Interferon alpha induces a good molecular response in a patient with chronic eosinophilic leukemia (CEL) carrying the JAK2V617F point mutation.

The JAK2 V617F point mutation is very rare in hypereosinophilic syndrome and/or chronic eosinophilic leukemia. Here we report on a patient with chronic eosinophilic leukemia and detectable JAK2 mutant clone, who achieved a good molecular response to interferon alpha-2a after 4 months of treatment. The molecular response correlated with only moderate haematological improvement.