Susceptibility to infections
In leukemia, there is an aberrant production of blood cells, and in some cases, you would have a deficiency in white blood cells and their immune function. There’s a very high chance that patients with leukemia develop various infections in the respiratory tract and even bacteremia (bacteria traveling through the blood vessels).
In a study about infections in patients diagnosed with leukemia, most patients were diagnosed with a mild and treatable infection. However, if they also had an abnormal decrease in the granulocyte count (one subtype of blood cells), there were high chances they had life-threatening bacteremia.