前降鈣素原可能作為全身性紅斑性狼瘡患者發燒時區分細菌性感染或疾病活動的生物指標

Procalcitonin may be a potential biomarker for distinguishing bacterial infection from disease activity in febrile patients with systemic lupus erythematosus

目的：研究於發燒之全身性紅斑性狼瘡患者前降鈣素原的實用性。方法：四十九位發燒之全身性紅斑性狼瘡患者，經由免疫螢光酵素分析法檢測其血清前降鈣素原，而由免疫比濁法測得C-反應性蛋白。於二十位正常人對照組血清中只測前降鈣素原。藉由接收器操作特徵（ROC）曲線來評估細菌感染與否的前降鈣素原和C-反應性蛋白的預測值。結果：參與的病患包含30位沒有臨床感染證據而偏向活動性全身性紅斑性狼瘡的患者，和19位有細菌性感染的病患。在發燒之全身性紅斑性狼瘡患者中，前降鈣素原在細菌性感染的組別比活動性全身性紅斑性狼瘡的組別顯著較高（中位數 7.11 ng/mL vs. 0.06 ng/mL, p<0.001），尤其是敗血症和敗血性休克的病患。於發燒之全身性紅斑性狼瘡患者前降鈣素原對於預測細菌性感染的最佳截點為0.74 ng/mL，而C-反應性蛋白為16.1 mg/dL。前降鈣素原在預測細菌性感染的敏感性和特異性都優於C-反應性蛋白。結論：我們的結果顯示血清前降鈣素原可作為早期區別發燒之全身性紅斑性狼瘡患者為細菌性感染或疾病活動的一個額外生物指標。

Objective: To investigate the utility of procalcitonin (PCT) in febrile patients with systemic lupus erythematosus (SLE). Methods: Serum PCT levels were measured with enzyme-linked fluorescent assay and C-reactive protein (CRP) with nephrometry in 49 febrile patients with SLE. Serum PCT levels were measured in 20 healthy people for normal control. The predictive values of PCT and CRP for detecting bacteria infection were evaluated by receiver operating characteristic (ROC) curves. Results: Enrolled patients included 30 patients without clinical evidence of infection favoring diagnosis of SLE disease flare, and 19 patients with bacterial infection. In febrile patients with SLE, PCT level was significantly higher in bacterial infection group compared with SLE disease flare group (median 7.11 ng/mL vs. 0.06 ng/mL, p<0.001), especially in patients with sepsis and septic shock. The most appropriate cutoff value of PCT was 0.74 ng/mL and CRP 16.1 mg/dL for predicting bacterial infection in febrile patients with SLE. The sensitivity (89.5%) and specificity (100%) of the PCT level for predicting bacterial infection were superior to those of CRP. Conclusion: Our results suggest that serum PCT level could be used as an additional biomarker for timely differential diagnosis between bacterial infection and disease flare in febrile patients with SLE.