Developed by Weizmann Institute mathematicians working with physicians at the Meir Medical Center in Israel, and Roche’s research center in Basel, Switzerland, a model demonstrates how the immune system functions under conditions of neutropenia resulting from chemotherapy or bone marrow transplant.
Corroborated by evaluation of healthy individuals, the model indicates that the ability of white blood cells, primarily neutrophils, to tackle bacterial infections doesn’t just depend on absolute cell number, or the bacteria-to-cell ratio, but is affected by factors including neutrophil function and the permeability of tissues to bacteria, which can increase as a result of chemotherapy. Effectively, in neutropenia the immune system is balanced on a knife-edge—described mathematically as bistability—which can go either way as a result of even minor disturbances to the equilibrium.
In healthy people, the fact that the effectiveness of neutrophils varies from one person to another usually has no significant consequences. In contrast, in patients with neutropenia, this individual variability can make a difference between life and death.