Abstract

Renal involvement in systemic lupus erythematosus (SLE) is a key predictor of morbidity and mortality. Immunofluorescence (IF) staining of glomeruli is typically positive for IgG, IgA, IgM, C3, and C1q - the "full house" (FH) pattern. However, a subset of patients with membranous lupus nephritis (MLN) have a "non-full house" (NFH) IF pattern more typical of idiopathic membranous nephropathy (IMN).From a multi-institutional cohort of 113 MLN cases, we identified 29 NFH MLN biopsies. NFH MLN was defined by IF criteria: =1+ glomerular capillary loop IgG staining; and <1+ IgA, IgM, and C1q. FH MLN was defined as =1+ staining for all five antibodies. "Intermediate" (Int) cases did not meet criteria for FH or NFH. We compared the pathological and clinical characteristics and outcomes among patients with FH, NFH, and Int IF patterns on kidney biopsy.NFH MLN represents a subset of MLN biopsies (13.4%). Compared to FH MLN patients, NFH MLN patients were older at SLE diagnosis (29 vs. 22.5 years), had a longer time to initial kidney biopsy (8 vs. 3.16 years), and had fewer SLE manifestations (2.5 vs. 3.36 involved systems). NFH MLN biopsies showed lower C3 IF intensity (1.16+ vs. 2.38+). Int biopsies had findings intermediate between those of NFH and FH groups.NFH IF pattern defines a small subset of MLN biopsies and appears to be associated with milder clinical manifestations and slower disease progression. Less robust C3 deposition in NFH MLN may suggest a pathophysiology distinct from that of FH MLN.

View details for DOI 10.34067/KID.0000000000000161

View details for PubMedID 37257088