Khosroshahi Arezou, Ayalon Rivka, Beck Laurence H, Salant David J, Bloch Donald B, Stone John H
Department of Medicine, Harvard Medical School and Rheumatology Unit, Massachusetts General Hospital, Boston, MA 02114, USA.
Int J Rheumatol. 2012;2012:139409. doi: 10.1155/2012/139409. Epub 2012 May 10.
Patients with IgG4-related disease (IgG4-RD) share histopathological characteristics that are similar across affected organs. The finding of infiltration with IgG4+ plasma cells in the proper clinical and histopathological contexts connects a large number of clinical entities that were viewed previously as separate conditions. The renal involvement in IgG4-RD is usually characterized by tubulointerstitial nephritis, but membranous nephropathy has also been reported to be one of the renal complications of IgG4-RD. The recent discovery that a high proportion of patients with idiopathic membranous nephropathy (IMN) have IgG4 autoantibodies to the M-type phospholipase A2 receptor (PLA2R) in the circulation and glomerular immune deposits, together with the profound IgG4 hypergammaglobulinemia and occasional reports of membranous nephropathy in IgG4-RD, raised the question of a common antigen. To assess the presence of anti-PLA2R antibody in patients with IgG4-RD, we screened sera from 28 IgG4-RD patients by immunoblot. None of the patients in this cohort had detectable circulating anti-PLA2R antibodies. This study suggests that despite some clinical and serological overlaps between IgG4-RD and IMN,anti-PLA2R antibodies do not play a role in the pathogenesis of IgG4-RD. Additional studies of IgG4-RD with evidence of membranous nephropathy are important to exclude any definite relationship.
IgG4相关疾病（IgG4-RD）患者受累器官具有相似的组织病理学特征。在适当的临床和组织病理学背景下发现IgG4+浆细胞浸润，将大量以前被视为不同疾病的临床实体联系了起来。IgG4-RD的肾脏受累通常表现为肾小管间质性肾炎，但膜性肾病也被报道为IgG4-RD的肾脏并发症之一。最近发现，高比例的特发性膜性肾病（IMN）患者循环中存在针对M型磷脂酶A2受体（PLA2R）的IgG4自身抗体以及肾小球免疫沉积物，再加上IgG4-RD中严重的IgG4高球蛋白血症以及偶尔关于膜性肾病的报道，引发了关于共同抗原的问题。为了评估IgG4-RD患者中抗PLA2R抗体的存在情况，我们通过免疫印迹法筛查了28例IgG4-RD患者的血清。该队列中的患者均未检测到循环抗PLA2R抗体。这项研究表明，尽管IgG4-RD和IMN之间存在一些临床和血清学重叠，但抗PLA2R抗体在IgG4-RD的发病机制中不起作用。对有膜性肾病证据的IgG4-RD进行更多研究对于排除任何明确关系很重要。
