Sequential administration of anti-complement component C5 eculizumab and type-2 anti-CD20 obinutuzumab for the treatment of early antibody-mediated rejection after kidney transplantation: A proof of concept.

Kidney transplant (KT) candidates with donor-specific antibodies (DSA) exhibit exceedingly high antibody-mediated rejection (ABMR) and allograft loss rates. Currently, treatment of ABMR remains an unmet clinical need. We report the use of the anti-C5 eculizumab and the type-2 anti-CD20 obinutuzumab in two patients with early ABMR. Eculizumab (900 mg IV) led to complete inhibition of the terminal complement cascade (unremarkable AP50 and CH50 activity) and prompt stoppage of complement-dependent antibody-mediated allograft injury (clearance of intra-graft C4d and C5b-9 deposition). Despite complement inhibition, obinutuzumab (1000 mg IV) determined full and long-lasting peripheral B-cell depletion, with significant reduction in all DSA. Graft function improved, remaining stable up to three years of follow-up. No signs of active ABMR and rebound DSA were detected. Obinutuzumab B-cell depletion and inhibition of DSA production were not affected by complement blockage. Further studies are needed to confirm the potential benefit of obinutuzumab in association with complement inhibitors.

Renal outcome and plasma methylmalonic acid levels after isolated or combined liver or kidney transplantation in patients with methylmalonic acidemia: A multicenter analysis.

BACKGROUND: Methylmalonic acidemia (MMAemia) is characterized by accumulation of methylmalonic acid (MMA) in all body tissues. To minimize disease-related complications, isolated kidney (KTx), liver (LTx) or combined liver-kidney transplantation (LKTx) have been suggested. However, the impact of these different transplant strategies on outcome are unclear. METHODS: In this multicenter retrospective observational study, we compared plasma MMA levels and estimated glomerular filtration rate (eGFR) data of 83 patients. Sixty-eight patients (82%) had a mut0-type MMAemia, one patient had a mut--type MMAemia, and seven (7.3%) had an inherited defect in cobalamin metabolism (cblA- or cblB-type MMAemia). Median observation period was 3.7 years (0-15.1 years). RESULTS: Twenty-six (31%) patients underwent KTx, 24 (29%) LTx and 33 (40%) LKTx. Posttransplant, mean plasma MMA concentration significantly decreased in all three cohorts; but at month 12, plasma MMA in KTx (1372 ± 1101 µmol/L) was 7.8-fold higher than in LTx (176 ± 103 µmol/L; P < 0.001) and 6.4-fold higher than in LKTx (215 ± 110 µmol/L; P < 0.001). Comparable data were observed at month 24. At time of transplantation, mean eGFR in KTx was 18.1 ± 24.3 mL/min/1.73 m2, in LTx 99.8 ± 29.9 mL/min/1.73 m2, and in LKTx 31.5 ± 21.2 mL/min/1.73 m2. At month 12 posttransplant, mean eGFR in KTx (62.3 ± 30.3 mL/min/1.73 m2) was 33.4% lower than in LTx (93.5 ± 18.3 mL/min/1.73 m2; P = 0.0053) and 25.4% lower than in LKTx (83.5 ± 26.9 mL/min/1.73 m2; P = 0.0403). CONCLUSIONS: In patients with isolated MMAemia, LTx and LKTx lead to markedly lower plasma MMA levels during the first 2 years posttransplant than KTx and are associated with a better preservation of kidney function. LTx should therefore be part of the transplant strategy in MMAemia.

Incidence and outcome of SARS-CoV-2 infection in a pediatric kidney transplant recipient cohort from a single center in Northern Italy.

BACKGROUND: Concern about SARS-CoV-2 infection has increased over the possible effects on immunocompromised patients. Among them, recipients of solid organ transplantation deserve special attention. Data from the adult population suggest they may be at high risk for developing severe COVID-19, but little data are available for pediatric solid organ transplantation recipients. METHODS: From March 2020 to April 2021, KT recipients aged <21 years, routinely managed at our center, who underwent RT-PCR testing with nasopharyngeal swabs to detect SARS-CoV-2 infection, were studied. Tests were performed according to clinical and/or epidemiological criteria. RESULTS: One hundred one transplanted patients were managed at our center during the observation period. Among this population, 57 patients were tested for SARS-CoV-2 infection with a RT-PCR test and were subsequently enrolled. A total of 111 swabs were performed. Twelve out of the 57 patients tested (21.1%) had a positive RT-PCR test result. Among the positive patients, eight were symptomatic (66.7%). Median duration of symptoms and RT-PCR positivity was two days (IQR 1-2.25) and 17 days (IQR 11-27.25), respectively. No patients required specific treatment or IS therapy reduction; no one was admitted to hospital. CONCLUSIONS: Our data show that pediatric renal transplant recipients are at low risk of clinically relevant COVID-19, as is the healthy age-related population. On the contrary, our results differed substantially from those seen in adult SOT recipient populations that have a high incidence and an even earlier and higher mortality rate.

IgM Autoantibodies to Complement Factor H in Atypical Hemolytic Uremic Syndrome.

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS), a severe thrombotic microangiopathy, is often related to complement dysregulation, but the pathomechanisms remain unknown in at least 30% of patients. Researchers have described autoantibodies to complement factor H of the IgG class in 10% of patients with aHUS but have not reported anti-factor H autoantibodies of the IgM class. METHODS: In 186 patients with thrombotic microangiopathy clinically presented as aHUS, we searched for anti-factor H autoantibodies of the IgM class and those of the IgG and IgA classes. We used immunochromatography to purify anti-factor H IgM autoantibodies and immunoenzymatic methods and a competition assay with mapping mAbs to characterize interaction with the target protein. RESULTS: We detected anti-factor H autoantibodies of the IgM class in seven of 186 (3.8%) patients with thrombotic microangiopathy presented as aHUS. No association was observed between anti-factor H IgM and homozygous deletions involving CFHR3-CFHR1. A significantly higher proportion of patients with bone marrow transplant-related thrombotic microangiopathy had anti-factor H IgM autoantibodies versus other patients with aHUS: three of 20 (15%) versus four of 166 (2.4%), respectively. The identified IgM autoantibodies recognize the SCR domain 19 of factor H molecule in all patients and interact with the factor H molecule, inhibiting its binding to C3b. CONCLUSIONS: Detectable autoantibodies to factor H of the IgM class may be present in patients with aHUS, and their frequency is six-fold higher in thrombotic microangiopathy forms associated with bone marrow transplant. The autoantibody interaction with factor H's active site may support an autoimmune mechanism in some cases previously considered to be of unknown origin.

Bloody Diarrhea and Shiga Toxin-Producing Escherichia coli Hemolytic Uremic Syndrome in Children: Data from the ItalKid-HUS Network.

OBJECTIVE: To analyze the results of an enhanced laboratory-surveillance protocol for bloody diarrhea aimed at identifying children with Shiga toxin-producing Escherichia coli (STEC) infection early in the course of the disease toward the early identification and management of patients with hemolytic uremic syndrome (HUS). STUDY DESIGN: The study (2010-2019) involved a referral population of 2.3 million children. Stool samples of patients with bloody diarrhea were screened for Shiga toxin (Stx) genes. Positive patients were rehydrated and monitored for hemoglobinuria until diarrhea resolved or STEC-HUS was diagnosed. RESULTS: A total of 4767 children were screened; 214 (4.5%) were positive for either Stx1 (29.0%) or Stx2 (45.3%) or both Stx1+2 (25.7%); 34 patients (15.9%) developed STEC-HUS (0.71% of bloody diarrheas). Hemoglobinuria was present in all patients with HUS. Patients with Stx2 alone showed a greater risk of STEC-HUS (23.7% vs 12.7%) and none of the patients with Stx1 alone developed HUS. During the same period of time, 95 other patients were diagnosed STEC-HUS but were not captured by the screening program (26 had nonbloody diarrhea, 11 came from areas not covered by the screening program, and 58 had not been referred to the screening program, although they did meet the inclusion criteria). At HUS presentation, serum creatinine of patients identified by screening was significantly lower compared with that of the remaining patients (median 0.9 vs 1.51 mg/dL). CONCLUSIONS: Nearly 1% of children with bloody diarrhea developed STEC-HUS, and its diagnosis was anticipated by the screening program for Stx. The screening of bloody diarrhea for Stx is recommended, and monitoring patients carrying Stx2 with urine dipstick for hemoglobinuria is suggested to identify the renal complication as early as possible.

Mortality in Children Treated With Maintenance Peritoneal Dialysis: Findings From the International Pediatric Peritoneal Dialysis Network Registry.

RATIONALE & OBJECTIVE: Research on pediatric kidney replacement therapy (KRT) has primarily focused on Europe and North America. In this study, we describe the mortality risk of children treated with maintenance peritoneal dialysis (MPD) in different parts of the world and characterize the associated demographic and macroeconomic factors. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: Patients younger than 19 years at inclusion into the International Pediatric Peritoneal Dialysis Network registry, who initiated MPD between 1996 and 2017. EXPOSURE: Region as primary exposure (Asia, Western Europe, Eastern Europe, Latin America, North America, and Oceania). Other demographic, clinical, and macroeconomic (4 income groups based on gross national income) factors also were studied. OUTCOME: All-cause MPD mortality. ANALYTICAL APPROACH: Patients were observed for 3 years, and the mortality rates in different regions and income groups were calculated. Cause-specific hazards models with random effects were fit to calculate the proportional change in variance for factors that could explain variation in mortality rates. RESULTS: A total of 2,956 patients with a median age of 7.8 years at the start of KRT were included. After 3 years, the overall probability of death was 5%, ranging from 2% in North America to 9% in Eastern Europe. Mortality rates were higher in low-income countries than in high-income countries. Income category explained 50.1% of the variance in mortality risk between regions. Other explanatory factors included peritoneal dialysis modality at start (22.5%) and body mass index (11.1%). LIMITATIONS: The interpretation of interregional survival differences as found in this study may be hampered by selection bias. CONCLUSIONS: This study shows that the overall 3-year patient survival on pediatric MPD is high, and that country income is associated with patient survival.

Fenoldopam and renal hemodynamics in shiga toxin-related hemolytic uremic syndrome.

BACKGROUND: Fenoldopam, a vasodilating agent, may represent a potential therapeutic opportunity to increase renal perfusion in those conditions where renal hemodynamics are severely impaired by vascular sub-occlusion, as, indeed, is the case in thrombotic microangiopathies. METHODS: The renal resistance index (RRI) was measured, on and off fenoldopam, in 27 children with STEC-HUS. RESULTS: A 12% decrease in RRI was observed on fenoldopam compared to off treatment without changes in the systemic hemodynamics and with no side effects. CONCLUSIONS: If confirmed in larger series, fenoldopam may become an important addition to supportive care to reduce ischemic damage in STEC-HUS and improve long-term outcomes.

Acute flaccid paralysis due to Echovirus 30 in an immunosuppressed transplant recipient.

An Italian 13-year-old boy immunosuppressed due to kidney transplant presented in November 2018 with acute flaccid paralysis with anterior horn cell involvement resembling the clinical, radiological, and laboratory features of poliomyelitis. Enterovirus was molecularly identified in cerebral spinal fluid and stool samples and the sequence analysis of the VP1 gene of enterovirus genome revealed the presence of Echovirus 30 both in CSF and in stool samples. Echovirus 30 is an emerging neurotropic virus able to cause outbreaks of aseptic meningitis and meningoencephalitis all over the world, but acute flaccid paralysis is not a classical manifestation. A 6-month follow-up revealed a poor outcome with severe motor deficits and only slight improvement in disability. Clinicians must be aware of the possible role of Echovirus 30 in acute flaccid paralysis and active surveillance should consider the possible influence of immunosuppression on the symptoms caused by the widening spectrum of enterovirus infections.

CYP and SXR gene polymorphisms influence in opposite ways acute rejection rate in pediatric patients with renal transplant.

BACKGROUND: We evaluated the role of CYP3A5, ABCB1 and SXR gene polymorphisms in the occurrence of acute kidney rejection in a cohort of pediatric renal transplant recipients. METHODS: Forty-nine patients were genotyped for CYP3A5, ABCB1 and SXR polymorphisms and evaluated with tacrolimus through levels in a retrospective monocenter study. RESULTS: Patients with the A allele of CYP3A5 treated with tacrolimus had a higher risk of acute rejection than those without the A allele, while patients carrying the homozygous GG variant for SXR A7635GG did not show any episode of acute rejection. CONCLUSION: Genetic analysis of polymorphisms implicated in drug metabolism and tacrolimus trough levels may help to forecast the risk of acute rejection and individualize drug dosage in children undergoing renal transplantation.

Neutral pH and low-glucose degradation product dialysis fluids induce major early alterations of the peritoneal membrane in children on peritoneal dialysis.

The effect of peritoneal dialysates with low-glucose degradation products on peritoneal membrane morphology is largely unknown, with functional relevancy predominantly derived from experimental studies. To investigate this, we performed automated quantitative histomorphometry and molecular analyses on 256 standardized peritoneal and 172 omental specimens from 56 children with normal renal function, 90 children with end-stage kidney disease at time of catheter insertion, and 82 children undergoing peritoneal dialysis using dialysates with low-glucose degradation products. Follow-up biopsies were obtained from 24 children after a median peritoneal dialysis of 13 months. Prior to dialysis, mild parietal peritoneal inflammation, epithelial-mesenchymal transition and vasculopathy were present. After up to six and 12 months of peritoneal dialysis, blood microvessel density was 110 and 93% higher, endothelial surface area per peritoneal volume 137 and 95% greater, and submesothelial thickness 23 and 58% greater, respectively. Subsequent peritoneal changes were less pronounced. Mesothelial cell coverage was lower and vasculopathy advanced, whereas lymphatic vessel density was unchanged. Morphological changes were accompanied by early fibroblast activation, leukocyte and macrophage infiltration, diffuse podoplanin presence, epithelial mesenchymal transdifferentiation, and by increased proangiogenic and profibrotic cytokine abundance. These transformative changes were confirmed by intraindividual comparisons. Peritoneal microvascular density correlated with peritoneal small-molecular transport function by uni- and multivariate analysis. Thus, in children on peritoneal dialysis neutral pH dialysates containing low-glucose degradation products induce early peritoneal inflammation, fibroblast activation, epithelial-mesenchymal transition and marked angiogenesis, which determines the PD membrane transport function.

Risk Factors for Early Dialysis Dependency in Autosomal Recessive Polycystic Kidney Disease.

OBJECTIVE: To identify prenatal, perinatal, and postnatal risk factors for dialysis within the first year of life in children with autosomal recessive polycystic kidney disease (ARPKD) as a basis for parental counseling after prenatal and perinatal diagnosis. STUDY DESIGN: A dataset comprising 385 patients from the ARegPKD international registry study was analyzed for potential risk markers for dialysis during the first year of life. RESULTS: Thirty-six out of 385 children (9.4%) commenced dialysis in the first year of life. According to multivariable Cox regression analysis, the presence of oligohydramnios or anhydramnios, prenatal kidney enlargement, a low Apgar score, and the need for postnatal breathing support were independently associated with an increased hazard ratio for requiring dialysis within the first year of life. The increased risk associated with Apgar score and perinatal assisted breathing was time-dependent and vanished after 5 and 8 months of life, respectively. The predicted probabilities for early dialysis varied from 1.5% (95% CI, 0.5%-4.1%) for patients with ARPKD with no prenatal sonographic abnormalities to 32.3% (95% CI, 22.2%-44.5%) in cases of documented oligohydramnios or anhydramnios, renal cysts, and enlarged kidneys. CONCLUSIONS: This study, which identified risk factors associated with onset of dialysis in ARPKD in the first year of life, may be helpful in prenatal parental counseling in cases of suspected ARPKD.

Unacylated ghrelin and obestatin: promising biomarkers of protein energy wasting in children with chronic kidney disease.

BACKGROUND: Impairment in orexigenic/anorexigenic hormone balance may be key in the pathogenesis of protein energy wasting in children with chronic kidney disease (CKD). Measurement of ghrelin and obestatin concentrations in children with CKD would help assess the potential contribution of these hormones to uremic protein energy wasting. METHODS: This was a cross-sectional case-control study. Acylated and unacylated ghrelin and obestatin were measured in 42 children on conservative treatment (CT), 20 children on hemodialysis, 48 pediatric renal transplant (RTx) recipients and 43 controls (CTR) (mean age 11.9, range 5-20 years). Weight, height and bicipital, tricipital, subscapular and suprailiac folds were measured, and the body mass index-standard deviation score (BMI-SDS), percentage of fat mass and fat-free mass were calculated. Urea and creatinine were measured and the glomerular filtration rate (GFR) calculated. RESULTS: Unacylated ghrelin level was higher in patients than controls (p = 0.0001), with the highest levels found in hemodialysis patients (p = 0.001 vs. CKD-CT, p = 0.0001 vs. RTx, p < 0.0001 vs. CTR). Obestatin level was significantly higher in patients on hemodialysis than those on conservative treatment, RTx recipients and controls (p < 0.0001 in each case). Unacylated ghrelin negatively correlated with weight-SDS (p < 0.0001), BMI-SDS (p = 0.0005) and percentage fat mass (p = 0.004) and positively correlated with percentage fat-free mass (p = 0.004). Obestatin concentration negatively correlated with weight-SDS (p = 0.007). Unacylated ghrelin and obestatin concentrations positively correlated with creatinine and urea and inversely with eGFR, even after adjustments for gender, age, puberty and BMI-SDS (p < 0.0001 for each model). CONCLUSIONS: Unacylated ghrelin and obestatin, negatively related to renal function, seem to be promising inverse indicators of nutritional status in children with CKD. Potential therapeutic implications in terms of optimization of their removal in patients on hemodialysis could be hypothesized.

Complement functional tests for monitoring eculizumab treatment in patients with atypical hemolytic uremic syndrome: an update.

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy (TMA) characterized by platelet consumption, hemolysis, and organ damage. Eculizumab (ECU), a humanized antibody that blocks complement activity, has been successfully used in aHUS, but the best treatment schedule is not yet clear. METHODS: Here, we report our experience with ECU maintenance treatment and the interval between subsequent doses being extended based on global classical complement pathway (CCP) activity aimed at <30% for maintaining aHUS into remission. RESULTS: We report on 38 patients with aHUS, 13 children, 21 female, with a median age of 25.0 years (range 0.5-60) at disease onset treated with ECU standard schedule for a median of 2.6 months (range 0.4-24.6). Once stable TMA remission was obtained, the interval between ECU doses was extended based on complement function, with a target CCP activity of <30%. With this approach, 22 patients regularly receive ECU infusion every 28 days and 16 every 21. During a median observation period on ECU, an extended interval of 26.9 months (range 0.8-80.9), with a cumulative observation period of 1,208 months, none of the patients relapsed. CONCLUSION: Monitoring complement activity allows a safe reduction in the frequency of ECU administration in aHUS while keeping the disease in remission.

Bioimpedance-based rather than weight-based ultrafiltration prescription for children on maintenance hemodialysis
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The determination of dry weight (DW) in young children on hemodialysis (HD) remains challenging. Bioimpedance analysis (BIA) is a potentially helpful means of estimating the need for ultrafiltration and monitoring body fluids in patients on renal replacement therapy, but its role has not yet been clearly defined. The aim of this paper is to share our experience of prescribing ultrafiltration on the basis of BIA parameters alone. The body weight (BW), resistance (Rx), and reactance (Xc) of a 3-year-old girl on chronic HD were recorded pre- and post-HD over a period of 16 months. The BIA parameter that best correlated with actual ultrafiltration (the difference between pre- and post-HD BW) was identified, and the equivalence between actual ultrafiltration and changes in Xc was derived to obtain the following equation: 1 ohm of Xc = 27.4 g of ultrafiltration. Finally, during 21 consecutive HD sessions, ultrafiltration was exclusively prescribed on the basis of the derived equation (BIA-based prescription) after having defined a target post-HD Xc of 45 ohm. The BIA-based prescription period was compared with 21 consecutive HD sessions in which ultrafiltration was prescribed using the conventional approach based on BW (BW-based prescription). Comparison of BIA-based and BW-based ultrafiltration prescription showed significantly fewer HD sessions complicated by hypotension (19 vs. 50%) or by the need for reinfusion (5 vs. 50%), and a better overall quality of HD sessions (86 vs. 37%). No difference in blood pressure was observed, and no acute fluid overload event was detected in either period. BIA-based ultrafiltration seems to be safe, feasible, and effective. The described approach can be particularly useful in the case of patients with problems in setting or maintaining the correct DW.
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A simple prognostic index for Shigatoxin-related hemolytic uremic syndrome at onset: data from the ItalKid-HUS network.

Shigatoxin Escherichia coli-related hemolytic uremic syndrome (eHUS) is a severe thrombotic microangiopathy (TMA) burdened by life-threatening complications and long-term sequelae. Since hemoconcentration is associated with worse outcome, we tried to develop a reliable and easy-to-calculate index for predicting complications and sequelae based on hemoglobin (Hb) at presentation. The first laboratory examinations with signs of TMA in eHUS patients were analyzed in relation to the outcomes with the receiver operating characteristic curves and their areas under the curve (AUC) for Hb and creatinine (sCr). A total of 197 eHUS patients were identified of whom 24% did not have anemia at presentation. Hb level was the best predictor of a poor outcome (AUC 0.67) but the combination of Hb with sCr, in the formula [(Hb in g/dL + (sCr in mg/dL × 2)], showed an even better AUC of 0.75. The described scoring system was also strongly associated and predictive of all complications and health care needs (8% of patients with scoring > 13 died or entered a permanent vegetative state compared with 0% of those with ≤ 13).Conclusion: The presented score is a simple and early predictor of both short- and long-term outcomes and identifies patients who should undergo rapid volume expansion to counteract hemoconcentration, the spreading of microvascular thrombosis, and the consequent increased organ damage. What is Known: • In eHUS, hemoconcentration is associated with worse short- and long-term outcome. • A prognostic index to identify patients at higher risk for complications at presentation is not available. What is New: • We developed a simple and early prognostic index for eHUS outcome with the combination of Hb and sCr at onset, in the following formula [(Hb in g/dL + (sCr in mg/dL × 2)]. • The proposed HUS Severity Score can promptly identify patients with good outcome and those with high risk of worse short- and long-term outcome.

Metabolic acidosis is common and associates with disease progression in children with chronic kidney disease.

Recent studies in adult chronic kidney disease (CKD) suggest that metabolic acidosis is associated with faster decline in estimated glomerular filtration rate (eGFR). Alkali therapies improve the course of kidney disease. Here we investigated the prevalence and determinants of abnormal serum bicarbonate values and whether metabolic acidosis may be deleterious to children with CKD. Associations between follow-up serum bicarbonate levels categorized as under 18, 18 to under 22, and 22 or more mmol/l and CKD outcomes in 704 children in the Cardiovascular Comorbidity in Children with CKD Study, a prospective cohort of pediatric patients with CKD stages 3-5, were studied. The eGFR and serum bicarbonate were measured every six months. At baseline, the median eGFR was 27 ml/min/1.73m2 and median serum bicarbonate level 21 mmol/l. During a median follow-up of 3.3 years, the prevalence of metabolic acidosis (serum bicarbonate under 22 mmol/l) was 43%, 60%, and 45% in CKD stages 3, 4, and 5, respectively. In multivariable analysis, the presence of metabolic acidosis as a time-varying covariate was significantly associated with log serum parathyroid hormone through the entire follow-up, but no association with longitudinal growth was found. A total of 211 patients reached the composite endpoint (ESRD or 50% decline in eGFR). In a multivariable Cox model, children with time-varying serum bicarbonate under 18 mmol/l had a significantly higher risk of CKD progression compared to those with a serum bicarbonate of 22 or more mmol/l (adjusted hazard ratio 2.44; 95% confidence interval 1.43-4.15). Thus, metabolic acidosis is a common complication in pediatric patients with CKD and may be a risk factor for secondary hyperparathyroidism and kidney disease progression.

Renal transplantation in sensitized children and young adults: a nationwide approach.

Background: High levels of preformed anti-HLA antibodies dramatically diminish renal transplant outcomes. Most desensitization programmes guarantee good intermediate outcomes but quite disappointing long-term prognosis. The search for a fully compatible kidney increases time on the waiting list. Methods: In February 2011, a nationwide hyperimmune programme (NHP) was begun in Italy: all available kidneys are primarily proposed to highly sensitized patients with a panel reactive antibody above 80%. In this manuscript, we evaluate the outcome of paediatric patients transplanted with this approach. Results: Twenty-one patients were transplanted. Complete data are available for 20 patients. Mean age at transplantation was 14.5 years [standard deviation (SD) ± 5.5)]. Mean time on the waiting list was 29.3 months (SD ± 27.5). Median follow-up was 29.2 months (range: 11.2-59.3). The average number of HLA mismatches in these patients was 2.3 versus 3.7 in 48 standard patients transplanted in the same period (P < 0.001). Only one graft was lost. Two cases of humoral rejection occurred and were successfully treated. No cellular rejection was reported. Median creatinine clearance was 84, 88, 77 and 77 mL/min/1.73 m 2 respectively 1, 6, 12 and 24 months after transplant. Conclusions: Transplantation of sensitized patients avoiding prohibited antigens is feasible, at least in a selected cohort of patients. In order to be able to further improve this approach, which in our opinion is very successful, it would be necessary to expand the donor pool, possibly increasing the number of countries participating in the programme. In this series, time on the waiting list did not increase significantly. This allocation policy should ideally lead to an outcome comparable to that expected in standard patients, which is particularly desirable in young patients who have the longest life expectancy. Since long-term results of desensitization programmes are not (yet) convincing, we suggest that these programmes should be reserved for selected cases where compatible organs cannot be found within a reasonable time span.

Plasma-exchange in pediatric patients: a single-center experience.

BACKGROUND: Plasma-exchange (PEX) has been well described in pediatrics, but most of the current indications are derived from adult experience. Aim of the study was to review the PEX treatments in our Unit over a six-year period. METHODS: Three hundred and seventy-seven PEX sessions were performed in 38 patients (median age 12.1 years, range 0.6-20.5). Double-needle and single-needle PEX combined with hemodialysis and PEX combined with ultrafiltration were performed in 9, 1 and 3 patients respectively. The most common indications to PEX were atypical hemolytic uremic syndrome (aHUS, 9 patients), focal segmental glomerulosclerosis (FSGS, 9 cases), antibody mediated rejection (AMR) in renal transplant (rTx) recipients (8 patients) and hyperimmunization in patients waiting for rTx (4 cases). RESULTS: We treated five patients with aHUS on native kidneys with PEX only, with complete remission in 4/6 recurrences; PEX was also successfully used to prevent HUS relapse in three patients undergoing rTx. Only one partial remission was obtained in four patients with FSGS on native kidneys, by means of treatment protocols based on PEX and immunosuppressants; conversely, a partial remission was observed in 6/6 patients with recurrence of FSGS on rTx. Immunosuppressive protocols combined with PEX proved useful in sensitized cadaveric rTx recipients (2/4 successfully transplanted), but failed in 6 patients with chronic AMR. As regards complications, two severe adverse reactions occurred: an anaphylactic shock after the use of albumin and an abdominal hemorrhage. CONCLUSIONS: PEX is a relatively safe procedure in children. Pediatric patients with aHUS, recurrent FSGS and sensitized rTx recipients seem to benefit from treatment strategies including PEX.

Epidemiology of haemolytic uremic syndrome in children. Data from the North Italian HUS network.

UNLABELLED: Despite the severity of HUS and the fact that it represents a leading cause of acute kidney injury in children, the general epidemiology of HUS is all but well documented. The present study provides updated, population-based, purely epidemiological information on HUS in childhood from a large and densely populated area of northern Italy (9.6 million inhabitants, 1.6 million children). We systematically reviewed the files concerning patients with STEC-HUS and atypical HUS (aHUS) over a 10-year observation period (January 2003-December 2012). We included all incident cases with a documented first episode of HUS before the age of 18 years. We identified 101 cases of HUS during the 10 years. The overall mean annual incidence was 6.3 cases/million children aged <18 years (range 1.9-11.9), and 15.7/million of age-related population (MARP) among subjects aged <5 years; aHUS accounted for 11.9 % of the cases (mean incidence 0.75/MARP). The overall case fatality rate was 4.0 % (3.4 % STEC-HUS, 8.3 % aHUS). CONCLUSION: Given the public health impact of HUS, this study provides recent, population-based epidemiological data useful for healthcare planning and particularly for estimating the financial burden that healthcare providers might have to face in treating HUS, whose incidence rate seems to increase in Northern Italy. WHAT IS KNOWN: • HUS is a rare disease, but it represents the leading cause of acute kidney injury in children worldwide. • STEC-HUS (also called typical, D + HUS) is more common compared to atypical HUS, but recent, population-based epidemiological data (incidence) are scanty. What is New: • Comprehensive, population-based epidemiological data concerning both typical and atypical HUS based on a long observational period.

Interdialytic weight gain in oligoanuric children and adolescents on chronic hemodialysis.

BACKGROUND: Little is known about the clinical impact of interdialytic weight gain (IDWG) on oligoanuric children undergoing chronic hemodialysis (HD). METHODS: We retrospectively assessed IDWG, left ventricular mass index (LVMI) and its changes (ΔLVMI), pre-HD systolic and diastolic blood pressure (DBP), residual urine output, Kt/V, the frequency of intradialytic symptoms, normalized protein catabolic rate, and the 3-month change in the dry weight of 16 hemodialyzed oligoanuric patients with a median age of 14.8 years (range 5.0-17.9). RESULTS: There was a significant correlation between IDWG and median LVMI (r 0.55, p = 0.026), which was 27.3 g/m(2.7) (22.5-37.6) in the patients with a median IDWG of <4 %, and 44.3 g/m(2.7) (28.2-68.7) in those with a median IDWG of >4 % (p = 0.003). None of the four patients with an IDWG of <4 % showed left ventricular hypertrophy, compared with 10 of the 12 patients (83.3 %) with an IDWG of >4 % (p = 0.003); the former also had a better median ΔLVMI (-33.5 % vs -13.0 %; p = 0.02) and a lower median DBP sds (0.24 vs 1.72, p = 0.04). CONCLUSIONS: There is a significant correlation between IDWG and LVMI in pediatric oligoanuric patients on chronic HD: those with an IDWG of >4 % are at a higher risk of left ventricular hypertrophy.