Hyperthermia induces eryptosis in hereditary spherocytosis

CRISP, R; VOTA, D; DONATO, H; VITTORI, D; GARCÍA, E; RAPETTI, C; NESSE, A

Milan

Congreso; 19th Congress of the European Hematology Association; 2014

Background: In patients with hereditary spherocytosis (HS) anemia frequently gets worse throughout the course of febrile infectious diseases, due to hemolytic crisis. Actually, the incidence of this complication is 67.2% in our series of HS patients. This observation and usual clinical practice suggest a potential harmful action of temperature on erythrocytes, which would affect their survival. Circulating erythrocytes can undergo premature self-destruction through a mechanism known as eryptosis. A variety of clinical disorders are associated with excessive eryptosis. This process can be triggered by the increase of intracellular calcium or high oxidative stress and can be accelerated by different environmental factors. Aims: To evaluate whether the temperature increment on erythrocytes may be one factor responsible for anemia worsening during febrile processes. Methods: Erythrocytes from 9 HS patients and 11 normal controls (NC) were incubated at different temperatures, mimicking either the physiologic body temperature (36.5ºC) or a febrile state (38.5ºC). Flow cytometry was used to analyze signs of eryptosis, such as cell shrinkage (forward scatter) and phosphatidylserine (PS) translocation. Intracellular calcium content, as well as reactive oxygen species (ROS) and reduced glutathione levels (GSH), were also determined by flow cytometry. Results: In NC, percentages of eryptotic cells and PS exposure either at 36.5 or 38.5°C showed no significant difference, while HS erythrocytes showed a significant increase in eryptotic cells (23.3 ± 4.4% vs. 40.4 ± 7.0%, for 36.5 and 38.5°C, respectively; n= 9; p