Steroids can indeed affect white blood cell (WBC) counts, but the specific impact depends on the type. Different classes interact with the immune system in distinct ways, leading to varied effects on WBC number and distribution. Understanding these differences is important for interpreting blood test results and comprehending the broader effects of these medications.
Different Types of Steroids
In a medical context, two main types of steroids are commonly discussed: corticosteroids and anabolic-androgenic steroids. These classes have different chemical structures, functions, and therapeutic uses, which dictate their effects on white blood cells.
Corticosteroids, such as prednisone, are synthetic versions of hormones naturally produced by the adrenal glands. These medications are primarily used for their anti-inflammatory and immunosuppressive properties. Doctors prescribe them to treat a wide range of conditions, including asthma, allergies, and autoimmune diseases. Their actions involve modulating the immune system to reduce inflammation and suppress overactive immune responses.
Anabolic-androgenic steroids (AAS) are synthetic derivatives of testosterone, the male sex hormone. These steroids are known for their anabolic effects, promoting muscle growth and increasing protein synthesis. They are sometimes used illicitly for performance enhancement or to increase muscle mass, though they also have legitimate medical uses for conditions like certain types of anemia or muscle wasting diseases. Their primary effects are on tissues involved in growth and development, rather than directly on the immune system’s inflammatory responses.
How Corticosteroids Impact White Blood Cells
Corticosteroids significantly alter white blood cell counts, most notably by increasing neutrophils and decreasing other types. These changes result from how corticosteroids interact with immune cells and their movement. The effects are generally dose-dependent, meaning higher doses lead to more pronounced changes.
Corticosteroid administration commonly causes an immediate increase in neutrophil count, known as neutrophilia. This rise happens quickly, often within hours, and lasts as long as medication continues. The increase is due to several mechanisms: neutrophils attached to blood vessel walls (demargination) are released into circulation.
Corticosteroids also reduce neutrophil movement from blood into tissues, keeping them in circulation longer. Additionally, these steroids delay programmed cell death (apoptosis) of neutrophils, extending their lifespan, and stimulate bone marrow to release more neutrophils, including immature “bands,” into the bloodstream.
While neutrophils increase, corticosteroids decrease other white blood cell types, including lymphocytes, eosinophils, and monocytes. This reduction is often transient, occurring because corticosteroids redistribute these cells from the bloodstream into areas like bone marrow, spleen, and lymph nodes. Eosinophils rapidly decrease due to migration into the bone marrow. Lymphocytes also undergo redistribution and, in some cases, increased programmed cell death. These effects contribute to the overall immunosuppressive action of corticosteroids.
How Anabolic Steroids Impact White Blood Cells
Anabolic-androgenic steroids (AAS) generally do not cause the same direct, significant, or rapid changes in white blood cell counts as corticosteroids. Their primary actions relate to promoting tissue growth and development, rather than directly modulating acute inflammatory responses. While some studies suggest mild to moderate increases, particularly in neutrophils, this effect is not as consistently pronounced or clinically relevant.
The mechanisms for any observed changes with anabolic steroids are often attributed to indirect influences. For instance, they are known to increase red blood cell production (erythrocytosis). While they can influence the immune system over time, potentially affecting lymphocyte differentiation and proliferation, their direct impact on circulating white blood cell numbers is not as well-defined or consistent as that of corticosteroids.
Any significant alterations in white blood cell counts in individuals using anabolic steroids may indicate other underlying health issues, complications from misuse, or other factors, rather than being solely due to the steroids. Interpreting these changes requires careful consideration of an individual’s complete medical picture.
What White Blood Cell Count Changes Mean
White blood cells (WBCs), also known as leukocytes, are an important component of the immune system, protecting the body from infection and disease. A normal WBC count typically ranges between 4,000 and 11,000 cells per microliter of blood, though this range can vary. Different types of WBCs—neutrophils, lymphocytes, monocytes, eosinophils, and basophils—each play specific roles in immune defense.
When white blood cell counts change due to steroid use, particularly corticosteroids, these alterations are often expected and part of the medication’s therapeutic effect. The increase in neutrophils and decrease in lymphocytes, eosinophils, and monocytes with corticosteroid use is a known response. These changes are generally temporary and reversible, with counts typically returning to baseline after discontinuation. An elevated white blood cell count caused by corticosteroids, primarily due to increased neutrophils, does not necessarily indicate an infection.
However, changes in white blood cell counts might warrant further attention. Unusually high or low counts, or persistent changes after steroid discontinuation, could signal an underlying issue. It is also important to consider the overall clinical picture, including signs of infection, as steroid-induced changes can sometimes mask or complicate infection diagnosis due to their immunosuppressive effects.
For any questions or concerns regarding specific lab results and their implications, consulting a healthcare provider is always recommended for personalized interpretation and guidance.