白细胞趋化因子2型淀粉样变性肾病15例临床病理学分析

Renal leukocyte chemokine type 2 amyloidosis:a clinicopathological analysis of fifteen cases

目的探讨白细胞趋化因子2型淀粉样变性肾病(ALECT2)的临床病理学特点。方法收集1993年1月至2023年12月山西医科大学第二医院肾脏病理中心经肾活检病理诊断为ALECT2的15例病例,其中8例为单纯ALECT2,7例合并其他肾病,总结其形态学特征,并结合免疫组织化学和质谱分析结果,复习相关文献。结果确诊为ALECT2患者共15例,占肾活检证实淀粉样变性病例的12.93%(15/116),男性5例,女性10例,中位年龄61岁,患者症状以蛋白尿为主要特点,7例表现为肾病综合征,3例患者肾功能不全,7例患者有镜下血尿。8例单纯ALECT2,光镜主要表现为系膜增生性改变,刚果红染色显示淀粉样蛋白沉积物主要分布于肾皮质间质、肾小球系膜区和血管壁。7例合并其他肾脏病,包括:4例膜性肾病,2例IgA肾病,1例亚急性肾小管间质肾病;与单纯ALECT2相比,合并其他肾脏病患者尿蛋白定量水平更高(3.48/24 h比4.58/24 h)。15例患者肾组织淀粉样蛋白免疫组织化学染色检测均显示LECT2阳性。9例患者经石蜡切片质谱检测到LECT2肽段。随访12.5个月2例患者肾功能恶化,其他患者在平均随访期内肾功能保持稳定。结论ALECT2是本中心淀粉样变性肾病的第二大常见亚型,部分患者合并其他肾脏疾病,以膜性肾病最多见;最常沉积于肾皮质间质及肾小球系膜区,ALECT2的免疫组织化学染色检测存在非特异表达,质谱检测是明确分型的金标准。

Objective To investigate the clinicopathological features of renal leukocyte chemokine type 2 amyloidosis(ALECT2).Methods The prevalence,clinical characteristics,renal histopathological features,and renal outcome of 15 patients with ALECT2 by kidney biopsy were collected in the Department of Kidney Pathology,Shanxi Medical University Second Hospital,Taiyuan,China from January 1993 to December 2023.Immunohistochemistry and mass spectrometry for amyloid proteins were carried out.Results Fifteen patients with ALECT2 were included in the study,representing 12.93%(15/116)of the renal biopsy-proven amyloidosis cases.There were 5 males and 10 females.The median age at diagnosis was 61 years.All patients had various degrees of proteinuria;7 patients had nephrotic syndrome;3 patients had renal insufficiency;7 patients had microscopic hematuria.Renal biopsy showed that strongly orangophilic amyloid proteins distributed mainly in the renal cortical interstitium,vascular walls,the glomerular mesangium and/or glomerular basement membrane.Eight cases were diagnosed with ALECT2 alone and 7 cases combined with other renal diseases,including 4 cases with membranous nephropathy,2 cases with IgA nephropathy,and 1 case with subacute tubular interstitial nephropathy.ALECT2 patients with concurrent renal disease showed a higher proteinuria level than those without(3.48 g/24 h versus 4.58 g/24 h).All patients were corroborated by immunohistochemistry to exhibit the specific location of LECT2 in the amyloid fibrils.Mass spectrometry analysis revealed LECT2 polypeptide in 9 patients.Except two patients with worsening renal function,the others showed stable renal function during the mean follow-up period of 12.5 months.Conclusions ALECT2 is the second common type of renal amyloidosis in our center.The majority of ALECT2 patients show concurrent renal diseases,with a high rate of membranous nephropathy.Amyloid deposits distribute mainly in the cortical interstitium of the kidney,the glomerular mesangium and vascular walls.Mass spectrometry is the most sensitive and specific method for detecting LECT2 amyloidosis.