Valentina Gracchi

Maintenance of Kidney Function Following Treatment With Eculizumab and Discontinuation of Plasma Exchange After a Third Kidney Transplant for Atypical Hemolytic Uremic Syndrome Associated With a CFH Mutation

Kidney transplant in patients with atypical hemolytic uremic syndrome (aHUS) is associated with a poor outcome because of recurrent disease, especially in patients known to have a factor H mutation. Long-term prophylactic plasma exchange and combined liver-kidney transplant have prevented graft loss caused by recurrence. However, the mortality associated with liver transplant is not negligible, and prophylactic plasma exchange requires permanent vascular access and regular hospitalization and exposes the patient to potential allergic reactions to plasma. Eculizumab is a high-affinity humanized monoclonal antibody that binds to C5 and thus prevents generation of C5a and the membrane attack complex. We report the case of a 17-year-old girl with aHUS associated with a mutation in the gene for complement factor H (CFH; c.3572C>T, Ser1191Leu) who was highly dependent on plasma exchange. Because of severe allergic reactions to plasma after the third renal graft, eculizumab was introduced in place of plasma exchange without problems. This and other reports suggest that the promise of complement inhibitors in the management of aHUS is going to be fulfilled.

Spirometry in young children: should computer-animation programs be used during testing?

Currently, computer-animation programs are frequently used to instruct and stimulate young children in performing maximal expiratory flow/volume (MEFV) curves. The reproducibility and maximal performance of MEFV manoeuvres with and without the use of two computer-animation programs (the “candles” and the “balloon” programs) were evaluated. Eighty-eight children, aged 4–8u2005yrs, were randomly assigned to one of the two animation programs. All children performed two series of at least three technically acceptable curves, one series with the incentive and one without, in random order. With the use of computer-animation programs, a lower proportion of children were able to fulfil international criteria for forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) reproducibility. The use of incentives improved reproducibility and performance of peak expiratory flow (PEF). Performance of FVC decreased significantly in 6–8‐yr-old children using the animation programs. Training with a program for a short period of time before the formal lung-function test may be valuable. According to the results, however, the use of these programs during tests under the guidance of an experienced lung-function technician cannot be routinely recommended because of possible deteriorating effects on reproducibility and performance of forced expiratory manoeuvres.

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

BackgroundThe 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.MethodsSerological profiles (C3, FH, FI, AP activity, C3d, C3bBbP, C3b/c, TCC, αFH) 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.ResultsThirty-seven patients were studied (26 STEC-HUS, 11 aHUS). In 39xa0% of them, including 28xa0% 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.ConclusionsIn 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.

A 1-Year Trial of Lamivudine for Chronic Hepatitis B in Children

We carried out a 1-year trial to evaluate the efficacy and tolerability of lamivudine, an oral nucleoside analogue, in a small group of children with vertically acquired chronic hepatitis B. Patients were assessed for serum alanine aminotransferase (ALT) and serum hepatitis B virus (HBV) DNA at baseline and every 4 weeks thereafter, and for hepatitis B s antigen, hepatitis B e antigen and their antibodies every 12 weeks. Analysis of HBV mutation was undertaken at entry and on the occasion of the last positive control of HBV DNA. Lamivudine suppressed serum HBV DNA to undetectable levels in all treated patients within 24 weeks. Serum ALT levels returned to normal values within 36 weeks. Therapy was well tolerated, and although nausea and vomiting were reported in one child, it was not necessary to stop treatment. A new observation was that, contrary to previous data, seroconversion appeared to occur earlier in children with lower ALT levels at baseline.

Prevalence and distribution of (micro)albuminuria in toddlers

BACKGROUNDnMicroalbuminuria is common in the general adult population, with a prevalence of ∼7%, and is an independent indicator of renal and cardiovascular risks. Whether albuminuria is acquired during life (as a result of hypertension/diabetes) or is congenital and already present at birth is unknown. We studied the prevalence of microalbuminuria in toddlers and compared the distribution of albuminuria with that of the general adult population. In addition, we looked for possible associations between microalbuminuria and antenatal, postnatal and maternal factors.nnnMETHODSnThe urinary albumin concentration (UAC) was measured in 1352 children and the urinary albumin:creatinine ratio (UACR) in 1288 children from the Groningen Expert Center for Kids with Obesity (GECKO) Drenthe cohort (age range 20-40 months). Albuminuria distribution was compared with the albuminuria distribution in 40 854 participants of the general adult cohort of the Prevention of Renal and Vascular End stage Disease (PREVEND) study. Associations between albuminuria (expressed as UAC and UACR) and antenatal, postnatal and maternal factors were tested with linear regression analysis.nnnRESULTSnThe median UAC in the GECKO study was 2.3 mg/L (5th-95th percentiles: 2.1-25.5) and in the PREVEND study it was 6.0 mg/L (2.3-28.6) (P distribution comparison 0.053). The prevalence of UAC ≥ 20 mg/L was 6.9% in the GECKO study and 7.8% in the PREVEND study (P = 0.195). The prevalence of UACR ≥ 30 mg/g in the GECKO study was 23.4%. UAC and UACR were lower in boys. UAC was not associated with other determinants, but UACR was associated with age and gestational diabetes.nnnCONCLUSIONSnThe distribution of UAC and the prevalence of UAC > 20 mg/L in toddlers and in the young general adult population are comparable. These findings suggest that microalbuminuria is a congenital condition that may predispose to a higher cardiovascular risk later in life.

Prevention of large-vessel stenoses in atypical hemolytic uremic syndrome associated with complement dysregulation

Sirs, n nThe oldest of three sisters, two of whom are monozygous twins, presenting all with atypical hemolytic uremic syndrome (aHUS) associated with a CFH mutation, was referred at the age of 3xa0years to the Emma Children’s Hospital/Academic Medical Centre of Amsterdam (Fig.xa01) [1, 2]. She never recovered renal function and commenced peritoneal dialysis. Bilateral nephrectomy was performed 1 year later because of hypertension. She lost two transplants by recurrence, one immediately posttransplantation and the other one 2xa0months posttransplant despite preventive plasma exchanges (PEs) contemporary to frequency reduction of PE. From the age of 15xa0years, she began to experience transient sensory and motor symptoms on both sides of her body associated with low blood pressure (BP) during hemodialysis. Magnetic resonance angiogram (MRA) showed severe stenoses of both middle and both anterior cerebral arteries (Fig.xa02a) (partial report in [3]). She did not present any additional risk factors for developing arteriosclerosis (such as long-duration hypertension, diabetes, uncontrolled hyperparathyroidism). No arterial calcification and no left ventricular hypertrophy were shown. n n n nFig.xa01 n nClinical course in patient and her twin sisters n n n n n nFig.xa02 n nThree-Tesla magnetic resonance images (MRIs) of patient 2 (a, b) and her sister (c). Coronal 3D time-of flight (TOF) MRA maximum intensity projection (MIP) (a) image of patient at the age of 15 years demonstrates (near) occlusion of the M1 segment of ... n n n nAt the age of 17xa0years, the patient was transplanted for the third time under pre- and postoperative prophylactic PEs [1, 2]. Postoperatively, she developed infarcts in the right frontal and frontoparietal regions (Fig.xa02b). She recovered almost completely. Ten months after transplantation, the child developed bronchospasm and hypotension during PE. For this reason, she was switched to eculizumab [2]. Under this treatment, she presented no HUS recurrence, and renal function remained stable (plasma creatinine 120xa0μmol/L) 16xa0months after PE discontinuation. The first of her twin sisters (twin 1) developed aHUS at the age of 5.3xa0years. She required chronic dialysis despite initial daily PE for 10xa0days and three intermittent courses of fresh frozen plasma (FFP) infusions. Two years later, she received a cadaver renal transplant under PE prophylaxis. At 7.5xa0years follow-up, the graft function is satisfactory (serum creatinine 137xa0μmol). The second twin (twin 2) presented aHUS at the age of 5.8xa0years (Fig.xa01) [1]. She was treated immediately with daily PE and, following remission, with one PE every 2xa0weeks to this time. At 9.5xa0years after HUS onset, native renal function (serum creatinine 49xa0μmol/L) was normal. MRA showed normal cerebral vasculature in both twins at age 14 years (Fig.xa02c). Contrary to their older sister with cerebral artery stenoses who was treated by prophylactic PE for 2xa0months only, the twin sisters received prophylactic PE without interruption for, respectively, 7.5 (twin 1) and 9xa0(twin 2) years. n nAlthough brain ischemia sometimes resulting in cerebral infarct is observed in aHUS, stenosis of large vessels has been reported in aHUS only once—in a child presenting with a Lys350Asp gain of function CFB mutation [4]. Of note, this patient, as ours, was dialyzed for long periods from the age of 4xa0months. At the age of 10xa0years, she started having episodes of bilateral hemiparesis during hemodialysis in relation with multiple stenoses of cerebral arteries. Stenoses of large arteries have never been reported as a complication of renal replacement therapy (RRT) in children [5]. Chronic continuous complement dysregulation might contribute to vascular lesions. Indeed complement activation occurs both in human and experimental atherosclerosis, and the deposition of C5b-9 correlates with disease state [6]. n nOur patient and the patient reported recently by Loirat et al. [4] suggest that aHUS with complement dysregulation, a disease of microvascularization, may also involve large arteries, especially when patients have to face long periods of dialysis when plasma therapy is not used. The latter reports also raise the question of preventing vascular lesions by avoiding complement system disorders. This emphasizes the importance of including patients at an early stage in specific programs of kidney transplantation using preventive plasma therapy or combined liver transplantation. Inhibition of the complement system by anti-C5 antibody that is actually under investigation might be valuable for this purpose in the future [2].

Long-term renal function under plasma exchange in atypical hemolytic uremic syndrome

Dear Sir, n nIn a paper by Waters and Licht published recently in Pediatric Nephrology, eculizumab is presented as the emerging drug to replace plasma exchange (PE) to treat and prevent atypical hemolytic uremic syndrome (aHUS) [1], allowing complications possibly associated with chronic PE use related to arteriovenous fistula and infusion of blood products (viral infections, allergic reaction) to be avoided. Eculizumab is an anti-C5 monoclonal humanized mouse antibody that binds to C5 and prevents the action of C5 convertase that splits C5 in C5a and C5b, impeding formation of the C5b-9 membrane-attack complex (or MAC) that binds to and permeabilizes cell membranes, thereby killing microorganisms but also damaging host endothelial cells, as in aHUS. Eculizumab treatment has been shown to be successful in several reported aHUS cases. However, the use of this drug over the long term is limited by extremely high cost, possible infectious complications by Neisseria, and by fetal morbidity in case of administration during pregnancy. Although it has not yet been demonstrated, the possibility of developing antieculizumab antibodies cannot be excluded. n nAnother recently proposed alternative to PE consists of combined kidney–liver transplantation, which remains, however, a high-risk procedure [1]. Because of the limitations of the latter techniques and the necessity of life-long treatment in a large number of cases, it seems important to us to emphasize the possibility that an adequate PE strategy could obtain long-term preservation of renal function in aHUS. In aHUS, CFH mutations are the most frequent. The prognosis in this group is poor, with most patients developing end-stage renal failure (ESRF) and a recurrence rate posttransplant of 80% [1] that, when not adequately treated, lead to graft loss in 100% of cases. Since our reports on successful aHUS treatment by intensive daily PE on native kidney and on kidney transplantation, followed by prophylactic PE pursued indefinitely and intensified during relapses [2, 3], this strategy has been widely recommended [4]. n nIn this letter, we present the evolution of three sisters, two of whom are homozygote twins presenting with aHUS associated with CFH mutation (c.3572xa0Cu2009>u2009T, Ser1191Leu) since data published in our previous paper [3]. These observations represent the longest successful prophylactic PE treatment used in aHUS. The oldest sister is more than 20xa0years old and received her third kidney transplant at the age of 17 under prophylactic PE initiated from before transplantation. Four months later, she experienced a severe relapse when the frequency of PE was reduced from two to one sessions per week. Immediate treatment by daily PE resulted in complete recovery of baseline renal function. Later on, due to severe reaction to plasma, PE had to be replaced with eculizumab treatment, which prevented HUS relapse and renal function deterioration (plasma creatinine 125xa0μmol/L 2xa0years after eculizumab initiation). Twin 1 [2, 3] presented an initial HUS episode at the age of 5xa0years. She reached ESRF 6xa0months later despite having received ten daily PE sessions initially and three courses of plasma infusion at the time of hematological exacerbation of the disease. She was transplanted with a cadaver kidney 2xa0years later under prophylactic PE (40xa0ml/kg of fresh frozen plasma) just before transplantation and then daily for 7xa0days, being progressively tapered and continued indefinitely once a week until now. Eight years posttransplantation, plasma creatinine was 145xa0μmol/L despite two relapses in the early posttransplantation period secondary to cytomegalovirus (CMV) infection, which responded well to daily PE sessions and ganciclovir. Twin 2 presented a first episode of HUS 6xa0months after her twin sister [3]. She was immediately treated with daily PE for 21xa0days until normalization of plasma creatinine and thereafter tapered to one session/2xa0weeks until now. Ten years after the first episode, plasma creatinine was normal (57xa0μmol/L), and the patient did not present any urinary abnormality. Long-term regular PE sessions did not worsen school performance and social life in that family. n nAll three patients presented reactions to plasma that indicated in each case the use of Octaplas instead of fresh frozen plasma. Octaplas is a plasma preparation that considerably reduces reaction risk by assuming complete removal of cells and cell debris by multiple size-exclusion filtration steps. The latter product is also submitted to virus inactivation by S/D methods. n nIn conclusion, in this family of patients with aHUS related to CFH mutation, intensive and prophylactic treatment with PE allowed long-term preservation of transplant and native renal function. However, because of the burden of this technique, the cost of eculizumab, and the high risk of liver transplantation, the best option for treating aHUS related to CFH mutation might be a human-plasma-derived CFH concentrate, presently being developed in France by the Laboratoire Francais du Fractionnement et des Biotechnologies.

Comparison of urine collection methods for albuminuria assessment in young children.

Cotton wool or pantyliners placed in a diaper can be used as urine collection devices for albuminuria measurements in young, not continent children. We tested a new collection method (PeeSpot(R)) for its analytical performance, and compared it with the pantyliner technique. Eighty-one urine samples with a wide range of albuminuria were pipetted on the pantyliner and PeeSpot in duplicate. These were incubated for 3h at 37°C (simulating the time a toddler wears a diaper), and subsequently 72h at room temperature (simulating transport to a central laboratory). Urine was extracted by centrifugation and albumin concentration (UAc) was measured. UAC measured by the two methods was compared with UAC in an unprocessed reference aliquot stored for 75h at 4°C. Bias (mean percentage UAC difference between test and reference), precision (interquartile range of the UAC difference) and accuracy (proportion of samples within 30% of reference UAC) were calculated. Median UAC in the reference aliquot was 66.0mg/L [IQR 25.0-211.0], pantyliner 32.0mg/L [4.7-165.0; P<0.001 vs reference], and PeeSpot 61.0mg/L [27.0-216.0; P=0.84 vs reference]. Bias, precision and accuracy in pantyliner were -34.2%, 31.3mg/L and 48.1%; in PeeSpot 3.3%, 5.0mg/L and 96.3%. Passing-Bablok regression and Bland-Altman plot showed an underestimation for the pantyliner but not for the PeeSpot. The PeeSpot is an accurate and precise tool for collecting urine for albumin measurement in young children and should be preferred over the alternative cotton wool collection technique.

Early Proteinuria Lowering by Angiotensin-Converting Enzyme Inhibition Predicts Renal Survival in Children with CKD

Background Although pharmacotherapeutic proteinuria lowering was found to be nephroprotective in adults, the predictive value of early drug-induced proteinuria reduction for long-term renal survival in pediatric CKD is unknown. We analyzed data from the ESCAPE Trial for a potential association between initial antiproteinuric effect of standardized angiotensin-converting enzyme (ACE) inhibition and renal disease progression in children with CKD.Methods In total, 280 eligible children with CKD stages 2-4 (mean age 11.7 years old, median eGFR 46 ml/min per 1.73 m2, 71% congenital renal malformations) received a fixed dose of ramipril (6 mg/m2 per day) and were subsequently randomized to conventional or intensified BP control. We assessed initial proteinuria reduction from baseline to first measurement on ramipril (at 2.5±1.3 months). We used multivariable Cox modeling to estimate the association between initial proteinuria reduction and the risk of reaching a renal end point (50% eGFR decline or ESRD), which occurred in 80 patients during 5 years of observation.Results Ramipril therapy lowered proteinuria by a mean of 43.5% (95% confidence interval, 36.3% to 49.9%). Relative to proteinuria reduction <30%, 30%-60% and >60% reduction resulted in hazard ratios (95% confidence intervals) of 0.70 (0.40 to 1.22) and 0.42 (0.22 to 0.79), respectively. This association was independent of age, sex, CKD diagnosis, baseline eGFR, baseline proteinuria, initial BP, and concomitant BP reduction.Conclusions The early antiproteinuric effect of ACE inhibition is associated with long-term preservation of renal function in children with CKD. Proteinuria lowering should be considered an important target in the management of pediatric CKD.

Genetic predisposition to infection in a case of atypical hemolytic uremic syndrome

Most cases of hemolytic uremic syndrome (HUS) are caused by infection with enterohemorrhagic Escherichia coli (EHEC). Genetic defects causing uncontrolled complement activation are associated with the more severe atypical HUS (aHUS). Non-EHEC infections can trigger the disease, however, complement defects predisposing to such infections have not yet been studied. We describe a 2-month-old patient infected with different Gram-negative bacterial species resulting in aHUS. Serum analysis revealed slow complement activation kinetics. Rare variant R229C was found in complement inhibitor vitronectin. Recombinant mutated vitronectin showed enhanced complement inhibition in vitro and may have been a predisposing factor for infection. Our work indicates that genetic changes in aHUS can not only result in uncontrolled complement activation but also increase vulnerability to infections contributing to aHUS.