Distribution of pathological types and epidemiological characteristics based on kidney biopsy in Northwest China

Analysis of Clinicopathological Characteristics of Malignancy Patients with Membranous Nephropathy and Literature Review

Purpose

In recent years, the incidence of malignancy patients with membranous nephropathy (MN) has gradually increased, but the clinical and pathological characteristics of these patients are still unclear. Our study aims at elucidating the clinical and pathological characteristics of malignancy patients with MN, especially the expression patterns of MN-specific antigens in both kidney and tumor tissue.

Patients and Methods

A retrospective analysis was performed to summarize the clinical and pathological data of MN patients with malignancy at Beijing Anzhen Hospital from January 1, 2012, to December 31, 2022, followed by a thorough review of relevant literature published between May 1, 2000 to May 1, 2023 and case aggregation.

Results

19 patients in our center's MN cohort and 21 patients from literature review were diagnosed with malignancy either before or after being diagnosed with MN. Among them, 16 (40.0%) and 17 (42.5%) patients tested PLA2R-only and THSD7A-only positive in renal tissue, respectively. And 16 of 26 patients showed similar staining in tumor and kidney tissues. Compared to the idiopathic membranous nephropathy (IMN) patients at our center, patients with malignancy were older, had a lower estimated glomerular filtration rate, and had a lower rate of partial or complete response to treatment. Renal tissue from MN patients with concomitant malignancy was less frequently PLA2R-positive, more frequently THSD7A-positive, and more often glomerular IgG subclass IgG2 (P = 0.033) but less frequently IgG4 (P < 0.001).

Conclusion

The clinical and pathological characteristics of MN patients with concomitant malignancy are different from those of IMN patients. Active screening for malignancy should be performed in non-PLA2R-positive elderly MN patients with a poor therapeutic response. Staining for MN target antigens in kidney and tumor tissues may be inconsistent, and the role of MN target antigens needs to be further explored.

Prognostic factors affecting long-term outcomes in patients with concurrent IgA nephropathy and membranous nephropathy

Background

The incidence of concurrent immunoglobulin A nephropathy and membranous nephropathy (cIgAN/MN) is low and rarely reported, and the prognosis of patients with cIgAN/MN remains unclear. This study was designed to compare the clinical and prognostic characteristics of cIgAN/MN with IgAN and MN and to identify crucial factors influencing the outcomes of patients with cIgAN/MN.

Methods

We included biopsy-proven cIgAN/MN patients between December 2012 and December 2020 at Xijing Hospital. In the same period, propensity score matching was employed to select an equal number of IgAN and MN patients according to the following criteria: age, sex, and follow-up time. The primary endpoint was defined as a composite of eGFR decline ≥30 %, end-stage renal disease, or death. The patient survival rate was examined using Kaplan-Meier survival curves. Univariate and multivariate Cox regression analysis models were utilized to identify the risk factors affecting renal prognosis.

Results

A total of 135 patients were finally included in this study and 35 (25.9 %) reached the primary endpoint. The median follow-up time of cIgAN/MN was 45.9 (24.0, 72.0) months. Compared to the IgAN group, the cIgAN/MN group exhibited a lower cumulative incidence rate of composite renal endpoints (P = 0.044), while no significant difference was found between MN and cIgAN/MN patients (P = 0.211). Univariate Cox analysis revealed that mean arterial pressure, serum potassium, blood urea nitrogen, serum IgA, segmental glomerulosclerosis (S1), and MN staging were associated with an increased risk of renal composite endpoints. The multivariate Cox regression analysis of clinical variables plus histological lesion scoring demonstrated that potassium (HR = 14.350, 95 % CI 2.637-78.090, P = 0.002), serum IgA (HR = 1.870, 95 % CI 1.109-3.153, P = 0.019), and S1 (HR = 11.965, 95 % CI 2.166-66.105, P = 0.004) were independent risk factors influencing renal outcomes in cIgAN/MN patients.

Conclusion

The prognosis of cIgAN/MN patients may exhibit an intermediate pattern between IgAN and MN, leaning towards being more similar to MN in certain aspects. Within the cIgAN/MN cohort, potassium, and serum IgA may be more predictive of rapid progression of renal endpoints, and S1 may indicate a more aggressive disease course.