Fervenza, Fernando C.

ABSTRACT C3 glomerulonephritis (C3GN) is a rare kidney disease driven by dysregulation of the alternative complement pathway. We report two challenging cases of patients with C3GN in whom various immunosuppressant therapies have failed to achieve complete remission, prompting treatment with eculizumab, an anti-C5 humanized monoclonal antibody that inhibits the terminal complement pathway. Although transient improvement in kidney function was observed, both patients eventually experienced worsening renal parameters, with increasing proteinuria and hematuria, culminating in progression to end-stage kidney disease. Repeated kidney biopsies following eculizumab therapy demonstrated persistent, granular mesangial and capillary wall C3 (3+) staining on immunofluorescence studies, indicating ongoing complement activation upstream of the C5 blockade and the perpetuation of C3 deposits in the glomeruli. These cases underscore the limited efficacy of terminal complement inhibition in halting disease progression in C3GN.

ABSTRACT We describe a case of immunoglobulin A nephropathy (IgAN) treated with targeted-release budesonide (Nefecon) that resulted in notable systemic adverse effects. The patient developed cushingoid features, weight gain, hyperglycaemia and leucocytosis within 3 months of therapy. During dose tapering he experienced symptomatic adrenal insufficiency confirmed by low morning cortisol, requiring hydrocortisone replacement. Despite Nefecon’s design for terminal ileum absorption, and hence assumed minimal systemic exposure, this case demonstrates clinically significant adverse effects and adrenal suppression. These findings underscore the need for careful monitoring and patient education when initiating and tapering Nefecon in IgAN management.

Key Points Baseline kidney function and chronic structural injury strongly predicted both renal recovery and long-term clinical outcomes. Tubulointerstitial nephritis was the predominant lesion in Sjögren syndrome with renal involvement. Early detection and management of renal involvement in Sjögren syndrome are critical to preventing irreversible kidney damage. Background Renal involvement in primary Sjögren syndrome (SS) is uncommon but clinically consequential. Previous studies have been limited by small samples and incomplete biopsy data. We evaluated a large biopsy-confirmed cohort to characterize clinicopathologic features of SS with renal involvement and identify predictors of renal recovery and long-term outcomes. Methods We retrospectively identified adults with SS and kidney biopsy at Mayo Clinic (2012–2025). Clinical, laboratory, and histologic data were extracted. Predictors of complete renal recovery within 6 months, defined as serum creatinine (sCr) returning to within 25% of baseline or <1.4 mg/dl if baseline was unknown, were evaluated using logistic regression. Cox regression assessed long-term risk of a composite end point: newly developed or progressive CKD, ESKD, or all-cause mortality. Results Fifty-six patients were included (median age 57 years; 91% female). Extraglandular manifestations occurred in 76% and baseline CKD in 65%. The median sCr at baseline and biopsy was 1.3 and 1.6 mg/dl, respectively. Anti-Sjogren's syndrome antigen A, often linked with Ro ribonucleoprotein was positive in 80%. Low C3 occurred in 14% and low C4 in 25%. Tubulointerstitial nephritis was the predominant lesion (71%). Moderate/severe interstitial fibrosis/tubular atrophy and arteriosclerosis were present in 36% and 41%, respectively. Immunosuppressive therapy was applied in 84%. Complete recovery occurred in 67%. Over a median 3.9 years (interquartile range, 1.4–7.2), 43% reached the composite end point. Baseline sCr ≥2 mg/dl, 24-hour proteinuria ≥1 g, and presence of segmental glomerulosclerosis were associated with lower odds of recovery (odds ratio=0.16, 0.13 and 0.11, P = 0.02, 0.001 and 0.008, respectively) and higher long-term risk (hazard ratio=4.51, 2.92 and 3.52; P = 0.002, 0.01 and 0.02, respectively). Moderate/severe arteriosclerosis also increased long-term risk (hazard ratio=2.56; P = 0.03). Conclusions In biopsy-confirmed SS-related renal involvement, the severity of kidney dysfunction and the extent of chronic glomerular and vascular injury strongly predict renal prognosis. Early detection and targeted management of high-risk features may improve long-term renal outcomes.

ABSTRACT Immunoglobulin A nephropathy (IgAN) is an immune-mediated disease of B-cell origin and the most common primary glomerulonephritis worldwide, which often progresses to kidney failure within 10–20 years of diagnosis. Microscopic hematuria is frequently observed in IgAN; it is thought to result from damage to the glomerular filtration barrier caused by pathogenic immune complex deposits, allowing red blood cells to leak into the urinary space. Emerging evidence suggests that microscopic hematuria in IgAN may be linked to active glomerular inflammation, poorer disease prognosis and progressive kidney function decline. Despite this, it remains an underutilized biomarker for IgAN because of a lack of standardization (which can lead to preanalytical errors), challenging logistical considerations in large multicenter trials and non-glomerular hematuria as a confounding factor. The “proteinuria-centric” approach by the nephrology community may overlook that active forms of glomerulonephritis manifest with both proteinuria and hematuria, in contrast to primary podocytopathies where proteinuria is the main feature. When properly assessed, microscopic hematuria is a prognostically relevant biomarker in IgAN that may improve risk stratification and assessment of therapeutic response when evaluated alongside traditional biomarkers. This review evaluates the methods of assessment, pathophysiology and clinical utility of microscopic hematuria in IgAN.