JAK inhibition for CD3- CD4+ lymphocytic-variant hypereosinophilic syndrome

Clin Immunol. 2023 Jun:251:109275. doi: 10.1016/j.clim.2023.109275. Epub 2023 Mar 2.


Alternatives are urgently needed in patients with CD3- CD4+ lymphocytic-variant hypereosinophilic syndrome (L-HES) requiring high-level steroids or who are unresponsive and/or intolerant to conventional alternative therapies. We report five L-HES patients (44-66 years) with cutaneous involvement (n = 5) and persistent eosinophilia (n = 3) despite conventional therapies, who successfully received JAK inhibitors (tofacitinib n = 1, ruxolitinib n = 4). JAKi led to complete clinical remission in the first 3 months in all (with prednisone withdrawal in four). Absolute eosinophil counts normalized in cases receiving ruxolitinib, while reduction was partial under tofacitinib. After switch from tofacitinib to ruxolitinib, complete clinical response persisted despite prednisone withdrawal. The clone size remained stable in all patients. After 3-13 months of follow-up, no adverse event was reported. Prospective clinical trials are warranted to examine the use of JAKi in L-HES.

Keywords: Hypereosinophilic syndrome; JAK inhibition; Lymphocytic variant; Ruxolitinib; T-cell clone.

MeSH terms

  • CD3 Complex
  • CD4-Positive T-Lymphocytes
  • Humans
  • Hypereosinophilic Syndrome* / drug therapy
  • Prednisone / therapeutic use
  • Prospective Studies


  • ruxolitinib
  • Prednisone
  • CD3 Complex