Infections that are unusually severe or caused by opportunistic pathogens are a hallmark of primary immunodeficiency (PID). Anti-cytokine autoantibodies (ACA) are an emerging cause of acquired immunodeficiency mimicking PID. Nocardia spp. are Gram-positive bacteria generally inducing disseminated infections in immunocompromised patients, but seldom also occurring in apparently immunocompetent hosts. Anti-GM-CSF autoantibodies are associated with autoimmune pulmonary alveolar proteinosis (PAP). In those patients, an increased incidence of disseminated nocardiosis and cryptococcosis has been observed. It is unclear whether the PAP or the autoantibodies predispose to the infection. We report an apparently immunocompetent woman presenting with disseminated nocardiosis without any evidence of PAP. Clinical data and radiological images were retrospectively collected. Lymphocyte populations were analyzed by flow cytometry. Anti-GM-CSF autoantibodies were measured by ELISA. A 55-year-old otherwise healthy woman presented with cerebral and pulmonary abscesses. Personal and familial history of infections or autoimmunity were negative. After extensive examinations, a final diagnosis of disseminated nocardiosis was made. Immunologic investigations including neutrophilic function and IFN-γ/IL-12 circuitry failed to identify a PID. Whole-exome sequencing did not find pathogenic variants associated with immunodeficiency. Serum anti-GM-CSF autoantibodies were positive. There were no clinical or instrumental signs of PAP. Trimethoprim-sulfamethoxazole and imipenem were administered, with progressive improvement and recovery of the infectious complication. We identified anti-GM-CSF autoantibodies as the cause of disseminated nocardiosis in a previously healthy and apparently immunocompetent adult. This case emphasizes the importance of including ACA in the differential diagnosis of PID, especially in previously healthy adults. Importantly, anti-GM-CSF autoantibodies can present with disseminated nocardiosis without PAP.

异常严重的感染或由机会性病原体引起的感染是原发性免疫缺陷 (PID) 的标志。抗细胞因子自身抗体 (ACA) 是导致类似 PID 的获得性免疫缺陷的新原因。诺卡氏菌属 革兰氏阳性菌通常在免疫功能低下的患者中引起播散性感染，但很少也发生在表面免疫功能正常的宿主中。抗 GM-CSF 自身抗体与自身免疫性肺泡蛋白沉积症 (PAP) 相关。在这些患者中，观察到播散性诺卡氏菌病和隐球菌病的发病率增加。目前尚不清楚 PAP 还是自身抗体是否容易感染。我们报告了一名明显免疫功能正常的女性，患有播散性诺卡氏菌病，但没有任何 PAP 证据。回顾性收集临床数据和放射学图像。通过流式细胞术分析淋巴细胞群。通过ELISA测量抗GM-CSF自身抗体。一名 55 岁健康女性因脑脓肿和肺脓肿就诊。个人和家族感染史或自身免疫病史均为阴性。经过广泛检查，最终诊断为播散性诺卡氏菌病。包括中性粒细胞功能和 IFN-γ/IL-12 回路在内的免疫学研究未能识别 PID。全外显子组测序没有发现与免疫缺陷相关的致病变异。血清抗GM-CSF自身抗体呈阳性。没有 PAP 的临床或仪器症状。给予甲氧苄氨嘧啶-磺胺甲恶唑和亚胺培南，感染并发症逐渐改善和恢复。我们确定抗 GM-CSF 自身抗体是先前健康且表面免疫功能正常的成年人播散性诺卡氏菌病的原因。该病例强调了将 ACA 纳入 PID 鉴别诊断的重要性，尤其是对于既往健康的成年人。重要的是，抗 GM-CSF 自身抗体可出现播散性诺卡氏菌病，但不伴有 PAP。