Key pathological features characterize minimal change disease-like IgA nephropathy

Area of Science:

• Nephrology
• Pathology
• Immunology

Background:

• A subset of IgA nephropathy (IgAN) patients exhibit minimal change disease (MCD)-like features, presenting with nephrotic-range proteinuria and necessitating immunosuppressive therapy (IST).
• Accurate diagnosis of MCD-like IgAN is challenging due to varying diagnostic criteria.
• Identifying key pathological features is crucial for guiding treatment decisions in these patients.

Purpose of the Study:

• To identify the key pathological features distinguishing minimal change disease (MCD)-like IgA nephropathy (IgAN).
• To correlate pathological findings with clinical manifestations and treatment outcomes.

Main Methods:

• Retrospective analysis of 228 biopsy-proven IgAN patients (2009-2021).
• Enrollment of 44 patients without segmental sclerosis, classified by segmental (<50%) or global (>50%) foot process effacement (FPE).
• Comparison of clinical data, treatment response, and renal outcomes based on FPE classification and IST use.

Main Results:

• Global FPE was observed in 40.9% of cases, segmental FPE in 59.1%.
• The global FPE group exhibited significantly more severe proteinuria (p=0.001) but a higher rate of complete remission (81.8% vs. 20%, p=0.018).
• In the global FPE group, patients not receiving IST showed a faster decline in estimated glomerular filtration rate (eGFR) compared to those treated with IST (p=0.004).

Conclusions:

• Absence of segmental sclerosis and presence of global foot process effacement (FPE) are critical pathological indicators for diagnosing MCD-like IgAN.
• These features aid in identifying patients who may benefit from immunosuppressive therapy (IST).
• Global FPE is linked to more severe proteinuria and a better response to IST.