Hemophagocytic lymphohistiocytosis secondary to virus infection and followed by lupus nephritis recurrence in a renal transplantation pediatric recipient: a case report.

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening disorder characterized by systemic inflammation and organ failure as a result of dysregulated immune cell activation. HLH can be induced by a variety of factors including infection, tumours and autoimmune disease and can also occur in patients following solid organ transplantation. Occurrence of HLH and lupus nephritis (LN) successively within a short period of time after renal transplantation is uncommon. CASE PRESENTATION: We described an 11-year-old female post-transplant patient who presented with hemocytopenia, fever, elevated serum ferritin, splenomegaly, hyperlipidemia, and hypofibrinemia, and was clinically diagnosed with HLH. After comprehensive treatment with corticosteroids, intravenous immunoglobulin (IVIG), and reducing immunosuppressants, her condition improved, but then hematuria ensued. The transplant kidney biopsy showed LN. She was treated with hydroxychloroquine and methylprednisolone while intensive immunosuppressive agents were given. She has remained in remission for two years until now. CONCLUSIONS: The main inducing factors of HLH should be identified as early as possible, and accurate treatment plans should be taken. The long-course IVIG regimen may be one of the effective treatments for virus-induced HLH. After remission of HLH, we need to be alert to the recurrence of autoimmune diseases in patients with underlying diseases, and timely increase immunosuppressants.

Population Pharmacokinetics of Polymyxin B and Dosage Optimization in Renal Transplant Patients.

Currently, polymyxin B has been widely used in the treatment of multidrug-resistant Gram-negative pathogen infections. Due to the limited pharmacokinetic/pharmacodynamic data, the optimal dosage regimen for the recently proposed therapeutic target of the area under the concentration-time curve over 24 h in steady state divided by the minimum inhibitory concentration 50-100 mg⋅h/L has not yet been established. Moreover, most studies have focused on critically ill patients, yet there have been no studies in the field of renal transplantation. To optimize the dosage strategy and reduce the risk of toxicity, a population pharmacokinetics model of polymyxin B with the Phoenix NLME program was developed in our study. A total of 151 plasma samples from 50 patients were collected in the present study. Polymyxin B plasma concentrations were measured by high-performance liquid chromatography-tandem mass spectrometry. A one-compartment model adequately described the data, and the clearance and volume of distribution were 1.18 L/h and 12.09 L, respectively. A larger creatinine clearance was associated with increased clearance of polymyxin B (p < 0.01). Monte Carlo simulation showed that a regimen of a 75 mg loading dose with a 50 mg maintenance dose was a better option to achieve an optimal therapeutic effect (minimum inhibitory concentration ≤1 mg/L) and to reduce the incidence of side effects for patients with renal impairments. The developed model suggested that dosing adjustment should be based on renal function in renal transplant patients.

Comparison of Outcomes of Kidney Transplantation From Extremely Low Body Weight ≤5kg Versus Larger Body Weight Pediatric Donors.

Background: Kidney transplantation from donors who weigh ≤5 kg is performed at only a few transplant centers owing to the high complication and low graft survival rates associated with this approach. Methods: We retrospectively compared the results of kidney transplantation at our center between January 2015 and December 2019 based on the following pediatric donor criteria: donor body weight ≤5 kg (n=32), 5 kg< donor weight ≤20 kg (n=143), and donor weight >20 kg (n=110). We also perform subgroup analysis of kidney transplantation outcomes from ≤5 kg donors, using conventional (dual separate and classic en-bloc KTx)/novel (en-bloc KTx with outflow tract) surgical methods and allocating to adult/pediatric recipients. Results: The death-censored graft survival rates from extremely low body weight ≤5kg at 1 month, and 1, 3, and 5 years were 90.6%, 80.9%, 77.5%, and 73.9%, respectively, which were significantly lower than that from larger body weight pediatric donors. However, the 3-, and 5-year post-transplantation eGFRs were not significantly different between the pediatric and adult recipient group. The thrombosis (18.8%) and urinary leakage (18.8%) rates were significantly higher in the donor weight ≤5 kg group. Compared with 5 kg< donor weight ≤20 kg group, donor weight ≤5kg group was at elevated risk of graft loss due to thrombosis (OR: 13.4) and acute rejection (OR: 6.7). No significant difference on the outcomes of extremely low body weight donor kidney transplantation was observed between adults and pediatric recipients. Urinary leakage rate is significantly lower in the novel operation (8.7%) than in the conventional operation group (44.4%). Conclusions: Although the outcomes of donor body weight ≤5kg kidney transplantation is inferior to that from donors with large body weight, it can be improved through technical improvement. Donors with body weight ≤5 kg can be considered as an useful source to expand the donor pool.