From the Guidelines
The medical term for an increase in lymphocytes in the blood is lymphocytosis, which is characterized by a sustained increase of peripheral blood lymphocytes ≥ 5 · 10^9 cells/l not explained by other clinical disorders, as defined by the ESMO clinical recommendations for diagnosis, treatment, and follow-up of chronic lymphocytic leukemia 1.
Definition and Diagnosis
Lymphocytosis can be caused by various factors including viral infections, certain bacterial infections, autoimmune disorders, specific cancers, or as a response to stress or medications. The condition may be acute or chronic depending on the underlying cause. Diagnosis typically involves a complete blood count (CBC) with differential to determine the specific elevation in lymphocytes, followed by additional testing to identify the root cause, such as immunophenotyping and bone marrow biopsy 1.
Key Characteristics
According to the guidelines for the diagnosis and treatment of chronic lymphocytic leukemia, a report from the international workshop on chronic lymphocytic leukemia, the primary treatment decisions are based on the presence of active disease, which is defined by criteria such as evidence of progressive marrow failure, massive or progressive splenomegaly, massive nodes, progressive lymphocytosis, autoimmune anemia, or constitutional symptoms 1.
Treatment Approach
Treatment focuses on addressing the underlying condition rather than the lymphocytosis itself. For patients with asymptomatic early-stage disease, a watch and wait strategy with regular controls of blood cell counts and clinical examinations is recommended, whereas patients with active disease or advanced stages usually benefit from the initiation of treatment 1.
Important Considerations
It is essential to note that the absolute lymphocyte count should not be used as the sole indicator for treatment, and factors contributing to lymphocytosis or lymphadenopathy other than CLL should be excluded 1. Hypogammaglobulinemia or monoclonal or oligoclonal paraproteinemia does not by itself constitute a basis for initiating therapy, but it is recommended to assess the change of these protein abnormalities if patients are treated 1.
From the Research
Lymphocytosis Definition
- Lymphocytosis refers to an increase in the number of lymphocytes in the blood 2.
- It can be caused by various factors, including infections, inflammation, and hematological disorders 3, 4, 2, 5.
Types of Lymphocytosis
- Reactive lymphocytosis: a non-neoplastic increase in lymphocytes, often seen in response to infections or inflammation 2.
- Neoplastic lymphocytosis: a monoclonal increase in lymphocytes, indicative of conditions such as chronic lymphatic leukemia (CLL) 2.
Clinical Significance
- Lymphocytosis can be a prognostic indicator in certain diseases, such as cancer 4.
- A decrease in lymphocyte count can be associated with immune incompetence and increased risk of opportunistic infections 5.
- Granulocyte colony-stimulating factor (G-CSF) treatment can increase lymphocyte counts in HIV-infected patients 3, 6.