Clinicopathological features and prognosis of primary membranous nephropathy in combination with crescent

Crescents as Independent Risk Factor in the Progression of Primary Membranous Nephropathy

Objective

The role of crescent formation in primary membranous nephropathy (PMN) and its potential impact on prognosis remain an area of ongoing investigation. This study stratifies patients with PMN into two cohorts: one with crescents and one without. It then compares these groups to investigate the influence of crescents on the prognosis of PMN.

Methods

In this retrospective analysis, we included patients who had a confirmed diagnosis of PMN and exhibited crescents upon renal biopsy. The study population was sourced from the medical records at the Affiliated Hospital of Guangdong Medical University in Zhanjiang, China, spanning from January 2017 to June 2023. To enable a comparative analysis of clinical, pathological, and prognostic features, a control group was established, comprising 106 patients diagnosed with PMN who did not have crescent formation. These controls were randomly selected from the same time frame. Regular follow-up of the patients continued in the outpatient setting for at least six months.

Results

A total of 53 patients with PMN and crescent formation were included in this study, while 106 individuals without crescents served as a randomly selected control group. Patients with PMN and crescents exhibited higher systolic blood pressure (P = 0.015), 24-hour proteinuria (P = 0.006), serum creatinine (P = 0.029) levels, and lower glomerular filtration rate (P = 0.002), compared to those without crescents. Histological examination revealed a higher proportion of focal segmental sclerosis (P < 0.001), spherical sclerosis (P < 0.001), arteriosclerosis (P = 0.02), and interstitial fibrosis with tubular necrosis (P = 0.002) in patients with PMN and crescent formation. Immunofluorescence staining demonstrated a weaker IgG4 fluorescence intensity in patients with PMN and crescent formation. At the end of the follow-up period, patients with PMN and crescents had a lower remission rate (P = 0.022), poorer renal function (P = 0.007), and lower albumin (P = 0.039) levels. Kaplan-Meier (KM) analysis identified proteinuria and crescent formation as independent risk factors for adverse outcomes in patients with PMN (P < 0.001 and P < 0.05). Immunohistochemistry staining revealed positive expression of CD68 and CD20 in the renal interstitium of patients with PMN, regardless of the presence of crescents.

Conclusion

Crescent formation is associated with a risk of adverse outcomes in patients with PMN. Patients with crescents exhibit severe clinical and pathological features and have poorer prognoses.

Evaluating the State of Glomerular Disease by Analyzing Urinary Sediments: mRNA Levels and Immunofluorescence Staining for Various Markers

Renal biopsy is the gold standard for making the final diagnosis and for predicting the progression of renal disease, but monitoring disease status by performing biopsies repeatedly is impossible because it is an invasive procedure. Urine tests are non-invasive and may reflect the general condition of the whole kidney better than renal biopsy results. We therefore investigated the diagnostic value of extensive urinary sediment analysis by immunofluorescence staining for markers expressed on kidney-derived cells (cytokeratin: marker for tubular epithelial cells, synaptopodin: marker for podocytes, claudin1: marker for parietal epithelial cells, CD68: marker for macrophages (MΦ), neutrophil elastase: marker for neutrophils). We further examined the expression levels of the mRNAs for these markers by real-time reverse transcription polymerase chain reaction. We also examined the levels of mRNAs associated with the M1 (iNOS, IL-6) and M2 (CD163, CD204, CD206, IL-10) MΦ phenotypes. Evaluated markers were compared with clinical and histological findings for the assessment of renal diseases. Claudin1- and CD68-positive cell counts in urinary sediments were higher in patients with glomerular crescents (especially cellular crescents) than in patients without crescents. The relative levels of mRNA for CD68 and the M2 MΦ markers (CD163, CD204, CD206, and IL-10) in urinary sediments were also higher in patients with glomerular crescents. These data suggest that immunofluorescence staining for claudin1 and CD68 in urinary sediments and the relative levels of mRNA for CD68 and M2 MΦ markers in urinary sediments are useful for evaluating the state of glomerular diseases.