Background: Autoimmune hemolytic anemia (AIHA) is caused by hemolysis induced by the reaction of autoantibodies with red blood cells. AIHA is usually classified as either warm antibody or cold antibody-mediated AIHA. In addition, AIHA caused by infection is classified as secondary AIHA. It is well-known that alteration of various cytokine levels is closely associated with a variety of disorders such as infectious diseases. In addition, it is known that IL-10/ IL-12 imbalance is an indicator of Th2-dominat conditions and a progressive marker of AIHA.

Case presentation: A 82-year-old Japanese man was brought to the emergency room with pneumonia and heart failure. After admission, we started antibiotics therapy. Next day, he had symptoms of jaundice and his total bilirubin level was elevated. Five days after admission, his inflammation markers were further elevated and he had hemolytic anemia. We finally diagnosed him as severe warm-type AIHA associated with pneumoniae infection. Seven days after admission, his severe leucocytosis was further aggravated, and then he suddenly had cardiac arrest and respiratory failure, and finally died of multiple organ failure. Unfortunately, we failed to rescue him from severe AIHA induced by pneumonia infection.

Conclusions: Herein, we report a subject with pneumonia-triggered warm-type AIHA together with marked cytokine storm. IL-18 levels were markedly elevated without elevation of IL-12 levels. In addition, IL-10/IL-12 imbalance was observed. These data suggest that once marked cytokine storm is induced, infection-induced AIHA is exacerbated very rapidly.

背景：自身免疫性溶血性贫血（AIHA）是由自身抗体与红细胞反应诱导的溶血引起的。AIHA通常分为温抗体或冷抗体介导的AIHA。另外，由感染引起的AIHA被分类为继发性AIHA。众所周知，各种细胞因子水平的改变与多种疾病如传染病密切相关。另外，已知IL-10 / IL-12失衡是Th2主导状态的指标和AIHA的进行性标志。

案例介绍：一名82岁的日本男子因肺炎和心力衰竭被带到急诊室。入院后，我们开始了抗生素治疗。第二天，他出现了黄疸症状，总胆红素水平升高。入院五天后，他的炎症指标进一步升高，患有溶血性贫血。我们最终将他诊断为伴有肺炎感染的严重温暖型AIHA。入院7天后，严重的白细胞增多症进一步加重，然后突然出现心搏停止和呼吸衰竭，最后因多器官衰竭而死亡。不幸的是，我们未能从肺炎感染引起的严重AIHA中救出他。

结论：在本文中，我们报告了患有肺炎触发的温暖型AIHA和明显的细胞因子风暴的受试者。IL-18水平显着升高而IL-12水平没有升高。另外，观察到IL-10 / IL-12失衡。这些数据表明，一旦诱导出明显的细胞因子风暴，感染诱导的AIHA就会迅速恶化。