Idiopathic Nonlupus Full-House Nephropathy: Clinicopathological Presentation and Comparison with Lupus Full-House Nephropathy.

Abstract

Full-house pattern on immunofluorescence (IF) on kidney biopsy in a patient without systemic lupus erythematosus is termed as nonlupus full-house nephropathy (FHN). In this study, we retrospectively compiled patients with nonlupus FHN and compared them with lupus FHN for clinicopathological presentation. We included patients with full-house IF patterns in renal biopsies collected from March 2007 to August 2018, clinical and histopathological data at the time of presentation were studied retrospectively. Treatment received and outcome at the end of follow-up was studied. Patients with nonlupus FHN who did not show any systemic disease (idiopathic group) were compared with a group of lupus nephritis patients. Of 178 patients, 34 had nonlupus FHN with 21 having idiopathic nonlupus FHN and 13 patients having secondary nonlupus FHN (membranous nephropathy, IgA nephropathy, postinfection glomerulonephritis). Males were more often in idiopathic nonlupus FHN patients than lupus FHN patients (P = 0.005). Kidney biopsies more often showed a mesangial (P = 0.0006) and less proliferative pattern of injury (P = 0.0002) and less intense C1q staining (P = 0.0001) in idiopathic nonlupus than lupus FHN. Clinically, idiopathic nonlupus FHN presented with more proteinuria (P = 0.0059) and less complement consumption (P = 0.001) than lupus FHN patients. Compared to lupus FHN, nonlupus has mainly nephrotic syndrome as clinical presentation. There was no difference in the clinical outcome between lupus FHN and idiopathic nonlupus FHN. Nonlupus FHN is not a very common condition and has less female involvement than in lupus FHN. Idiopathic nonlupus FHN has certain histopathological features with less C1q staining by IF, less frequent proliferative lesions and higher mesangial or membranous lesions by light microscopy compared to lupus FHN. Regarding outcomes, there is no significant difference between lupus FHN and idiopathic nonlupus FHN.