A leukemoid reaction is an increase in white blood cell count similar to what occurs in people with leukemia . However, the reaction is actually due to an infection or another disease and is not a sign of cancer.
Blood counts will usually return to normal when the underlying condition is treated.
Bagby GC. Leukopenia and leukocytosis. In Goldman L, Ausiello D, eds. . 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011: chap 170.