Immune recovery and the role of recent thymic emigrated T lymphocytes after pediatric hematopoietic stem cell transplantation.

BACKGROUND AIMS: Adequate re-establishment of thymopoiesis is critical for long-term immune reconstitution after hematopoietic cell transplantation (HCT), potentially impacting patient survival rates. This study aimed to evaluate immune reconstitution in pediatric HCT recipients by quantifying recent thymic emigrants (RTEs), specifically CD3+CD31+CD45RA+ cells. METHODS: We conducted a retrospective analysis of 186 pediatric patients transplanted between 2013 and 2020, undergoing their first allogeneic HCT, who were alive in the first 100 days after transplantation with immune recovery evaluation at three time points: day 100, day 180 and day 360 after HCT. We analyzed the distribution of peripheral blood subsets of T, B and natural killer lymphocytes and assessed the impact of underlying disease, HCT type, stem cell source, recipient age, conditioning regimen, graft-versus-host disease (GVHD) occurrence and cytomegalovirus (CMV) reactivation on immune recovery. RESULTS: At day 100, patients under 10 years exhibited higher RTE CD4+ and CD8+CD31+CD45RA+ counts compared with older patients (5.3 versus 2.2 cells/µL, P = 0.022 and 48 versus 72.8 cells/µL, P = 0.049, respectively). Patients with haploidentical HCT had lower RTE CD4+ counts compared with those with unrelated or related donors (2.4 versus 4.4 versus 7.9 cells/µL, P = 0.024). Administration of rabbit anti-thymocyte globulin negatively impacted RTE CD4+ production (median, 6.5 versus 2.4 cells/µL, P = 0.007). At day 180, the presence of GVHD had a negative influence on RTE production (11.7 versus 56.8 cells/µL, P < 0.001), particularly higher-grade acute GVHD (without, 56.8 cells/µL, grade 1-2, 28.1 cells/µL, grade 3-4, 6.0 cells/µL, P < 0.001). Patients with CMV reactivation had higher CD8+CD31+CD45RA+ compared with those without reactivation (median, 204.6 versus 100.2 cells/µL, P = 0.022). At day 360, no variables significantly affected RTE recovery. Overall survival at 5-year follow-up was 87.7%, with a median of 1170 days (range, 122-3316). Multivariate analysis showed that age >10 years (P = 0.038), negative CMV donor serology (P = 0.0029) and acute GVHD (P = 0.0026) had a negative impact on survival. CONCLUSIONS: This study highlights variations in RTE production based on patient age, donor type and immunosuppression regimen employed.

Analysis of baseline characteristics, disease burden and long-term follow-up of 167 patients with Paroxysmal Nocturnal Hemoglobinuria at a single center in Brazil.

Paroxysmal nocturnal hemoglobinuria (PNH) can occur as a hemolytic form or small PNH clone found in a patient with bone marrow failure. METHODS: Describe Brazilian retrospective PNH cohort and identify the impact of disease burden on long-term follow-up. RESULTS: 167 patients, mean age at diagnosis 28.4 (7.1-71.2 years), four years mean interval between onset of cytopenia/aplasia diagnosis and PNH clone detection. Patients were divided into 15 Classic PNH, 55 Hemolytic PNH with bone marrow hypoplasia (PNH/AA), and 97 Subclinical PNH (sc-PNH). Hypocellular bone marrow was found in 89.2%; 55 had hemoglobinuria and 22 thrombosis during monitoring. WBC PNH clone correlated with RBC PNH clone, LDH and cytopenia. Subclinical patients had lower median lower RBC clone (2.0% vs 24.0% vs 57.8%) and WBC clone (11.7% vs 58.8% vs 81.2%) than PNH/AA and Classic PNH, respectively. PNH granulocyte clone was 89.1% in thrombotic patients. Ten-year overall survival 80.4% and mortality in transplanted patients 9.6%. Sepsis was mortality cause in subclinical PNH (16/18, 88.8%), and thrombosis in hemolytic PNH (11/13, 84.6%). CONCLUSION: Large PNH clones and LDH burden were associated with increased hemolysis and thrombosis risks, while young patients were associated with small PNH clones and subclinical form of the disease. Knowledge of the patient profile, the low risk associated with HSCT, and the use of long-term IST may be instrumental in the clinical management of PNH in restricted-resources countries.

Survival benefit of pediatric-based regimen for adults with acute lymphoblastic leukemia: A single-center retrospective cohort.

INTRODUCTION: Improving survival of Acute Lymphoblastic Leukemia (ALL) in adult patients has been a challenge. Despite intensive chemotherapy treatment, overall survival is poor. However, several studies demonstrate that young adult patients have better survival when treated with pediatric-based intensive regimens. Considering these results, We decided to treat newly diagnosed ALL patients according to age and risk factors. The goal of this study was to describe the results of this intensive chemotherapy treatment approach for ALL adult patients diagnosed at our institution. METHODS: Fifty-eight ALL patients, diagnosed from 2004 to 2013, were included in the analysis. Patients were assigned to either the St. Jude Total Therapy XIIIB high-risk arm (St Jude) or the CALGB 8811 (CALGB). The Kaplan-Meier survival curve was used for the survival analyses and the Cox proportional hazard regression, for multivariable analysis. RESULTS: The overall survival was 22.9% at 10 years. The St. Jude improved survival, compared to the CALGB (p = 0.007), with 32.6% vs. 7.4% survival rate at 10 years. However, no survival benefit was found for patients younger than 20 years old (p = 0.32). The multivariable analysis demonstrated that undetectable minimal residual disease (MRD) and hematopoietic stem cell transplantation (HSCT) had beneficial impact on survival (p = 0.0007 and p = 0.004, respectively). CONCLUSION: ALL is a disease of poor prognosis for adults. The joint effort to standardize treatment and seek solutions is the way to start improving this scenario.

Use of flow cytometry and cytology to differentiate breast implant-associated anaplastic large cell lymphoma from reactive seromas in Brazilian patients.

INTRODUCTION: The combination of cytology and multiparametric flow cytometry (MFC) may be useful in the diagnosis of breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) and may be a practical way to differentiate lymphoma from benign and reactive seromas. Although the Brazilian breast implant market is the second largest in the world, with several manufacturers and the almost exclusive use of textured implants, the occurrence of BIA-ALCL in Brazil is underreported. METHODS: One hundred seventeen sequential collections of suspicious periprosthetic fluid (PF) from 105 Brazilian patients registered between March/2018 and March/2021 were evaluated by routine cytomorphology and flow cytometry. The combination of CD30, HLA-DR, and CD25 was used together with T and B lymphocyte and monocyte evaluation. The PF samples were divided into positive, acute reactive (neutrophilic exudate), or chronic reactive (macrophage or lymphocyte rich), and unavailable samples. RESULTS: Nine BIA-ALCL positive cases (7.7%) were identified, with typical morphology and increased FSC/SSC dispersion, bright expression of CD30, CD25 and HLA-DR, and absence or weakness of T-cell antigens (CD3, CD8, CD4, CD5, and CD7). Reactive samples were acute (n = 18, 15.4%) and chronic (n = 70, 59.8%). Twenty samples were excluded. The mean age of BIA-ALCL patients was 50 years (31-57 years) and 35 years in reactive patients (20-69 years). CONCLUSION: Use of MFC with a comprehensive antibody panel consisting of CD30 in conjunction with CD25 and HLA-DR can discriminate anaplastic cells of BIA-ALCL from lymphoid or neutrophilic reactive cells and should be considered in the initial evaluation of seroma.

Safety and long-term improvement of mesenchymal stromal cell infusion in critically COVID-19 patients: a randomized clinical trial.

BACKGROUND: COVID-19 is a multisystem disease that presents acute and persistent symptoms, the postacute sequelae (PASC). Long-term symptoms may be due to consequences from organ or tissue injury caused by SARS-CoV-2, associated clotting or inflammatory processes during acute COVID-19. Various strategies are being chosen by clinicians to prevent severe cases of COVID-19; however, a single treatment would not be efficient in treating such a complex disease. Mesenchymal stromal cells (MSCs) are known for their immunomodulatory properties and regeneration ability; therefore, they are a promising tool for treating disorders involving immune dysregulation and extensive tissue damage, as is the case with COVID-19. This study aimed to assess the safety and explore the long-term efficacy of three intravenous doses of UC-MSCs (umbilical cord MSCs) as an adjunctive therapy in the recovery and postacute sequelae reduction caused by COVID-19. To our knowledge, this is one of the few reports that presents the longest follow-up after MSC treatment in COVID-19 patients. METHODS: This was a phase I/II, prospective, single-center, randomized, double-blind, placebo-controlled clinical trial. Seventeen patients diagnosed with COVID-19 who require intensive care surveillance and invasive mechanical ventilation-critically ill patients-were included. The patient infusion was three doses of 5 × 105 cells/kg UC-MSCs, with a dosing interval of 48 h (n = 11) or placebo (n = 6). The evaluations consisted of a clinical assessment, viral load, laboratory testing, including blood count, serologic, biochemical, cell subpopulation, cytokines and CT scan. RESULTS: The results revealed that in the UC-MSC group, there was a reduction in the levels of ferritin, IL-6 and MCP1-CCL2 on the fourteen day. In the second month, a decrease in the levels of reactive C-protein, D-dimer and neutrophils and an increase in the numbers of TCD3, TCD4 and NK lymphocytes were observed. A decrease in extension of lung damage was observed at the fourth month. The improvement in all these parameters was maintained until the end of patient follow-up. CONCLUSIONS: UC-MSCs infusion is safe and can play an important role as an adjunctive therapy, both in the early stages, preventing severe complications and in the chronic phase with postacute sequelae reduction in critically ill COVID-19 patients. Trial registration Brazilian Registry of Clinical Trials (ReBEC), UTN code-U1111-1254-9819. Registered 31 October 2020-Retrospectively registered, https://ensaiosclinicos.gov.br/rg/RBR-3fz9yr.

Combined Use of Tocilizumab and Mesenchymal Stromal Cells in the Treatment of Severe Covid-19: Case Report.

The coronavirus pandemic is one of the most significant public health events in recent history. Currently, no specific treatment is available. Some drugs and cell-based therapy have been tested as alternatives to decrease the disease's symptoms, length of hospital stay, and mortality. We reported the case of a patient with a severe manifestation of COVID-19 in critical condition who did not respond to the standard procedures used, including six liters of O2 supplementation under a nasal catheter and treatment with dexamethasone and enoxaparin in prophylactic dose. The patient was treated with tocilizumab and an advanced therapy product based on umbilical cord-derived mesenchymal stromal cells (UC-MSC). The combination of tocilizumab and UC-MSC proved to be safe, with no adverse effects, and the results of this case report prove to be a promising alternative in the treatment of patients with severe acute respiratory syndrome due to SARS-CoV-2.

3D Telomere Structure Analysis to DetectGenomic Instability and Cytogenetic Evolutionin Myelodysplastic Syndromes.

The disease course of myelodysplastic syndromes (MDS) features chromosome instability and clonal evolution, leading to the sequential acquisition of novel cytogenetic aberrations and the accumulation of these abnormalities in the bone marrow. Although clonal cytogenetic abnormalities can be detected by conventional cytogenetics in 50% of patients with MDS, such distinguishing patterns are lacking in the other 50%. Despite the increase in the prognostic value of some biomarkers, none of them is specific and able to discriminate between stable and unstable patients that subsequently progress to acute myeloid leukemia. This pilot study aimed to investigate the potential use of the 3D telomere profiling to detect genomic instability in MDS patients with or without clonal cytogenetic evolution. The comparison between different time points in patients with cytogenetic changes showed that in the CD34+ MDS cells, there was a significant decrease in the total number of telomeric signals, the average intensity of signals and the total intensity of telomeres. By contrast, the number of aggregates increased during cytogenetic evolution (p < 0.001). This pattern was observed only for MDS patients with cytogenetic evolution but was absent in patients without cytogenetic changes. In conclusion, we demonstrated that the 3D nuclear telomere organization was significantly altered during the MDS disease course, and may have contributed to cytogenetic clonal evolution.

Linfoma anaplásico de células grandes associado a implante mamários: um desafio diagnóstico / Breast implant-associated anaplastic large cell lymphoma: a diagnostic challenge

O linfoma anaplásico de células grandes associado a implante mamário (BIA-ALCL ) é uma entidade provisória com características morfológicas e imunofenotípicas indistinguíveis do linfoma anaplásico de células grandes (ALCL) ALK negativo. Ao contrário do ALCL, o BIA-ALCL surge principalmente em associação ao implante mamário. A confirmação diagnóstica do BIA-ALCL pode ser difícil e a associação de características morfológicas e patológicas com citometria de fluxo e imuno-histoquímica pode auxiliar no diagnóstico. O objetivo deste relatório é descrever um caso de BIA-ALCL no qual a análise citológica e imunofenotipológica utilizando citometria de fluxo sugeriu a presença de grandes células positivas para CD30 no líquido de derrame.

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a provisional entity with morphological and immunophenotypic characteristics indistinguishable from ALKnegative anaplastic large cell lymphoma (ALCL). Unlike ALCL, BIA-ALCL arises mainly in association with breast implantation. Diagnostic confirmation of BIA-ALCL can be difficult and associating morphological and pathological hallmarks with flow cytometry and immunohistochemistry can assist in the diagnosis. The objective of this report is to describe a case of BIA-ALCL in which cytological and immunophenotypological analysis using flow cytometry suggested the presence of large CD30-positive cells in the effusion fluid.

Paroxysmal nocturnal hemoglobinuria clone in 103 Brazilian patients: diagnosis and classification.

BACKGROUND: Paroxysmal nocturnal hemoglobinuria is an acquired chronic hemolytic anemia, which often manifests as peripheral blood cytopenias and thrombosis. OBJECTIVE: The aim of this study is to describe a Brazilian population of paroxysmal nocturnal hemoglobinuria patients. METHODS: One hundred and three paroxysmal nocturnal hemoglobinuria cases were retrospectively reviewed and the clinical presentation, thrombosis, survival, and clone size were assessed. Diagnosis was established by flow cytometry. RESULTS: Fifty-two male and 51 female patients with a median age of 24.1 years (5.5-62 years) were studied. Clinical symptoms included hemoglobinuria (18.4%), infection (46.6%) and thrombosis (16.5%), and 80.6% had pancytopenia. Patients were classified as classic paroxysmal nocturnal hemoglobinuria (10), paroxysmal nocturnal hemoglobinuria with aplastic anemia (39), and paroxysmal nocturnal hemoglobinuria with subclinical features and aplastic anemia (54). There were significant differences in terms of median age, size of clone, clinical symptoms, and peripheral blood cell counts between the three subcategories. The clone size in erythrocytes and granulocytes were respectively 0.04% (range: 0-18%) and 7.3% (range: 0.3-68.7%) in patients with subclinical features and aplastic anemia, 15.8% (range: 0-99.7%) and 63.0% (range: 1.7-99.8%) in patients with aplastic anemia alone, and 82.2% (range: 0-99.85%) and 98.0% (81.3-100.0%) in Classic disease. Statistical differences were identified for platelets (p-value=0.001), lactate dehydrogenase (p-value=0.002) and the clone size (p-value<0.001) in patients who suffered thrombotic events compared to those who did not. Overall survival was 81.7%, with patients with subclinical features and aplastic anemia having lower overall survival (76.5%). CONCLUSION: This retrospective review of 103 patients over an 11-year period represents the largest collection of paroxysmal nocturnal hemoglobinuria cases from a single center in Brazil. Flow cytometry showed that a larger clone was associated with classical symptoms and increased risk of thrombosis, even in patients with bone marrow failure, whereas a smaller clone was associated with bone marrow aplasia.

Contribution of multiparameter flow cytometry immunophenotyping to the diagnostic screening and classification of pediatric cancer.

Pediatric cancer is a relatively rare and heterogeneous group of hematological and non-hematological malignancies which require multiple procedures for its diagnostic screening and classification. Until now, flow cytometry (FC) has not been systematically applied to the diagnostic work-up of such malignancies, particularly for solid tumors. Here we evaluated a FC panel of markers for the diagnostic screening of pediatric cancer and further classification of pediatric solid tumors. The proposed strategy aims at the differential diagnosis between tumoral vs. reactive samples, and hematological vs. non-hematological malignancies, and the subclassification of solid tumors. In total, 52 samples from 40 patients suspicious of containing tumor cells were analyzed by FC in parallel to conventional diagnostic procedures. The overall concordance rate between both approaches was of 96% (50/52 diagnostic samples), with 100% agreement for all reactive/inflammatory and non-infiltrated samples as well as for those corresponding to solid tumors (n = 35), with only two false negative cases diagnosed with Hodgkin lymphoma and anaplastic lymphoma, respectively. Moreover, clear discrimination between samples infiltrated by hematopoietic vs. non-hematopoietic tumor cells was systematically achieved. Distinct subtypes of solid tumors showed different protein expression profiles, allowing for the differential diagnosis of neuroblastoma (CD56(hi)/GD2(+)/CD81(hi)), primitive neuroectodermal tumors (CD271(hi)/CD99(+)), Wilms tumors (>1 cell population), rhabdomyosarcoma (nuMYOD1(+)/numyogenin(+)), carcinomas (CD45(-)/EpCAM(+)), germ cell tumors (CD56(+)/CD45(-)/NG2(+)/CD10(+)) and eventually also hemangiopericytomas (CD45(-)/CD34(+)). In summary, our results show that multiparameter FC provides fast and useful complementary data to routine histopathology for the diagnostic screening and classification of pediatric cancer.