The Risk of Severe Infections Following Rituximab Administration in Patients With Autoimmune Kidney Diseases: Austrian ABCDE Registry Analysis.

Objective: To characterize the incidence, type, and risk factors of severe infections (SI) in patients with autoimmune kidney diseases treated with rituximab (RTX). Methods: We conducted a multicenter retrospective cohort study of adult patients with immune-related kidney diseases treated with at least one course of RTX between 2015 and 2019. As a part of the ABCDE Registry, detailed data on RTX application and SI were collected. SI were defined by Common Terminology Criteria for Adverse Events v5.0 as infectious complications grade 3 and above. Patients were dichotomized between "nephrotic" and "nephritic" indications. The primary outcome was the incidence of SI within 12 months after the first RTX application. Results: A total of 144 patients were included. Twenty-five patients (17.4%) presented with SI, mostly within the first 3 months after RTX administration. Most patients in the nephritic group had ANCA-associated vasculitis, while membranous nephropathy was the leading entity in the nephrotic group. Respiratory infections were the leading SI (n= 10, 40%), followed by urinary tract (n=3, 12%) and gastrointestinal infections (n=2, 8%). On multivariable analysis, body mass index (BMI, 24.6 kg/m2versus 26.9 kg/m2, HR: 0.88; 95%CI: 0.79-0.99; p=0.039) and baseline creatinine (HR: 1.25; 95%CI: 1.04-1.49; p=0.017) were significantly associated with SI. All patients in the nephritic group (n=19; 100%) who experienced a SI received oral glucocorticoid (GC) treatment at the time of infection. Hypogammaglobulinemia was frequent (58.5%) but not associated with SI. Conclusions: After RTX administration, impaired kidney function and lower BMI are independent risk factors for SI. Patients with nephritic glomerular diseases having concomitant GC treatment might be at higher risk of developing SI.

Hypomagnesemia Is a Risk Factor for Infections after Kidney Transplantation: A Retrospective Cohort Analysis.

INTRODUCTION: Magnesium (Mg2+) deficiency is a common finding in the early phase after kidney transplantation (KT) and has been linked to immune dysfunction and infections. Data on the association of hypomagnesemia and the rate of infections in kidney transplant recipients (KTRs) are sparse. METHODS: We conducted a single-center retrospective cohort study of KTRs transplanted between 2005 and 2015. Laboratory data, including serum Mg2+ (median time of the Mg2+ measurement from KT: 29 days), rate of infections including mainly urinary tract infections (UTI), and common transplant-related viral infections (CMV, polyoma, EBV) in the early phase after KT were recorded. The primary outcome was the incidence of infections within one year after KT, while secondary outcomes were hospitalization due to infection, incidence rates of long-term (up to two years) infections, and all-cause mortality. RESULTS: We enrolled 376 KTRs of whom 229 patients (60.9%) suffered from Mg2+ deficiency defined as a serum Mg2+ < 0.7 mmol/L. A significantly higher incidence rate of UTIs and viral infections was observed in patients with versus without Mg2+ deficiency during the first year after KT (58.5% vs. 47.6%, p = 0.039 and 69.9% vs. 51.7%, p < 0.001). After adjustment for potential confounders, serum Mg2+ deficiency remained an independent predictor of both UTIs and viral infections (odds ratio (OR): 1.73, 95% CI: 1.04-2.86, p = 0.035 and OR: 2.05, 95% CI: 1.23-3.41, p = 0.006). No group differences according to Mg2+ status in hospitalizations due to infections and infection incidence rates in the 12-24 months post-transplant were observed. In the Cox regression analysis, Mg2+ deficiency was not significantly associated with all-cause mortality (HR: 1.15, 95% CI: 0.70-1.89, p = 0.577). CONCLUSIONS: KTRs suffering from Mg2+ deficiency are at increased risk of UTIs and viral infections in the first year after KT. Interventional studies investigating the effect of Mg2+ supplementation on Mg2+ deficiency and viral infections in KTRs are needed.

Effect of short-interval rituximab and high-dose corticosteroids on kidney function in systemic sclerosis: Long-term experience of a single centre.

INTRODUCTION: Scleroderma renal crisis (SRC) is a rare but one of the most recognised complications of systemic sclerosis (SSc). Corticosteroid (CS) use has been considered as a major risk factor for SRC. Several studies reported the efficacy of rituximab (RTX) with an acceptable safety profile in SSc. However, data on the long-term effect of high-dose CS concomitant to RTX on kidney function are lacking. METHODS: We retrospectively analysed SSc patients (n = 35) treated with a lower dosage and short-interval RTX and concomitant high-dose CS at the Department of Internal Medicine at the Medical University of Graz between 2010 and 2019. The kidney function was assessed using the estimated glomerular filtration rate (eGFR) at every RTX admission. The annual decline of kidney function was evaluated by linear mixed model analysis. RESULTS: At the RTX initiation, one patient had a decreased kidney function indicated by eGFR < 60 mL/min/1.73 m2 (median: 96 mL/min/1.73 m2 ; interquartile range (IQR): 43-136). Patients received RTX and complementary high-dose CS for a median follow-up time of 3.4 years (range 0.6-9.5). A linear mixed model analysis with the patient as random effect and time from first RTX as fixed effect estimated an annual decline of 1.98 mL/min/1.73 m2 of the eGFR (95% confidence interval: [-2.24, -1.72]; P <.001). During the follow-up period, no patient experienced SRC or a significant drop in kidney function. CONCLUSIONS: A regular, high-dose CS given contemporary to RTX seems to be a safe option for kidney function in patients with SSc. Our findings provide additional knowledge in risk evaluation and planning of individualised therapies or designing clinical studies using RTX.