Prognostic impact of eosinophils in mastocytosis: analysis of 2350 patients collected in the ECNM Registry

• DOI: 10.1038/s41375-019-0632-4
• Publication Date: 2019-11-18T18:02:07Z
• Authors: Hanneke C. Kluin-...; Andreas Reiter; Anja Illerhaus; Bjorn van Anrooij; Karin Hartmann; Lambertus F. R. Span; Aleksandra Gorska; Marek Niedoszytko; Magdalena Lange; Luigi Scaffidi; Roberta Zanotti; Patrizia Bonadonna; Cecelia Perkins; Chiara Elena; Luca Malcovati; Khalid Shoumariyeh; Nikolas von Bubnoff; Roberta Parente; Massimo Triggiani; Juliana Schwaab; Mohamad Jawhar; Francesca Caroppo; Anna Belloni Fortina; Knut Brockow; Alexander Zink; David Fuchs; Alex Kilbertus; Akif Selim Yavuz; Michael Doubek; Mattias Mattsson; Hans Hagglund; Jens Panse; Vito Sabato; Elisabeth Aberer; Dietger Niederwieser; Christine Breynaert; Judit Várkonyi; Vanessa Kennedy; Olivier Lortholary; Thilo Jakob; Olivier Hermine; Julien Rossignol; Michel Arock; Jason Gotlib; Peter Valent; Wolfgang R. Sperr
• Keywords: EXPRESSION; Adult; Male; Adolescent; DISORDERS; 610; CLASSIFICATION; Young Adult; 03 medical and health sciences; Eosinophilia; Humans; MAST-CELL DISEASE; ACTIVATING MUTATION; Child; Aged; Aged, 80 and over; 0303 health sciences; LEUKEMIA Author Information; Science & Technology; Infant, Newborn; Infant; Hematology; SYSTEMIC MASTOCYTOSIS; Middle Aged; Prognosis; 3. Good health; C-KIT; Eosinophils; Survival Rate; MANIFESTATIONS; Oncology; Child, Preschool; Female; Human medicine; Life Sciences & Biomedicine; LEUKEMIA; Mastocytosis; Follow-Up Studies

Systemic mastocytosis (SM) is frequently associated with eosinophilia. To examine its prevalence and clinical impact in all WHO classification-based subcategories, we analyzed eosinophil counts in 2350 mastocytosis patients using the dataset of the European Competence Network on Mastocytosis. Ninety percent of patients had normal eosinophil counts, 6.8% mild eosinophilia (0.5-1.5 × 109/l), and 3.1% hypereosinophilia (HE; >1.5 × 109/l). Eosinophilia/HE were mainly present in patients with advanced SM (17%/19%), and only rarely recorded in patients with indolent and smoldering SM (5%/1%), and some patients with cutaneous mastocytosis. The eosinophil count correlated with organomegaly, dysmyelopoiesis, and the WHO classification, but not with mediator-related symptoms or allergy. Eosinophilia at diagnosis had a strong prognostic impact (p < 0.0001) on overall survival (OS) and progression-free survival (PFS), with a 10-year OS of 19% for patients with HE, 70% for those with mild eosinophilia, and 88% for patients with normal eosinophil counts. In 89% of patients with follow-up data (n = 1430, censored at start of cytoreductive therapy), eosinophils remained stable. In those with changing eosinophil counts (increase/decrease or mixed pattern), OS and PFS were inferior compared with patients with stable eosinophil counts. In conclusion, eosinophilia and HE are more prevalent in advanced SM and are predictors of a worse outcome.