Correlation of anti-M-type phospholipase A2 receptor antibody with disease severity in adult patients with idiopathic membranous nephropathy / 中华肾脏病杂志

ABSTRACT

Objective To investigate the correlation of serum anti-M-type phospholipase A2 receptor (PLA2R) antibody with laboratory parameters of idiopathic membranous nephropathy (IMN) in adult patients with membranous nephropathy (MN),and to explore the role of anti-PLA2R antibody in the pathogenesis of IMN. Methods Forty-six adult patients with biopsy-proved glomerular diseases were involved in this study,including 20 cases with IMN,7 cases with IgA nephropathy (IgAN),6 cases with hepatitis B-associated membranous nephropathy (HBV-MN),6 cases with minimal change nephropathy (MCN),4 cases with focal segmental glomerulosclerosis (FSGS) and 3 cases with class Ⅴ lupus nephritis.Total RNA was extracted from human glomeruli and was reversely transcribed to the first-strand cDNA.The full-length human M-type PLA2R was amplified by PCR and the 605 bp product was subcloned into eukaryotic expression vector containing CMV promoter.The recombinant human M-type PLA2R plasmid vector was transiently transfected into human embryonic kidney (HEK) 239T cell line using the FuGene6 transfection reagent.Western blotting was used to detect serum anti-PLA2R antibodies.Correlations of antiPLA2R antibody level with laboratory parameters,including serum albumin,total cholesterol,Scr and 24-hour urine protein,of IMN patients were evaluated. Results Among 20 cases with IMN,15 cases showed positive anti-PLA2R antibodies (positive rate 75％).Of 7 cases with IgAN and 6 cases with HBV-MN,only 1 case showed positive anti-PLA2R antibody respectively (positive rate 14.29％ and 16.67％ respectively).Anti-PLA2R antibody was negative in other patients.The positive rate of anti-PLA2R antibody in IMN patients was significantly higher than that in patients with secondary MN and other types of glomerlonephritis (all P＜0.01).Furthermore,anti-PLA2R antibody level was positively correlated with 24-hour urine protein(r=0.803,P＜0.01) and negatively correlated with serum albumin in IMN patients (r=-0.816,P＜0.01). Conclusions The high positive ratio of anti-PLA2R antibody may indicate that it is the specific autoantibody in IMN.AntiPLA2R antibody is correlated with IMN disease severity,which indicates that it may be the pathogenic autoantibody in IMN.