Analysis of treatment responses and kidney prognosis of atypical membranous nephropathy / 中华肾脏病杂志

ABSTRACT

Objective:To analyze the clinicopathological characteristics, treatment responses and kidney outcomes of patients with atypical membranous nephropathy (MN), and to provide information for the clinical practice.Methods:The clinical data of patients with atypical MN and synchronous primary MN who were diagnosed, treated and followed up in Peking University First Hospital from January 2008 to June 2020 were retrospectively collected and analyzed. Clinicopathological features, treatment responses and kidney prognosis were compared between the two groups. The expression of phospholipase A2 receptor (PLA2R) in kidney tissues was detected by immunofluorescence. Serum anti-PLA2R antibody was detected by enzyme-linked immunosorbent assay. Clinicopathological indexes were compared between PLA2R-related MN group and non-PLA2R-related MN group. Kaplan-Meier (Log-rank test) survival curve and multivariate Cox regression analysis methods were used to analyze the influencing factors of kidney prognosis in patients with atypical MN. The primary endpoint of renal adverse outcome was renal insufficiency, defined as end-stage renal disease or estimated glomerular filtration rate (eGFR) decline>30% baseline and<60 ml·min -1·(1.73 m 2) -1. Results:A total of 65 atypical MN patients were enrolled in this study. Compared with primary MN ( n=324), patients with atypical MN had younger age ( Z=-4.229, P<0.001), higher proportion of hematuria ( χ2=5.555, P=0.018), higher level of urinary protein ( Z=2.228, P=0.026) and lower level of eGFR ( t=-5.108, P<0.001); the proportion of IgG4 deposition in kidneys was lower ( χ2=8.081, P=0.004), and the proportions of IgA ( χ2=16.969, P<0.001) and IgM ( χ2=9.281, P=0.002) deposition were higher. There was no significant difference on gender, serum albumin, positive proportion of anti-PLA2R antibody, anti-PLA2R antibody level and kidney C3/C1q deposition between the two groups (all P>0.05). The proportions of atypical MN patients receiving renin-angiotensin aldosterone system inhibitors (49.3% vs 57.1%), calcineurin inhibitors (27.7% vs 19.1%) and cyclophosphamide (21.5% vs 23.8%) were comparable to those of primary MN patients (all P>0.05). The rates of clinical remission (80.0% vs 77.2%), partial remission (44.6% vs 44.1%), complete remission (35.4% vs 33.1%), spontaneous remission (36.9% vs 42.6%), response to cyclophosphamide (85.7% vs 81.8%), response to calcineurin inhibitor (88.9% vs 79.0%), and relapse (30.8% vs 26.8%) in atypical MN patients were comparable to those in primary MN patients (all P>0.05). During the follow-up 30.0(21.5, 61.5) months, 15 atypical MN patients (23.1%) had eGFR reduction>30%, among whom 7 patients (10.8%) had eGFR reduction>50% and 3 patients (4.6%) had end-stage kidney disease. There was no significant difference on poor kidney prognosis between the two groups (all P>0.05). Kaplan-Meier survival curve showed that patients with age>39 years old ( χ2=10.092, P=0.001), eGFR≤100 ml·min -1·(1.73 m 2) -1( χ2=5.491, P=0.019), tubular interstitial lesion ( χ2=6.999, P=0.008) and no nephropathy remission ( χ2=22.952, P<0.001) had earlier poor renal prognosis. Multivariate Cox regression analysis showed that no nephropathy remission ( HR=12.604, 95% CI 2.691-59.037, P=0.001) was an independent influencing factor for poor renal prognosis in atypical MN patients. Conclusion:No significant difference is found between atypical MN and primary MN on treatment responses and kidney prognosis, which implies that clinical practice of atypical MN can be performed by referring to the guidelines and experience of primary MN.