Abnormalities of the Bone Marrow Immune Microenvironment in Patients with Prolonged Isolated Thrombocytopenia after Allogeneic Hematopoietic Stem Cell Transplantation

Abstract

Prolonged isolated thrombocytopenia (PT) is a serious complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Whether abnormalities of the bone marrow (BM) immune microenvironment are involved in the pathogenesis of PT remains unknown, however. Twenty patients with PT, 40 matched patients with good graft function (GGF) after allo-HSCT, and 20 healthy donors (HD) were enrolled in this nested case-control study. Th1, Th2, Tc1, Tc2, Th17, and Treg cells were analyzed by flow cytometry, and IFN-γ, IL-4, IL-17, IL-6, IL-21, and thrombopoietin levels in BM plasma were evaluated with a cytometric bead assay and ELISA. Relative to GGF patients and HD controls, PT patients had significantly higher proportions of Th1 and Tc1 cells, resulting in higher Th1/Th2 and Tc1/Tc2 ratios in the BM microenvironment. In addition, the excessive polarization of Th17 was observed in patients with PT. Changes in BM plasma cytokines were consistent with our cellular findings. These results suggest that dysregulated T cell responses in the BM microenvironment might play an important role in the pathogenesis of PT.

N‐acetyl‐L‐cysteine improves bone marrow endothelial progenitor cells in prolonged isolated thrombocytopenia patients post allogeneic hematopoietic stem cell transplantation

“…Prolonged isolated thrombocytopenia was defined as the engraftment of all peripheral blood cell lines (absolute neutrophil cells (ANCs) >0.5 × 10 9 /L and hemoglobin (Hb) >70 g/L without transfusion support) other than a PLT count less than 20 × 10 9 /L or a dependence on PLT transfusions for more than 60 days following allo‐HSCT in the presence of complete donor chimerism. Good graft function was characterized by ANCs >0.5 × 10 9 /L for 3 consecutive days, a PLT count >20 × 10 9 /L for 7 consecutive days, and Hb >70 g/L without transfusion support beyond day +28 post‐HSCT. Patients with evidence of poor graft function, severe G v HD including III‐IV acute G v HD and severe chronic G v HD or hematologic relapse following allo‐HSCT were excluded.…”

“…Prolonged isolated thrombocytopenia, which is defined as the engraftment of all peripheral blood cell lines other than platelet (PLT) count of less than 20 × 10 9 /L or dependence on PLT transfusions for more than 60 days following allogeneic hematopoietic stem cell transplantation (allo‐HSCT), is a serious complication associated with an increased risk of bleeding and poor overall survival following allo‐HSCT . Although several clinical risk factors, such as the dose of infused CD34 + cells, infection, and graft‐versus‐host disease (GvHD), have been reported to be associated with the occurrence of prolonged isolated thrombocytopenia, the pathogenesis underlying prolonged isolated thrombocytopenia remains unclear, and effective clinical management is challenging.…”

Evaluation of blood vessel injury, oxidative stress and circulating inflammatory factors in an L‑NAME‑induced preeclampsia‑like rat model

“…The LEGENDplex ™ Rat Panel is a bead-based multiplex assay panel using fluorescence-encoded beads that are suitable for use on various flow cytometers. Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, IL-17A and monocyte chemoattractant protein 1 (MCP-1) levels were examined according to methods described in a previous study ( 21 – 23 ). In brief, the standard was prepared by dissolving in 250 µl Assay Buffer and 4-fold dilution; Assay Buffer was used as the C0 standard (0 pg/ml).…”

Different subsets of haematopoietic cells and immune cells in bone marrow between young and older donors

“…Lymphocyte subpopulations were quantified via flow cytometry using the following directly conjugated mouse anti-human monoclonal antibodies: anti-CD3-PE/Cy7, anti-CD4-APC/H7, anti-CD8-V500, anti-CD45RA-BV605, and anti-CCR7-BUV395 (BD Biosciences). As previously described [31], effector T cells, naïve T cells, effector memory T cells and central memory T cells were identified as CD45RA + CCR7 − , CD45RA + CCR7 + , CD45RA − CCR7 − , and CD45RA − CCR7 + , respectively, in CD3 + CD4 + CD8 − cells and CD3 + CD4 − CD8 + cells.…”

“…As previously described [31][32][33][34], cellular cytokine secretions were determined after incubating the cells with phorbol myristate acetate (100 ng/mL) and ionomycin (2 μg/mL, both from Sigma-Aldrich, St. Louis, MO, USA) for 4 hours to stimulate maximal IFN-γ and IL-4 production. GolgiStop (0.7 μL/mL) was added to the samples during this 4-hour incubation to sequester proteins in the cytoplasm.…”