresele, Paolo. Università di Perugia; Italia Fil: Heller, Paula Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina Fil: Pujol Moix, Nuria. Universitat Autònoma de Barcelona; España Fil: Kunishima, Shinji. National Hospital Organization Nagoya Medical Center; Japón Fil: Cattaneo, Marco. Università degli Studi di Milano; Italia Fil: Bussel, James. Cornell University; Estados Unidos Fil: de Candia, Erica. Universita Cattolica del Sacro Cuore; Italia Fil: Cagioni, Claudia. University of Pavia; Italia Fil: Ramenghi, Ugo. Università di Torino; Italia Fil: Barozzi, Serena. University of Pavia; Italia Fil: Fabris, Fabrizio. Università di Padova; Italia Fil: Balduini, Carlo L.. University of Pavia; Italia

Background. Bernard-Soulier syndrome is a very rare form of inherited thrombocytopenia that derives from mutations in GPIb alpha, GPIb beta, or GPIX and is typically inherited as a recessive disease. However, some years ago it has been shown that the monoallelic c.515C>T transition in the GPIBA gene (Bolzano mutation) was responsible for macrothrombocytopenia in a few Italian patients. Design and Methods. In the past 10 years, we have searched for Bolzano mutation in all subjects referred to our institutions for an autosomal, dominant form of thrombocytopenia of unknown origin. Results. We identified 42 new Italian families (103 cases) with a thrombocytopenia induced by monoallelic Bolzano mutation. Analyses of the geographic origin of affected pedigrees and haplotypes indicated that this mutation originated in southern Italy. Although the clinical expressivity was variable, patients with this mutation typically had a mild form of Bernard-Soulier syndrome with a mild thrombocytopenia and bleeding tendency. The most indicative laboratory findings were an enlarged platelet size and reduced GPIb/IX/V platelet expression, although in vitro platelet aggregation was normal in nearly all of the cases. Conclusions. Our study indicates that monoallelic Bolzano mutation is the most frequent cause of inherited thrombocytopenia in Italy, affecting 20% of patients recruited at our institutions during the last 10 years. Because many people from southern Italy have emigrated during the last century, this mutation may have spread to other countries.

Background Bernard-Soulier syndrome is a severe bleeding disease due to a defect of GPIb/IX/V, a platelet complex that binds the von Willebrand factor. Due to the rarity of the disease, there are reports only on a few cases compromising any attempt to establish correlations between genotype and phenotype. In order to identify any associations, we describe the largest case series ever reported, which was evaluated systematically at the same center. Design and Methods Thirteen patients with the disease and seven obligate carriers were enrolled. We collected clinical aspects and determined platelet features, including number and size, expression of membrane glycoproteins, and ristocetin induced platelet aggregation. Mutations were identified by direct sequencing of the GP1BA, GP1BB, and GP9 genes and their effect was shown by molecular modeling analyses. Results Patients all had a moderate thrombocytopenia with giant platelets and a bleeding tendency whose severity varied among individuals. Consistent with expression levels of GPIb alpha always lower than 10% of control values, platelet aggregation was absent or severely reduced. Homozygous mutations were identified in the GP1BA, GP1BB and GP9 genes; six were novel alterations expected to destabilize the conformation of the respective protein. Except for obligate carriers of a GP9 mutation with a reduced GPIb/IX/V expression and defective aggregation, all the other carriers had no obvious anomalies. Conclusions Regardless of mutations identified, the patients' bleeding diathesis did not correlate with thrombocytopenia, which was always moderate, and platelet GPIba expression, which was always severely impaired. Obligate carriers had features similar to controls though their GPIb/IX/V expression showed discrepancies. Aware of the limitations of our cohort, we cannot define any correlations. However, further investigations should be encouraged to better understand the causes of this rare and underestimated disease.

Summary. Background: Distinguishing inherited thrombocytopenias from immune thrombocytopenia (ITP) can be difficult, and patients are therefore at risk of misdiagnosis and inappropriate treatments. Although it is known that the most common inherited forms of thrombocytopenia are characterized by increased platelet size, the diagnostic power of this feature has never been investigated. Objectives: The aim of this study was to test the hypothesis that platelet size can be used to differentiate ITP from inherited macrothrombocytopenias. Patients/methods: We measured mean platelet volume (MPV) and mean platelet diameter (MPD), within 2 h of blood sampling, in 35 patients with inherited macrothrombocytopenias [15 MYH9-related disease (MYH9-RD), three biallelic and 17 monoallelic Bernard–Soulier syndrome (BSS)], and 56 with ITP. Using receiving operating characteristic analysis, we searched for the best cut-off values to differentiate between these conditions. Results: As expected, platelets were larger in inherited macrothrombocytopenias than in ITP. An MPD larger than 3.3 μm differentiated MYH9-RD and BSS from ITP with 0.89 sensitivity and 0.88 specificity, and an MPV larger than 12.4 fL had 0.83 sensitivity and 0.89 specificity. Combining MPD with MPV increased sensitivity and specificity to 0.97 and 0.89, respectively. Conclusion: Platelet size evaluation by both an appropriate cell counter and blood film examination is useful for differentiating inherited macrothrombocytopenias from ITP.

Abstract 2214 Bernard-Soulier syndrome (BSS) has been historically described as an autosomal recessive disease, and more than 50 different mutations have been identified in homozygous or double-heterozygous patients. However, a few reports have suggested that BSS may be occasionally transmitted in an autosomal-dominant fashion. In 2001, we described six Italian families that were previously diagnosed with Mediterranean macrothrombocytopenia and possessed the monoallelic c.515C>T transition in the GPIBA gene, which results in a p.Ala156Val substitution (Bolzano mutation) in GPIb alpha (Savoia et al, Blood 2001;97:1330–5) Since 2001, we have searched for this mutation in all patients referred to us for a non-syndromic, autosomal dominant form of inherited macrothrombocytopenia of unknown origin. Screening for the c.515C>T mutation identified 42 carriers and genetic molecular testing in all of the available relatives indicated that this mutation was present in 61 additional individuals. When the 42 families described here are added to the 6 families previously described, our database of 210 pedigrees of inherited thrombocytopenia includes 48 families with monoallelic, dominant BSS caused by the Bolzano mutation; 22 of the pedigrees have MYH9-related disease, 21 have thrombocytopenia 2 caused by ANKRD26 mutations (Noris et al, Blood 2011;117:6673–80), and 10 pedigrees have the classic biallelic, recessive form of BSS (Savoia et al, Haematologica 2011;96:417-23). Our experience therefore indicates that the Bolzano mutation is the most frequent cause of inherited thrombocytopenia in Italy. Analyses of the geographic origin of affected pedigrees and haplotypes indicated that this mutation originated in southern Italy. The bleeding tendency was variable, with 42% of the cases presenting recurrent, spontaneous hemorrhages that only rarely were severe (5 patients required medical intervention and platelet transfusions). 19 women delivered 32 children (vaginal and caesarean births) with no platelet transfusions, and excessive bleeding was reported in one case only. None of the patients experienced abnormal bleeding associated with dental extractions or surgery. Thrombocytopenia was usually mild (a few subjects even had normal platelet counts), and electronic counters overestimated the degree of platelet deficiency with respect to manual counting with optical microscopy in a Neubauer chamber (Table 1). Platelets were larger than normal in most patients, and their GPIb/IX/V content was 50% of controls. However, in vitro platelet aggregation in response to ristocetin 1.5 mg/mL was defective only in 22% of cases. The serum thrombopoietin level was two-fold greater than that of healthy subjects and similar to that observed in a case series of patients with ITP. Beta 1-tubulin polymorphisms, which have been associated with platelet size and function (Freson et al, Blood 2005;106:2356–62), did not explain the variation in clinical and laboratory features of our patients. In conclusion, our study indicates that the monoallelic Bolzano mutation is a frequent cause of macrothrombocytopenia in Italy and that this mutation induces a mild form of BSS that is often misdiagnosed with ITP. Further analyses in other countries will reveal whether this form of the disease is exclusive to Italy or if it also affects other populations.Table 1.Platelet count and size in patients with the Bolzano mutation in GPIb alpha.PatientsControlsmean±SD (range)Manual platelet count, x10e9/L114±36† (42–184)276±50 (170–420)Impedance platelet count, x10e9/L89±33**† (21–147)255±53 (141–396)Optical platelet count, x10e9/L103±32*† (21–162)280±54 (164–412)MPV, fL, by optical counter15±1.7† (9.7–17.8)8.2±0.8 (7.1–11.1)MPD, um, by optical microscopy3.6±0.5† (2.6–5.1)2.4±0.3 (1.9–3.4)*: p Disclosures: Cattaneo: Eli Lilly Daiichi Sankyo: Honoraria; AstraZeneca: Honoraria, Research Funding.

Abstract 2533 MYH9-Related Disease (MYH9-RD) is one of the less rare forms of inherited thrombocytopenia. It derives from mutations of the gene MYH9 for the heavy chain of nonmuscle myosin IIA and is characterized by congenital macrothrombocytopenia variably associated with young-adult onset of hearing loss, cataract, and a severe proteinuric nephropathy. Only platelet transfusions are available for increasing platelet counts in this condition, but they expose to the risks of acute reactions, transmission of infectious diseases, and refractoriness to subsequent platelet transfusions. Moreover, this treatment suffers from scarceness of blood donors. Novel thrombopoiesis-stimulating agents have been developed and 2 of them, eltrombopag and romiplostin, have been approved for increasing platelet count in a few forms of acquired thrombocytopenia. Since it has been recently shown that megakaryocytes of patients with MYH9-RD respond in vitro to TPO stimulation, we reasoned that TPO-mimetics could be effective also in this condition and decided to test the effect of eltrombopag. Therefore, we performed a phase II, multicentre, open-label, dose escalation trial. Twelve adult patients with a platelet count lower than 50×10e9/L and a diagnosis of MYH9-RD confirmed by identification of the causative MYH9 mutations received orally eltrombopag 50 mg daily for 21 days (Revolade®, GSK). Patients with platelet counts lower than 100×10e9/L at day 21 increased eltrombopag to 75 mg daily for 21 additional days. Patients with platelet counts between 100 and 150×10e9/L at day 21 continued eltrombopag 50 mg daily for the following 21 days, while patients with more than 150×10e9 platelets/L stopped therapy. The primary endpoints were the achievement of a platelet count over 100×10e9/L or at least three times the baseline value (major response), or at least twice the baseline value but less than major response (minor response). Secondary end points included safety and tolerability, and the reduction of bleeding tendency. After 3 weeks at the eltrombopag dose of 50 mg daily, 3 patients achieved platelet counts of 150×10e9/L or more and stopped therapy. Two had a platelet counts between 100 and 150×10e9/L and continued treatment at the same dosage, while 7 had less than 100×10e9 platelets/L and received eltrombopag 75 mg daily for 3 weeks. A major response was obtained in 8 patients (67%), in 5 of them after 3 weeks of eltrombopag 50 mg daily, and in 3 cases after 3 additional weeks at the dose of 75 mg. Three patients (25%) achieved a minor response, 1 after 3 weeks at 50 mg daily, and 2 after 3 additional weeks at 75 mg. In one patient the treatment resulted in no response. Mean platelet count at the end of treatment was significantly higher than at baseline (105 versus 31×10e9 platelets/L, p=0.0022). In the 11 patients that achieved major or minor responses, mean platelet count was still higher than baseline 15 days after discontinuation of the drug, while it returned to levels near baseline 15 days later. Platelet size did not change either during treatment or after its cessation, and this indicates that the increases in platelet count were paralleled by corresponding increases in total platelet mass. The extent of platelet aggregation was within the normal range after all tested agonists in 5 of the 7 patients that achieved platelet counts higher than 100×10e9/L, while it was slightly reduced after ADP and collagen in 2 patients. Mean serum TPO level was higher than the normal range and this figure did not change neither during treatment with eltrombopag nor after its discontinuation. Ten of 12 patients had grade 1 or 2 bleeding symptoms, as measured by the WHO bleeding scale, at baseline, while 2 were asymptomatic. Upon treatment, bleeding diathesis quickly ameliorated and disappeared in 8 cases, while it remained unchanged in the only patient with no response to eltrombopag and in another one with a minor response. The benefit in terms of bleeding diathesis lasted well beyond treatment discontinuation. Treatment was well tolerated in all cases, with only two patients reporting mild and transient headache and one patient suffering from transient dry mouth at the beginning of treatment. In conclusion, 50–75 mg of eltrombopag per day increased platelet count and reduced bleeding tendency in most patients with MYH9-RD. Further research is required to ascertain whether TPO mimetics are effective also in other forms of inherited thrombocytopenia. Disclosures: Off Label Use: Eltrombopag for MYH9-related disease.