Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, 2301 Erwin Road, Durham, NC, 27710, USA.
Duke Global Health Institute, Duke University, Durham, NC, USA.
Eur J Clin Microbiol Infect Dis. 2020 Nov;39(11):2121-2131. doi: 10.1007/s10096-020-03955-z. Epub 2020 Jul 4.
The complement system is a vital component of the innate immune system, though its role in bacteremia is poorly understood. We present complement levels in Staphylococcus aureus bacteremia (SAB) and Gram-negative bacteremia (GNB) and describe observed associations of complement levels with clinical outcomes. Complement and cytokine levels were measured in serum samples from 20 hospitalized patients with SAB, 20 hospitalized patients with GNB, 10 non-infected hospitalized patients, and 10 community controls. C5a levels were significantly higher in patients with SAB as compared to patients with GNB. Low C4 and C3 levels were associated with septic shock and 30-day mortality in patients with GNB, and elevated C3 was associated with a desirable outcome defined as absence of (1) septic shock, (2) acute renal failure, and (3) death within 30 days of bacteremia. Low levels of C9 were associated with septic shock in patients with GNB but not SAB. Elevated IL-10 was associated with increased 30-day mortality in patients with SAB. Complement profiles differ in patients with SAB and those with GNB. Measurement of IL-10 in patients with SAB and of C4, C3, and C9 in patients with GNB may help to identify those at higher risk for poor outcomes.
补体系统是先天免疫系统的重要组成部分，但它在菌血症中的作用尚未被充分了解。我们报告了金黄色葡萄球菌菌血症（SAB）和革兰氏阴性菌血症（GNB）患者的补体水平，并描述了补体水平与临床结局的关联。我们测量了 20 例住院 SAB 患者、20 例住院 GNB 患者、10 例非感染住院患者和 10 例社区对照者的血清样本中的补体和细胞因子水平。与 GNB 患者相比，SAB 患者的 C5a 水平显著升高。GNB 患者中，低 C4 和 C3 水平与感染性休克和 30 天死亡率相关，而 C3 升高与理想结局相关，定义为（1）无感染性休克，（2）急性肾衰竭，和（3）菌血症后 30 天内无死亡。低 C9 水平与 GNB 患者的感染性休克相关，但与 SAB 患者无关。SAB 患者中，IL-10 升高与 30 天死亡率增加相关。SAB 和 GNB 患者的补体谱不同。在 SAB 患者中测量 IL-10，在 GNB 患者中测量 C4、C3 和 C9，可能有助于识别那些预后不良风险较高的患者。
