THE SPECTRUM OF HYPEREOSINOPHILIA AND ASSOCIATED CLONAL DISORDERS – A REAL WORLD DATA FROM A TROPICAL SETTING.

Abstract

Objective: To determine the frequency, etiological spectrum and treatment outcome of hypereosinophilia (HE) and hypereosinophilic syndrome (HES) in a tropical setting. Methods: A retrospective analysis of hospital data of five years and a comprehensive prospective evaluation of patients presenting with HE/HES over a period of 33 months was performed. Results: HE/HES was diagnosed in total of 125 patients during study period with an estimated prevalence of 0.5-1 case per one lakh population in our hospital settings. Infections, especially helminthes were the commonest cause (34%) followed by primary/clonal HE/HES (24%) and reactive HE/HES secondary to various clonal disorders (14.3%). Lymphocytic variant of HES and FIP1L1-PDGFRA positive HES were diagnosed in 3.6% each. Imatinib responsive BCR-ABL1 negative HE/HES constitute 7.1% in our patients. Conclusions: None of the clinical or routine laboratory features including the age of patients, duration of HE, presence or absence of organomegaly, hemoglobin levels, eosinophil %, absolute eosinophil count, total leukocyte count, platelet counts, serum IgE levels or presence of myelofibrosis can be used to predict or exclude malignancy in patients with HE/HES. The absence of blasts in peripheral blood or the absence of >5% blasts in bone marrow does not exclude primary/clonal HES. Clonal disorders (Primary HES and reactive HES secondary to clonal disorders; 38%) are diagnosed with nearly equal frequency compared to infections (34%) in tropical settings necessitating a thorough follow-up and comprehensive work-up in these patients.

Keywords

• Hypereosinophilia
• Hypereosinophilic syndromes
• Flow cytometry
• fluorescent in situ hybridization
• FIP1L1-PDGFRA
• clonal hypereosinophilia
• Imatinib responsive hypereosinophilia
• lymphocytic variant of hypereosinophilia