背景:冷凝集综合征是自身免疫性溶血性贫血的一种亚型。这种情况被称为“冷”,因为抗体在低温下变得活跃并诱导溶血,通常为3-4°C,这在其他类型的自身免疫性溶血性贫血中并不总是如此。尽管原发性冷凝集综合征可能在没有潜在疾病的情况下发生,继发性冷凝集综合征与潜在感染的存在有关,包括2019年冠状病毒病。
方法:我们报告了一名69岁的日本牙周炎妇女,该妇女因棕色尿液和胸痛而被转诊到我们医院。她的血红蛋白水平为6.1g/dL。计算机断层扫描显示多发肺脓肿。她的直接抗体检测结果是抗补体直接抗球蛋白阳性(2+),免疫球蛋白G阴性,她的冷凝集素滴度在1:4096升高。贫血的检查显示冷凝集综合征的阳性结果。患者接受了第四剂2019年冠状病毒病疫苗接种。使用实时逆转录聚合酶链反应检测严重急性呼吸综合征冠状病毒2的鼻咽拭子试验得出的循环阈值为42.3,病毒特异性免疫球蛋白G的水平升高至7.71S/C(正常范围-1.4S/C)。
结论:2019年冠状病毒病患者血红蛋白下降可能与继发性冷凝集综合征有关。假设该患者在2019年冠状病毒疾病后发展为多发性肺脓肿,伴有继发性冷凝集综合征。因此,2019年冠状病毒病之后,患者可以发展为继发性冷凝集综合征,这可能会由于相关的血液细菌感染而恶化。
BACKGROUND: Cold agglutination syndrome is a subtype of autoimmune hemolytic anemia. The condition is referred to as \"cold\" because the antibodies become active and induce hemolysis at cold temperatures, typically 3-4 °C, which is not always the case in other kinds of autoimmune hemolytic anemia. Whereas primary cold agglutination syndrome may occur in the absence of underlying conditions, secondary cold agglutination syndrome is associated with the presence of underlying infections, including coronavirus disease 2019.
METHODS: We report the case of a 69-year-old Japanese woman with periodontitis who was referred to our hospital with complaints of brown-colored urine and chest pain. Her hemoglobin level was 6.1 g/dL. Computed tomography revealed multiple lung abscesses. Her direct antibody test results were positive (2+) for anti-complement direct antiglobulin and negative for immunoglobulin G, and her cold agglutinin titer was elevated at 1:4096. Workup for anemia revealed a positive result for cold agglutination syndrome. The patient had received the fourth dose of coronavirus disease 2019 vaccination. Nasopharyngeal swab test for detecting severe acute respiratory syndrome coronavirus 2 using a real-time reverse-transcription polymerase chain reaction gave a cycle threshold value of 42.3, and the level of virus-specific immunoglobulin G was elevated at 7.71 S/C (normal range -1.4 S/C).
CONCLUSIONS: A decrease in hemoglobin in patients with coronavirus disease 2019 may be associated with secondary cold agglutination syndrome. The patient was hypothesized to have developed multiple lung abscesses with secondary cold agglutination syndrome following coronavirus disease 2019. Thus, following coronavirus disease 2019, patients can develop secondary cold agglutination syndrome, which could worsen owing to associated bloodstream bacterial infections.