WBC is an acronym for white blood cell. Low WBC refers to a decreased concentration of white blood cells in the body. White blood cells, also known as leukocytes, are essential in fighting off invasive microorganisms that can circulate in the blood and cause disease. Leukopenia is the medical term referring to a deficiency in white blood cells. There are many causes for a low WBC count.
Myelodysplastic Syndromes
The University of Maryland Marlene and Steward Greenebaum Cancer Center lists myelodysplastic syndromes---diseases involving abnormal bone marrow function---as one of the causes of decreased white blood cell counts.
Since white blood cells are a primary means of defense against infections, it follows that a deficiency of white blood cells can lead to an increase in infections. An infecton can, in turn, exhaust the body's remaining supply of white blood cells in a vicious cycle that leads to a continuing decline in health.
Neutropenia
Neutrophils are a type of white blood cell that engulfs bacterial cells and digests them. Neutropenia is the name for leukopenia that occurs when neutrophil counts decline to abnormally low levels. This is the most common type of white blood cell deficiency, according to the University of Virginia School of Medicine.
Certain drug therapies can cause neutropenia. RNCeus Interactive lists anticonvulsants, diuretics and cardiovascular drugs as potential causes of leukopenia. Typically, symptoms manifest after one to three days, and include common cold symptoms such as sore throat and chills.
Agranulocytosis
Agranulocytosis is a condition in which white blood cell counts have fallen in such a way that the patient is experiencing extremely low neutrophil levels.
Agranulocytosis can occur as a result of medical treatments for other diseases, a condition referred to as acquired agranulocytosis. The disorder can be inherited genetically, a condition referred to as congenital agranulocytosis.
The Langone Medical Center at New York University notes that the patient with agranulocytosis may experience symptoms such as bleeding gums, or ulcers that affect the inside of the mouth, but adds that less serious conditions can also cause these symptoms. Consultation with a doctor is the best way to discern the cause of symptoms such as these.
