Polymorphonuclear neutrophil and megakaryocyte mutual involvement in myelofibrosis pathogenesis.
ABSTRACT The study presented here, performed on the bone marrow from patients with idiopathic myelofibrosis (MF) and on a murine model of MF, demonstrates a pathological interaction between PMN leukocytes and megakaryocyte (Mk), correlated with MF development. The data obtained revealed abnormal subcellular P-selectin distribution, which appeared to correlate with excessive and pathological emperipolesis of PMN leukocytes within Mk, leading to the destruction of Mk storage organelles and leakage of alpha-granular contents into the bone marrow microenvironment. The prominent role of growth factors, PDGF and TGFbeta, stored in the Mk alpha-granular compartment in the generation of MF has been previously largely documented. Both growth factors are essential for the Mk-dependent fibroblast proliferation. The destructive mutual cellular interaction of Mk and PMN leading to the pathological release of PDGF and TGFbeta within the bone marrow microenvironment may participate, through fibroblast activation, to the generation of MF. Therefore, this study provides insight into the possible pathophysiological mechanisms for the genesis of MF.
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ABSTRACT: This study was designed to describe the bone marrow features of multisystem Langerhans cell histiocytosis (LCH) at diagnosis in patients with or without hematologic dysfunction. A retrospective review of bone marrow biopsies from patients with multisystem LCH was performed. Cases were diagnosed at the Garrahan Hospital between 1987 and 2004. Routine and immunohistochemistry techniques (hematoxylin-eosin, periodic acid-Schiff, Giemsa, Gomori reticulin, and CD1a, CD68, and CD61) were evaluated. Clinical outcome and laboratory data were obtained from the medical charts. Twenty-two bone marrow biopsies from patients with multisystem LCH were reviewed at onset of disease. Four patients had no hematologic dysfunction and the other 18 patients had monocytopenia (9), bicytopenia (7), or tricytopenia (2). Increased number and dysplasia of megakaryocytes were evident in 22/22 samples and emperipolesis was present in 21/22 (95%). Aggregates of histiocytes and hemophagocytosis were seen in 9/22 samples. Myelofibrosis was found in 16/17 (94%) evaluable samples at diagnosis. No association of myelofibrosis and cytopenias or clinical outcome was found. Positive CD1a confirmed the presence of LCH cells in 3/22 (14%) samples. Hemophagocytosis and poor outcome were significantly more common in patients with bilineage and trilineage cytopenias. Langerhans cell histiocytosis cells were rarely seen in the bone marrow of these patients (14%); increased histiocytes and hemophagocytosis were more commonly found (41%). Hemophagocytosis was associated with severe cytopenias. Bicytopenia and tricytopenia were associated with poor outcome (death). Myelofibrosis, megakaryocytic dysplasia, and emperipolesis were common findings.Pediatric and Developmental Pathology 10/2009; 13(2):101-6. · 0.86 Impact Factor
- Leukemia & lymphoma 05/2013; · 2.61 Impact Factor
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ABSTRACT: Although cell-in-cell structure was noted 100 years ago, the molecular mechanisms of 'entering' and the destination of cell-in-cell remain largely unclear. It takes place among the same type of cells (homotypic cell-in-cell) or different types of cells (heterotypic cell-in-cell). Cell-in-cell formation affects both effector cells and their host cells in multiple aspects, while cell-in-cell death is under more intensive investigation. Given that cell-in-cell has an important role in maintaining homeostasis, aberrant cell-in-cell process contributes to the etiopathology in humans. Indeed, cell-in-cell is observed in many pathological processes of human diseases. In this review, we intend to discuss the biological models of cell-in-cell structures under physiological and pathological status.Cell Death & Disease 05/2013; 4:e630. · 5.18 Impact Factor