摘要目的：探讨血清降钙素原（PCT）在非获得性免疫缺陷综合征（AIDS）免疫受损危重患者感染诊断及预后评估中的应用价值。方法回顾性分析2011年1月至2014年12月收入中南大学湘雅医院重症医学科的非AIDS但免疫受损患者的感染相关临床资料，记录患者的人口学资料、原发疾病、入科时急性生理学与慢性健康状况评分系统Ⅱ（APACHEⅡ）评分，入ICU后28 d内生存结局，分别记录体温、白细胞计数（WBC）、PCT的初始值及峰值，并详细记录患者感染部位、感染性质（细菌感染、真菌感染、混合感染）及感染严重程度（脓毒症、严重脓毒症及脓毒性休克）。绘制受试者工作特征曲线（ROC）用于相关参数诊断或预测价值的评估。结果共入选98例免疫受损的危重患者，男性43例，女性55例；年龄44（28，52）岁；原发疾病包括：血液系统恶性肿瘤47例，自身免疫疾病45例，实体器官移植术后6例；APACHEⅡ评分为17（11，20）分；28 d内死亡53例（54.1%）。非感染全身炎症反应综合征（SIRS）患者27例；感染患者71例，其中细菌感染45例，真菌感染10例，混合感染16例；脓毒症7例，严重脓毒症32例，脓毒性休克32例。①感染患者PCT初始值和峰值、WBC初始值和峰值以及体温初始值与非感染SIRS患者比较差异均无统计学意义，而感染患者的体温峰值明显高于非感染SIRS患者〔℃：39.4（38.9，40.0）比38.8（37.8，39.2），Z＝-3.268，P＝0.001〕。亚组分析显示，在血液系统恶性肿瘤患者中或是在自身免疫疾病患者中，感染组较非感染SIRS组体温峰值更高〔℃：39.5（39.0，40.0）比39.0（38.4，39.4），Z＝-2.349，P＝0.019；39.0（38.4，39.5）比38.2（37.0，38.9），Z＝-2.221， P＝0.026〕。②非感染SIRS患者及细菌感染、真菌感染、混合感染患者PCT（μg/L）初始值分别为0.54（0.20，4.19）、2.78（0.50，9.54）、1.00（0.45，6.89）、0.22（0.07，1.86），峰值分别为4.19（1.95，13.42）、12.37（3.82，45.89）、1.82（0.49，17.86）、5.14（2.66，12.62）。不同性质感染患者间比较，细菌感染患者PCT初始值显著高于非感染SIRS患者（P＝0.026）及混合感染患者（P＝0.001），PCT峰值显著高于非感染SIRS患者（P＝0.009）及真菌感染患者（P＝0.016）。ROC曲线显示，高水平的PCT初始值及峰值对细菌感染具有显著的诊断价值〔初始值ROC曲线下面积（AUC）＝0.681±0.054，P＝0.001；峰值AUC＝0.690±0.054，P＝0.002〕；在血液系统恶性肿瘤患者亚组中，PCT初始值及峰值对细菌感染的诊断价值更高（初始值AUC＝0.687±0.080，P＝0.008；峰值AUC＝0.697±0.079，P＝0.021）。③脓毒症、严重脓毒症、脓毒性休克患者PCT峰值（μg/L）分别为4.05（0.53，31.22）、5.78（2.14，16.68）、11.64（2.94，58.14），组间比较差异无统计学意义（P＞0.05）。ROC曲线显示，高水平的PCT峰值在整体人群中对脓毒性休克具有较高的诊断价值（AUC＝0.646±0.060，P＝0.019），其诊断价值在自身免疫疾病亚组中更高（AUC＝0.689±0.081，P＝0.035）。④APACHEⅡ＞18分组PCT峰值明显高于APACHEⅡ≤18分组〔38例比60例，PCT峰值（μg/L）：11.64（3.36，39.39）比4.42（1.32，14.70），P＝0.016〕；提示PCT峰值与患者病情严重程度有一定相关性。⑤死亡组患者PCT峰值明显高于存活组〔μg/L：9.07（3.05，33.09）比4.19（1.26，14.61），P＝0.043〕；ROC曲线显示，PCT峰值对免疫受损患者预后具有较高的预测价值（AUC＝0.619±0.057，P＝0.043）。结论在免疫受损危重患者尤其是血液系统恶性肿瘤患者中，PCT有助于细菌感染的诊断，同时对疾病严重程度的判断及预后评估具有良好的应用价值。

abstractsObjective To evaluate the diagnostic and prognostic value of the serum procalcitonin ( PCT ) level in the non-acquired immune deficiency syndrome ( AIDS ) immunocompromised critically ill patients suspected to have infection. Methods A retrospective study was conducted in the non-AIDS immunocompromised patients who were admitted to Department of Critical Care Medicine of Xiangya Hospital, Central South University during January 2011 to December 2014. Demographic characteristics, underlying disease, acute physiology and chronic health evaluationⅡ( APACHEⅡ) score at admission, and clinical records including baseline and peak levels of temperature, white blood count ( WBC ), PCT, and survival rate within 28 days, infection focus, infectious agents ( bacterial, fungi or mixed infection ), and the severity of infection ( sepsis, severe sepsis, or septic shock ) were recorded. Receiver operating characteristic ( ROC ) curve was plotted, and the diagnostic and protective value of above parameters was evaluated. Results A total of 98 patients ( 43 male and 55 female ) were enrolled in the study with a median age of 44 ( 28, 52 ) years old and a median APACHEⅡscore of 17 ( 11, 20 );47 with malignant hematological tumor, 45 with autoimmune diseases, and 6 post solid organ transplantation. Among them 53 patients ( 54.1%) died within 28 days. Twenty-seven patients were diagnosed as systemic inflammatory response syndrome ( SIRS ) without infection. Among 71 patients with infection, 45 were diagnosed as bacterial infection, 10 with fungal infection, and 16 with mixed infection. Sepsis was diagnosed in 7 patients, severe sepsis in 32 patients , and septic shock in 32 patients .①There was no statistical significance in the baseline and peak levels of PCT and WBC, or baseline level of temperature between the groups of SIRS patients without infection and infected patients. The peak level of temperature was significantly higher in the patients with infection as compared with that of the SIRS without infection patients [℃:39.4 ( 38.9, 40.0 ) vs. 38.8 ( 37.8, 39.2 ), Z=-3.268, P=0.001 ]. It was showed by subgroup analysis that in patients with hematological malignant disease or autoimmune diseases, higher level of body temperature was found in infection group compared with non-infection SIRS group [℃:39.5 ( 39.0, 40.0 ) vs. 39.0 ( 38.4, 39.4 ), Z=-2.349, P=0.019;39.0 ( 38.4, 39.5 ) vs. 38.2 ( 37.0, 38.9 ), Z=-2.221, P=0.026 ].②The baseline level of PCT (μg/L ) were 0.54 ( 0.20, 4.19 ), 2.78 ( 0.50, 9.54 ), 1.00 ( 0.45, 6.89 ), and 0.22 ( 0.07, 1.86 ) in non-infection SIRS patients or the patients with bacterial, fungal, and mixed infection, respectively. The peak level of PCT (μg/L ) were 4.19 ( 1.95, 13.42 ), 12.37 ( 3.82, 45.89 ), 1.82 ( 0.49, 17.86 ), and 5.14 ( 2.66, 12.62 ), respectively, in each subgroup. When the comparison was conducted among the patients with different infectious agent, the baseline level of PCT in patients with bacterial infection was significantly higher than that in SIRS patients without infection ( P=0.026 ) and mixed infection patients ( P=0.001 ), and the peak level of PCT was significantly higher than that in the SIRS patients without infection ( P=0.009 ) and the patients with fungal infection ( P=0.016 ). ROC curve showed that the higher value was found in the baseline and peak levels of PCT for diagnosis of septic shock in all patients [ area under ROC curve ( AUC ) of baseline level = 0.681±0.054, P = 0.001; AUC of peak level = 0.690±0.054, P=0.002 ], and the same value was also found in the baseline and peak levels of PCT for diagnosis of bacterial infection in the patients with malignant hematological tumor ( AUC of baseline level=0.687±0.080, P=0.008;AUC of peak level=0.697±0.079, P=0.021 ).③The peak level of PCT (μg/L ) were 4.05 ( 0.53, 31.22 ), 5.78 ( 2.14, 16.68 ), and 11.64 ( 2.94, 58.14 ) in subgroup of patients with sepsis, severe sepsis and septic shock, respectively, and they showed no statistical significance among subgroups ( P>0.05 ). A high serum level of peak PCT strongly indicated the presence of septic shock ( AUC=0.646±0.060, P=0.019 ), especially in the subgroup of patients with systemic autoimmune disease ( AUC=0.689±0.081, P=0.035 ).④The peak level of PCT (μg/L ) in the APACHEⅡ>18 group ( 38 cases ) was significantly higher than that of APACHEⅡ≤18 group [ 60 cases, PCT (μg/L ):11.64 ( 3.36, 39.39 ) vs. 4.42 ( 1.32, 14.70 ), P=0.016 ];there was a certain correlation between the peak level of PCT and the severity of the disease.⑤The peak level of PCT in death group was significantly higher than that of the survival group [μg/L:9.07 ( 3.05, 33.09 ) vs. 4.19 ( 1.26, 14.61 ), P=0.043 ]. ROC curve showed that the peak level of PCT might be valuable in predicting the prognosis in immunocompromised patients ( AUC=0.619±0.057, P=0.043 ). Conclusions The serum level of PCT is found to be a reliable marker for the diagnosis of bacterial infection in immunocompromised critical patients, especially in those with hematologic malignancy. Additionally, PCT provides a useful tool for evaluating the severity of infection and the prognosis of critically ill patients.