尿足细胞监测活动性狼疮肾炎的意义

目的探讨尿足细胞作为无创监测肾活动性损伤的实用性。方法选31例肾活检病理确诊为狼疮肾炎的患者。用抗足细胞表面标志蛋白podoealyxin抗体免疫化学法检测尿沉渣足细胞,并与肾活检病理、血尿、蛋白尿进行对比分析;用抗podoealyxin和抗增殖细胞核抗原的抗体双重免疫组化法检测各型狼疮肾组织和尿中增殖的足细胞。全身活动指标积分用系统性红斑狼疮疾病活动指数评估。结果31例狼疮肾炎病理显示Ⅲ型占25．8％,Ⅳ型占64．5％,Ⅴ型占9．7％。31例患者尿中足细胞阳性者28例,尿足细胞阳性总检出率为90％。除Ⅴ型狼疮肾炎患者无足细胞尿和血尿外,其余病例均有不同程度的足细胞尿和血尿,且尿足细胞数与血尿程度、肾小球病理活动指数呈正相关（r=0．639,P=0．000;r=0．487,P=0．014）。31例患者均有蛋白尿,其量与肾小球病理活动指数不相关。免疫组化双重染色显示,Ⅳ型狼疮肾炎肾小球和尿沉渣均有增殖的足细胞。8例患者在免疫炎症抑制治疗过程中上述各项指标呈平行下降之势,其中6例尿足细胞消失。结论尿足细胞是监测狼疮肾炎活动和评估药物治疗反应的无创指标。

The significance of urinary podocytes in patients with active lupus nephritis

OBJECTIVE: To assess the significance of urinary podocyte and its possible implication as a marker of activity of lupus nephritis. METHODS: The presence of podocytes in urinary sediment was detected with immunochemical staining using anti-podocalyxin antibody. The correlation of the number of urinary podocytes with activity index of renal pathological lesions, hematuria, and proteinuria was analyzed respectively. The proliferating podocytes in renal biopsy tissue and urine from patients with class IV lupus nephritis were examined with double immunohistochemical staining. RESULTS: Thirty-one patients with lupus nephritis undergoing renal biopsy were enrolled into the study. Renal pathological findings of the patients could be classified into WHO class III (25.8%), class IV (64.5%) and class V (9.7%). 90% of the patients had positive urinary podocytes. The number of urinary podocytes was strongly and positively correlated with the severity of hematuria (r=0.639, P=0.000) and glomerular pathological activity index (r=0.487, P=0.014) in patients of class III and class IV. The amount of proteinuria was not correlated with pathological activity index, even though all the patients had proteinuria. Furthermore, the number of urinary podocytes, the severity of hematuria and the amount of proteinuria were all decreased after treatment with methyl prednisone, cyclophosphamide or mycophenolate mofetil. Interestingly, the urinary podocytes could disappear even before the remission of hematuria and proteinuria after treatment. Proliferative podocytes were observed both in biopsied kidney tissue and urinary sediments in patients of class IV. CONCLUSION: The presence and the number of urinary podocytes can be used as a valuable marker to grade the activity of lupus nephritis and to evaluate the efficacy of steroid therapy.