Urinary protein markers predict the severity of renal histological lesions in children with IgA nephropathy and IgM nephropathy / 中华实用儿科临床杂志

ABSTRACT

Objective To compare the clinical manifestations,renal histological lesions,and the levels of urinary protein markers between the children with IgA nephropathy (IgAN) and those with IgM nephropathy (IgMN), and to determine whether urinary protein markers could predict the severity of renal histological lesions in children with IgAN and IgMN.Methods Seventy-four children with renal biopsy-proven IgAN and IgMN from January 2002 to October 2014 were enrolled in the study.The levels of IgG, albumin (Alb), transferrin (TRF), α1-microglobulin (α1-MG) ,β2-microglobulin (β2-MG) and N-acetyl-β-glucosaminidase (NAG) in morning urine samples before biopsy were measured.The semi-quantitative scores of mesangial hypercellularity (MC), glomerulosclerosis (GS), and tubule-interstitial damage (TID) were used to assess renal histological lesions.Multivariate Logistic regression analysis was used to determine whether urinary protein levels were independently associated with renal histological lesions.The area under the receiver-operating-characteristic curve (AUC) was calculated to assess the predictive ability of urinary protein markers.Results Seventy-four children (44 cases with IgAN,30 cases with IgMN) were included.The urinary levels of α1-MG and Alb were significantly higher in children with IgAN as compared to those with IgMN.The differences, however, did not remain significant after adjustment for age.The urine protein, as an independent factor associated with severe MC(＞ 5 mesangial cells per mesangial area) was TRF(B =0.010), and severe GS (≥ 10％ glomeruli showing segmental adhesion or sclerosis) was significantly correlated with Alb(B =0.001) ,and severe TID (focal or diffuse tubular and interstitial lesions) was significantly correlated with NAG(B =0.038).Urinary β2-MG was not significantly associated with severe MC, GS and TID.Urinary TRF, Alb and NAG achieved the best AUC of 0.85 (P ＜ 0.001) ,0.78 (P =0.002), and 0.78 (P =0.003), respectively, for predicting severe MC, GS, and TID.Conclusions Urinary proteins are useful to predict the severity of renal histological lesions in children with IgAN and IgMN.Urinary TRF, Alb and NAG have better predictive value.