Molecular Pathogenesis and Treatment Perspectives for Hypereosinophilia and Hypereosinophilic Syndromes

Int J Mol Sci. 2021 Jan 6;22(2):486. doi: 10.3390/ijms22020486.


Hypereosinophilia (HE) is a heterogeneous condition with a persistent elevated eosinophil count of >350/mm3, which is reported in various (inflammatory, allergic, infectious, or neoplastic) diseases with distinct pathophysiological pathways. HE may be associated with tissue or organ damage and, in this case, the disorder is classified as hypereosinophilic syndrome (HES). Different studies have allowed for the discovery of two major pathogenetic variants known as myeloid or lymphocytic HES. With the advent of molecular genetic analyses, such as T-cell receptor gene rearrangement assays and Next Generation Sequencing, it is possible to better characterize these syndromes and establish which patients will benefit from pharmacological targeted therapy. In this review, we highlight the molecular alterations that are involved in the pathogenesis of eosinophil disorders and revise possible therapeutic approaches, either implemented in clinical practice or currently under investigation in clinical trials.

Keywords: NGS; PDGFRα and PDGFRβ fusions; TCR rearrangements; hypereosinophilia; hypereosinophilic syndromes.

Publication types

  • Review

MeSH terms

  • Antibodies, Monoclonal / therapeutic use
  • Cytokines / metabolism
  • Eosinophils / cytology
  • Eosinophils / metabolism
  • Gene Rearrangement
  • Humans
  • Hypereosinophilic Syndrome / drug therapy
  • Hypereosinophilic Syndrome / genetics
  • Hypereosinophilic Syndrome / pathology*
  • Protein Kinase Inhibitors / therapeutic use
  • Receptor, Platelet-Derived Growth Factor alpha / genetics
  • Receptor, Platelet-Derived Growth Factor beta / genetics
  • Receptor, Platelet-Derived Growth Factor beta / metabolism
  • Receptors, Antigen, T-Cell / genetics*


  • Antibodies, Monoclonal
  • Cytokines
  • Protein Kinase Inhibitors
  • Receptors, Antigen, T-Cell
  • Receptor, Platelet-Derived Growth Factor alpha
  • Receptor, Platelet-Derived Growth Factor beta