Expression And Clinical Significance Of Serum Anti-PLA2R Antibody And Glomerular C1q Deposition In Idiopathic Membranous Nephropathy

Objective: To investigate the expression and clinical significance of the determination of serum anti-PLA2 R antibody as well as C1 q glomerular deposition in idiopathic membranous nephropathy(IMN)and atypical membranous nephropathy(AMN).Methods: Patients with biopsy–proven IMN and AMN from January 2017 to September 2018 in Department of Nephrology of Affiliated Yantai Yuhuangding Hospital of Qingdao University were enrolled.There were 40 patients in each group.And renal specimens were evaluated with electron microscopy in the First Hospital of Peking University.We determined the serum anti-PLA2 R antibody by enzyme-linked immunosorbent assay.According to the concentration of the antibody,it could be divided into anti-PLA2 R antibody positive group(its concentration ?20RU/ml)and anti-PLA2 R antibody negative group(its concentration < 20RU/ml).Direct immunofluorescence method was used to detect the deposition site and intensity of glomerulus C1 q,which were divided into C1 q positive group and C1 q negative group according to C1 q deposited or not.Meanwhile anti-PLA2 R antibody and C1 q deposition were divided into double positive group,single positive group and double negative group.The data of patients,24-hour urine protein,serum albumin,creatinine and other biochemical indicators were collected.The patients were given glucocorticoid combined with immunosuppressive therapy and/or supportive therapy(controlling blood pressure,reducing proteinuria by ACEI/ARB drugs and other non-glucocorticoid therapy),which were dependent on clinical symptoms and laboratory test results.The patients were followed up for ? 6 months.We detected their serum albumin and 24 h urine protein regularly.Evaluation criteria: ?complete remission:albumin were greater than or equal to 35g/L and proteinuria less than 0.3g/24h;?Partial remission: albumin were greater than or equal to 30g/L,meanwhile 24 h urine protein decreased by about 50% comparing with the original level and it fluctuated between0.3~ 3.5g,albumin were higher than before.?Non-remission: Not meeting the above criteria.Results: ? In IMN and AMN patients,the 24-hour urine protein in the positive group of serum anti-PLA2 R antibody were significantly higher than that in the negative group,so did the total cholesterol in blood,however the serum albumin were the complete opposite.The difference were statistically significant(P<0.05),but there were no significant difference in age,gender,blood uric acid,urea nitrogen,triglyceride(P>0.05).? In AMN patients,the serum creatinine value of positive group with anti-PLA2 R antibody were higher than that of negative group(P<0.05).? Immunofluorescence: There were no statistical difference in the deposition of IgG,IgA,IgM,C3 and FIB in renal tissues of patients in each group.Compared with IMN patients,the deposition rate of C1 q in renal tissue of AMN patients were higher(P<0.05),and in AMN patients,the male patients in the positive group of C1 q deposition were less than those in the negative group(P<0.05).(4)Clinical remission: Compared with the negative group of serum anti-PLA2 R antibody,the remission rate of the positive group of anti-PLA2 R antibody were lower.In IMN patients,the prognosis of patients complicated with C1 q deposition in renal tissue were poor(P<0.05).There were no effect on prognosis in AMN patients if C1 q were deposited or not(P>0.05).Conclusion:(1)We found that the positive rates of serum anti-PLA2 R antibody in IMN and AMN patients were 65% and 57.5% respectively.In AMN,the average titer of the antibody was higher than that of IMN,which suggested that we could not diagnose IMN only if the antibody was positive.Meanwhile renal biopsy was required to determine whether there was atypical membranous nephropathy.(2)No matter in IMN and AMN groups,patients with positive serum anti-PLA2 R antibody had more severe clinical symptoms and lower spontaneous remission rate than those with negative serum anti-PLA2 R antibody.IMN patients with C1 q deposition had lower clinical remission rate,suggesting poor therapeutic effect.We should apply glucocorticoid and immunosuppressive drugs as early as possible.(3)PLA2R positive with C1 q deposition in IMN patients indicated the poor prognosis.