Acute leukemias (both myeloid and lymphoblastic) are a group of diseases for which each year more successful therapies are implemented. However, in a subset of cases the overall survival (OS) is still exceptionally low due to the infiltration of leukemic cells in the central nervous system (CNS) and the subsequent formation of brain tumors. The CNS involvement is more common in acute lymphocytic leukemia (ALL), than in adult acute myeloid leukemia (AML), although the rates for the second case might be underestimated. The main reasons for CNS invasion are related to the expression of specific adhesion molecules (VLA-4, ICAM-1, VCAM, L-selectin, PECAM-1, CD18, LFA-1, CD58, CD44, CXCL12) by a subpopulation of leukemic cells, called "sticky cells" which have the ability to interact and adhere to endothelial cells. Moreover, the microenvironment becomes hypoxic and together with secretion of VEGF-A by ALL or AML cells the permeability of vasculature in the bone marrow increases, coupled with the disruption of blood brain barrier. There is a single subpopulation of leukemia cells, called leukemia stem cells (LSCs) that is able to resist in the new microenvironment due to its high adaptability. The LCSs enter into the arachnoid, migrate, and intensively proliferate in cerebrospinal fluid (CSF) and consequently infiltrate perivascular spaces and brain parenchyma. Moreover, the CNS is an immune privileged site that also protects leukemic cells from chemotherapy. CD56/NCAM is the most important surface molecule often overexpressed by leukemic stem cells that offers them the ability to infiltrate in the CNS. Although

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Recently, an increasing number of novel drugs were approved in oncology and hematology. Nevertheless, pharmacology progress comes with a variety of side effects, of which cytokine release syndrome (CRS) is a potential complication of some immunotherapies that can lead to multiorgan failure if not diagnosed and treated accordingly. CRS generally occurs with therapies that lead to highly activated T cells, like chimeric antigen receptor T cells or in the case of bispecific T-cell engaging antibodies. This, in turn, leads to a proinflammatory state with subsequent organ damage. To better manage CRS there is a need for specific therapies or to repurpose strategies that are already known to be useful in similar situations. Current management strategies for CRS are represented by anticytokine directed therapies and corticosteroids. Based on its pathophysiology and the resemblance of CRS to sepsis and septic shock, as well as based on the principles of initiation of continuous renal replacement therapy (CRRT) in sepsis, we propose the rationale of using CRRT therapy as an adjunct treatment in CRS where all the other approaches have failed in controlling the clinically significant manifestations.

Hematopoiesis is the formation of blood cellular components and, consequently, immune cells. In a more complete definition, this process refers to the formation, growth, maturation, and specialization of blood cells, from the hematopoietic stem cell, through the hematopoietic progenitor cells, to the s pecialized blood cells. This process is tightly regulated by several elements of the bone marrow microenvironment, such as growth factors, transcription factors, and cytokines. During embryonic and fetal development, hematopoiesis takes place in different organs: the yolk sac, the aorta–gonad mesonephros region, the lymph nodes, and not lastly, the fetal liver and the spleen. In the current review, we describe extramedullary hematopoiesis of the spleen and liver, with an emphasis on myeloproliferative conditions.