Abstract:

Objective To analyze the pathological features associated with the clinical prognosis of C₃ glomerulopathy (C₃G). Methods A total of consecutive 7 cases, all hospitalized in the Department of Nephrology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine between 2012 and 2022, and histologically diagnosed with C₃G by renal biopsy, were collected. Their clinical, pathological, and follow-up data were retrospectively analyzed to observe pathological characteristics related to prognosis. Results The cohort consisted of 7 C₃G patients (male/female: 3/4). The median age at onset was 51 years, and the median age at diagnosis was 54 years. The median follow-up time was 84 months (range: 48-144 months). Two patients (Case 1, Case 7) were lost to follow-up. Two patients (Case 5, Case 6) had a poor prognosis, while three patients (Case 2-4) had a favorable prognosis. Clinically, 2 patients (Case 3, Case 7) presented with nephrotic syndrome, 3 patients (Case 1, Case 3, Case 6) had renal insufficiency, 6 patients (Case 1-6) had hematuria, and all 7 patients exhibited hypocomplementemia and hypertension, without significant extrarenal manifestations.Among the 5 patients with long-term follow-up, at the 2-year mark: 1 patient (Case 3) achieved complete remission of proteinuria and serum creatinine; 3 patients (Case 2, Case 4, Case 5) had stable proteinuria and renal function; and 1 patient (Case 6) showed increased proteinuria and declining renal function. At the 6-year follow-up: 2 patients (Case 2, Case 4) maintained a good prognosis; 1 patient (Case 3) was no longer followed up after achieving complete remission of proteinuria and creatinine; 1 patient (Case 6), who already had a poor prognosis at 2 years, exhibited a further increase in proteinuria and a significant decline in renal function; and 1 patient (Case 5) newly progressed to heavy proteinuria.At the 6-year follow-up, a review of renal pathology revealed that the 3 cases with a favorable prognosis (Case 2-4) primarily showed diffuse capillary endothelial cell hyperplasia with neutrophil infiltration on light microscopy, while global glomerulosclerosis and glomerular basement membrane pseudo-double contour formation were not prominent. Electron microscopy demonstrated relatively few electron-dense deposits in the mesangial region. In contrast, the 2 cases with a poor prognosis (Case 5, Case 6) were characterized by an increased proportion of global glomerulosclerosis[ greater than (age-20)/2 × 100%] ,extensive glomerular basement membrane pseudo-double contours on light microscopy, and abundant mesangial electron-dense deposits on electron microscopy, with minimal capillary endothelial cell hyperplasia and neutrophil infiltration. Conclusions C₃G patients whose histopathology is predominantly characterized by acute lesions (such as glomerular capillary endothelial cell hyperplasia and neutrophil infiltration) have a more favorable prognosis and can be treated aggressively with corticosteroids and immunosuppressants. Conversely, C₃G patients whose histopathology is predominantly characterized by chronic lesions (such as global glomerulosclerosis, glomerular basement membrane pseudo-double contour formation, and a high quantity of mesangial electron-dense deposits) have a poor prognosis, and conservative management is recommended to avoid overtreatment.

Key words: C₃ glomerulopathy, Clinical manifestation, Renal pathology, Prognosis