From the Guidelines
Low white blood cell (WBC) count, or leukopenia, can be caused by several factors, including bone marrow disorders, viral infections, certain medications, autoimmune conditions, nutritional deficiencies, congenital disorders, radiation exposure, severe infections, hypersplenism, and certain cancers that infiltrate bone marrow. The most recent and highest quality study 1 provides guidance on the management of acute myeloid leukemia, which is a type of bone marrow disorder that can cause leukopenia. According to this study, treatment of leukopenia depends on identifying and addressing the underlying cause, which may involve stopping problematic medications, treating infections, providing nutritional supplements, or using medications like filgrastim to stimulate WBC production in severe cases.
Some of the key causes of leukopenia include:
- Bone marrow disorders like leukemia, myelodysplastic syndrome, and aplastic anemia, which directly impair WBC production 1
- Viral infections including HIV, hepatitis, and influenza, which can temporarily suppress bone marrow function 1
- Certain medications, particularly chemotherapy drugs, antibiotics (like trimethoprim-sulfamethoxazole), antipsychotics (clozapine), and immunosuppressants (methotrexate, mycophenolate) 1
- Autoimmune conditions such as lupus and rheumatoid arthritis, which can destroy white blood cells 1
- Nutritional deficiencies, especially vitamin B12 and folate, which impair proper cell production 1
- Congenital disorders like Kostmann syndrome and cyclic neutropenia, which cause chronically low WBCs 1
- Radiation exposure, severe infections, hypersplenism (where the spleen removes too many blood cells), and certain cancers that infiltrate bone marrow, which can also reduce WBC counts 1
Treatment of leukopenia should prioritize identifying and addressing the underlying cause, and may involve a combination of stopping problematic medications, treating infections, providing nutritional supplements, and using medications like filgrastim to stimulate WBC production in severe cases. It is essential to note that the management of leukopenia should be individualized based on the underlying cause and the patient's overall health status.
From the Research
Causes of Low White Blood Cell Count
- Infection, drugs, malignancy, megaloblastosis, hypersplenism, and immunoneutropenia are responsible for most cases of neutropenia, a condition characterized by an abnormally low count of white blood cells, especially granulocytes 2
- Extrinsic causes of neutropenia can be varied, while intrinsic causes can include impaired proliferation and maturation of myeloid progenitor cells in the bone marrow 3
- Systemic lupus erythematosus (SLE) is also associated with leukopenia, lymphopenia, and neutropenia, with a reported prevalence of 22-41.8% for leukopenia, 15-82% for lymphopenia, and 20-40% for neutropenia 4
- Other causes of low white blood cell count include chemotherapy-induced leukopenia, which is a common side effect of chemotherapy for small-cell lung cancer 5
- Immune cytopenias, such as anemia, leukopenia, neutropenia, and lymphopenia, can also occur in patients with SLE, and may require treatment depending on the underlying cause 6
Risk Factors and Associations
- Low white blood cell count can increase the risk of infection, particularly in patients with neutropenia or those undergoing chemotherapy 2, 3
- The severity and duration of leukopenia, as well as the clinical status of the patient, should be considered when assessing the risk of infection 3
- Some studies have found a strong association between low lymphocyte or neutrophil count and the risk of major infections in patients with SLE 4
- Chemotherapy-induced leukopenia has been associated with the survival of small-cell lung cancer patients, with mild leukopenia being strongly associated with longer survival time 5