Bramlage Carsten P, Froelich Britta, Wallbach Manuel, Minguet Joan, Grupp Clemens, Deutsch Cornelia, Bramlage Peter, Müller Gerhard A, Koziolek Michael
Department of Nephrology and Rheumatology, Georg-August-University Goettingen, Robert-Koch Str. 40, 37075, Göttingen, Germany.
Institute for Pharmacology and Preventive Medicine, Cloppenburg, Germany.
Rheumatol Int. 2017 Apr;37(4):599-605. doi: 10.1007/s00296-017-3666-9. Epub 2017 Feb 18.
The risk of infection in patients with rheumatic diseases is elevated, but a clear marker to differentiate the cause of the systemic inflammation is missing. We assessed the ability urinary immunoglobulin free light chains (FLCs) to indicate the presence of infection in patients with rheumatic disease. We performed a retrospective analysis of patients with rheumatic disease attending the Georg-August University Hospital in Goettingen, Germany, from January 2011 to December 2013. Subjects were included if they had urine levels of κ and λ FLCs available. A reference group of patients without autoimmune disease, but with documented infection, was constructed. A total of 1500 patients had their urinary FLCs quantified during the study period. Of the 382 patients with rheumatic disease, 172 (45%) displayed no systemic inflammation, 162 (42%) had inflammation due to the underlying disease activity, and 48 (13%) had inflammation due to a confirmed infection. Urinary FLC concentrations were much higher in patients with rheumatic diseases and infection (κ 68.8 ± 81.8 mg/L, λ 31.4 ± 53.5 mg/L) compared to those with inflammation due to rheumatic disease activity (κ 22.7 ± 26.3 mg/L, λ 8.1 ± 9.1 mg/L, κ p < 0.001, λ p = 0.004). Urinary κ FLCs demonstrated good ability to predict infection, with a sensitivity of 63% and specificity of 84%. Urinary λ FLCs gave similar values, with a sensitivity of 65% and specificity of 81%. FLCs may be useful for distinguishing inflammation due to rheumatic disease activity from that due to the additional presence of infection. The ability to quantify these proteins in urine provides a simple alternative to the use of blood.
风湿性疾病患者的感染风险升高，但目前缺乏一个能够明确区分全身炎症病因的标志物。我们评估了尿免疫球蛋白游离轻链（FLC）用于指示风湿性疾病患者是否存在感染的能力。我们对2011年1月至2013年12月期间在德国哥廷根的格奥尔格 - 奥古斯特大学医院就诊的风湿性疾病患者进行了一项回顾性分析。纳入标准为有κ和λ FLCs尿液水平数据的患者。构建了一个无自身免疫性疾病但有记录感染的患者参考组。在研究期间，共有1500名患者的尿FLC进行了定量分析。在382例风湿性疾病患者中，172例（45%）无全身炎症，162例（42%）因基础疾病活动出现炎症，48例（13%）因确诊感染出现炎症。与因风湿性疾病活动导致炎症的患者相比（κ 22.7±26.3 mg/L，λ 8.1±9.1 mg/L，κ p<0.001，λ p = 0.004），风湿性疾病合并感染患者的尿FLC浓度要高得多（κ 68.8±81.8 mg/L，λ 31.4±53.5 mg/L）。尿κ FLCs预测感染的能力良好，敏感性为63%，特异性为84%。尿λ FLCs的结果类似，敏感性为65%，特异性为81%。FLC可能有助于区分风湿性疾病活动引起的炎症和因合并感染引起的炎症。在尿液中对这些蛋白质进行定量的能力为血液检测提供了一种简单的替代方法。
