Levamisole and ANCA positivity in childhood nephrotic syndrome

An open label non-inferiority randomized controlled trial evaluated alternate day prednisolone given daily during infections vs. levamisole in frequently relapsing nephrotic syndrome

Initial therapies for children with frequently relapsing nephrotic syndrome include alternate-day prednisolone that is given daily during infections, or levamisole. In this open label, non-inferiority trial, 160 patients, 2 to 18-years-old with frequent relapses, were randomly assigned to receive either prednisolone (0.5-0.7 mg/kg/alternate-day, given daily during infections), or levamisole (2-2.5 mg/kg/alternate-days) for one-year. Patients with relapses on alternate day prednisolone at over 1 mg/kg, prior use of potent steroid-sparing therapies, eGFR under 60 ml/min/1.73 m2 and significant steroid toxicity were excluded. Primary outcome was the proportion of patients with frequent relapses, defined as three-relapses in one-year, or two-relapses within six-months if associated with significant steroid toxicity or loss to follow up. Eighty patients each were randomized to receive prednisolone and levamisole. Baseline features showed preponderance of young patients presenting within two-years of disease onset. On intention-to-treat analysis, frequent relapses were more common in patients administered prednisolone (40% versus 22.5%; risk difference 17.5%; 95% confidence interval 3.4-31.6%). Prednisolone was not non-inferior to levamisole in preventing frequent relapses. However, the two groups showed similar proportions of patients in sustained remission, comparable frequency of relapses, and low frequency of adverse events. The decline in steroid requirement from baseline was higher in the levamisole group. Per-protocol analysis showed similar results. These results have implications for choice of therapy for frequently relapsing nephrotic syndrome. Although therapy with alternate-day prednisolone was not non-inferior to levamisole in preventing frequent relapses, both therapies were effective in other outcome measures. Thus, levamisole was relatively steroid-sparing and may be preferred in patients at risk of steroid toxicity.

Antineutrophil cytoplasmic antibody in children with nephrotic syndrome treated with levamisole: a cross-sectional cohort study

BACKGROUND

Levamisole is a commonly used steroid-sparing agent (SSA), but the reported incidence of antineutrophil cytoplasmic antibody (ANCA) positivity has been concerning.

METHODS

Observational cross-sectional study wherein children aged 2 to 18 years with frequently relapsing/steroid dependent nephrotic syndrome (FRNS/SDNS) on levamisole for ≥ 12 months were tested for ANCA.

RESULTS

A total of 210 children (33% female), median age of 7.3 (IQR: 5.6-9.6) years, and a median duration of levamisole exposure of 21 (IQR: 15-30) months were tested. ANCA was positive in 18% (n = 37): 89% (n = 33) perinuclear ANCA (pANCA), 3% (n = 1) cytoplasmic ANCA (cANCA), and 8% (n = 3) both. Of ANCA-positive children, none had reduced eGFR or abnormal urinalysis. The majority of these children were asymptomatic (81%, n = 30). Rash was more common among ANCA-positive children [6/37 (16%) vs. 3/173 (2%), p = 0.0001]. On multivariate analysis, higher age (OR = 1.02, [95th CI: 1.01 to 1.03], p = 0.007) and longer duration of levamisole exposure (OR = 1.05, [95th CI: 1.02 to 1.08], p = 0.0007) were associated with ANCA positivity. Levamisole was stopped in ANCA-positive children with the resolution of any clinical manifestations if present. Repeat ANCA testing was performed in 54% (20/37), and all were ANCA negative by 18 months.

CONCLUSIONS

Children with FRNS/SDNS on longer duration of levamisole were associated with increasing prevalence of ANCA positivity, but most of these children were clinically asymptomatic. Prospective studies are required to determine the chronology of ANCA positivity and its clinical implication.

Childhood nephrotic syndrome

Idiopathic nephrotic syndrome is the most common glomerular disease in children. Corticosteroids are the cornerstone of its treatment, and steroid response is the main prognostic factor. Most children respond to a cycle of oral steroids, and are defined as having steroid-sensitive nephrotic syndrome. Among the children who do not respond, defined as having steroid-resistant nephrotic syndrome, most respond to second-line immunosuppression, mainly with calcineurin inhibitors, and children in whom a response is not observed are described as multidrug resistant. The pathophysiology of nephrotic syndrome remains elusive. In cases of immune-mediated origin, dysregulation of immune cells and production of circulating factors that damage the glomerular filtration barrier have been described. Conversely, up to a third of cases of steroid-resistant nephrotic syndrome have a monogenic origin. Multidrug resistant nephrotic syndrome often leads to kidney failure and can cause relapse after kidney transplant. Although steroid-sensitive nephrotic syndrome does not affect renal function, most children with steroid-sensitive nephrotic syndrome have a relapsing course that requires repeated steroid cycles with significant side-effects. To minimise morbidity, some patients require steroid-sparing immunosuppressive agents, including levamisole, mycophenolate mofetil, calcineurin inhibitors, anti-CD20 monoclonal antibodies, and cyclophosphamide. Close monitoring and preventive measures are warranted at onset and during relapse to prevent acute complications (eg, hypovolaemia, acute kidney injury, infections, and thrombosis), whereas long-term management requires minimising treatment-related side-effects. A subset of patients have active disease into adulthood.

Late Onset of ANCA Vasculitis as a Side Effect of Levamisole Treatment in Nephrotic Syndrome

Levamisole is effectively used in steroid-dependent nephrotic syndrome and the more frequent side effects reported are cytopenia and liver enzymes alterations. Several studies have demonstrated that this drug can induce high titers of circulating perinuclear antineutrophil cytoplasmic autoantibodies (ANCA) and vasculitis, most of them occurring in the case of prolonged use. A four-year-old boy that was affected with steroid-dependent nephrotic syndrome was treated with Levamisole as a steroid-sparing agent at a dose of 2 mg/kg/48 h. After initiation of the treatment, the number of relapses drastically decreased, enabling a significant reduction in the cumulative steroid dose. Levamisole was well tolerated, and was therefore administered for several years. At the age of 15, he was also diagnosed with celiac disease. After nine years of continuous Levamisole treatment, he presented with a high fever, hand and foot joint arthritis, and increased levels of total and direct bilirubin. Since the symptoms started two days after the injection of the second dose of the COVID-19 vaccine, it was initially concluded that these manifestations were rare vaccination side effects. Therefore, he did not receive any specific treatments, and Levamisole was continued at the same dose. After an initial improvement, two months later, the patient presented with the same symptoms. Suspecting Levamisole-induced vasculitis, an ANCA titer was measured and this returned positive. Clinical manifestations and double positivity for both myeloperoxidase (MPO) and anti-proteinase 3 (PR3) antibodies argued against the fact that that these findings were secondary to vaccination, cocaine abuse, or celiac disease. Assuming that we were facing a rare drug reaction, Levamisole was promptly interrupted. This resulted in a rapid remission of fever and arthritis improvement, and a decrease in ANCA titers. By reporting this case, we want to raise awareness among clinicians regarding a rare complication of treatment with Levamisole that is often misdiagnosed due to the fact that the current literature lacks univocal guidelines regarding the precise timing of ANCA titrations and the duration of the treatment.

Levamisole causes a transient increase in plasma creatinine levels but does not affect kidney function based on cystatin C

BACKGROUND

In pediatric patients treated with levamisole to prevent relapses of idiopathic nephrotic syndrome (INS), a transient and non-progressive rise in creatinine levels has been observed. It has been suggested that levamisole affects tubular secretion of creatinine. However, other potential mechanisms - nephrotoxicity and interference with the analytical assay for creatinine - have never been thoroughly investigated.

METHODS

In three steroid-sensitive nephrotic syndrome (SSNS) patients with elevated plasma creatinine levels, treated with levamisole 2.5 mg/kg every other day, serum cystatin C was determined. The glomerular filtration rate (GFR) was estimated using the full age spectrum for creatinine and the full age spectrum for cystatin C equations. Interference of levamisole with the enzymatic creatinine assay was tested using spare human plasma of different creatinine concentrations spiked with levamisole (4, 20, and 100 µM).

RESULTS

Three patients who received levamisole with elevated plasma creatinine levels had normal serum cystatin C levels and corresponding estimated GFR. There was no assay interference.

CONCLUSION

Levamisole increases plasma creatinine levels, which is most probably due to impaired tubular secretion of creatinine since there was no assay interference and patients had normal eGFR based on serum cystatin C. However, interference of metabolites of levamisole could not be excluded. To monitor GFR, cystatin C in addition to creatinine should be used and be measured before and during levamisole use.