# Clinical analysis of six eosinophilia cases with Löeffler endocarditis as the main clinical feature

## TL;DR

This paper presents clinical findings from six patients with Loeffler endocarditis and eosinophilia, highlighting treatment responses and outcomes.

## Contribution

The study provides a detailed clinical analysis of six rare cases of Loeffler endocarditis with novel fusion gene findings and treatment outcomes.

## Key findings

- Two patients with FIP1L1::PDGFRA fusion responded well to imatinib therapy.
- One patient with TLS::ERG-positive AML achieved remission with chemotherapy and stem cell transplant but later relapsed.
- Three patients improved with corticosteroid treatment and remained alive at follow-up.

## Abstract

为提高对Löeffler心内膜炎的认识，回顾性分析2019年1月至2024年10月期间苏州大学附属第一医院收治的6例以Löeffler心内膜炎为主要临床特征的嗜酸性粒细胞增多症患者。6例患者中男性5例，中位年龄45.5（31～77）岁，所有患者外周血WBC、嗜酸性粒细胞计数均有增高，临床症状及影像学检查考虑为Löeffler心内膜炎，2例合并脑梗死。5例患者完善了融合基因检测，例4、例5检测到FIP1L1::PDGFRA阳性，例6诊断为TLS::ERG（+）急性髓系白血病。2例FIP1L1::PDGFRA阳性患者经伊马替尼治疗后迅速缓解；例6经糖皮质激素、羟基脲治疗后症状缓解，后接受IAG（阿糖胞苷+伊达比星+G-CSF）方案化疗后完全缓解，并于8个月后进行异基因造血干细胞移植，移植后1年因本病复发合并感染死亡。其余3例患者经糖皮质激素治疗后好转。除例6外其余患者至随访终点均存活，例4停用伊马替尼后28个月复发，再次启动治疗后缓解。