The Analysis of Clinicopathological Characters and Short-term Prognosis in Idiopathic Membranous Nephropathy Patients with Immunoglobulin G4 Combined with Other Different Immunoglobulin G Subtypes Deposition

Abstract

Background The immunoglobulin (Ig) G subtype deposited pathologically in patients with idiopathic membranous nephropathy (IMN) is mainly IgG4, and the deposition of IgG1, IgG2 and IgG3 can also be detected. At present, there has been no report on the damage effect of different IgG subtypes in IMN on the pathological of kidney. Objective The purpose of the study was to investigate the clinicopathological characters and short-term prognosis in IMN patients with IgG4 combined with other different IgG subtypes deposition. Methods 604 patients diagnosed with IMN in the First Affiliated Hospital of Zhengzhou University from January 2015 to June 2018 were included in the study, the baseline information, pathological test results of renal tissue specimens and treatment protocols of the patients were collected. According to the test results of IgG subtypes in renal pathology, the patients were divided into the simple IgG4 deposition group (n=259) , IgG4 combined with IgG1 deposition group (n=259) , IgG4 combined with IgG2 deposition group (n=29) , and IgG4 combined with IgG3 deposition group (n=57) . Starting from the date of percutaneous renal biopsy, the follow-up was performed until 2018-11-06. Kaplan-Meier survival curves of patients with different IgG subtypes were plotted, Log-rank test was used for survival curve comparison. Results 24-h urine protein in IgG4 combined with IgG1 deposition group was higher than that in the simple IgG4 deposition group (P<0.05) ; the white blood cell count, neutrophil count, monocyte count and 24-h urine protein in the IgG4 combined with IgG3 deposition group were higher than those in the simple IgG4 group (P<0.05) . The positive deposition rates of C3, C4 and λ in the IgG4 combined with IgG1 deposition group were higher than those in the simple IgG4 deposition group (P<0.05) ; the positive deposition rate of C3 in the IgG4 combined with IgG2 deposition group was higher than that in the simple IgG4 deposition group (P<0.05) ; the positive deposition rates of C3, C4 and C1q, semi-quantitative scores of renal tubular atrophy and renal interstitial fibrosis were significantly different between the IgG4 combined with IgG3 deposition group and the simple IgG4 deposition group (P<0.05) . Log-rank test results showed no significant difference in cumulative response rates among the four groups (χ2=0.684, P=0.408) . Conclusion The renal clinical and pathological changes were more serious in IgG4 combined with other different IgG subtypes patients than those with IgG4 alone, patients with IgG3 deposition had a more prominent clinicopathological phenotype. There was no significant difference in remission rate after 6 months of follow-up, which may be related to the different intensity of inflammatory response caused by different capacities to fix complement of different IgG subtypes.

Keywords

• glomerulonephritis, membranous|idiopathic membranous nephropathy|immunoglobulin g|prognosis|root cause analysis