Mesangial proliferative lupus nephritis with podocytopathy: a special entity of lupus nephritis

Mesangial proliferative lupus nephritis may coexist with podocytopathy, but its clinical-morphological features, treatment response and outcomes have not been compared with mesangial proliferative lupus nephritis without podocytopathy. In this study, 125 biopsies of lupus nephritis patients showing mesangial proliferation with mesangial immune deposits were collected and divided into podocytopathy group (defined as podocyte foot process effacement (FPE) >50% with nephrotic syndrome (NS)) and mesangial group (FPE ≤50%, or FPE >50% without NS). Mesangial proliferation and tubular- interstitial lesions were semi-quantitatively analyzed. We found that the incidence of renal involvement as the onset symptoms ( P < .001), nephrotic syndrome ( P < .001), acute kidney injury ( P < .001), the degree of acute tubular- interstitial lesions ( P < .001), and renal relapse (51.6% vs. 23.7%, P = .005) were significantly higher in the podocytopathy group than in the mesangial group. In contrast, the incidence of arthritis ( P < .001), fever ( P = .042), low serum C4 ( P = .008) and hematuria ( P = .033) was significantly lower in the podocytopathy group than in the mesangial group. No patients developed end stage renal disease or death during a median follow-up of 64 (interquartile range (IQR) 37-103) months in the podocytopathy group and 53 (IQR 30-83) months in the mesangial group. In conclusion, mesangial proliferative lupus nephritis with and without podocytopathy should be subdivided into two separate classes of lupus nephritis.