PMC6196619_01
First biopsy 2009 (a-c) and second biopsy 2017 (d-f). The first kidney biopsy in 2009 revealed (a) a typical MN with thickening of glomerular basement membranes in the Masson trichrome stain, (b) diffuse granular IgG deposits in subepithelial localization, and (c) PLA2R-positivity. The current biopsy in 2017 disclosed an active crescentic GN (d; periodic acid Schiff (PAS) staining), with (e) finely granular and (f) co-existing linear IgG and C1q deposits along the GBM on immunohistology.
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We report a 55-year-old man with biopsy-confirmed MN (Figure 1(a)-(c)) 8 years ago and a preexisting chronic renal disease (CRD) KDIGO 2 with a baseline serum creatinine of 1.3 mg/dL and a protein/creatinine ratio of approximately 7 g/molCr. The biopsy revealed predominantly circumferential cellular crescents with occasional segmental necrosis (Figure 1(d)). The immunofluorescent analysis showed granular, subepithelial IgG-positive immune complex deposits, in addition to areas with linear IgG and C1q positivity, indicating complement activation via the classical pathway through anti-GBM antibodies (Figure 1(e) and (f)).
Therapy of MN followed by anti-GBM disease and progress of serum creatinine (a) and anti-GBM antibody titer (b). Initial treatment with 125 mg glucocorticoids (GC) for 3 days, followed by oral GC 60 mg per day. In addition, cyclophosphamide (CYC) i.v. once per week in a dose of 250 mg for three times was administered. Immunoadsorption (IA) was conducted 18 times. After 2 months the GC dose was reduced to 40 mg and the application of another three times cyclophosphamide 750 mg i.v. monthly for maintenance therapy was scheduled. (a) Kidney function improved after 1 month with serum creatinine declining from 4.2 to 1.6 mg/dL and (b) anti-GBM titers decreasing from 1:2560 to 1:80 during therapy.
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In addition, immunoadsorption was conducted 18 times (Figure 2). The renal function improved and the serum creatinine concentration recovered to 2.5 mg/dL after 2 weeks (Figure 2(a)). The anti-GBM titer declined from initial 1:2560 to 1:1250 after 2 weeks (Figure 2(b)). The prednisolone dose was reduced to 40 mg and three additional applications of CYC 750 mg i.v. monthly for maintenance therapy were scheduled (Figure 2).