第一部分 组织细胞病血清细胞因子表达谱

目的:本研究旨在描绘组织细胞病患者的血清细胞因子表达谱，为组织细胞病的发病机制探索和疾病监测提供指导。

方法:通过 Luminex 高通量的蛋白测定技术，检测朗格汉斯细胞组织细胞增生症 (LCH)和 Erdheim-Chester 病(ECD)患者血清 48 种细胞因子表达水平，分析其与疾病特征、预后的关系，比较初治患者及其在治疗后细胞因子表达谱差别， 分析细胞因子与临床资料的相关性。

结果:LCH 病人相较于健康人群高表达 Eotaxin、GRO-α、IL-2Ra、IL-4、IL-13、 IL-18、IP-10、MIP-1β、Rantes、SCF、SDF-1α、TNF-β 和 TRAIL 共 13 种细胞因子;MIP-1β 的表达水平在 SS-m 患者中显著高于 SS-s 患者;IL-18 和 IP-10 的高表达往往提示患者存在危险脏器受累。携带 BRAF V600E 突变的 LCH 患者，Eotaxin、 SCF、SDF-1α、TRAIL 水平显著高于携带其他突变或无突变的患者;而 GRO-α 和 MIP-1β 的水平显著低于携带其他突变或无突变的患者。上述 13 种细胞因子在 LCH 患者治疗后，除了 IL-18 和 TRAIL 之外，其余均显著下降。ECD 患者较健康人群高表达 HGF、IL-1Ra、IL-2、IL-2Ra、IL-6、IL-18、IP-10、MCP-1、MCP- 3、M-CSF 和 SCF 共 11 种细胞因子;携带 BRAF V600E 突变的 ECD 患者 IL-6 和 MCP-3 显著升高;治疗后只有 IL-2、IL-2Ra、MCP-3 和 M-CSF 显著下降，其余无 显著性变化。

结论:LCH 患者和 ECD 患者血清细胞因子谱明显区别于健康人。IL-18 和 IP-10 的高表达或可提示 LCH 患者存在危险脏器受累;携带 BRAF V600E 突变的 LCH 或 ECD 患者血清细胞因子含量与不携带该突变的患者明显不同;血清高水平表达 IL- 2Ra 的多系统受累 LCH 患者预后不佳。

关键词:朗格汉斯细胞组织细胞增生症，Erdheim-Chester 病，BRAF V600E 突变，细胞因子水平

第二部分 血浆cfDNA在组织细胞病中的应用前景

目的:探讨血浆 cfDNA 在组织细胞病中的应用前景，探寻组织细胞病的血清分子标记物与临床表现、治疗反应以及预后的关系。

方法:提取 LCH 和 ECD 患者血浆 cfDNA，使用数字 PCR，对拟定基因 BRAF、 MAP2K1 的 27 个位点进行检测，系统评估其在不同临床亚型的生物学作用及表达 特征，探索其在疾病诊断、治疗反应监测及预后评估中的潜在价值，同时联合分析 PET-CT 成像评估结果。

结果:在 92 例 LCH 患者基线血浆 cfDNA 中，共有 41 例患者检测到与组织相同的突变，血浆 cfDNA 灵敏度为 44.6%;在 28 例 ECD 患者基线血浆 cfDNA 中，共 有 27 例患者检测到与组织相同的突变，血浆 cfDNA 灵敏度为 96.4%。LCH 患者 处于多系统受累及高炎症状态时，血浆 cfDNA 阳性率明显更高;早期完全清除 cfDNA 的 LCH 患者，治疗有效率和预后均明显较好。ECD 血浆 cfDNA 阳性率与受累器官和炎症状态无关。

结论:LCH 患者血浆 cfDNA 可反映其疾病严重程度，应尽早完全清除 cfDNA 防止疾病复发;ECD 患者血浆 cfDNA 阳性率较高，完全清除较难且短暂。

关键词:朗格汉斯细胞组织细胞增生症，Erdheim-Chester 病，cfDNA

Part I Serum Cytokine Expression Profile in Histiocytic Disorders

Objective: This study aimed to characterize the serum cytokine expression profiles in patients with histiocytic disorders, providing insights into the pathogenesis and potential biomarkers for disease monitoring.

Methods: Using Luminex multiplex protein assay technology, the expression levels of 48 serum cytokines were measured in patients with Langerhans cell histiocytosis (LCH) and Erdheim-Chester disease (ECD). The associations between cytokine levels and clinical features or prognosis were analyzed. Differences in cytokine profiles between newly diagnosed and post-treatment patients were compared, and correlations with clinical parameters were assessed.

Results: Compared to healthy individuals, LCH patients showed significantly elevated serum levels of 13 cytokines: Eotaxin, GRO-α, IL-2Ra, IL-4, IL-13, IL-18, IP-10, MIP- 1β, RANTES, SCF, SDF-1α, TNF-β, and TRAIL. Among LCH patients, MIP-1β levels were significantly higher in those with SS-m involvement than in SS-s, while elevated IL-18 and IP-10 levels were indicative of risk organ involvement. LCH patients carrying the BRAF V600E mutation exhibited significantly higher levels of Eotaxin, SCF, SDF-1α, and TRAIL, and significantly lower levels of GRO-α and MIP-1β, compared to those with other or no mutations. After treatment, levels of the above 13 cytokines significantly declined, except for IL-18 and TRAIL. ECD patients showed elevated levels of 11 cytokines compared to healthy controls: HGF, IL-1Ra, IL-2, IL-2Ra, IL-6, IL-18, IP-10, MCP-1, MCP-3, M-CSF, and SCF. In BRAF V600E-mutated ECD patients, IL-6 and MCP-3 levels were significantly higher. Following treatment, only IL-2, IL-2Ra, MCP-3, and M-CSF levels showed significant decreases, while the others remained unchanged.

Conclusion: LCH and ECD patients exhibit distinct serum cytokine profiles compared to healthy individuals. Elevated IL-18 and IP-10 may indicate risk organ involvement in LCH. The cytokine expression patterns in patients harboring the BRAF V600E mutation differ significantly from those without the mutation in both LCH and ECD. Additionally, high serum IL-2Ra levels in MS LCH patients may be associated with poor prognosis.

Keywords: Langerhans cell histiocytosis, Erdheim-Chester disease, BRAF V600E mutation, cytokine levels

Part II Clinical Potential of Plasma cfDNA in Histiocytic Disorders

Objective: To explore the potential applications of plasma cell-free DNA (cfDNA) in histiocytic disorders and lay the foundation for establishing a multidimensional molecular monitoring system for these diseases.

Methods: Plasma cfDNA was extracted from patients with Langerhans cell histiocytosis (LCH) and Erdheim-Chester disease (ECD). Digital PCR was performed to detect 27 predefined hotspot mutations in the BRAF and MAP2K1 genes. The biological roles and expression characteristics of these mutations were systematically evaluated across different clinical subtypes. The potential value of cfDNA in disease diagnosis, treatment response monitoring, and prognostic assessment was investigated. Additionally, PET-CT imaging findings were jointly analyzed to assess correlations.

Results: At baseline, tissue-concordant mutations were detected in plasma cfDNA from 41 out of 92 patients with LCH, corresponding to a detection sensitivity of 44.6%. In contrast, plasma cfDNA from 27 out of 28 patients with ECD harbored mutations identical to those found in matched tissue samples, yielding a sensitivity of 96.4%. Among LCH patients, cfDNA positivity was significantly associated with multisystem involvement and high inflammatory states. Those who achieved early complete clearance of cfDNA showed markedly better overall response rate and prognoses. In ECD, cfDNA positivity was not correlated with the extent of organ involvement or systemic inflammation.

Conclusion: In LCH, plasma cfDNA reflects disease severity and should be completely cleared as early as possible to prevent relapse. In ECD, cfDNA positivity is high, clearance is difficult and often temporary.

Keywords: Langerhans cell histiocytosis, Erdheim-Chester disease, cfDNA