Eosinophilia and Associated Disorders in Hematologic Malignancies

Eosinophilia, defined by an elevated peripheral blood eosinophil count, is a frequent manifestation in a spectrum of haematologic neoplasms. In primary clonal disorders, eosinophils arise from malignant progenitors harbouring chromosomal abnormalities or gene fusions that drive unchecked proliferation. Reactive eosinophilia may accompany cytokine-producing tumours, while idiopathic hypereosinophilia encompasses cases lacking identifiable drivers. Clinical consequences range from asymptomatic blood eosinophilia to organ-damaging hypereosinophilic syndromes, where cardiac, pulmonary and neurological involvement can determine prognosis. Advances in molecular diagnostics have refined the classification of eosinophil-associated malignancies, distinguishing myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions from chronic eosinophilic leukaemia and hypereosinophilic syndrome variants. Targeted therapies, especially tyrosine kinase inhibitors, have transformed outcomes in fusion-positive disease, while anti-interleukin-5 antibodies and novel small molecules offer promise in fusion-negative cases. Integrating genetic, immunological and clinical markers has enabled personalised risk stratification and therapeutic selection, underscoring the global significance of this field. Nonetheless, challenges persist in diagnosing rare variants, monitoring minimal residual disease and managing refractory or organ-threatening presentations.

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Eosinophilia and Associated Disorders in Hematologic Malignancies publication trend

The graph below shows the total number of articles in eosinophilia and associated disorders in hematologic malignancies across all publications each year (not limited to Nature Index journals).

Technical terms

Eosinophilia: An increased concentration of eosinophils in peripheral blood, typically above 0.5 × 10^9/L.

Hypereosinophilia: Persistent eosinophilia exceeding 1.5 × 10^9/L, often associated with end-organ damage.

Hypereosinophilic syndrome (HES): A group of disorders defined by hypereosinophilia with evidence of eosinophil-mediated organ dysfunction, after exclusion of secondary causes.

Myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions (MLN-TK): A category of clonal haematologic malignancies driven by gene rearrangements involving tyrosine kinase domains, resulting in aberrant eosinophil proliferation.

Tyrosine kinase inhibitor (TKI): A targeted therapeutic agent that blocks kinase activity of fusion oncoproteins, thereby suppressing malignant cell growth and eosinophil overproduction.

References

1. Myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions: reevaluation of the defining characteristics in a registry-based cohort. Leukemia (2023).
2. Proposed refined diagnostic criteria and classification of eosinophil disorders and related syndromes. Allergy (2022).