IgG4-related disease in Italy: clinical features and outcomes of a large cohort of patients

<b>Objectives</b>: To describe the clinical features, treatment response, and follow-up of a large cohort of Italian patients with immunoglobulin (Ig)G4-related disease (IgG4-RD) referred to a single tertiary care centre. <b>Method</b>: Clinical, laboratory, histological, and imaging features were retrospectively reviewed. IgG4-RD was classified as ‘definite’ or ‘possible’ according to international consensus guidelines and comprehensive diagnostic criteria for IgG4-RD. Disease activity was assessed by means of the IgG4-RD Responder Index (IgG4-RD RI). <b>Results</b>: Forty-one patients (15 females, 26 males) were included in this study: 26 with ‘definite’ IgG4-RD and 15 with ‘possible’ IgG4-RD. The median age at diagnosis was 62 years. The median follow-up was 36 months (IQR 24–51). A history of atopy was present in 30% of patients. The pancreas, retroperitoneum, and major salivary glands were the most frequently involved organs. Serum IgG4 levels were elevated in 68% of cases. Thirty-six patients were initially treated with glucocorticoids (GCs) to induce remission. IgG4-RD RI decreased from a median of 7.8 at baseline to 2.9 after 1 month of therapy. Relapse occurred in 19/41 patients (46%) and required additional immunosuppressive drugs to maintain long-term remission. Multiple flares occurred in a minority of patients. A single case of orbital pseudotumour did not respond to medical therapy and underwent surgical debulking. <b>Conclusions</b>: IgG4-RD is an elusive inflammatory disease to be considered in the differential diagnosis of isolated or multiple tumefactive lesions. Long-term disease control can be achieved with corticosteroids and immunosuppressive drugs in the majority of cases.

**研究目的**：本研究旨在描述就诊于单家三级医疗中心的大样本意大利免疫球蛋白G4相关疾病（immunoglobulin G4-related disease, IgG4-RD）患者队列的临床特征、治疗应答情况及随访结局。
**研究方法**：本研究对患者的临床、实验室检查、组织病理学及影像学特征进行回顾性分析。依据免疫球蛋白G4相关疾病的国际共识指南及综合诊断标准，将患者分为"确诊"与"疑似"两类。采用IgG4-RD应答指数（IgG4-RD Responder Index, IgG4-RD RI）评估疾病活动度。
**研究结果**：本研究共纳入41例患者（女性15例，男性26例），其中26例为确诊IgG4-RD，15例为疑似IgG4-RD。患者诊断时的中位年龄为62岁，中位随访时长为36个月（四分位间距24~51）。30%的患者存在特应性病史。胰腺、腹膜后组织及大唾液腺为最常受累的器官。68%的患者血清IgG4水平升高。36例患者初始接受糖皮质激素（glucocorticoids, GCs）治疗以诱导疾病缓解。治疗1个月后，IgG4-RD RI的中位值从基线时的7.8降至2.9。41例患者中有19例（46%）出现疾病复发，需加用免疫抑制剂以维持长期缓解。少数患者出现多次发作。仅1例眼眶假瘤患者对药物治疗无应答，接受了手术减瘤术。
**研究结论**：免疫球蛋白G4相关疾病是一种隐匿性炎症性疾病，在孤立性或多发性肿胀性病变的鉴别诊断中需纳入考量。多数患者可通过糖皮质激素及免疫抑制剂实现长期疾病控制。