特发性炎症性肌病患者血清铁蛋白的检测及临床意义

Detection of serum ferritin in patients with idiopathic inflammatory myopathies and its clinical significance Diao

目的探讨皮肌炎、临床无肌病性皮肌炎和多发性肌炎等特发性炎症性肌病患者的血清铁蛋白水平与疾病活动性特别是肺间质病变之间的关系。方法分析120例特发性炎症性肌病患者铁蛋白与炎症指标、自身抗体、血清肌酶以及肺问质病变严重程度的相关性。结果①36例患者铁蛋白升高，84例铁蛋白正常。铁蛋白升高组的C反应蛋白（14．1±6．5）mg／L、血细胞沉降率（34．8±8．2）mm／1h、天冬氨酸转氨酶（111．8±44．6）U／L和乳酸脱氢酶（388．6±81．5）U／L分别高于铁蛋白正常组的C反应蛋白（3．6±1．7）mg／L、血细胞沉降率（15．4±2．7）mm／1h、天冬氨酸转氨酶（46．0±9．0）U／L、乳酸脱氢酶（260．7±29．1）U／L；均P〈0．01。但两组之间肌酸激酶水平差异无统计学意义；②合并急进性／亚急性肺间质病变和慢性肺间质病变患者的铁蛋白水平分别为（650．5±268．5）和（489．94-157．3）ng]ml，两者均显著高于不伴有肺间质病变（155．7±90．8）ng／ml以及仅有影像学改变而无临床症状的肺间质病变患者（193．3±62．1）ng／ml，均P〈0．01；③铁蛋白升高组慢性肺间质病变（52．8％）和急进性／亚急性肺间质病变（22．2％）的发生率高于正常组（慢性肺间质病变为25．9％，急进性／亚急性肺间质病变为3．5％），均P〈0．01；④铁蛋白升高组肺高分辨率CT的磨玻璃样影（67．6％）和蜂窝状改变（14．7％）的发生率分别高于正常组（磨玻璃样影43．4％，蜂窝状2．6％，均P〈0．05）。结论在特发性炎症性肌病中，铁蛋白与血细胞沉降率、C反应蛋白、天冬氨酸转氨酶、乳酸脱氢酶、肺间质病变的发生以及肺高分辨率CT的影像学之间高度相关，提示其在判断疾病活动性特别是肺间质病变病情严重程度中有重要的临床意义。

Objective To determine serum ferritin levels in patients with idiopathic inflammatory myopathies （IIM）, including dermatomyositis （DM）, clinical amyopathic dermatomyositis （CADM） and polymyositis （PM）, and to evaluate their association with disease activity, especially with interstitial lung disease （ILD）. Methods Clinical data and laboratory results were collected from 120 patients with IIM. A double-site enzyme immunoassay was conducted to measure serum ferritin levels in 120 patients with IIM and 63 healthy human controls. Statistical analysis was carried out to assess the relationship of serum ferritin levels with inflammatory biomarkers, autoantibodies, serum muscle enzymes, and severity of ILD in patients with IIM. Results Serum ferritin levels were elevated in 36 out of the 120 patients, but normal in the other 84 patients. Compared with patients with normal serum ferritin levels, those with elevated serum ferritin levels showed increased levels of C-reactive protein （14.1 ± 6.5 vs. 3.6 ± 1.7 mg/L, P 〈 0.01 ）, aspartate aminotransferase （ 111.8± 44.6 vs. 46.0 ±9.0 U/L, P 〈 0.01 ）, lactate dehydrogenase （388.6 ± 81.5 vs. 260.7± 29.1 U/L, P 〈 0.01 ）, as well as erythrocyte sedimentation rate （34.8± 8.2 vs. 15.4± 2.7 mm/h, P〈 0.01 ）. However, no significant difference was observed in the level of creatine kinase between patients with elevated and normal serum ferritin levels. Moreover, serum ferritin levels were significantly higher in both IIM patients complicated with aeute/subacute interstitial pneumonia （A/SIP, 650.5 ± 268.5 ng/ml） and those with chronic interstitial pneumonia （CIP, 489.9 ± 157.3 ng/ml） than in those without ILD （ 155.7 ± 90.8 ng/ml） and those with imageological changes but no clinical symptoms of ILD （ 193.3 ± 62.1 ng/ml） （all P〈 0.01 ）. Moreover, compared with patients with normal serum ferritin levels, those with elevated serum ferritin levels showed a significant increase in the incidence of CIP （52.8% vs. 25.9%, P 〈 0.01 ）, A/SIP （22.2% vs. 3.5%, P 〈 0.01 ） , as well as appearance of ground-glass opacity （67.6% vs. 43.4%, P 〈 0.05） and honeycomb-like changes （14.7% vs. 2.6%, P 〈 0.05） on high-resolution CT scans. Conclusion Serum ferritin levels are highly correlated with erythrocyte sedimentation rate, C-reactive protein, aspartate aminotransferase, lactate dehydrogenase, ILD and high- resolution CT findings, and may be of great clinical significance for the evaluation of disease activity, especially the severity of ILD.