Largest comparison between onset and relapses of acquired thrombotic thrombocytopenic purpura reveals severe neurological involvement and worse analytic parameters at debut.

It has been proposed that the onset of Acquired Thrombotic Thrombocytopenic Purpura (iTTP) is more severe than subsequent relapses; however, existing studies have limitations. We conducted a retrospective observational study to compare analytical and clinical severity of onset and relapse aTTP cases between 2012 and 2023. A total of 370 episodes of aTTP were analyzed, comprising 272 at initial diagnosis and 98 relapses. At onset, analytical parameters indicative of severity (low hemoglobin, low platelet count, and increased LDH) were significantly worse; patients had severe neurological symptoms (p<0.001) and ≥ 3 points in the TMA mortality score (p<0.001). In conclusion, the onset of aTTP is associated with worse analytical parameters and severe neurological involvement.

Combined Immune Defect in B-Cell Lymphoproliferative Disorders Is Associated with Severe Infection and Cancer Progression.

B cell chronic lymphoproliferative diseases (B-CLPD) are associated with secondary antibody deficiency and other innate and adaptive immune defects, whose impact on infectious risk has not been systematically addressed. We performed an immunological analysis of a cohort of 83 B-CLPD patients with recurrent and/or severe infections to ascertain the clinical relevance of the immune deficiency expression. B-cell defects were present in all patients. Patients with combined immune defect had a 3.69-fold higher risk for severe infection (p = 0.001) than those with predominantly antibody defect. Interestingly, by Kaplan-Meier analysis, combined immune defect showed an earlier progression of cancer with a hazard ratio of 3.21, than predominantly antibody defect (p = 0.005). When B-CLPD were classified in low-degree, high-degree, and plasma cell dyscrasias, risk of severe disease and cancer progression significantly diverged in combined immune defect, compared with predominantly antibody defect (p = 0.001). Remarkably, an underlying primary immunodeficiency (PID) was suspected in 12 patients (14%), due to prior history of infections, autoimmune and granulomatous conditions, atypical or variegated course and compatible biological data. This first proposed SID classification might have relevant clinical implications, in terms of predicting severe infections and cancer progression, and might be applied to different B-CLPD entities.

Next generation sequencing for diagnosis of hereditary anemia: Experience in a Spanish reference center.

BACKGROUND AND AIMS: Hereditary anemia (HA) encloses a wide group of rare inherited disorders with clinical and hematologic overlaps that complicate diagnosis. MATERIALS AND METHODS: A 48-gene panel was developed to diagnose HA by Next Generation Sequencing (NGS) in a large cohort of 165 patients from 160 unrelated families. RESULTS: Patients were divided in: A) patients who had a suspicion of a specific type of HA (n = 109), and B) patients who had a suspicion of HA but with no clear type (n = 56). Diagnostic performance was 83.5% in group A and a change of the initial diagnosis occurred in 11% of these patients. In group B, 35.7% of patients achieved a genetic diagnosis. NGS identified 6 cases of xerocytosis, 6 of pyruvate kinase (PK) deficiency, 4 of G6PD, and 1 case of phytosterolemia with no initial suspicion of these pathologies, which is clinically relevant since they have specific treatment. Five patients were found to carry variants associated to two different pathologies (4 of them combining a metabolic deficiency and a membrane defect), and 44 new variants were identified in 41 patients. CONCLUSION: The use of NGS is a sensitive technique to diagnose HA and it shows better performance when patients are better characterized.

Immunophenotyping and Cell Sorting of Human MKs from Human Primary Sources or Differentiated In Vitro from Hematopoietic Progenitors.

Megakaryocyte (MK) differentiation encompasses a number of endomitotic cycles that result in a highly polyploid (reaching even >64N) and extremely large cell (40-60 µm). As opposed to the fast-increasing knowledge in megakaryopoiesis at the cell biology and molecular level, the characterization of megakaryopoiesis by flow cytometry is limited to the identification of mature MKs using lineage-specific surface markers, while earlier MK differentiation stages remain unexplored. Here, we present an immunophenotyping strategy that allows the identification of successive MK differentiation stages, with increasing ploidy status, in human primary sources or in vitro cultures with a panel integrating MK specific and non-specific surface markers. Despite its size and fragility, MKs can be immunophenotyped using the above-mentioned panel and enriched by fluorescence-activated cell sorting under specific conditions of pressure and nozzle diameter. This approach facilitates multi-Omics studies, with the aim to better understand the complexity of megakaryopoiesis and platelet production in humans. A better characterization of megakaryopoiesis may pose fundamental in the diagnosis or prognosis of lineage-related pathologies and malignancy.

Mild dyserythropoiesis and ß-like globin gene expression imbalance due to the loss of histone chaperone ASF1B.

The expression of the human ß-like globin genes follows a well-orchestrated developmental pattern, undergoing two essential switches, the first one during the first weeks of gestation (ε to γ), and the second one during the perinatal period (γ to ß). The γ- to ß-globin gene switching mechanism includes suppression of fetal (γ-globin, HbF) and activation of adult (ß-globin, HbA) globin gene transcription. In hereditary persistence of fetal hemoglobin (HPFH), the γ-globin suppression mechanism is impaired leaving these individuals with unusual elevated levels of fetal hemoglobin (HbF) in adulthood. Recently, the transcription factors KLF1 and BCL11A have been established as master regulators of the γ- to ß-globin switch. Previously, a genomic variant in the KLF1 gene, identified by linkage analysis performed on twenty-seven members of a Maltese family, was found to be associated with HPFH. However, variation in the levels of HbF among family members, and those from other reported families carrying genetic variants in KLF1, suggests additional contributors to globin switching. ASF1B was downregulated in the family members with HPFH. Here, we investigate the role of ASF1B in γ- to ß-globin switching and erythropoiesis in vivo. Mouse-human interspecies ASF1B protein identity is 91.6%. By means of knockdown functional assays in human primary erythroid cultures and analysis of the erythroid lineage in Asf1b knockout mice, we provide evidence that ASF1B is a novel contributor to steady-state erythroid differentiation, and while its loss affects the balance of globin expression, it has no major role in hemoglobin switching.

Trained Immunity-Based Vaccine in B Cell Hematological Malignancies With Recurrent Infections: A New Therapeutic Approach.

Infectious complications are a major cause of morbidity and mortality in B-cell hematological malignancies (HM). Prophylaxis for recurrent infections in HM patients with antibody deficiency consists of first-line antibiotics and when unsuccessful, gammaglobulin replacement therapy (IgRT). Recent knowledge of trained immunity-based vaccines (TIbV), such as the sublingual polybacterial formulation MV130, has shown a promising strategy in the management of patients with recurrent infections. We sought to determine the clinical benefit of MV130 in a cohort of HM patients with recurrent respiratory tract infections (RRTIs) who underwent immunization with MV130 for 3 months. Clinical information included the frequency of infections, antibiotic use, number of visits to the GP and hospitalizations previous and after MV130 immunotherapy. Improvement on infection rate was classified as: clear (>60% reduction of infection), partial (26%-60%) and low (≤25%) improvement. Fifteen HM patients (aged 42 to 80 years; nine females) were included in the study. All patients reduced their infection rate. Analysis of paired data revealed that the median (range, min - max) of respiratory infectious rate significantly decreased from 4.0 (8.0-3.0) to 2.0 (4.0-0.0) (p<0.001) at 12 months of MV130. A clear clinical improvement was observed in 53% (n = 8) of patients, partial improvement in 40% (n = 6) and low improvement in 7% (n = 1). These data correlated with a decrease on antibiotic consumption from 3.0 (8.0-1.0) to 1.0 (2.0-0.0) (p = 0.002) during 12 months after initiation of treatment with MV130. The number of infectious-related GP or emergency room visits declined from 4.0 (8.0-2.0) to 2.0 (3.0-0.0) (p<0.001), in parallel with a reduction in hospital admissions due to infections (p = 0.032). Regarding safety, no adverse events were observed. On the other hand, immunological assessment of serum IgA and IgG levels demonstrated an increase in specific antibodies to MV130-contained bacteria following MV130 immunotherapy. In conclusion, MV130 may add clinical benefit reducing the rate of infections and enhancing humoral immune responses in these vulnerable patients.

Identification of underlying and transfusion-related platelet qualitative alterations in the hemato-oncologic patient.

Hemato-oncologic patients with chemotherapy-induced thrombocytopenia are one of the populations receiving platelet transfusions. The general practice with these patients is to give prophylactic platelet transfusions when platelet counts fall below 10×109PLT/L. However, in more than 40% of these patients, platelet transfusion does not prevent bleeding. The reason of the low efficacy of platelet transfusion in the context of chemotherapy patients is not entirely understood. We therefore aimed at immunophenotyping the expression of platelet surface and activation markers and thrombopoietin levels from hemato-oncologic patients before and after transfusion. A more detailed follow-up was performed in three patients that underwent autologous bone marrow transplantation. As previously reported, basal platelet activation was observed in hemato-oncologic patients. Based on flow cytometry parameters, i.e. the percentage of positivity and mean fluorescence intensity (MFI) distribution, our data provide an additional interpretation of platelet acquired qualitative changes in the hemato-oncologic patient. From our results we propose: first, the underlying activation of platelets in the hemato-oncologic patient is accompanied by loss of expression of the platelet receptors that are susceptible to protease-mediated shedding; second, soon after transfusion, the newly circulating donor platelets show additional activation, which may result in subsequent platelet receptor recycling and potential accelerated clearance of these activated platelets. In conclusion, the immunophenotype of circulating platelets changes after prophylactic platelet transfusion. Next to platelet count increment, exploration of this immunophenotype might help to explain transfusion refractory bleeding in hemato-oncologic patients. Eventually this may lead to personalization and improvement of the present platelet transfusion support regime.

Infiltración meníngea de linfoma linfoplasmocítico: síndrome de Bing-Neel / Meningeal infiltration by lymphoplasmacytic lymphoma: Bing-Neel syndrome

La macroglobulinemia de Waldenström es un linfoma linfoplasmocítico caracterizado por una proliferación monoclonal de linfocitos B productores de inmunoglobulina M que infiltran la médula ósea. Las manifestaciones neurológicas asociadas a la macroglobulinemia de Waldenström suelen ser debidas al fenómeno de hiperviscosidad o a neuropatías desmielinizantes mediadas por inmunoglobulina M. Cuando la afectación neurológica es debida a la infiltración del sistema nervioso central por las células linfoplasmocitoides, se produce un síndrome denominado de Bing-Neel, con baja prevalencia y variedad de manifestaciones clínicas. Se presenta el caso clínico de una mujer de 76 años con antecedentes de macroglobulinemia de Waldenström, con un cuadro neurológico repentino de alteración del lenguaje y torpeza en la mano derecha. Cabe destacar la relevancia del laboratorio clínico en el diagnóstico del síndrome de Bing-Neel y en el seguimiento del tratamiento (AU)

Waldenström macroglobulinemia is a lymphoplasmacytic lymphoma defined by a monoclonal proliferation of bone marrow infiltrating immunoglobulin M producing B lymphocytes. Neurological simptoms of Waldenström macroglobulinemia are mainly dominated by signs of hyperviscosity and autoimmune neuropathies mediated by immunoglobulin M. Neurological involvement secondary to the infiltration of IgM producing B lymphocytes, is defined as a Bing-Neel syndrome. This syndrome has a low prevalence and the clinical manifestations are variable. The case described is about a 76 year-old female with a history of Waldenström macroglobulinemia, who presents sudden neurological signs such as alteration of spoken language and clumsiness of the right hand. The clinical laboratory has a primary role in the diagnosis of Bing-Neel syndrome and monitoring of the treatment (AU)