What causes an abnomaly low WBC?

An abnormally low white blood cell (WBC) count, known as leukopenia, can be caused by various factors, including infections that suppress bone marrow function, autoimmune disorders, certain medications (like chemotherapy), and bone marrow diseases such as aplastic anemia or leukemia. Nutritional deficiencies, particularly of vitamin B12, folate, or copper, can also lead to decreased WBC production. Additionally, exposure to toxins or radiation may impair the bone marrow's ability to produce white blood cells.