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Background: Rituximab, a monoclonal antibody targeting B lymphocytes, effectively sustains remission in steroid-dependent nephrotic syndrome (SDNS). We studied its effects on lymphocyte subsets and urinary CD80 excretion (uCD80) in patients with SDNS., Methods: Blood and urine samples were collected from 18 SDNS patients before rituximab, and after 1 month and 1 year or at first relapse. T and B lymphocytes and uCD80 were determined by flow cytometry and ELISA, respectively., Results: Treatment was associated with reduction in counts of Th17, Th2, and memory T cells, and increased T-regulatory (Treg) cells. The Th17/Treg ratio declined from baseline (median 0.6) to 1 month (0.2, P = 0.006) and increased during relapse (0.3, P = 0.016). Ratios of Th1/Th2 cells at baseline, 1 month after rituximab, and during relapse were 7.7, 14.0 (P = 0.0102), and 8.7, respectively. uCD80 decreased 1 month following rituximab (45.5 vs. 23.0 ng/g creatinine; P = 0.0039). B lymphocytes recovered earlier in relapsers (60.0 vs.183.0 days; P < 0.001). Memory B cells were higher during relapse than remission (29.7 vs.18.0 cells/µL; P = 0.029)., Conclusion: Rituximab-induced sustained remission and B-cell depletion was associated with reduced numbers of Th17 and Th2 lymphocytes, and increased Treg cells; these changes reversed during relapses. Recovery of B cells and memory B cells predicted the occurrence of a relapse.

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. [ABSTRACT FROM AUTHOR]

Atypical HUS associated with anti- CFH autoantibodies is an uncommon illness associated with high risk of progression to end-stage renal disease. Disease relapses after transplantation, observed in one-third cases, often lead to graft loss. We report four patients with anti- CFH antibody-associated HUS who underwent renal transplantation 16-62 months from initial presentation. Two patients each received organs from deceased and living-related donors. Anti- CFH antibody titers were monitored during the illness and following transplantation. All patients received two doses of IV rituximab before or after transplantation; three patient each received 1-2 g/kg of IV immunoglobulin or underwent 2-5 sessions of plasma exchanges. The use of therapeutic plasma exchange, IV immunoglobulin, and rituximab in two cases enabled two-third reduction in anti- CFH antibody titers before transplantation. At 5- to 26-month follow-up, all patients showed satisfactory graft function without recurrence of HUS. This is the first report of patients with anti- CFH antibody-associated HUS who underwent living-related renal transplantation. Clearance of anti- CFH antibody by therapeutic plasma exchange and adjuvant immunosuppression aimed at decreasing antibody levels may enable successful transplantation and recurrence-free survival. [ABSTRACT FROM AUTHOR]

Rituximab offers an alternative to current immunosuppressive therapies for difficult-to-treat nephrotic syndrome. The best outcomes are seen in patients with steroid-dependent nephrotic syndrome who have failed to respond to multiple therapies. By contrast, the benefits of rituximab therapy are limited in patients with steroid-resistant nephrotic syndrome, particularly those with focal segmental glomerulosclerosis (FSGS). Therapy with plasma exchange and one or two doses of rituximab has shown success in patients with recurrent FSGS. Young patients and those with normal serum albumin at recurrence of nephrotic syndrome are most likely to respond to rituximab therapy. A substantial proportion of rituximab-treated patients with idiopathic membranous nephropathy show complete or partial remission of proteinuria, and reduced levels of phospholipase A2 receptor autoantibodies, which are implicated in the pathogenesis of this disorder. Successful rituximab therapy induces prolonged remission and enables discontinuation of other medications without substantially increasing the risk of infections and other serious adverse events. However, the available evidence of efficacy of rituximab therapy is derived chiefly from small case series and requires confirmation in prospective, randomized, controlled studies that define the indications for use and predictors of response to this therapy. [ABSTRACT FROM AUTHOR]

Although therapy with intravenous (IV) rituximab and tacrolimus reduces the relapse rate in steroid-dependent nephrotic syndrome (SDNS), studies on comparative efficacy are lacking. We retrospectively reviewed the records of patients with difficult-to-treat SDNS who had previously received levamisole, cyclophosphamide and/or mycophenolate mofetil, then treated with either rituximab or tacrolimus and followed for 12 months. Between January 2009 and April 2010, ten patients received two to three doses of IV rituximab (375 mg/m/week) and 13 received tacrolimus (0.1-0.2 mg/kg/day) for 12 months; none had previously received either agent. Patients received tapering doses of alternate-day prednisolone; other immunosuppressive agents were discontinued. The mean age of the patients at treatment initiation with rituximab and tacrolimus was 12.2 ± 2.3 and 12.3 ± 3.0 years, respectively. The respective pre-treatment relapse rates (3.1 ± 1.1 and 3.5 ± 1.6 relapses per year) and cumulative prednisolone dose (137.2 ± 69.4 and 140.5 ± 59.0 mg/kg/year) were similar. Therapy resulted in a decline in relapse rate in both groups ( P < 0.001). The number of relapses in the rituximab and tacrolimus groups was similar at 6 months (0.3 ± 0.5 vs. 0.3 ± 0.6 episodes, respectively), 12 months (0.8 ± 1.0 vs. 0.9 ± 1.1 episodes) and last follow-up (1.2 ± 1.0 vs. 1.5 ± 1.3 episodes). There were no differences in relapse-free survival at 6, 12 and 18 months. Therapy resulted in a significant decline in the cumulative prednisolone dose (67.2% in the rituximab group and 43.6% in the tacrolimus group) and a reduced body mass index. These findings suggest that in our patients with difficult-to-treat SDNS, treatment with two to three doses of rituximab was as effective as 12 months of therapy with tacrolimus in terms of steroid sparing and reduction in the relapse rate. [ABSTRACT FROM AUTHOR]

C1q nephropathy is a rare idiopathic glomerulopathy characterized by mesangial deposition of immunoglobulin and complement with C1q dominance or co-dominance, and the absence of clinical and laboratory evidence of systemic lupus erythematosus. Its clinical course is unpredictable and the response to corticosteroid or cytotoxic treatment is variable. Here, we report two cases of C1q nephropathy, one in a child and one in an adult, both presenting with impaired renal function and massive proteinuria. Both patients failed to respond to immunosuppressive medications; however, rituximab, an anti-CD20 antibody, was effective in preserving renal function in one patient and eliminating the need for hemodialysis in the other. In one patient, histologic regression of abnormalities was documented over 3 years post-treatment. Both patients have remained off other immunosuppressive medication for a prolonged period with stable renal function. These cases are, to our knowledge, the first reported successful treatment of C1q nephropathy with rituximab. [ABSTRACT FROM AUTHOR]

This article presents a letter to the editor offering a study of rituximab in patients with steroid-resistant nephrotic syndrome.