IgG4-related disease complicated by PLA2R-associated membranous nephropathy: A case report

Abstract

IgG4-related tubulointerstitial nephritis (IgG4-related TIN) is the prevalent clinical manifestation of IgG4-related diseases (IgG4-RD). However, there are limited cases of IgG4-RD occurring with membranous nephropathy (MN) in the absence of phospholipase A2 receptor (PLA2R). There have been no indications of treatment using Tripterygium wilfordii. This study reported a rare case of IgG4-RD with PLA2R-associated MN without any of the distinct IgG4-related TIN. The patient was treated effectively with T. wilfordii. A 71-year-old patient was admitted to the medical facility after presenting with a 1 month history of edema and 8 months of albuminuria. The renal biopsy tissue examination confirmed the presence of MN (phase II) in the absence of pathological manifestations of IgG4-related TIN. Immunohistochemistry identified PLA2R++ (granular capillaries). The serum PLA2R antibody titer was 1:180 (1:20). The patient met the diagnosis with IgG4-RD. Over 8 years of follow-up, the patient was effectively treated with low-dose hormones and T. wilfordii, without any adverse effects. This MN is considered a unique form of IgG4-RD, regardless of whether PLA2R antibodies are present or not. Research suggests that T. wilfordii could be a promising option for elderly people with IgG4-related MN, as it has been found to have fewer adverse effects.

Keywords: IgG4-related disease; IgG4-related kidney disease; Tripterygium wilfordii; membranous nephropathy; phospholipase A2 receptor.

Figure 1

Histopathological examination of the kidney reveals MN via periodic acid Schiff-methenamine staining (400×).

Figure 2

Immunohistochemical analysis of IgG4+ plasma cells < 10/high power field (Hp) (400×).

Figure 3

Immunohistochemical analysis of the kidney reveals PLA2R++ (400×).

Figure 4

Disease progression is monitored by quantifying serum proteinuria, serum albumin, serum IgG4 level, serum IgG level, and serum C3 level. T. wilfordii were administered after the initiation of prednisolone therapy. W = week.