Primary immunodeficiencies (PIDs) are heterogeneous disorders, characterized by variable clinical and immunological features. National PID registries offer useful insights on the epidemiology, diagnosis, and natural history of these disorders. In 1999, the Italian network for primary immunodeficiencies (IPINet) was established. We report on data collected from the IPINet registry after 20 years of activity. A total of 3352 pediatric and adult patients affected with PIDs are registered in the database. In Italy, a regional distribution trend of PID diagnosis was observed. Based on the updated IUIS classification of 2019, PID distribution in Italy showed that predominantly antibody deficiencies account for the majority of cases (63%), followed by combined immunodeficiencies with associated or syndromic features (22.5%). The overall age at diagnosis was younger for male patients. The minimal prevalence of PIDs in Italy resulted in 5.1 per 100.000 habitants. Mortality was similar to other European registries (4.2%). Immunoglobulin replacement treatment was prescribed to less than one third of the patient cohort. Collectively, this is the first comprehensive description of the PID epidemiology in Italy.

原发性免疫缺陷 (PID) 是异质性疾病，其特征在于不同的临床和免疫学特征。国家 PID 登记处提供了有关这些疾病的流行病学、诊断和自然史的有用见解。1999 年，意大利原发性免疫缺陷网络（IPINet）成立。我们报告了经过 20 年活动后从 IPNet 注册中心收集的数据。数据库中登记了总共 3352 名受 PID 影响的儿科和成人患者。在意大利，观察到 PID 诊断的区域分布趋势。根据 2019 年更新的 IUIS 分类，意大利的 PID 分布显示，抗体缺陷占大多数病例 (63%)，其次是具有相关或综合征特征的联合免疫缺陷 (22.5%)。男性患者的总诊断年龄更年轻。意大利 PID 的最低流行率导致每 100,000 名居民中有 5.1 人。死亡率与其他欧洲登记处相似（4.2%）。不到三分之一的患者队列接受了免疫球蛋白替代治疗。总的来说，这是对意大利 PID 流行病学的首次全面描述。