#6227 SPONTANEOUS REMISSION OF MEMBRANOUS VARIANT OF PGNMID WITH MONOCLONAL IGG2κ

Abstract Background and Aims The clinical significance of the morphological patterns glomerular injury each IgG subclass in proliferative glomerulonephritis (GN) with monoclonal immunoglobulin deposits (PGNMID) is not well understood. Literature suggests that PGNMID certain histological features such as membranous or mesangio-proliferative non-IgG3 staining may be associated a more favourable renal prognosis. We present patient variant IgG2κ who had spontaneous remission without recurrence over 2-year follow-up. Method Not applicable Results A 62-year-old Malay gentleman presented new onset nephrotic range proteinuria, on background type 2 diabetes mellitus diabetic duration 5 years, hypertension hyperlipidemia. He was mildly hypertensive (blood pressure 148/87) non-edematous at presentation. Investigations revealed preserved kidney function [serum creatinine (sCr) 66µmol/L], bland urinalysis, 24-hour urinary total protein (UTP) 3.74g/day. Serum albumin (sAlb) 35g/L. complements were low. Autoimmune markers inclusive anti-double stranded DNA antibodies, anti-neutrophil cytoplasmic anti-phospholipase A2 receptor (PLA2R) antibodies negative. Viral serologies also unremarkable. No band detected serum electrophoresis, while immunofixation performed. Kidneys normal sized. Renal biopsy performed demonstrated 28 glomeruli, which only 1 globally sclerosed. Glomeruli capillary walls diffusely thickened by vacuolations. Capillary loops mostly single contoured although occasional focal double contouring seen. Masson trichome stain fuchsinophilic subepithelial immune periodic acid methenamine silver showed argyrophilic basement membrane spikes. Variable mesangial expansion hypercellularity observed, mesangiolysis. Focal leukocyte margination present, but significant endocapillary proliferation There no Kimmelstiel-Wilson lesions. Tubular atrophy interstitial fibrosis overall mild (10% parenchymal area) there tubulointerstitial infiltrates. Immunofluoresence granular (1-2+), C3 (2-3+) along walls, presence kappa light chain restriction (κ 1-2+; λ negative glomeruli). Immunostaining for PLA2R analysis view isolated deposition IgG2. Electron microscopy available. Overall findings most consistent IgG2κ. Age-appropriate symptom-directed malignancy screening did reveal abnormalities. Given minimally symptomatic, trial conservative therapy initiated optimized non-immunosuppressive anti-proteinuric using renin-angiotensin-aldosterone sodium-glucose co-transporter-2 inhibitors. Gradual observed years follow-up (sCr 77µmol/L; sAlb 40g/L; UTP 0.22g/day). Conclusion Our case adds to literature better outcomes. Despite lack changes, it possible variants share similar underlying disease mechanisms other variants. Large international registries allow correlation subclasses outcomes are required confirm our observation.