Published Online: September 2, 2015
Eosinophils are specialized white blood cells that help to fight parasitic infections. Elevated eosinophil levels also can occur in the context of certain allergic diseases, autoimmune diseases, and cancer. In most cases, slight elevations in eosinophil numbers are a non-specific finding and do not portend an ominous diagnosis. However, in rare cases elevated eosinophil levels can occur with the onset of specific leukemias and lymphomas.
In their study published in The Journal of Allergy and Clinical Immunology: In Practice, Jin et al set out to answer the question of which specific leukemias and lymphomas occurred most often in people who had significantly elevated eosinophil levels. Knowing the probability of one type of cancer versus another can help physicians and other healthcare practitioners determine the best approach for expedited evaluation.
In people who develop symptoms suggestive of cancer but also have markedly high eosinophil levels, non-Hodgkin lymphomas were diagnosed more often than other lymphomas or leukemias. Non-Hodgkin lymphoma is a general term that groups together many different subtypes of lymphoma. Within this larger group are more common and less common lymphomas. Jin et al showed that rarer subtypes of these non-Hodgkin lymphomas occurred more frequently in the people who had high eosinophil levels. They also observed that eosinophil levels tended to return to normal after treatment of the underlying cancer and that in some cases the eosinophil levels increased again with recurrence of cancer.
When there is a concern for cancer, recognition of a high eosinophil count on blood work should prompt immediate referral to a specialist with the capability of diagnosing very rare lymphomas and leukemias. Often this means referring a patient to a larger medical center with more experienced clinicians, well-coordinated multispecialty care, and research-based treatment options.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.