COVID-19 Impact on Chronic Myeloid Leukemia Patients.

(1) Background: Chronic myeloid leukemia (CML) is a blood dyscrasia that accounts for about 20% of all leukemia cases. Tyrosine kinase inhibitors (TKIs) are used as first line treatment of CML. The 2019 SARS-CoV-2 outbreak raised new concerns for CML patients, such as whether CML increases the risk of contracting COVID-19, whether TKIs increase that risk, whether these drugs are safe to use during the infection, and whether any other hematologic parameters influence infection outcomes. (2) Methods: In our study we addressed these intriguing questions by using a retrospective analysis of 51 CML patients treated at the Ion Chiricuta Cancer Center, Cluj-Napoca, Romania. Furthermore, we investigated the effects of currently approved COVID-19 vaccines in our CML patients treated with tyrosine kinase inhibitors. (3) Results: Our results have shown that hemoglobin level upon diagnosis of CML has been the only hematologic parameter correlated to the risk of contracting COVID-19 in our CML patients. (4) Conclusions: TKI treatment did not negatively influence COVID-19 risk or the response to the vaccine in our patients. The safety profile of the currently approved COVID-19 vaccines was similar to that of the general population.

A narrative review of central nervous system involvement in acute leukemias.

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 asymptomatic or with unspecific symptoms, CNS leukemia should be assessed in both AML/ALL patients, through a combination of flow cytometry and cytological analysis of CSF. Intrathecal therapy (ITT) is a preventive measure for CNS involvement in AML and ALL, still much research is needed in finding the appropriate target that would dramatically lower CNS involvement in acute leukemia.