Low endogenous immunoglobulin(Ig)-levels are common in critically ill patients with sepsis, but it is unknown whether low Ig-levels are associated with poor outcome, and in which patients Ig-replacement therapy (IgRT) improves outcome. Given the crucial role of immunoglobulins in eliminating certain encapsulated pathogens, we examined the relationship between serial Ig-levels and disease course in critically ill patients with community acquired pneumonia (sCAP) caused by encapsulated or other pathogens. We included a cohort of consecutive critically ill patients with CAP, and PaO2/FiO2-ratio < 200 with or without septic shock, from an existing biorepository where microbiological causes of infection had been adjudicated in a protocolized manner. We used generalized linear mixed models to assess the association between IgG and IgM (measured on admission days 1, 3 and 7) and disease course (Sequential Organ Failure Assessment (SOFA)-score on day 2, 4, and 8) for all-cause sCAP and for episodes caused by Streptococcus (S.) pneumoniae or Haemophilus (H.) influenzae. We included 255 eligible patients admitted with CAP, of which 82 (32%) episodes were caused by S. pneumoniae or H. influenzae. 151 (59%) patients had low IgG (< 7.0 g/L), 77 (30%) had low IgM (< 0.4 g/L), and 56 (22%) had both. A lower IgG-level was related to a slightly higher SOFA-score at admission (β = − 0.07 per 1 g/L IgG, p = 0.029), but an IgG-level decline over time was not associated with a SOFA-score increase (β = − 0.04, p = 0.564). IgM-levels were not associated with changes in SOFA-score over time. Neither association was affected by the presence or absence of S. pneumoniae and H. influenzae. In critically ill patients with CAP, IgG and IgM dynamics in the first week of ICU stay are not associated with clinically relevant changes in disease course, regardless of the causative pathogen.

中文翻译：

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社区获得性肺炎危重症患者免疫球蛋白反应和疾病进展的纵向评估


低内源性免疫球蛋白 （Ig） 水平在脓毒症危重患者中很常见，但尚不清楚低 Ig 水平是否与不良结局相关，以及 Ig 替代疗法 （IgRT） 可改善患者预后。鉴于免疫球蛋白在消除某些包膜病原体中的关键作用，我们检查了由包膜或其他病原体引起的社区获得性肺炎 （sCAP） 危重患者连续 Ig 水平与病程之间的关系。我们纳入了一组连续的 CAP 危重患者，PaO2/FiO2 比值 < 200，伴或不伴感染性休克，来自现有生物储存库，其中感染的微生物学原因已以协议化方式判定。我们使用广义线性混合模型来评估 IgG 和 IgM （在入院第 1 、 3 和 7 天测量）和病程 （第 2 、 4 和 8 天的序贯器官衰竭评估 （SOFA） 评分）之间的相关性对于全因 sCAP 和由肺炎链球菌 （S.） 或流感嗜血杆菌 （H.） 引起的发作。我们纳入了 255 例符合条件的 CAP 患者，其中 82 例 （32%） 发作由肺炎链球菌或流感嗜血杆菌引起。151 例 （59%） 患者 IgG 水平低 （< 7.0 g/L），77 例 （30%） IgM 水平低 （< 0.4 g/L），56 例 （22%） 两者兼而有之。较低的 IgG 水平与入院时略高的 SOFA 评分相关 （β = - 0.07/1 g/L IgG，p = 0.029），但 IgG 水平随时间下降与 SOFA 评分增加无关 （β = − 0.04，p = 0.564）。IgM 水平与 SOFA 评分随时间的变化无关。这两种关联都不受肺炎链球菌和流感嗜血杆菌存在与否的影响。 在 CAP 危重患者中，无论致病病原体如何，ICU 住院第一周的 IgG 和 IgM 动态与病程的临床相关变化无关。