From the Guidelines
Elevated absolute lymphocytes, or lymphocytosis, is not an indication for treatment in itself, but rather a sign of an underlying condition that needs to be evaluated and addressed accordingly. This condition can be caused by various factors including viral infections, certain bacterial infections, stress responses, autoimmune disorders, or blood cancers like chronic lymphocytic leukemia and lymphoma 1. The management of lymphocytosis depends on the underlying cause, and treatment may involve managing symptoms, antibiotics for bacterial infections, immunosuppressants or corticosteroids for autoimmune-related cases, or chemotherapy, immunotherapy, or targeted therapies for blood cancers.
Causes and Evaluation
Lymphocytosis can be caused by:
- Viral infections (particularly Epstein-Barr virus, cytomegalovirus, and hepatitis)
- Certain bacterial infections
- Stress responses
- Autoimmune disorders
- Blood cancers like chronic lymphocytic leukemia and lymphoma A diagnostic work-up for lymphocytosis should include a history and physical examination, evaluation of nutritional state, spleen size, CBC with differential and reticulocyte counts, CXR for evaluation of presence of thymoma, and bacterial cultures and evaluation for infection (fungal, viral, bacterial, specifically CMV/HIV) 1.
Treatment Approach
For most viral infections, treatment focuses on managing symptoms while the body fights the infection. If lymphocytosis is caused by a bacterial infection, antibiotics specific to the causative organism are prescribed. For autoimmune-related lymphocytosis, immunosuppressants or corticosteroids may be recommended. In cases of blood cancers, treatment may involve chemotherapy, immunotherapy, or targeted therapies depending on the specific diagnosis, considering factors such as patient age, performance status, and the presence or absence of del(17p) or TP53 mutation 1.
Key Considerations
- Absolute lymphocyte count alone is not an indication for treatment 1.
- Symptoms related to leukostasis are exceedingly rare in CLL patients 1.
- A "watch and wait" approach is often appropriate for patients with stage II–IV SLL, low-risk CLL, or intermediate-risk CLL, and treatment will be beneficial if they become symptomatic or show evidence of progressive disease 1.
From the Research
Elevated Absolute Lymphocytes
Elevated absolute lymphocytes can be an indicator of various conditions, including infections, autoimmune diseases, and lymphoproliferative disorders.
- The Epstein-Barr virus (EBV) is a common cause of infectious mononucleosis, which can lead to elevated lymphocytes 2.
- In patients with rheumatoid arthritis (RA), EBV infection can contribute to the development of lymphoproliferative disorders, particularly in those treated with immunosuppressive drugs like methotrexate (MTX) 3, 4, 5.
- The absolute lymphocyte count (ALC) threshold for further evaluation of lymphocytosis is not well established, but a study suggests a threshold of 4.4 × 10^9 cells/L in patients younger than 75 years and 4.0 × 10^9 cells/L in patients 75 years and older 6.
Lymphoproliferative Disorders
Lymphoproliferative disorders, such as diffuse large B-cell lymphoma, can occur in patients with RA, particularly those treated with MTX.
- EBV positivity and non-DLBCL histology are associated with spontaneous regression of lymphoproliferative disorders in patients with RA 4.
- The combination of RA and MTX is associated with an increased risk of developing EBV-associated lymphoproliferative disorders 5.
Diagnostic Considerations
Diagnostic considerations for elevated absolute lymphocytes include: