From the Guidelines
Basophilia is most commonly caused by myeloproliferative disorders, such as chronic myeloid leukemia (CML), where it is defined as a basophil count greater than 20% 1.
Causes of Basophilia
The causes of raised basophils can be categorized into several groups, including:
- Myeloproliferative disorders: CML, polycythemia vera, and essential thrombocythemia are examples of conditions that can lead to basophilia due to abnormal bone marrow production 1.
- Inflammatory conditions: Ulcerative colitis, chronic sinusitis, and certain dermatological disorders can trigger basophilia as part of the immune response.
- Allergic reactions: IgE-mediated hypersensitivity reactions often cause basophil elevation as these cells release histamine during allergic responses.
- Endocrine disorders: Hypothyroidism and Addison's disease may also lead to basophilia.
- Infections: Certain parasitic infections, such as hookworm and schistosomiasis, can trigger basophil production as part of the body's defense mechanism.
- Other causes: Basophilia may also occur following radiation therapy, during recovery from bone marrow suppression, or as a reaction to certain medications.
Clinical Context
When basophilia is detected, it is essential to consider the clinical context and other laboratory findings to determine the underlying cause. In the case of CML, basophilia is a significant indicator of disease progression, particularly in the accelerated phase (AP) or blast phase (BP) 1.
Key Findings
- Basophilia is defined as a basophil count greater than 20% in CML 1.
- CML is a common cause of basophilia, particularly in the AP or BP 1.
- Other causes of basophilia include inflammatory conditions, allergic reactions, endocrine disorders, infections, and other factors.
- Clinical context and laboratory findings are crucial in determining the underlying cause of basophilia.
From the Research
Causes of Raised Basophils
- Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm that can cause an increase in basophils, with approximately 90% of people with CML presenting with an indolent chronic phase of CML, defined as blasts of less than 10% in the blood or bone marrow, absence of extramedullary evidence of leukemia, basophils of less than 20%, and platelet counts of 100 to 1000 × 10^9/L 2
- The most advanced stage is CML blastic phase (CML-BP), characterized by the World Health Organization as 20% or more blasts/immature cells and by the MD Anderson Cancer Center and European LeukemiaNet as 30% or more, which may also be associated with raised basophils 2
- Other myeloproliferative neoplasms, such as polycythemia vera, essential thrombocythemia, and primary myelofibrosis, can also cause an increase in basophils, although this is not explicitly stated in the provided studies
- Certain medications, such as hydroxyurea, can cause muco-cutaneous changes, including acral erythema, dermatomyositis-like changes, and ulcers, but their effect on basophil count is not mentioned in the provided studies 3
- Histamine dihydrochloride, a synthetic derivative of the biogenic amine histamine, has been used in the management of acute myeloid leukemia, and its use has been associated with eosinophilia, but its effect on basophil count is not mentioned in the provided studies 4
Diagnosis and Treatment
- CML is characterized by a balanced genetic translocation, t(9;22)(q34;q11.2), involving a fusion of the Abelson gene (ABL1) from chromosome 9q34 with the breakpoint cluster region (BCR) gene on chromosome 22q11.2, which can be diagnosed using molecular tests 5, 6
- Tyrosine kinase inhibitors (TKIs), such as imatinib, dasatinib, bosutinib, and nilotinib, are approved for first-line treatment of newly diagnosed CML in chronic phase (CML-CP) 5, 6
- Allogeneic stem cell transplantation remains an important therapeutic option for patients with CML-CP who have failed at least 2 TKIs, and for all patients in advanced phase disease 5, 6