Department of Rheumatology, Niigata Rheumatic Center, Shibata City, Niigata, Japan.
J Rheumatol. 2012 Aug;39(8):1517-23. doi: 10.3899/jrheum.111601. Epub 2012 Jul 1.
Rheumatoid arthritis (RA) is a chronic inflammatory disease accompanied by many complications, and serious infections are associated with many of the advanced therapeutics used to treat it. We assessed serum procalcitonin (PCT) levels to distinguish bacterial infection from other complications in patients with RA.
One hundred eighteen patients experiencing an RA flare, noninfectious complication of RA or its treatment, nonbacterial infection, or bacterial infection were studied. Serum PCT concentrations were determined with a chemiluminescent enzyme immunoassay.
All patients experiencing an RA flare showed negative PCT levels (≤ 0.1 ng/ml; n = 18). The PCT level was higher in the bacterial infection group (25.8% had levels ≥ 0.5 ng/ml) than in the other 3 groups (0.0-4.3% had levels ≥ 0.5 ng/ml) and the difference was significant among groups (p = 0.003). Conversely, no statistically significant difference was observed among the groups with C-reactive protein (CRP) concentration ≥ 0.3 mg/dl (p = 0.513), white blood cell (WBC) count > 8500/mm(3) (p = 0.053), or erythrocyte sedimentation rate (ESR) > 15 mm/h (p = 0.328). The OR of high PCT level (≥ 0.5 ng/ml) for detection of bacterial infection was 19.13 (95% CI 2.44-149.78, p = 0.005). Specificity and positive likelihood ratio of PCT ≥ 0.5 ng/ml were highest (98.2% and 14.33, respectively) for detection of bacterial infection, although the sensitivity was low (25.8%).
Serum PCT level is a more specific marker for detection of bacterial infection than either CRP, ESR, or WBC count in patients with RA. High PCT levels (≥ 0.5 ng/ml) strongly suggest bacterial infection. However, PCT < 0.5 ng/ml, even if < 0.2 ng/ml, does not rule out bacterial infection and physicians should treat appropriately.
类风湿关节炎（RA）是一种伴有多种并发症的慢性炎症性疾病，严重感染与许多用于治疗该病的先进疗法有关。我们评估血清降钙素原（PCT）水平，以区分 RA 患者的细菌感染与其他并发症。
研究了 118 例 RA 发作、RA 或其治疗的非感染性并发症、非细菌性感染或细菌感染的患者。采用化学发光酶免疫分析法测定血清 PCT 浓度。
所有 RA 发作的患者均表现出阴性 PCT 水平（≤0.1ng/ml；n=18）。细菌感染组的 PCT 水平较高（25.8%的患者水平≥0.5ng/ml），高于其他 3 组（0.0-4.3%的患者水平≥0.5ng/ml），组间差异有统计学意义（p=0.003）。相反，C 反应蛋白（CRP）浓度≥0.3mg/dl（p=0.513）、白细胞（WBC）计数>8500/mm³（p=0.053）或红细胞沉降率（ESR）>15mm/h（p=0.328）的患者之间无统计学差异。高 PCT 水平（≥0.5ng/ml）对细菌感染检测的 OR 为 19.13（95%CI 2.44-149.78，p=0.005）。PCT≥0.5ng/ml 对细菌感染检测的特异性和阳性似然比最高（分别为 98.2%和 14.33），尽管敏感性较低（25.8%）。
与 CRP、ESR 或 WBC 计数相比，血清 PCT 水平是 RA 患者细菌感染检测更特异的标志物。高 PCT 水平（≥0.5ng/ml）强烈提示细菌感染。然而，即使 PCT<0.5ng/ml，甚至<0.2ng/ml，也不能排除细菌感染，医生应进行适当治疗。
