Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA.
Biostatistics Core, Research Institute and General Clinical Research Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
Nephrol Dial Transplant. 2021 May 27;36(6):1016-1022. doi: 10.1093/ndt/gfaa039.
Some renal biopsies cannot distinguish minimal change disease (MCD) from primary focal segmental glomerulosclerosis (FSGS) because of inadequate sampling and/or a lack of sampled glomeruli with segmental sclerosis. As protein excretion in MCD has been described as being albumin-selective, we examined whether the ratio of immunoglobulin G (IgG)/albumin staining in protein reabsorption droplets (tPRD) might help distinguish MCD from FSGS.
Frozen tissue from 144 native renal biopsies from patients with nephrotic syndrome and a diagnosis of MCD or FSGS [73 MCD, 30 FSGS tip variant (FSGS-tip), 38 FSGS-not otherwise specified (FSGS-NOS), 3 FSGS collapsing] was retrospectively stained by direct immunofluorescence for IgG and albumin; none of these samples showed diagnostic lesions of FSGS. IgG and albumin staining of tPRD were graded on a scale of 0 to 3+ based on the distribution and intensity of staining.
Mean (standard deviation) IgG/albumin staining ratios were 0.186 ± 0.239 for MCD, 0.423 ± 0.334 for FSGS-tip (P = 0.0001 versus MCD) and 0.693 ± 0.297 for FSGS-NOS (P < 0.0001 versus MCD; P = 0.0001 versus FSGS-tip). Of 84 biopsies with a ratio ≤0.33, 63 (75%) showed MCD, whereas among 21 with a ratio of 1.0, all but one showed FSGS (15 FSGS-NOS).
In summary, IgG/albumin staining in tPRD was correlated with histologic diagnosis in renal biopsies with MCD and FSGS. A ratio of ≤0.33 was associated with MCD, whereas a ratio of 1.0 was most often seen with FSGS-NOS.
由于采样不足和/或缺乏节段性硬化的肾小球，一些肾活检无法将微小病变性疾病（MCD）与原发性局灶节段性肾小球硬化症（FSGS）区分开来。由于 MCD 中的蛋白排泄被描述为白蛋白选择性，我们研究了蛋白重吸收滴（tPRD）中 IgG/白蛋白染色的比值是否有助于区分 MCD 和 FSGS。
对 144 例肾病综合征患者的肾活检组织进行回顾性分析，这些患者的诊断为 MCD 或 FSGS[73 例 MCD、30 例 FSGS 尖端变异（FSGS-tip）、38 例 FSGS 未特指（FSGS-NOS）、3 例 FSGS 塌陷]，直接免疫荧光法检测 IgG 和白蛋白。这些标本均未显示 FSGS 的诊断病变。根据染色的分布和强度，tPRD 的 IgG 和白蛋白染色按 0 至 3+分级。
MCD 的 IgG/白蛋白染色比值平均（标准差）为 0.186±0.239，FSGS-tip 为 0.423±0.334（P=0.0001 与 MCD 相比），FSGS-NOS 为 0.693±0.297（P<0.0001 与 MCD 相比；P=0.0001 与 FSGS-tip 相比）。84 例比值≤0.33 的活检中，63 例（75%）为 MCD，而 21 例比值为 1.0 的活检中，除 1 例外均为 FSGS-NOS。
总之，tPRD 中的 IgG/白蛋白染色与 MCD 和 FSGS 肾活检的组织学诊断相关。比值≤0.33 与 MCD 相关，而比值为 1.0 时最常与 FSGS-NOS 相关。
