Department of Pediatrics and Child Health, School of Medicine, Kurume University, 67, Asahimachi, Kurume 830-0011, Japan; Department of Pathology, School of Medicine, University of Occupational and Environmental Health, 1-1, Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan.
Department of Pathology and Oncology, School of Medicine, University of Occupational and Environmental Health, 1-1, Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan.
Ann Diagn Pathol. 2023 Oct;66:152154. doi: 10.1016/j.anndiagpath.2023.152154. Epub 2023 May 15.
Immunofluorescent deposition of immunoglobulin G (IgG) in the tubular basement membrane (TBM) has been evaluated in the diagnosis of various diseases; however, few studies have investigated the immunofluorescence of acute tubular injury (ATI). Herein, we attempted to clarify IgG expression in the proximal tubular epithelium and TBM in ATI due to various causes. Patients with ATI with nephrotic-range proteinuria, including focal segmental glomerulosclerosis (FSGS, n = 18) and minimal change nephrotic syndrome (MCNS, n = 8), ATI with ischemia (n = 6), and drug-induced ATI (n = 7), were enrolled. ATI was evaluated by light microscopy. CD15 and IgG double staining and IgG subclass staining were performed to evaluate immunoglobulin deposition in the proximal tubular epithelium and TBM. IgG deposition was identified in the proximal tubules only in the FSGS group. Furthermore, IgG deposition in the TBM was observed in the FSGS group showing severe ATI. IgG3 was predominantly deposited by the IgG subclass study. Our results indicate that IgG deposition in the proximal tubular epithelium and TBM suggests the leaking of IgG from the glomerular filtration barrier and its reabsorption by proximal tubules, which may predict disruption of the glomerular size barrier, including subclinical FSGS. FSGS with ATI should be included as a differential diagnosis when IgG deposition in TBM is observed.
免疫球蛋白 G（IgG）在管状基底膜（TBM）中的免疫荧光沉积已在各种疾病的诊断中得到评估；然而，很少有研究调查急性肾小管损伤（ATI）的免疫荧光。在此，我们试图阐明各种原因引起的 ATI 中近端肾小管上皮细胞和 TBM 中的 IgG 表达。纳入了伴有肾病范围蛋白尿的 ATI 患者，包括局灶节段性肾小球硬化症（FSGS，n=18）和微小病变肾病综合征（MCNS，n=8）、缺血性 ATI（n=6）和药物诱导的 ATI（n=7）。通过光镜评估 ATI。进行 CD15 和 IgG 双重染色和 IgG 亚类染色，以评估近端肾小管上皮细胞和 TBM 中的免疫球蛋白沉积。仅在 FSGS 组中观察到 IgG 在近端小管中的沉积。此外，在 FSGS 组中观察到 TBM 中 IgG 沉积，提示存在严重的 ATI。通过 IgG 亚类研究发现 IgG3 主要沉积。我们的结果表明，近端肾小管上皮细胞和 TBM 中的 IgG 沉积提示 IgG 从肾小球滤过屏障漏出并被近端肾小管重吸收，这可能预示着肾小球大小屏障的破坏，包括亚临床 FSGS。当观察到 TBM 中 IgG 沉积时，应将伴有 ATI 的 FSGS 纳入鉴别诊断。
