From the Guidelines
Lymphocytosis should be managed based on its underlying cause, with treatment ranging from supportive care for viral infections to chemotherapy or immunotherapy for conditions like chronic lymphocytic leukemia (CLL) or lymphoma, as indicated by the most recent guidelines 1. The approach to lymphocytosis involves identifying the cause, which could range from benign viral infections to more serious conditions like leukemia. Key considerations include:
- The presence of symptoms such as fever, night sweats, weight loss, or enlarged lymph nodes, which can guide the diagnosis and management.
- Laboratory findings, including a complete blood count with differential, peripheral blood smear examination, and potentially bone marrow examination or flow cytometry if a blood cancer is suspected.
- The specific criteria for initiating treatment in conditions like CLL, which include evidence of progressive marrow failure, massive or progressive splenomegaly, massive nodes, progressive lymphocytosis, autoimmune anemia or thrombocytopenia, and constitutional symptoms 1.
- The importance of not using the absolute lymphocyte count as the sole indicator for treatment, especially in CLL, where symptoms and disease progression are more critical factors 1.
- For patients with CLL, treatment should only be given to those with active, symptomatic disease, as defined by specific conditions such as significant B-symptoms, cytopenias, or a lymphocyte doubling time of less than 6 months in patients with more than 30,000 lymphocytes/μL 1. Given the complexity and potential severity of conditions associated with lymphocytosis, management should be tailored to the individual patient's needs and guided by the most current clinical practice guidelines, prioritizing morbidity, mortality, and quality of life outcomes.
From the Research
Definition and Diagnosis of Lymphocytosis
- Lymphocytosis is a common blood-test finding that requires clinical review to determine whether the cause is benign or malignant 2.
- A thorough history, examination, and preliminary investigations such as blood tests and blood film are necessary to establish the cause of lymphocytosis 2.
- Flow cytometry is a powerful tool for etiological diagnosis of lymphocytosis, allowing distinction between chronic lymphocytic leukemia (CLL) and other causes of lymphocytosis 3.
Chronic Lymphocytic Leukemia (CLL)
- CLL is a type of cancer that can present with lymphocytosis, and patient outcomes vary based on genetic pre-disposition and prognostic markers such as age, Binet or Rai staging, and B2-microglobulin 2, 4.
- CLL is often diagnosed incidentally due to a lymphocytosis found on routine blood tests, and clinical staging remains the foundation for determining prognosis 2, 4.
- Treatment options for CLL have expanded in recent years and include chemo-immunotherapy, novel oral therapies, and monoclonal antibodies used alone or in combination with other agents 2, 4.
Other Causes of Lymphocytosis
- Reactive T-lymphocytosis is a common cause of lymphocytosis, particularly in adults with a lymphocyte count below 10,000/microliter 5.
- Other causes of lymphocytosis include hairy cell leukemia, follicular lymphoma, and large granular T lymphoma (LGL-T), which can be diagnosed using flow cytometry 3.
- Herpes simplex virus infections can also cause lymphocytosis, although this is not directly related to the diagnosis or management of CLL 6.