Serum sickness with refractory nephrotic syndrome following treatment with rituximab

Sequential rituximab therapy sustains remission of nephrotic syndrome but carries high risk of adverse effects

BACKGROUND

Sequential rituximab (RTX) administration has emerged as an important strategy to sustain remission of disease in patients with difficult-to-treat nephrotic syndrome.

METHODS

We report the efficacy and safety of sequential therapy with two or more courses of intravenous RTX in 250 patients with difficult-to-treat steroid dependence (n = 127) and calcineurin inhibitor (CNI)-dependent or CNI-refractory steroid resistance (n = 123) managed at one center during 2015-2021. Subsets of patients were cross-sectionally tested for hypogammaglobulinemia, seroprotection against and hyporesponsiveness to vaccines for hepatitis B and tetanus, BK/JC viruria and human antichimeric antibodies (HACAs).

RESULTS

Sequential RTX therapy, initiated at a median of 10 years [interquartile range (IQR) 7.3-14.4], was administered for 1.8 courses/person-year [95% confidence interval (CI) 1.7-2.0] over 2.0 years (95% CI 1.2-3.0). Therapy was associated with postponement of relapses by a median of 3 years in patients with steroid-sensitive disease and 2 years in those with steroid resistance. Relapses were reduced by a mean of 2.0 relapses/person-year (95% CI 1.8-2.2), enabling a reduction in prednisolone dose to 0.04 mg/kg/day (95% CI 0.01-0.11) and withdrawal of additional immunosuppression in 154 (62%) patients. RTX-associated adverse events, occurring at 0.20 events/person-year (95% CI 0.17-0.23), were chiefly comprised of infusion reactions (n = 108) and infections (n = 46); serious adverse events were observed in 10.8% patients, at 0.03 events/person-year (95% CI 0.02-0.05). Hypogammaglobulinemia was observed in 35% of 177 patients and was moderate to severe in 8.5% of cases. Rates of seroprotection at baseline and response following vaccination were lower for hepatitis B [1.9% and 29.4% (n = 52)] than tetanus [65.5% and 34.5% (n = 58)]. BK/JC viruria, without viremia, was observed in 7.3% of 109 cases. A total of 19 of 107 patients (17.8%) had HACAs, which were associated with B cell nondepletion and serum sickness. Age at therapy of <9-10 years was associated with a risk of early relapse, treatment failure and hypogammaglobulinemia following RTX therapy.

CONCLUSIONS

Sequential therapy with RTX effectively reduces relapses in patients with difficult-to-treat steroid- and/or CNI-dependent or CNI-refractory nephrotic syndrome. Therapy is associated with high rates of hypogammaglobulinemia and infusion reactions.

Rituximab-induced serum sickness in a girl with nephrotic syndrome

Rituximab (RTX) has been used to treat B cell lineage lymphoma/leukemia or autoimmune or autoinflammatory disorders. RTX therapy has been extensively applied to cases of frequently relapsing nephrotic syndrome (FRNS) and steroid-dependent nephrotic syndrome. Rituximab-induced serum sickness (RISS) has been recognized as a rare severe type-3 hypersensitivity reaction in patients treated with RTX. We herein report a 10-year-old girl with RISS in FRNS. She was diagnosed with RISS based on characteristic symptoms, such as a fever, rash, arthritis, or proteinuria, during RTX therapy associated with a high level of human anti-chimeric antibody. Even after recovering from acute symptoms by RISS, she suffered from worsening relapses of nephrotic syndrome. The symptoms of RISS are non-specific, resembling viral infections, autoinflammatory diseases and Kawasaki disease, especially in children. While RISS is a rare complication among patients with nephrotic syndrome, it should be carefully considered as a severe complication in patients being treated with RTX.

Serum sickness following rituximab therapy in a patient with pemphigus vulgaris: A case report

Serum sickness, a reaction presenting with a classic triad (fever, rash, myalgia/arthralgia), is considered as a rare adverse event following monoclonal antibodies and specifically following treatment with rituximab. This report describes a case of serum sickness in a newly treated young male patient with rituximab for pemphigus vulgaris.

The case of Kawasaki disease after rituximab infusion triggered by human anti-chimeric antibodies

Rituximab (RTX) is an effective treatment for refractory nephrotic syndrome (NS), but may produce human anti-chimeric antibodies (HACA) which can cause severe infusion reaction or rituximab-induced serum sickness (RISS). RISS presents with a fever, rash, and arthralgia, which typically occurs 7-21 days after RTX infusion. On the other hand, Kawasaki disease (KD) also presents with fever and rash. There have been no reports of KD developed after RTX infusion. A 6-year-old girl with frequently relapsing NS was admitted to our hospital for fever and rash on day 7 after receiving RTX. Although it was suggestive of RISS at first, she also had conjunctival hyperemia, swelling, and erythema of the hands and feet, and a right coronary artery abnormality on echocardiography. Her symptoms met the diagnostic criteria of KD. We administered intravenous immunoglobulin (IVIg) (2 g/kg), and her symptoms resolved within a few days. The HACA titer determined using the serum collected at admission was very high. This is the first report of KD with a clinical course similar to RISS. It should be noted that a careful follow-up of coronary arteries should be performed in patients suspected of RISS.

Rituximab-induced serum sickness in a 6-year-old boy with steroid-dependent nephrotic syndrome

Rituximab (RTX) is a murine-human chimeric monoclonal antibody against CD20 that has been proven effective for preventing relapse in frequently-relapsing or steroid-dependent nephrotic syndrome (NS). Serum sickness, a type-3 hypersensitivity reaction resulting from injection of foreign proteins, has been reported in patients treated with RTX. Herein, we describe a case of RTX-induced serum sickness (RISS) in a 6-year-old boy with steroid-dependent NS. He presented to the hospital with fever and polyarthralgia at 10 days after his fourth dose of RTX. Although he was started on empiric intravenous antibiotics, there was no evidence of septic arthritis and his symptoms resolved over the course of 4 days. He was diagnosed with RISS based on the chronology of RTX administration and the acute-onset self-limiting course of the polyarthritis. His serum human anti-chimeric antibody (HACA) level on day 53 exceeded the limit of quantification (5000 ng/mL). The pathogenesis of RISS and the role of HACAs remain unclear. It is important for clinicians to recognize RISS, because further infusions of RTX may cause more severe reactions in patients with a history of RISS.

Rituximab Use in the Management of Childhood Nephrotic Syndrome

Childhood nephrotic syndrome is a challenging and often persistent renal disorder, and its incidence varies between different ethnicities and regions. Corticosteroids have been the main treatment for decades and are effective in most children with idiopathic NS, although 10-15% of these children become steroid resistant. Furthermore, some initially steroid sensitive children follow a steroid dependent or frequently relapsing course and are therefore at increased risk for developing steroid toxicity. In such children, alternative immunosuppressive medications are used to induce and/or maintain remission of NS. One such drug, rituximab, is a monoclonal antibody directed against the B lymphocyte CD20 marker which induces depletion of B cells, and has shown promising results in the management of NS in children. In this review, we summarize recent studies on the efficacy and safety of rituximab in the different types of childhood nephrotic syndrome, the known and potential mechanisms of action of rituximab, its possible complications and side effects, and the available and potential biomarkers of rituximab activity.