Systemic Lupus Erythematosus (lupus) is a chronic autoimmune condition where the body’s immune system mistakenly attacks its own healthy tissues and organs. This article explores the typical impact of lupus on white blood cell counts and discusses factors that can lead to variations in their numbers.
Understanding White Blood Cells
White blood cells, also known as leukocytes, are a fundamental part of the body’s immune system, playing a role in defending against infections and managing inflammation. These cells are produced in the bone marrow and circulate throughout the bloodstream and lymphatic system. There are five primary types of white blood cells: neutrophils, lymphocytes, monocytes, eosinophils, and basophils, each with specific functions in the immune response.
Neutrophils combat bacterial and fungal infections, while lymphocytes, including T cells and B cells, target viral infections and produce antibodies. Monocytes help clear damaged cells, and eosinophils and basophils are involved in allergic reactions and fighting parasites. The normal range for a total white blood cell count in adults typically falls between 4,000 and 11,000 cells per microliter of blood, although these ranges can vary slightly between different laboratories.
Lupus and Its Usual Effect on White Blood Cells
Lupus commonly leads to a decrease in white blood cell counts, a condition referred to as leukopenia. This reduction often involves lymphocytes, a condition known as lymphopenia, which is a frequent finding in individuals with active lupus. Up to 95% of lupus patients may experience leukopenia, with lymphopenia occurring in 20% to 75% of cases.
The immune system in lupus mistakenly produces autoantibodies that target and destroy healthy white blood cells, leading to their reduction. This immune-mediated destruction, particularly of lymphocytes, often correlates with disease activity. Drug-induced suppression of white blood cell production can also contribute to lower counts in lupus patients.
Factors That Can Cause Elevated White Blood Cell Counts in Lupus Patients
While lupus typically causes a decrease in white blood cell counts, several factors can lead to elevated levels. These increases are often a response to other physiological events or treatments, rather than a direct manifestation of lupus itself.
Infections are a common cause of elevated white blood cell counts. Individuals with lupus have a heightened susceptibility to various infections, and the body’s response involves increasing white blood cell production, particularly neutrophils, to fight off pathogens.
Severe inflammation associated with lupus flares can also sometimes lead to an increase in certain types of white blood cells. This occurs as part of the body’s general inflammatory response. Elevated levels of neutrophils can be observed during active lupus, particularly due to the complement pathway’s inability to clear lupus neutrophils, leading to their accumulation.
Medications frequently prescribed for lupus, such as corticosteroids like prednisone, are another common cause of increased white blood cell counts. Corticosteroids can cause a temporary rise in white blood cells, primarily neutrophils, by mobilizing them from the bone marrow and slowing their movement out of the bloodstream into tissues. This effect, known as steroid-induced leukocytosis, can result in a mean increase of approximately 2,400 cells/mm³ within 48 hours of administration, though increases can be highly variable and sometimes exceed 20,000 cells/mm³.
Other co-occurring conditions or stressors, not directly related to lupus, can also contribute to elevated white blood cell counts. These include significant physical or emotional stress, burns, or other inflammatory diseases.
Monitoring White Blood Cell Counts in Lupus
Regular monitoring of white blood cell counts is a routine part of managing lupus, providing valuable insights into disease activity and overall health. Complete blood count (CBC) tests, which include white blood cell counts, are frequently performed to assess various blood components in lupus patients. These tests help healthcare providers track trends in white blood cell numbers over time.
When reviewing white blood cell results, doctors look for sudden changes or consistent patterns, interpreting them in the context of other symptoms and the patient’s medical history. For instance, a persistent low white blood cell count, particularly below 2,000 cells/mm³, may indicate active lupus or drug toxicity and can increase the risk of infection. Conversely, an elevated count could signal an infection, a lupus flare, or a side effect of medications such as corticosteroids.
White blood cell counts assist in guiding treatment decisions and indicating complications. For example, if an infection is suspected due to a high white blood cell count, additional tests like cultures may be ordered. Patients should consult their doctor if they receive abnormal white blood cell results, experience new symptoms like fever or persistent cough, or notice any worsening of their lupus symptoms.