Nephrotic range proteinuria in c-ANCA-positive crescentic glomerulonephritis with linear immune deposits

Levamisole and ANCA positivity in childhood nephrotic syndrome

BACKGROUND

This study aimed to determine the prevalence of ANCA positivity in children managed with levamisole as a steroid-sparing agent for nephrotic syndrome (NS).

METHODS

Medical records of children with steroid-sensitive NS managed with levamisole therapy at Sydney Children's Hospital between 1/1/2000 and 31/12/2018 were retrospectively reviewed. Main outcome measure was side effects of levamisole therapy including ANCA positivity.

RESULTS

Seventy-one children, median age 3 years and 1 month (IQR 29-68 months) at first presentation, were subsequently managed with levamisole. 60.6% were male and 65% Caucasian. 47.9% had frequently relapsing (FR)NS and 52.1% steroid-dependent (SD)NS. Overall, there was a median reduction in relapses from 3 (IQR 1-5) to 0.4 relapses (IQR 0-1) per year after levamisole was commenced. Levamisole was successful in preventing relapse in 19 (29%) patients and was used for median 24 (22 to 25) months. Levamisole was discontinued due to relapse in 25 patients (38%) after median 12 (5-28) months. Side effects occurred in 28 patients (42.4%); the most common side effect was ANCA positivity in 12 patients. In eleven of these patients, levamisole was discontinued; in one patient, low-level titres were documented and spontaneously resolved without cessation of levamisole. Two patients developed ANCA-associated vasculitis.

CONCLUSION

ANCA positivity is a common side effect of levamisole and was seen in 18.2% of our patients. Monitoring is required to determine side effects including ANCA positivity and treatment modified accordingly.

Clinical and pathologic characteristics of pauci-immune anti-myeloperoxidase antibody associated glomerulonephritis with nephrotic range proteinuria

Background: Heavy proteinuria in antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (GN) is usually considered to be associated with immune deposits in renal biopsy. Nephrotic ANCA GN without immune deposits (pauci-immune) is rare and has not been studied specially. In this study characteristics of these patients are to be investigated.

Methods: Clinical and pathological characteristics from 20 kidney biopsy-proven pauci-immune anti-myeloperoxidase antibody-associated GN patients with nephrotic proteinuria were analyzed and were compared with ANCA GN patients without nephrotic proteinuria.

Results: Acute kidney injury (AKI) and gross hematuria were much prevalent but extra-renal involvement was less prevalent in pauci-immune ANCA GN with nephrotic proteinuria than in pauci-immune ANCA GN without nephrotic proteinuria. No more severe hypoalbuminemia, hypercoagulability, hyperlipidemia or higher thrombosis incidence were found between two groups. Compared with patients without nephrotic proteinuria, patients with nephrotic proteinuria had more prevalent crescentic category in histopathology. Proteinuria decreased quickly after treatment but much poorer renal prognosis was found in pauci-immune ANCA GN with nephrotic proteinuria. The results of urinary albumin to total protein ratio and urinary protein electrophoresis showed pauci-immune ANCA GN with nephrotic proteinuria had obvious non-selective proteinuria.

Conclusions: Pauci-immune ANCA GN with nephrotic proteinuria do not have more severe hypoalbuminemia, hypercoagulability or hyperlipidemia than patients without nephrotic proteinuria. Non-selective proteinuria might be the reason. However, pauci-immune ANCA GN with nephrotic proteinuria have more prevalent crescentic category in histopathology, higher incidence of AKI, gross hematuria and poorer renal prognosis despite of good sensitivity to therapy of proteinuria.