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Background: Hemolytic uremic syndrome (HUS) is an important cause of acute kidney injury in children. HUS is known as an acute disease followed by complete recovery, but patients may present with kidney abnormalities after long periods of time. This study evaluates the long-term outcome of Shiga toxin-producing Escherichia coli-associated HUS (STEC-HUS) in pediatric patients, 10 years after the acute phase of disease to identify risk factors for long-term sequelae., Methods: Over a 6-year period, 619 patients under 18 years of age with HUS (490 STEC-positive, 79%) were registered in Austria and Germany. Long-term follow-up data of 138 STEC-HUS-patients were available after 10 years for analysis., Results: A total of 66% (n = 91, 95% CI 0.57-0.73) of patients fully recovered showing no sequelae after 10 years. An additional 34% (n = 47, 95% CI 0.27-0.43) presented either with decreased glomerular filtration rate (24%), proteinuria (23%), hypertension (17%), or neurological symptoms (3%). Thirty had sequelae 1 year after STEC-HUS, and the rest presented abnormalities unprecedented at the 2-year (n = 2), 3-year (n = 3), 5-year (n = 3), or 10-year (n = 9) follow-up. A total of 17 patients (36.2%) without kidney abnormalities at the 1-year follow-up presented with either proteinuria, hypertension, or decreased eGFR in subsequent follow-up visits. Patients needing extracorporeal treatments during the acute phase were at higher risk of presenting symptoms after 10 years (p < 0.05)., Conclusions: Patients with STEC-HUS should undergo regular follow-up, for a minimum of 10 years following their index presentation, due to the risk of long-term sequelae of their disease. An initial critical illness, marked by need of kidney replacement therapy or plasma treatment may help predict poor long-term outcome., (© 2024. The Author(s).)

Background: The complement factor H antibody (CFH-Ab)-associated hemolytic uremic syndrome (HUS) forms a distinct subgroup within the complement-mediated HUS disease spectrum. The autoimmune nature of this HUS subgroup implies the potential benefit of a targeted immunosuppressive therapy. Data on long-term outcome are scarce., Methods: This observational study evaluates the clinical outcome of 19 pediatric CFH-Ab HUS patients from disease onset until their 5-year follow-up., Results: All but one relapse occurred during the first 2 years, and patients who had no relapse within the first 6 months were relapse-free until the end of the observation period. Kidney function at disease onset determines long-term kidney function: all individuals with normal kidney function at disease onset had normal kidney function after 5 years, and all patients with reduced kidney function at onset had impaired kidney function at the last follow-up. Level of CFH-Ab titer at disease onset was not correlated with a higher risk of recurrences or worse long-term outcome after 5 years. Resolution of CFH-Ab titers after 5 years was common., Conclusions: CFH-Ab HUS patients have a varied overall long-term course. Early relapses are common, making close surveillance during the first years essential, regardless of the initial CFH-Ab titer.

Objectives: Vaccine-preventable diseases remain a major cause of morbidity and mortality in solid-organ transplant candidates and recipients. Newer recommendations include vaccination of all household members to create a herd immunity around the transplant recipient. This study evaluated the vaccination status of pediatric solid-organ transplant recipients and their household members., Materials and Methods: We evaluated 30 pediatric solid-organ transplant recipients (14 kidney, 13 liver, 3 heart) and their household members (26 siblings, 30 parents) at time of transplant., Results: Fourteen recipients (47%) received scheduled vaccinations before solid-organ transplant and were up to date for their age with their diphtheria, tetanus, pertussis; hepatitis B virus; poliomyelitis; Haemophilus influenzae type B; Streptococcus pneumoniae conjugate vaccine; and measles, mumps, and rubella vaccinations. Another 7 recipients (23%) had partially completed their schedules, only missing the second dose of the measles, mumps, and rubella vaccine. Fifteen siblings (58%) had either completed (n = 13, 50%) or partially completed (n = 2, 8%) their vaccinations. All 30 parents were either unaware of their vaccination status (n = 10, 33%) or had only incomplete vaccination records (n = 20, 67%)., Conclusions: We found that most pediatric solid-organ transplant recipients to be appropriately vaccinated. However, vaccination status in household members, especially in parents, was disappointing.

Primary focal segmental glomerulosclerosis (FSGS) recurs in up to 55% of patients after kidney transplantation. Herein we report the successful management of recurrent FSGS. A 5-year-old boy with primary FSGS received a deceased donor renal transplant. Immediate and fulminant recurrence of FSGS caused anuric graft failure that was resistant to plasmapheresis and rituximab. After exclusion of structural or immunologic damage to the kidney by repeated biopsies, the allograft was retrieved from the first recipient on day 27 and transplanted into a 52-year-old second recipient who had vascular nephropathy. Immediately after retransplantation, the allograft regained function with excellent graft function persistent now at 3 years after transplant. After 2 years on hemodialysis, the boy was listed for kidney retransplantation. To prevent FSGS recurrence, pretreatment with ofatumumab was performed. Nephrotic range proteinuria still occurred after the second transplantation, which responded, however, to daily plasma exchange in combination with ofatumumab. At 8 months after kidney retransplantation graft function is good. The clinical course supports the hypothesis of a circulating permeability factor in the pathogenesis of FSGS. Successful ofatumumab pretreatment implicates a key role of B cells. Herein we provide a description of successful management of kidney failure by FSGS, carefully avoiding waste of organs., (© 2018 The Authors. American Journal of Transplantation published by Wiley Periodicals, Inc. on behalf of The American Society of Transplantation and the American Society of Transplant Surgeons.)

Background: Therapeutic plasma exchange (TPE) has evolved to an accepted therapy for selected indications. However, it is technically challenging in children. Moreover, data on safety and efficacy are mainly derived from adult series. The aim of this study was to review the procedure in the context of clinical indications, effectiveness, and safety., Study Design and Methods: All TPE procedures performed at a tertiary care hospital during a 12-year period (2005-2016) were retrospectively evaluated., Results: Eighteen patients with a median age of 8.5 (0.2-17) years underwent a total of 280 TPE sessions. Eleven (61%) patients were treated for renal diseases. Three (17%) patients were diagnosed with neurological diseases, two had liver failure, and one patient each had sepsis and stem cell transplant-associated thrombotic microangiopathy. Seven patients (39%) were classified as American Society for Apheresis Category I, four (22%) as Category II, two (13%) each as Category III and IV, and two (13%) were not classified. Two patients with atypical hemolytic-uremic syndrome received TPE as long-term therapy over 2 and 5 years. All procedures were performed using the filtration technique and heparin anticoagulation. Twelve (67%) patients showed full or partial recovery after TPE, six had no response or an uncertain response. Minor adverse events occurred in 30/280 (10.6%) procedures, and one major complication (0.4%) was reported., Conclusion: TPE is a safe apheresis method in children, even when performed as a long-term therapy. Efficacy is high under selected conditions. A highly skilled and experienced staff is mandatory to ensure patient safety and efficacy., (© 2017 Wiley Periodicals, Inc.)

We identified two unrelated consanguineous families with three children affected by the rare association of congenital nephrotic syndrome (CNS) diagnosed in the first days of life, of hypogonadism, and of prenatally detected adrenal calcifications, associated with congenital adrenal insufficiency in one case. Using exome sequencing and targeted Sanger sequencing, two homozygous truncating mutations, c.1513C>T (p.Arg505*) and c.934delC (p.Leu312Phefs*30), were identified in SGPL1-encoding sphingosine-1-phosphate (S1P) lyase 1. SGPL1 catalyzes the irreversible degradation of endogenous and dietary S1P, the final step of sphingolipid catabolism, and of other phosphorylated long-chain bases. S1P is an intracellular and extracellular signaling molecule involved in angiogenesis, vascular maturation, and immunity. The levels of SGPL1 substrates, S1P, and sphingosine were markedly increased in the patients' blood and fibroblasts, as determined by liquid chromatography-tandem mass spectrometry. Vascular alterations were present in a patient's renal biopsy, in line with changes seen in Sgpl1 knockout mice that are compatible with a developmental defect in vascular maturation. In conclusion, loss of SGPL1 function is associated with CNS, adrenal calcifications, and hypogonadism., (© 2017 Wiley Periodicals, Inc.)

CFH-Ab-associated aHUS requires different diagnostic and therapeutic approaches and then the genetically defined aHUS forms. The risk of post-transplant recurrence with graft dysfunction in CFH-Ab aHUS is not well documented. It is suggested that recurrence can be expected if a significant CFH-Ab load persists at the time of transplantation. A pretransplant procedure to reduce CFH-Ab titer seems reasonable, but accurate recommendations are lacking. Whether further prophylactic interventions after transplantation are necessary has to be decided on an individual basis. We report the case of a late diagnosed CFH-Ab HUS with initial ESRD and a successful living-related renal transplantation over a post-transplant period of four and a half years on the basis of a prophylactic pretransplant IVIG admission., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

A 15-year-old girl presented with acute bilateral loss of central visual acuity due to hypertensive retinopathy level IV. She was found to have unrecognized malignant arterial hypertension associated with end-stage renal failure. At the time of diagnosis she also had severe left ventricular hypertrophy (LVH). Hypertension was successfully treated with combined anti-hypertensive therapy, but renal function did not recover. The patient underwent successful kidney transplant 4 months later and over a period of 20 months hypertensive retinopathy and LVH gradually resolved. This report emphasizes the importance of routine measurement of blood pressure and describes the possible consequences of unrecognized arterial hypertension in children. Early diagnosis and appropriate treatment are necessary to avoid development and progression of target organ damage and promote better long-term cardiovascular prognosis., (© 2015 Japan Pediatric Society.)

Thrombotic microangiopathies (TMA) are rare but severe disorders, characterized by endothelial cell activation and thrombus formation leading to hemolytic anemia, thrombocytopenia, and organ failure. Complement over activation in combination with defects in its regulation is described in an increasing number of TMA and if primary for the disease denominated as atypical hemolytic-uremic syndrome. Although TMA predominantly affects the renal microvasculature, extra-renal manifestations are observed in 20% of patients including involvement of the central nerve system, cardiovascular system, lungs, skin, skeletal muscle, and gastrointestinal tract. Prompt diagnosis and treatment initiation are therefore crucial for the prognosis of disease acute phase and the long-term outcome. This review summarizes the available evidence on extra-renal TMA manifestations and discusses the role of acute and chronic complement activation by highlighting its complex interaction with inflammation, coagulation, and endothelial homeostasis.

Background: Kawasaki disease (KD) is a rare vasculitis seen predominantly in children. In developing countries, it is the leading cause of childhood-acquired heart disease. Besides a case report from 1981 there have been no data published dealing with the epidemiology and clinical aspects of KD in Austria., Methods: The purpose of the present study was to investigate the clinical spectrum of KD in a geographically determined cohort of infants, children, and adolescents that were diagnosed and treated at the University Hospital of Innsbruck from 2003-2012., Results: Thirty-two patients were included in the study with a median age of 32.96 months (2-192). 59.4% of the patients were aged between six months and four years. The male-to-female ratio was 1:1.13. Clinical examination revealed non-purulent conjunctivitis and exanthema as the most common symptoms (84.4%). 75% showed oropharyngeal changes, 21.9% had gastrointestinal complaints such as diarrhoe, stomachache or vomiting prior to diagnosis. One third of the patients were admitted with a preliminary diagnosis, whereas 78.1% were pre-treated with antibiotics. The median fever duration at the time of presentation was estimated with 4.96 days (1-14), at time of diagnosis 6.76 days (3-15).75% were diagnosed with complete KD, and 25% with an incomplete form of the disease. There was no significant difference in the duration of fever neither between complete and incomplete KD, nor between the different age groups. Typical laboratory findings included increased C-reactive protein (CRP) (80.6%) and erythrocyte sedimentation rate (ESR) (96%),leukocytosis (48.4%) and thrombocytosis (40.6%) without any significant quantitative difference between complete and incomplete KD. Coronary complications could be observed in six patients: one with a coronary aneurysm and five with tubular dilatation of the coronary arteries. Our patient cohort represents the age distribution as described in literature and emphasizes that KD could affect persons of any age. The frequency of occurrence of the clinical symptoms differs from previous reports - in our study, we predominantly observed non-purulent conjunctivitis and exanthema., Conclusion: KD should always be considered as a differential diagnosis in a child with fever of unknown origin, as treatment can significantly decrease the frequency of coronary complications.

There has been rapid progress in the understanding of the pathophysiology of the hemolytic uremic syndrome (HUS) disease spectrum; thus, complex diagnostic and therapeutic requirements have emerged in parallel. Current recommendations for diagnosis and therapy were rapidly adapted from the prior skilled scientific groundwork. However, such recommendations can be realized only when highly specialized laboratories and sufficient financial resources are available. Thus, many recommendations are not feasible for patients living and working in developing countries. More than one-third of the world's population has no access to essential drugs and more than half of this group lives in the poorest regions of Africa and Asia. From this perspective, distinct initial diagnostic and therapeutic recommendations, as well as international cooperations are needed to complete proper diagnostic work-ups in a stringent and cost-efficient manner and to enable patients to be adequately treated with available resources. However, while costs for complement-targeted drugs remain tremendously high, state-of-the-art treatment options remain unavailable for the vast majority of patients in developing areas., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

The presence of circulating autoantibodies, primarily to complement factor H antibodies (CFH-Abs) in plasma characterizes the autoimmune form of atypical hemolytic uremic syndrome (aHUS). This acquired form of aHUS defines a distinct subgroup of aHUS patients, which requires diagnostic and treatment approaches in part different from those of the genetically defined forms. The mechanisms leading to CFH-Ab production and disease onset are not completely understood, but CFH-Ab HUS seems to be secondary to a combination of genetic predisposition and environmental factors. Early diagnosis of this specific aHUS entity is important, as prompt induction of plasma exchange and concomitant immunosuppression leads to a favorable outcome. Nevertheless, information on clinical features and outcome in children is limited. Here, we review the literature on the biological and clinical features of CFH-Ab HUS and discuss therapeutic options., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Oncocytomas are benign tumors most often occurring in salivary or lacrimal glands and thyroid tissue. As cutaneous oncocytoma is exceptionally rare, this tumor is uncommonly encountered by dermatopathologists. Herein, we illustrate the case of an 80-year-old man who presented with a slowly growing papule of the lower eyelid. Histopathologically, the adenomatous tumor was composed of large monomorphic cells with eosinophilic granular cytoplasm. Electron microscopy revealed abundant, enlarged and abnormally shaped mitochondria. These findings were consistent with an oncocytoma of the skin. The presented case is unique in that the thorough work-up of the tumor tissue revealed not only hyperplastic mitochondria, representing the ultrastructural correlate of the observed granular cytoplasm, but additionally disclosed functional consequences with elevated levels of reactive oxygen specimen (ROS) within the tumor. Disrupted oxygen metabolism may result from cellular aging processes and may putatively represent the underlying pathogenesis of oncocytoma., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Constitutional mismatch repair deficiency (CMMR-D) due to biallelic germline mutations in one of four mismatch repair genes causes a childhood cancer syndrome characterized by a broad tumor spectrum including hematological malignancies, and brain and Lynch syndrome-associated tumors. Herein, we report three children who had in addition to CMMR-D-associated malignancies multiple pilomatricomas. These are benign skin tumors of hair matrical differentiation frequently associated with somatic activating mutations in the ß-catenin gene CTNNB1. In two of the children, the diagnosis of CMMR-D was confirmed by the identification of biallelic germline PMS2 mutations. In the third individual, we only found a heterozygous germline PMS2 mutation. In all nine pilomatricomas with basophilic cells, we detected CTNNB1 mutations. Our findings indicate that CTNNB1 is a target for mutations when mismatch repair is impaired due to biallelic PMS2 mutations. An elevated number of activating CTNNB1 alterations in hair matrix cells may explain the development of multiple pilomatricomas in CMMR-D patients. Of note, two of the children presented with multiple pilomatricomas and other nonmalignant features of CMMR-D before they developed malignancies. To offer surveillance programs to CMMR-D patients, it may be justified to suspect CMMR-D syndrome in individuals fulfilling multiple nonmalignant features of CMMR-D (including multiple pilomatricomas) and offer molecular testing in combination with interdisciplinary counseling., (Copyright © 2013 Wiley Periodicals, Inc.)

Background and Objectives: This study evaluated the relevance of complement factor H (CFH)-related protein (CFHR) 1 deficiency in pediatric patients with atypical hemolytic uremic syndrome (aHUS) by evaluating both the frequency of deletions in CFHR1 and the presence of complement factor H (CFH) antibodies., Design, Setting, Participants, & Measurements: A total of 116 patients (mainly from central Europe) and 118 healthy blood donors were included from 2001 to 2012. The presence of CFHR1 gene deletions was determined in 90 pediatric patients with aHUS and 118 controls by an easy, fast, and cheap PCR assay; 100 patients with aHUS and 42 controls were tested for CFH antibodies by ELISA. Questionnaires were administered to evaluate the clinical and laboratory data., Results: Homozygous deletion in CFHR1 was detected in 32% of the patients with aHUS tested, compared with 2.5% of controls (P<0.001). CFH antibodies were present in 25% of the patients and none of the controls. CFH antibodies were detected in 82% of patients with homozygous CFHR1 gene deletion and in 6% of patients without. CFH antibody-positive patients with aHUS showed a significantly lower platelet nadir at disease onset and significantly less frequent involvement of the central nervous system than did antibody-negative patients. Antibody-positive patients also received plasma therapy more often., Conclusion: Homozygous deletion in CFHR1 is strongly associated with occurrence of CFH antibodies in pediatric patients with aHUS. However, despite this apparent genetic disease predisposition, it cannot be considered an exclusive cause for aHUS. Initial presentation of Shiga toxin-negative HUS with severe thrombocytopenia and no central nervous system complications in pediatric patients is especially suspicious for CFH antibody aHUS.

Multiple myeloma (MM) displays an NFκB activity-related gene expression signature and about 20% of primary MM samples harbor genetic alterations conducive to intrinsic NFκB signaling activation. The relevance of blocking the classical versus the alternative NFκB signaling pathway and the molecular execution mechanisms involved, however, are still poorly understood. Here, we comparatively tested NFκB activity abrogation through TPCA-1 (an IKK2 inhibitor), BAY 11-7082 (an IKK inhibitor poorly selective for IKK1 and IKK2), and MLN4924 (an NEDD8 activating enzyme (NAE)-inhibitor), and analyzed their anti-MM activity. Whereas TPCA-1 interfered selectively with activation of the classical NFκB pathway, the other two compounds inhibited classical and alternative NFκB signaling without significant discrimination. Noteworthy, whereas TPCA-1 and MLN4924 elicited rather mild anti-MM effects with slight to moderate cell death induction after 1 day BAY 11-7082 was uniformly highly toxic to MM cell lines and primary MM cells. Treatment with BAY 11-7082 induced rapid cell swelling and its initial effects were blocked by necrostatin-1 or the ROS scavenger BHA, but a lasting protective effect was not achieved even with additional blockade of caspases. Because MLN4924 inhibits the alternative NFκB pathway downstream of IKK1 at the level of p100 processing, the quite discordant effects between MLN4924 and BAY 11-7082 must thus be due to blockade of IKK1-mediated NFκB-independent necrosis-inhibitory functions or represent an off-target effect of BAY 11-7082. In accordance with the latter, we further observed that concomitant knockdown of IKK1 and IKK2 did not have any major short-term adverse effect on the viability of MM cells.

The capability of soluble CD95L trimers to trigger CD95-associated signaling pathways is drastically increased by oligomerization. The latter can be achieved, for example, by antibodies recognizing a N-terminal epitope tag in recombinant CD95L variants or by genetic engineering-enforced formation of hexamers. Using highly sensitive and accurate binding studies with recombinant CD95L variants equipped with a Gaussia princeps luciferase reporter domain, we found that oligomerization of CD95L has no major effect on CD95 occupancy. This indicates that the higher activity of oligomerized CD95L trimers is not related to an avidity-related increase in apparent affinity and points instead to a crucial role of aggregation of initially formed trimeric CD95L-CD95 complexes in CD95 activation. Furthermore, binding of soluble CD95L trimers was found to be insufficient to increase the association of CD95 with the lipid raft-containing membrane fraction. However, when Gaussia princeps luciferase-CD95L trimers were used as tracers to "mark" inactive CD95 molecules, increased association of these inactive receptors was observed upon activation of the remaining CD95 molecules by help of highly active hexameric Fc-CD95L or membrane CD95L. Moreover, in cells expressing endogenous CD95 and chimeric CD40-CD95 receptors, triggering of CD95 signaling via endogenous CD95 resulted in co-translocation of CD40-CD95 to the lipid raft fraction, whereas vice versa activation of CD95-associated pathways with Fc-CD40L via CD40-CD95 resulted in co-translocation of endogenous CD95. In sum, this shows that signaling-active CD95 molecules not only enhance their own association with the lipid raft-containing membrane fraction but also those of inactive CD95 molecules.