Serological and genetic complement alterations in infection-induced and complement-mediated hemolytic uremic syndrome

Contains fulltext : 175097.pdf (Publisher’s version ) (Open Access

Serological and genetic complement alterations in infection-induced and complement-mediated hemolytic uremic syndrome

The role of complement in the atypical form of hemolytic uremic syndrome (aHUS) has been investigated extensively in recent years. As the HUS-associated bacteria Shiga-toxin-producing Escherichia coli (STEC) can evade the complement system, we hypothesized that complement dysregulation is also important in infection-induced HUS. Serological profiles (C3, FH, FI, AP activity, C3d, C3bBbP, C3b/c, TCC, alpha FH) and genetic profiles (CFH, CFI, CD46, CFB, C3) of the alternative complement pathway were prospectively determined in the acute and convalescent phase of disease in children newly diagnosed with STEC-HUS or aHUS. Serological profiles were compared with those of 90 age-matched controls. Thirty-seven patients were studied (26 STEC-HUS, 11 aHUS). In 39 % of them, including 28 % of STEC-HUS patients, we identified a genetic and/or acquired complement abnormality. In all patient groups, the levels of investigated alternative pathway (AP) activation markers were elevated in the acute phase and normalized in remission. The levels were significantly higher in aHUS than in STEC-HUS patients. In both infection-induced HUS and aHUS patients, complement is activated in the acute phase of the disease but not during remission. The C3d/C3 ratio displayed the best discrepancy between acute and convalescent phase and between STEC-HUS and aHUS and might therefore be used as a biomarker in disease diagnosis and monitoring. The presence of aberrations in the alternative complement pathway in STEC-HUS patients was remarkable, as well

Disparities in dialysis treatment and outcomes for Dutch and Belgian children with immigrant parents

BACKGROUND: In Belgium and the Netherlands, up to 40% of the children on dialysis are children with immigrant parents of non-Western European origin (non-Western). Concerns exist regarding whether these non-Western patients receive the same quality of care as children with parents of Western European origin (Western). We compared initial dialysis, post-initial treatment, and outcomes between non-Western and Western patients on dialysis. METHODS: All children <19 years old on chronic dialysis in the Netherlands and Belgium between September 2007 and May 2011 were included in the study. Non-Western patients were defined as children of whom one or both parents were born in non-Western countries. RESULTS: Seventy-nine of the 179 included patients (44%) were non-Western children. Compared to Western patients, non-Western patients more often were treated with hemodialysis (HD) instead of peritoneal dialysis (PD) as first dialysis mode (52 vs. 37%, p = 0.046). Before renal transplantation, non-Western patients were on dialysis for a median (range) of 30 (5-99) months, vs. 15 (0-66) months in Western patients (p = 0.007). Renal osteodystrophy was diagnosed in 34% of non-Western vs. 18% of Western patients (p = 0.028). The incidence rate ratio [95% confidence interval] for acute peritonitis was 2.44 [1.43-4.17] (p = 0.032) for non-Western compared to Western patients. CONCLUSIONS: There are important disparities between children on chronic dialysis with parents from Western European origin and those from non-Western European origin in the choice of modality, duration, and outcomes of dialysis therapy

Diagnosis and management in Rubinstein-Taybi syndrome: first international consensus statement

Rubinstein-Taybi syndrome (RTS) is an archetypical genetic syndrome that is characterised by intellectual disability, well-defined facial features, distal limb anomalies and atypical growth, among numerous other signs and symptoms. It is caused by variants in either of two genes (CREBBP, EP300) which encode for the proteins CBP and p300, which both have a function in transcription regulation and histone acetylation. As a group of international experts and national support groups dedicated to the syndrome, we realised that marked heterogeneity currently exists in clinical and molecular diagnostic approaches and care practices in various parts of the world. Here, we outline a series of recommendations that document the consensus of a group of international experts on clinical diagnostic criteria for types of RTS (RTS1: CREBBP; RTS2: EP300), molecular investigations, long-term management of various particular physical and behavioural issues and care planning. The recommendations as presented here will need to be evaluated for improvements to allow for continued optimisation of diagnostics and care

Proposal for individualized dosing of eculizumab in atypical hemolytic uremic syndrome: patient friendly and cost-effective

BACKGROUND: Eculizumab is a lifesaving yet expensive drug for atypical hemolytic uremic syndrome. Current guidelines advise a fixed-dosing schedule, which can be suboptimal and inflexible in the individual patient. METHODS: We evaluated pharmacokinetics (PK) and pharmacodynamics (PD) (classical pathway (CP) activity levels) of eculizumab in 48 patients, consisting of 849 time-concentration data and 569 CP activity levels. PK-PD modeling was performed with non-linear mixed effects modeling. The final model was used to develop improved dosing strategies. RESULTS: A PK-model with parallel linear and non-linear elimination rates best described the data with the parameter estimates: clearance 0.163L/day, Volume of distribution 6.42L, maximal rate 29.6mg/day, concentration for 50% of maximum rate 37.9mg/L. The PK-PD relation between eculizumab concentration and CP activity was described using an inhibitory Emax model with the parameter estimates: baseline 101%, maximal inhibitory effect 95.9%, concentration for 50% inhibition 22.0mg/L, Hill coefficient 5.42. A weight-based loading dose, followed by pharmacokinetically-guided dosing was found to improve treatment. On day 7, we predict 99.95% of the patients to reach the efficacy target (CP activity <10%), compared to 94.75% with standard dosing. Comparable efficacy was predicted during the maintenance phase, while the dosing interval could be prolonged in ∼33% of the population by means of individualized dosing. With a fixed-dose four-week dosing interval to allow holidays, treatment costs will increase with 7.1% and we predict 91% of the patients to reach the efficacy target. CONCLUSIONS: A patient-friendly individualized dosing strategy of eculizumab has the potential to improve treatment response at reduced costs

Correction to: Levamisole causes a transient increase in plasma creatinine levels but does not affect kidney function based on cystatin C (Pediatric Nephrology, (2022), 37, 10, (2515-2519), 10.1007/s00467-022-05547-9)

The original version of this article unfortunately contained a mistake. During the process of typesetting, the institutional author attribution “on behalf of the LEARNS consortium” was left out of the author group. The correct attribution is as shown above. The publisher apologizes for this mistake. The original article was updated

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

The Use of Patient-Reported Outcome Measures in Daily Clinical Practice of a Pediatric Nephrology Department

(1) Background: Health-related quality of life (HRQoL) is lower in patients with chronic kidney disease (CKD) compared to the general population. In 2011, the KLIK PROM portal was implemented in the Emma Children’s Hospital to monitor and discuss HRQoL in daily care. This study describes and assesses the implementation and use of the KLIK PROM portal in the pediatric nephrology department. (2) Methods: CKD patients (self-report, if 8–18 years of age) and their parents (proxy-report, if 1–8 years) were invited to complete HRQoL patient-reported outcome measures (PROMs): TNO-AZL Preschool children Quality Of Life (TAPQOL) or Pediatric Quality of Life Inventory for Children (PedsQL). The PROMs were completed before and discussed during outpatient consultations. The adaptation rate—the proportion of patients/parents who were invited and completed at least one PROM—was calculated. Reported HRQoL scores of CKD patients were compared to the general population. (3) Results: In total, 142 patients (proxy-and self-report) were invited, 112 patients completed at least one PROM (adaptation rate 79%). Patients (n = 84 with informed consent for scientific use) with CKD reported lower HRQoL and HRQoL was more often impaired compared to the general Dutch population. (4) Conclusions: The implementation of KLIK was successful and its use is feasible for daily care. Using KLIK, HRQoL problems can be easily identified and monitored