Muhsin Saif A, Masia Ricard, Smith Rex N, Wallace Zachary S, Perugino Cory A, Stone John H, Niles John L, Cortazar Frank B
Division of Nephrology.
Department of Pathology.
Medicine (Baltimore). 2019 May;98(20):e15616. doi: 10.1097/MD.0000000000015616.
IgG4-related disease (IgG4-RD) is a multiorgan disease of unestablished prevalence that is characterized histopathologically by a dense lymphoplasmacytic infiltrate enriched with IgG4-expressing plasma cells and associated with storiform fibrosis. Tubulointerstitial nephritis (TIN) is the most common renal manifestation of IgG4-RD, but membranous nephropathy (MN) has also been described and often occurs in the context of concurrent TIN. Patients with IgG4-related MN have been characteristically negative for autoantibodies to the phospholipase A2 receptor (PLA2R).
A 45-year-old man presented with abdominal pain and lower extremity edema.
Histopathological evaluation of pancreas and liver biopsies established a diagnosis of IgG4-RD. Renal biopsy confirmed a diagnosis of PLA2R-associated MN without evidence of concurrent TIN.
The patient was treated with rituximab, a short course of low-dose, oral cyclophosphamide, and a rapid glucocorticoid taper.
The patient achieved remission of MN after 8 months of therapy and maintained remission of IgG4-RD.
PLA2R-associated MN may be a rare manifestation of IgG4-RD. Systematic evaluation of larger cohorts of IgG4-RD patients for the presence of PLA2R autoantibodies and the investigation of PLA2R-associated MN cohorts for evidence of IgG4-RD would facilitate the understanding of the nature of the relationship between these observations.
IgG4相关疾病（IgG4-RD）是一种患病率尚未明确的多器官疾病，其组织病理学特征为富含表达IgG4的浆细胞的致密淋巴浆细胞浸润，并伴有席纹状纤维化。肾小管间质性肾炎（TIN）是IgG4-RD最常见的肾脏表现，但膜性肾病（MN）也有报道，且常与并发的TIN同时出现。IgG4相关MN患者的抗磷脂酶A2受体（PLA2R）自身抗体通常为阴性。
一名45岁男性出现腹痛和下肢水肿。
胰腺和肝脏活检的组织病理学评估确诊为IgG4-RD。肾活检证实为PLA2R相关MN，无并发TIN的证据。
患者接受了利妥昔单抗、短疗程低剂量口服环磷酰胺以及快速减量的糖皮质激素治疗。
治疗8个月后患者的MN缓解，IgG4-RD保持缓解。
PLA2R相关MN可能是IgG4-RD的一种罕见表现。对更大规模的IgG4-RD患者队列进行PLA2R自身抗体存在情况的系统评估，以及对PLA2R相关MN队列进行IgG4-RD证据的调查，将有助于理解这些观察结果之间关系的本质。
