MO252: Complement 3 Deposits on Renal Tubule and Glomeruli in Phospholipase A2 Receptor-Related Idiopathic Membranous Nephropathy

Abstract BACKGROUND AND AIMS Evidence shows galactose-deficient IgG4 is able to act complement system via lectin pathway in phospholipase A2 receptor (PLA2R) related idiopathic membranous nephropathy (IMN). However, the severity of PLA2R-related IMN runs parallel with neither the electron microscope stage nor the complement density in situ. We find positive complement factor 3 (C3) deposition on renal proximal tubule in some IMN patients and manage to analysis the relationship between it and the severity of the disease. METHOD We retrospectively involved 113 PLA2R related IMN patients from March 2017 to October 2019. The inclusion criteria were diagnosed by kidney biopsy with complete clinical and pathological data. The exclusion criteria were with any secondary causes such as lupus nephritis type V, Sjogren's syndrome, hepatitis B associated glomerulonephritis and atypical membranous nephropathy. We divided total patients into four subgroups according to the C3 deposition site. We defined no C3 deposition subgroup (40,35%) as C3 appeared in neither glomeruli nor tubule, C3 glomeruli deposition subgroup (32, 28%) as C3 deposited on glomeruli only, C3 tubule deposition subgroup (12, 11%) as C3 deposited on tubule only, C3 extensive deposition subgroup (29, 26%) as C3 deposited on both glomeruli and tubule. RESULTS Clinical data of four groups were as follows: Male/female ratio were 22/18, 23/9, 5/7, 16/13, P = .252; The median of age were 50 (33, 57), 51 (42, 57), 57 (49, 61), 51 (33, 57), P = .412; The median of were 24-h urine protein were 4.4 (2.0, 6.9), 5.0 (2.7, 8.3), 4.9 (2.5, 11.2), 5.5 (2.4, 10.2) g/L, P = .427. The average serum albumin were 28.6 ± 6.8, 27.2 ± 6.7, 24.6 ± 2.7, 25.5 ± 6.0 g/L, P = .046. The median of serum creatinine were 70 (57, 82), 77 (65, 92), 68 (57, 89), 69 (58, 80) μmol/L, P = .255. The median of serum C3 were 1.14 (1.0, 1.33), 1.17 (1.04, 1.36), 1.22 (1.0, 1.34), 1.11 (0.99, 1.23) g/L, P = .291. The median of anti-PLA2R antibody were 0 (0, 55), 29 (25, 33), 12 (0, 136), 35 (19, 131) RU/mL, P = .049. CONCLUSION There were differences in serum anti-PLA2R antibody and Alb in patients with different C3 deposition. Patients with extensive C3 deposition showed higher PLA2R antibody.