Photo Credit: Nemes Laszlo

The following is a summary of “Redefining hyperviscosity in acute leukemia: Potential implications for red cell transfusions in the microvasculature,” published in the April 2024 issue of Hematology by Musick et al.

Researchers conducted a prospective study investigating the role of hematocrit/hemoglobin levels (Hct/Hgb) in mediating hyperviscosity and microvascular obstruction in acute leukemia, mainly focusing on leukostasis.

They encountered challenges conducting and interpreting in vivo hemorheological studies due to difficulties visualizing and manipulating the microvasculature. Consequently, a multi-vessel microfluidic device mimicking the size scale and geometry of the microvasculature was designed to explore how Hct/Hgb interacts with acute leukemia to induce “in vitro” leukostasis.

The results showed variations in leukostasis degree among leukemia immunophenotypes based on white blood cell (WBC) count and Hct/Hgb levels. Severe anemia was found to protect against in vitro leukostasis among lymphoid immunophenotypes. Hct/Hgb thresholds were identified, above which in vitro leukostasis significantly increased, especially in B-cell acute lymphoblastic leukemia (ALL) compared to T-cell ALL. In acute myeloid leukemia, WBC counts primarily drove in vitro leukostasis, with minimal interaction with Hct/Hgb.

Investigators concluded that after redefining hyperviscosity in acute leukemia, further studies are needed to investigate how red blood cell transfusions might impact the risk of leukostasis in patients with different acute leukemia immunophenotypes.

Source: onlinelibrary.wiley.com/doi/abs/10.1002/ajh.27308