目的 分析肾损害伴单克隆免疫球蛋白（M蛋白）血症患者的临床表现和肾活检病理改变特征，旨在探讨两者之间的关系。 方法 收集2013年1月至2015年12月在北京协和医院住院的肾损害伴单克隆免疫球蛋白（M蛋白）血症患者64例的临床和病理资料。用血清蛋白电泳（SPE），和/或血、尿免疫固定电泳（IFE），和/或血清游离轻链（FLC）检查诊断M蛋白血症。按照临床和肾病理检查结果将患者分为3组：与肾脏相关的M蛋白血症（MGRS）组（36例）；意义未明的M蛋白血症（MGUS）组（17例）和血液肿瘤组（11例）。分析各组患者临床和病理改变特征。 结果 MGRS组患者肾脏病理改变类型包括：原发性系统性肾淀粉样变性28例（77.8%），轻链沉积病（LCDD）7例（19.4%），纤维样肾小球病1例（2.8%）。LCDD亚组患者肾功能低于肾淀粉样变性亚组[估算肾小球滤过率（eGFR）28 ml?min-1?(1.73 m2)-1比93 ml?min-1?(1.73 m2)-1，P＜0.01]，高血压发生率高于肾淀粉样变性亚组（100%比35.7%，P＜0.01）。MGUS组患者肾脏病理改变类型包括：膜性肾病10例（58.8%），局灶节段性肾小球硬化3例（17.6%），糖尿病肾病、紫癜性肾炎、抗肾小球基底膜（GBM）病合并膜性肾病、肾小球肥大病变各1例。血液肿瘤组患者肾脏病理改变类型包括：轻链管型肾病3例（27.3%），肾小管-间质损害2例（18.2%），肾淀粉样变性、LCDD、IgA肾病、系膜增生性肾小球肾炎、毛细血管内增生性肾小球肾炎及急性肾小管坏死各1例。MGRS组的SPE、血IFE和尿IFE阳性率分别为40.6%、52.8%和69.4%。MGUS组SPE、血IFE和尿IFE阳性率分别为68.8%、100.0%和37.5%。血液肿瘤组SPE、血IFE、尿IFE阳性率分别为54.5%、72.7%和81.8%。MGRS组血IFE阳性率低于MGUS组（P＜0.001）。上述3组血FLC比值异常率分别为83.3%、17.6%和90.9%， MGUS 组与MGRS组、MGUS组与血液肿瘤组的组间差异均有统计学意义（均P＜0.001）。 结论 肾损害合并M蛋白血症患者须结合临床资料及肾组织病理改变明确诊断和意义，二者不具有相关性。

Objectives To analyze the spectrum of renal diseases associated with monoclonal gammopathy and unrelated renal diseases. Methods Hospitalized patients in Peking Union Medical College Hospital who underwent renal biopsy between January, 2013 and December, 2015. They had monoclonal gammopathy on serum protein electrophoresis (SPE), serum immunofixation electrophoresis (IFE), urine IFE and/or serum free light chain (FLC). 64 patients met the inclusion criteria and were classified as monoclonal gammopathy of renal significance (MGRS) (n=36), monoclonal gammopathy of undetermined significance (MGUS) (n=17) and hematologic malignancy (n=11). Results Renal lesions in MGRS subgroup included light chain amyloidosis (n=28, 77.8%), light chain deposition disease (n=7, 19.4%), and fibrillary glomerulopathy (n=1, 2.8%). eGFR in light chain amyloidosis subgroup differed significantly, compared with light chain deposition disease [eGFR 93 ml?min-1?(1.73 m2)-1 vs 28 ml?min-1?(1.73 m2)-1, P＜0.01], as well as HTN incidence (35.7% vs 100.0%, P＜0.01). Renal diseases in MGUS subgroup included membranous nephropathy (n=10, 58.8%), focal segmental glomerulosclerosis (n=3, 17.6%), diabetic glomerulopathy (n=1, 5.9%), Henoch-Schonlein purpura nephritis (n=1, 5.9%), anti-glomerular basement membrane disease concurrent with membranous nephropathy (n=1, 5.9%) and glomerulomegaly (n=1, 5.9%). Various renal lesions related/unrelated to hematologic malignancy were seen in third subgroup, including light chain cast nephropathy (n=3, 27.3%), tubulo-interstitial lesions (n=2, 18.2%), light chain amyloidosis (n=1, 9.1%), light chain deposition disease(n=1, 9.1%), IgA nephropathy (n=1, 9.1%), mesangial proliferative glomerulonephritis (n=1, 9.1%), endocapillary proliferative glomerulonephritis (n=1, 9.1%) and acute tubular necrosis (n=1, 9.1%). Positive rates of SPE, serum IFE and urine IFE in MGRS subgroup were 40.6%, 52.8% and 69.4%, respectively. Positive rates of SPE, serum IFE and urine IFE in MGUS subgroup were 68.8%, 100.0% and 37.5%, respectively. Positive rates of SPE, serum IFE and urine IFE in hematologic malignancy subgroup were 54.5%, 72.7% and 81.8% respectively. MGRS and MGUS subgroups differed significantly in positive rate of serum IFE (P＜0.001). Abnormal rates of serum FLC ratio in above three subgroups were 83.3%, 17.6% and 90.9%, respectively, with that in MGUS group being significantly lower than the rates in other two groups (P＜0.001, respectively). Conclusions The significance of monoclonal gammopathy in patients with renal disease should be evaluated by other clinical data, as well as renal pathology.