Refers to a decrease in the number of white blood cells. White blood cells fight infection, help things heal.
Neutropenia--used interchangably much of the time with leukopenia--is the absence of neutrophils which are part of the white blood cells.
I have been neutropenic--a count of zero--since I have large granular leukemia (lgl). I'm under treatment now so it's better. I got lots of infections without a high white cell count.
A low white cell count is a symptom of something or it's caused by chemo treatments other things...