Clinical Study On Detection Of Gd-IgA1 In Patients With IgA Nephropathy By KM55 Antibody

Background and Objective:Primary IgA nephropathy is the most common primary glomerular disease and the leading cause of end-stage renal disease.The available data show that the abnormality of O-glycosylation in the hinge region of IgA1 plays a key role in IgA nephropathy.The serum Gd-IgA1 level in IgA nephropathy patients is correlated with the clinicopathological features and prognosis of patients.Gd-IgA1 is currently considered as a biomarker for the diagnosis,disease severity,and prognosis of IgA nephropathy.Recently,foreign researchers have proposed a new method monoclonal antibody-KM55 ELISA method,which could specifically recognize Gd-IgA1 molecules.At present,there is no research report on the detection of serum Gd-IgA1 by this method in patients with IgA nephropathy in China.This study intends to detect serum and mesangial Gd-IgA1 level by monoclonal antibody-KM55,observe the correlation among serum Gd-IgA1 level,clinical manifestations,pathological features,prognosis and complement activation level in patients with IgA nephropathy,and verify the role of KM55 monoclonal antibody in diagnosis,disease assessment and prognosis of IgA nephropathy.Methods:This study selected seventy-five subjects who were confirmed IgA nephropathy at the first renal biopsy in the Tianjin Medical University General Hospital from March 2017 to January 2019.The clinical and pathological data and prognosis of the patients were recorded.Seventy-five healthy volunteers matched with the age and sex and received physical examination in the Tianjin Medical University General Hospital Health Checkup Center were selected.Serum and mesangial Gd-IgA1 levels were measured by monoclonal antibody-KM55 in IgA nephropathy patients and healthy controls,and the difference in serum Gd-IgA1levels was compared.According to the median level of serum Gd-IgA1 in patients with IgA nephropathy,patients were divided into high serum Gd-IgA1 group and low serum Gd-IgA1 group.Clinical observations of proteinuria,serum creatinine,eGFR and serum complement in renal biopsy were observed.Differences in the indicators with pathological parameters in Oxford pathological classification were compared between the two groups of patients,and prognostic analysis was performed by Kaplan-Meier curve.The correlation between serum Gd-IgA1 and the above indicators in IgA nephrapa patients was investIgated by person correlation analysis.Results:1.Serum Gd-IgA1 levels(11.09±4.87?g/mL)in patients with IgA nephropathy were significantly higher than those in healthy controls(7.20±4.00?g/mL,p=0.000compared with IgA nephropathy).2.Serum uric acid,IgA and IgA/C3 ratio in the high serum Gd-IgA1 group(>10.32?g/mL)were significantly higher than those in the low serum Gd-IgA1 group(?10.32?g/mL)(all p value<0.01).But there were no significant differences in other clinical indexes and the pathological types of M1,E1,S1,T1/2 and C1/2 between the two groups(all p>0.05).3.Serum Gd-IgA1 levels were positively correlated with serum uric acid levels,total IgA levels,and IgA/C3 ratio in patients with IgA nephropathy(r=0.31,p=0.007;r=0.54,p=0.000 and r=0.55,p=0.000),and there is no correlation with other clinical indicators.4.Serum Bb,C3a,C4d and MAC were higher in patients with high serum Gd-IgA1levels than those with low serum Gd-IgA1 levels(p<0.01).Serum Gd-IgA1 levels were positively correlated with serum Bb,C3a,C4d and MAC levels(Bb:r=0.49,p=0.001;C3a:r=0.56,p=0.000;C4d:r=0.56,p=0.000 and MAC:r=0.40,p=0.012).5.The Kaplan-Meier survival curve showed that the median time to the rate of complete renal remission in patients with high serum Gd-IgA1 group and low serum Gd-IgA1 group was 9 months and 17 months and the median tiam to eGFR decreased by 20%in both two groups were 19 months.There was no significant difference in the distribution of the rate of complete renal remission and eGFR in the two groups(?~2=2.282,p=0.101;?~2=056,p=0.812).6.Mesangial Gd-IgA1 was positive in IgAN.High level of plasma Gd-IgA1 was related to the deposition of mesangial Gd-IgA1,although the difference was not significant(r=0.44,p=0.090).Conclusion:KM55 monoclonal antibody test confirmed that IgA nephropathy patients had evelated levels of serum and mesangial Gd-IgA1,and the higher serum Gd-IgA1 in patients with IgA nephropathy was along with the higher blood uric acid,IgA,IgA/C3,complement Bb,C3a,C4d and C5b-9 level.These results suggest that The KM55 monoclonal antibody assay is a simple and reliable tool for the diagnosis of IgA nephropathy,but further research is needed to confirm the role of KM55monoclonal antibody assay in the assessment and prognosis of IgA nephropathy.