What causes low monocytes?

Low monocytes, also known as monocytopenia, can have several causes, including:

1. Bone Marrow Disorders: Monocytes originate in the bone marrow. Therefore, any disorder that affects bone marrow function, like leukemia, myelodysplastic syndromes, or aplastic anemia, can result in low monocytes.

2. Sepsis and Infections: Overwhelming infections, such as sepsis, or certain viral and bacterial infections like brucellosis or tuberculosis, can lead to a decrease in monocyte production.

3. Autoimmune Diseases: Some autoimmune conditions like rheumatoid arthritis or systemic lupus erythematosus can cause the immune system to attack and destroy monocytes.

4. Corticosteroids and Chemotherapy: Certain medications, especially high-dose corticosteroids and chemotherapy drugs, can temporarily suppress bone marrow function, leading to low monocyte counts.

5. Congenital Conditions: Rare genetic disorders, like Chediak-Higashi syndrome or Wiskott-Aldrich syndrome, can cause low monocytes from birth.

6. Splenomegaly: An enlarged spleen (splenomegaly) can sequester and trap monocytes, leading to low counts in the bloodstream.

7. Liver Cirrhosis: Advanced liver disease, such as cirrhosis, can impair the production and release of monocytes.

8. HIV/AIDS: Infection with the human immunodeficiency virus (HIV) can damage bone marrow and affect monocyte production.

It's important to note that low monocyte counts are often a consequence of an underlying medical condition. If you have persistent monocytopenia, consult your doctor for a proper evaluation and diagnosis to determine the cause.