From the Guidelines
Basophilia is a significant finding that warrants further investigation to identify the underlying cause, particularly in the context of chronic myeloid leukemia (CML), where it is a common feature and can be associated with disease progression 1.
Definition and Clinical Significance
Basophilia refers to an increased number of basophils in the peripheral blood. In the context of CML, basophilia is defined as more than 20% basophils, which is one of the criteria for accelerated phase (AP) according to the European LeukemiaNet (ELN) and World Health Organization (WHO) guidelines 1. This condition can lead to various symptoms, including bleeding, thrombosis, gouty arthritis, retinal hemorrhages, and upper gastrointestinal ulceration, primarily due to elevated histamine levels.
Diagnostic Approach
When basophilia is detected, a comprehensive diagnostic approach should be undertaken, including:
- Complete blood count with differential to confirm the presence and extent of basophilia
- Peripheral blood smear examination to assess for other abnormal cells
- Relevant clinical history to identify potential underlying causes such as allergic reactions, inflammatory conditions, or infections
- Further testing as indicated by the clinical context, such as bone marrow biopsy or molecular studies for CML
Management
Management of basophilia focuses on treating the underlying condition rather than the basophilia itself. For example:
- Tyrosine kinase inhibitors like imatinib are used for CML
- Antihistamines and corticosteroids may be beneficial for allergic reactions
- Addressing the underlying cause of inflammatory or infectious conditions
Prognostic Implications
In CML, the presence of basophilia, particularly when it exceeds 20%, is a significant prognostic indicator, suggesting potential disease progression to accelerated or blast phase 1. Therefore, prompt recognition and appropriate management of the underlying condition are crucial to improve outcomes in terms of morbidity, mortality, and quality of life.
From the Research
Definition and Prevalence of Basophilia
- Basophilia is a rare disorder of the complete blood count (CBC) 2
- Basophils are the rarest granulocytes, representing approximately 0.01 to 0.3% of the blood leukocytes 3
- Basophils are distinct from mast cells and have important and non-redundant functions [(3, 4)]
Causes and Associations of Basophilia
- Basophilia is associated with myeloid neoplasm, especially chronic myeloid neoplasm [(2, 3)]
- Basophilia can be caused by reactive conditions, such as allergic reactions or infections [(2, 4)]
- Basophilia has been observed in various benign and malignant pathologies, including allergy, autoimmunity, tumors, and COVID-19 [(3, 5)]
- In animals, basophilia is associated with respiratory disease, lymphoma, and mast cell neoplasia 6
Diagnosis and Management of Basophilia
- The reliability of basophil count is insufficient, whether performed by microscopic slide examination or hematology analyzer 2
- A practical approach to manage basophilia involves checking for spurious basophilia, looking for symptoms of reactive basophilia, and deciding which examinations to prescribe to confirm a neoplastic basophilia 2
- Further studies on basophil biology could lead to the identification of novel biomarkers or therapeutic targets in a broad range of diseases 5