Do glucocorticoids cause a stress leukogram with neutrophilia and lymphopenia?

The physiological response to glucocorticoids, whether from systemic stress or exogenous administration, leads to a characteristic hematological pattern known as a stress leukogram. In a 73-year-old female, this pattern typically includes an increase in neutrophils (neutrophilia) and a decrease in lymphocytes (lymphopenia).

Clinical and mechanistic evidence

The "stress leukogram" is a well-documented clinical phenomenon driven by the specific effects of glucocorticoids on leukocyte kinetics and trafficking.

• Neutrophilia development: The primary driver of elevated neutrophil counts is demargination. Under normal conditions, approximately 50% of neutrophils in the blood are "marginated," adhering to the walls of small blood vessels rather than circulating freely. Glucocorticoids cause these cells to detach and enter the main bloodstream, often doubling the measured neutrophil count within 4–6 hours.
• Lymphopenia development: Conversely, glucocorticoids cause a rapid drop in circulating lymphocytes. Unlike the immediate destruction seen in chronic or high-dose therapy, acute lymphopenia is primarily a redistribution phenomenon. Lymphocytes move from the intravascular space into other tissue compartments, particularly the bone marrow and secondary lymphoid organs.

Mechanistic explanations

The redistribution of these white blood cells is mediated by specific molecular changes in cell adhesion and signaling:

• Adhesion molecule modulation: Glucocorticoids down-regulate or cause the shedding of L-selectin (CD62L) on the surface of neutrophils. L-selectin is required for the "tethering and rolling" phase of adhesion; its loss prevents neutrophils from sticking to the vessel wall, forcing them into circulation. Additionally, steroids reduce the binding strength of beta-2 integrins (CD11/CD18).
• CXCR4 upregulation: For lymphocytes, glucocorticoid signaling increases the expression of the CXCR4 chemokine receptor. This makes the cells highly sensitive to the CXCL12 gradient in the bone marrow, effectively "homing" them out of the blood and sequestering them in the marrow stroma.
• Survival signaling: Glucocorticoids also prolong the lifespan of neutrophils by inhibiting programmed cell death (apoptosis) through the PI3K/Akt and MAPK pathways. This ensures that once neutrophils enter the circulating pool, they remain there longer than usual.

Clinical implications

In a patient context, it is critical to distinguish a stress leukogram from an inflammatory leukogram (e.g., infection).

• Differential markers: A stress leukogram is typically characterized by mature neutrophilia (a "shift to the right") and the absence of a "left shift" (immature band neutrophils), which is more indicative of acute infection.
• Timing: These changes are transient. In acute stress, the leukogram often returns to baseline within 24 hours once the glucocorticoid stimulus is removed.

Bottom line

Glucocorticoid signaling causes a stress leukogram by inducing neutrophil demargination (via down-regulation of L-selectin) and lymphocyte redistribution into the bone marrow (via CXCR4 upregulation). This results in a rapid, measurable increase in circulating neutrophils and a corresponding decrease in lymphocytes.