The role of anticomplement therapy in the management of the kidney allograft.

As the number of patients living with kidney failure grows, the need also grows for kidney transplantation, the gold standard kidney replacement therapy that provides a survival advantage. This may result in an increased rate of transplantation from HLA-mismatched donors that increases the rate of antibody-mediated rejection (AMR), which already is the leading cause of allograft failure. Plasmapheresis, intravenous immunoglobulin therapy, anti-CD20 therapies (i.e., rituximab), bortezomib and splenectomy have been used over the years to treat AMR as well as to prevent AMR in high-risk sensitized kidney transplant recipients. Eculizumab and ravulizumab are monoclonal antibodies targeting the C5 protein of the complement pathway and part of the expanding field of anticomplement therapies, which is not limited to kidney transplant recipients, and also includes complement-mediated microangiopathic hemolytic anemia, paroxysmal nocturnal hemoglobinuria, and ANCA-vasculitis. In this narrative review, we summarize the current knowledge concerning the pathophysiological background and use of anti-C5 strategies (eculizumab and ravulizumab) and C1-esterase inhibitor in AMR, either to prevent AMR in high-risk desensitized patients or to treat AMR as first-line or rescue therapy and also to treat de novo thrombotic microangiopathy in kidney transplant recipients.

Urine soluble TLR4 levels may contribute to predict urinary tract infection in children: the UTILISE Study.

BACKGROUND: One of the most common bacterial infections in childhood is urinary tract infection (UTI). Toll-like receptors (TLRs) contribute to immune response against UTI recognizing specific pathogenic agents. Our aim was to determine whether soluble TLR4 (sTLR4), soluble TLR5 (sTLR5) and interleukin 8 (IL-8) can be used as biomarkers to diagnose UTI. We also aimed to reveal the relationship between urine Heat Shock Protein 70 (uHSP70) and those biomarkers investigated in this study. METHODS: A total of 802 children from 37 centers participated in the study. The participants (n = 282) who did not meet the inclusion criteria were excluded from the study. The remaining 520 children, including 191 patients with UTI, 178 patients with non-UTI infections, 50 children with contaminated urine samples, 26 participants with asymptomatic bacteriuria and 75 healthy controls were included in the study. Urine and serum levels of sTLR4, sTLR5 and IL-8 were measured at presentation in all patients and after antibiotic treatment in patients with UTI. RESULTS: Urine sTLR4 was higher in the UTI group than in the other groups. UTI may be predicted using 1.28 ng/mL as cut-off for urine sTLR4 with 68% sensitivity and 65% specificity (AUC = 0.682). In the UTI group, urine sTLR4 levels were significantly higher in pyelonephritis than in cystitis (p < 0.0001). Post-treatment urine sTLR4 levels in the UTI group were significantly lower than pre-treatment values (p < 0.0001). CONCLUSIONS: Urine sTLR4 may be used as a useful biomarker in predicting UTI and subsequent pyelonephritis in children with UTI. A higher resolution version of the Graphical abstract is available as Supplementary information.

Urinary HSP70 improves diagnostic accuracy for urinary tract infection in children: UTILISE study.

BACKGROUND: The accuracy of conventional urinalysis in diagnosing urinary tract infection (UTI) in children is limited, leading to unnecessary antibiotic exposure in a large fraction of patients. Urinary heat shock protein 70 (uHSP70) is a novel marker of acute urinary tract inflammation. We explored the added value of uHSP70 in discriminating UTI from other infections and conditions confused with UTI. METHODS: A total of 802 children from 37 pediatric centers in seven countries participated in the study. Patients diagnosed with UTI (n = 191), non-UTI infections (n = 178), contaminated urine samples (n = 50), asymptomatic bacteriuria (n = 26), and healthy controls (n = 75) were enrolled. Urine and serum levels of HSP70 were measured at presentation in all patients and after resolution of the infection in patients with confirmed UTI. RESULTS: Urinary (u)HSP70 was selectively elevated in children with UTI as compared to all other conditions (p < 0.0001). uHSP70 predicted UTI with 89% sensitivity and 82% specificity (AUC = 0.934). Among the 265 patients with suspected UTI, the uHSP70 > 48 ng/mL criterion identified the 172 children with subsequently confirmed UTI with 90% sensitivity and 82% specificity (AUC = 0.862), exceeding the individual diagnostic accuracy of leukocyturia, nitrite, and leukocyte esterase positivity. uHSP70 had completely normalized by the end of antibiotic therapy in the UTI patients. Serum HSP70 was not predictive. CONCLUSIONS: Urine HSP70 is a novel non-invasive marker of UTI that improves the diagnostic accuracy of conventional urinalysis. We estimate that rapid urine HSP70 screening could spare empiric antibiotic administration in up to 80% of children with suspected UTI. A higher resolution version of the Graphical abstract is available as Supplementary information.

COVID-19 in pediatric nephrology centers in Turkey.

BACKGROUND: There is limited data on COVID-19 disease in children with kidney disease. We aimed to investigate the characteristics and prognosis of COVID-19 in pediatric nephrology patients in Turkey. METHODS: This was a national, multicenter, retrospective cohort study based on an online survey evaluating the data between 11th March 2020 and 11th March 2021 as an initial step of a detailed pediatric nephrology COVID-19 registry. RESULTS: Two hundred and three patients (89 girls and 114 boys) were diagnosed with COVID-19. One-third of these patients (36.9%) were between 10-15 years old. Half of the patients were on kidney replacement therapy: kidney transplant (KTx) recipients (n = 56, 27.5%), patients receiving chronic hemodialysis (n = 33, 16.3%) and those on peritoneal dialysis (PD) (n = 18, 8.9%). Fifty-four (26.6%) children were asymptomatic. Eighty-two (40.3%) patients were hospitalized and 23 (28%) needed intensive care unit admission. Fifty-five percent of the patients were not treated, while the remaining was given favipiravir (20.7%), steroid (16.3%), and hydroxychloroquine (11.3%). Acute kidney injury developed in 19.5% of hospitalized patients. Five (2.4%) had MIS-C. Eighty-three percent of the patients were discharged without any apparent sequelae, while 7 (3.4%) died. One hundred and eight health care staff were infected during the study period. DISCUSSION: COVID-19 was most commonly seen in patients who underwent KTx and received HD. The combined immunosuppressive therapy and frequent exposure to the hospital setting may increase these patients' susceptibility. Staff infections before vaccination era were alarming, various precautions should be taken for infection control, particularly optimal vaccination coverage.

PROGRESS STUDY: Progression of chronic kidney disease in children and heat shock proteins.

Various molecular and cellular processes are involved in renal fibrosis, such as oxidative stress, inflammation, endothelial cell injury, and apoptosis. Heat shock proteins (HSPs) are implicated in the progression of chronic kidney disease (CKD). Our aim was to evaluate changes in urine and serum HSP levels over time and their relationships with the clinical parameters of CKD in children. In total, 117 children with CKD and 56 healthy children were examined. The CKD group was followed up prospectively for 24 months. Serum and urine HSP27, HSP40, HSP47, HSP60, HSP70, HSP72, and HSP90 levels and serum anti-HSP60 and anti-HSP70 levels were measured by ELISA at baseline, 12 months, and 24 months. The urine levels of all HSPs and the serum levels of HSP40, HSP47, HSP60, HSP70, anti-HSP60, and anti-HSP70 were higher at baseline in the CKD group than in the control group. Over the months, serum HSP47 and HSP60 levels steadily decreased, whereas HSP90 and anti-HSP60 levels steadily increased. Urine HSP levels were elevated in children with CKD; however, with the exception of HSP90, they decreased over time. In conclusion, our study demonstrates that CKD progression is a complicated process that involves HSPs, but they do not predict CKD progression. The protective role of HSPs against CKD may weaken over time, and HSP90 may have a detrimental effect on the disease course.

Improving the urine spot protein/creatinine ratio by the estimated creatinine excretion to predict proteinuria in pediatric kidney transplant recipients.

BACKGROUND: Since the daily creatinine excretion rate (CER) is directly affected by muscle mass, which varies with age, gender, and body weight, using the spot protein/creatinine ratio (Spot P/Cr) follow-up of proteinuria may not always be accurate. Estimated creatinine excretion rate (eCER) can be calculated from spot urine samples with formulas derived from anthropometric factors. Multiplying Spot P/Cr by eCER gives the estimated protein excretion rate (ePER). We aimed to determine the most applicable equation for predicting daily CER and examine whether ePER values acquired from different equations can anticipate measured 24 h urine protein (m24 h UP) better than Spot P/Cr in pediatric kidney transplant recipients. METHODS: This study enrolled 23 children with kidney transplantation. To estimate m24 h UP, we calculated eCER and ePER values with three formulas adapted to children (Cockcroft-Gault, Ghazali-Barratt, and Hellerstein). To evaluate the accuracy of the methods, Passing-Bablok and Bland-Altman analysis were used. RESULTS: A statistically significant correlation was found between m24 h UP and Spot P/Cr (p < .001, r = 0.850), and the correlation was enhanced by multiplying the Spot P/Cr by the eCER equations. The average bias of the ePER formulas adjusted by the Cockcroft-Gault, Ghazali-Barratt, and Hellerstein equations were -0.067, 0.031, and 0.064 g/day, respectively, whereas the average bias of Spot P/Cr was -0.270 g/day obtained by the Bland-Altman graphics. CONCLUSION: Using equations to estimate eCER may improve the accuracy and reduce the spot urine samples' bias in pediatric kidney transplantation recipients. Further studies in larger populations are needed for ePER reporting to be ready for clinical practice.

Macrophage Activation Syndrome in a Child with Juvenile Idiopathic Arthritis Secondary to SARS-CoV-2.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused a pandemic affecting many countries and millions of people. Physicians have encountered some rare and challenging cases related to SARS-CoV-2, a novel virus with still many unknowns. In order to share our experience of a such clinical picture, we present here a child with SARS-CoV-2-induced macrophage activation syndrome in the setting of juvenile idiopathic arthritis.

Different approaches among physicians to treat pediatric stone disease: a survey-based study. / Distintos enfoques adoptados por los médicos para tratar la nefrolitiasis en pediatría: estudio basado en una encuesta.

INTRODUCTION: Pediatricians, surgeons and subspecialties as pediatric urology and nephrology are involved in the diagnosis and treatment of pediatric renal stone disease (RSD). The aim of this study was to determine diagnostic and treatment approaches, of different disciplines, and to assess differences in their routine diagnostic and treatment protocols. POPULATION AND METHODS: A questionnaire was designed and administered to the participants of the RSD sessions in national congresses of all disciplines in 2017 to evaluate the diagnostic and treatment routines of specialties (surgeons and pediatricians) and subspecialties (pediatric nephrologists and pediatric urologists) for RSD. RESULTS: A total, of 324 questionnaires were analyzed, from 88 pediatricians (27 %), 121 urologists (37 %), 23 pediatric surgeons (7 %), 54 pediatric nephrologists (17 %), and 38 pediatric urologists (12 %). Both groups agreed on the necessity of metabolic evaluation. For distal ureter stones that were ≥ 6 mm; surgeons preferred ureteroscopy (URS), pediatricians preferred shock wave lithotripsy (SWL) (p < 0.001) and subspecialties preferred URS for the treatment (p = 0.636). For lower calix stones less than 1 cm surgeons and subspecialists preferred SWL, while pediatricians preferred hydration (p < 0.001, p = 0.371). For the stone between 1.1 and 2 cm, surgeons preferred intrarenal surgery (RIRS) and SWL, pediatricians preferred SWL (p = 0.001). For larger stones, surgeons and subspecialists preferred percutaneous nephrolithotomy (PCNL), and pediatricians preferred SWL (p = 0.458 p = 0.001). Pediatric urologist chose low-dose computerized tomography as a diagnostic radiologic evaluation (p = 0.029). CONCLUSION: There are differences between the disciplines who take an active role in diagnosis and treatment of RSD.

Introducción. Los pediatras, cirujanos y subespecialistas, como urólogos y nefrólogos pediátricos, participan en el diagnóstico y tratamiento de la nefrolitiasis pediátrica. El objetivo fue determinar los enfoques de distintas disciplinas y evaluar las diferencias en sus protocolos de diagnóstico y tratamiento habituales. Población y métodos. Cuestionario administrado a participantes de sesiones sobre nefrolitiasis en congresos nacionales en 2017 para evaluar las rutinas de diagnóstico y tratamiento de la nefrolitiasis entre distintas especialidades (cirujanos y pediatras) y subespecialidades (nefrólogos pediátricos y urólogos pediátricos). Resultados. Se analizaron 324 cuestionarios de 88 pediatras, 121 urólogos, 23 cirujanos pediátricos, 54 nefrólogos pediátricos y 38 urólogos pediátricos. Ambos grupos coincidieron en la necesidad de una evaluación metabólica. Para los cálculos ureterales distales ≥6 mm, los cirujanos preferían una ureteroscopía; los pediatras, una litotricia por ondas de choque (LOC) (p < 0,001); y los subespecialistas, una ureteroscopía (p = 0,636). Para los cálculos en la parte inferior de los cálices renales < 1 cm, los cirujanos y los subespecialistas preferían la LOC y los pediatras, la hidratación (p < 0,001; p = 0,371). Para los cálculos de entre 1,1 cm y 2 cm, los cirujanos preferían la cirugía retrógrada intrarrenal (CRIR) y la LOC, y los pediatras, la LOC (p = 0,001). Para los cálculos más grandes, los cirujanos y subespecialistas preferían la nefrolitotomía percutánea (NLP) y los pediatras, la LOC (p = 0,458; p = 0,001). Conclusión. Existen diferencias entre las disciplinas que participan activamente en el diagnóstico y tratamiento de la nefrolitiasis.

Rituximab treatment for difficult-to-treat nephrotic syndrome in children: a multicenter, retrospective study

Background/aim: This study aimed to evaluate the efficacy of rituximab in children with difficult-to-treat nephrotic syndrome, considering the type of disease (steroid-sensitive or ­resistant) and the dosing regimen. Materials and methods: This multicenter retrospective study enrolled children with difficult-to-treat nephrotic syndrome on rituximab treatment from 13 centers. The patients were classified based on low (single dose of 375 mg/m2) or high (2-4 doses of 375 mg/m2) initial dose of rituximab and the steroid response. Clinical outcomes were compared. Results: Data from 42 children [20 steroid-sensitive (frequent relapsing / steroid-dependent) and 22 steroid-resistant nephrotic syndrome, aged 1.9­17.3 years] were analyzed. Eleven patients with steroid-sensitive nephrotic syndrome (55%) had a relapse following initial rituximab therapy, with the mean time to first relapse of 8.4 ± 5.2 months. Complete remission was achieved in 41% and 36% of steroid-resistant patients, with the median remission time of 3.65 months. At Year 2, eight patients in steroid-sensitive group (40%) and four in steroid-resistant group (18%) were drug-free. Total cumulative doses of rituximab were higher in steroid-resistant group (p = 001). Relapse rates and time to first relapse in steroid-sensitive group or remission rates in steroid-resistant group did not differ between the low and high initial dose groups. Conclusion: The current study reveals that rituximab therapy may provide a lower relapse rate and prolonged relapse-free survival in the steroid-sensitive group, increased remission rates in the steroid-resistant group, and a significant number of drug-free patients in both groups. The optimal regimen for initial treatment and maintenance needs to be determined.

Is there a unique symptom in lower urinary tract dysfunction in children?

OBJECTIVES: Lower urinary tract symptoms (LUTS), particularly urgency, incontinence and intermittency are common in children and it is suggested that the specific symptoms may be used for definite diagnosis for LUT dysfunction (LUTD). This study was performed to investigate the relationship between each LUTD and its associated symptoms, using uroflowmetry/electromyography (UF/EMG) as a diagnostic tool. METHODS: Each patient was categorized into one of four LUT conditions which were overactive bladder (OAB), dysfunctional voiding (DV), underactive bladder and primary bladder neck dysfunction (PBND), according to UF/EMG results. Patients' complaints and findings were documented by using voiding dysfunction symptom score, bladder diary, urine analysis and ultrasonography. In addition, a detailed history of bowel habits (including use of Rome III criteria) was obtained. RESULTS: There were 189 children of which 106 were female. The OAB was the largest group including 91 patients, followed by the DV group which had 61 patients. The symptoms specific to any LUTD group were constipation and hesitancy (P < .05). Hesitancy was present in 89.4% with PBND and constipation was present in 78.6% of patients with DV. None of other symptoms were able to differentiate any LUTD group from the other. CONCLUSIONS: While certain symptoms are often presumed by clinicians to imply specific diagnoses, the main outcome of this study is that there is a generally weak correlation between the specificity of symptoms and LUTD. Symptoms-based approach may lead to misdiagnosis in LUTD. Thus, it may be essential to focus on the underlying pathologies and UF/EMG test may help this.

Symptomatology and Clinic of Hydronephrosis Associated With Uretero Pelvic Junction Anomalies.

The most common cause of hydronephrosis in the pediatric age group is ureteropelvic junction-type hydronephrosis (UPJHN). Since the advent of widespread maternal ultrasound screening, clinical presentation of hydronephrosis associated with UPJ anomalies has changed dramatically. Today most cases are diagnosed in the prenatal period, and neonates present without signs or symptoms. For those who are not detected at birth, UPJHN eventually presents throughout childhood and even adulthood with various symptoms. Clinical picture of UPJHN highly depends on the presence and severity of obstruction, and whether it affects single or both kidneys. Abdominal or flank pain, abdominal mass, hematuria, kidney stones, urinary tract infections (UTI), and gastrointestinal discomfort are the main symptoms of UPJHN in childhood. Other less common findings in such patients are growth retardation, anemia, and hypertension. UTI is a relatively rare condition in UPJHN cases, but it may occur as pyelonephritis. Vesicoureteric reflux should be kept in mind as a concomitant pathology in pediatric UPJHN that develop febrile UTI. Although many UPJHN cases are known to improve over time, close clinical observation is critical in order to avoid irreversible kidney damage. The most appropriate approach is to follow-up the patients considering the presence of symptoms, the severity of hydronephrosis and the decrease in kidney function and, if necessary, to decide on early surgical intervention.

Ambulatory arterial stiffness index is increased in obese children.

BACKGROUND AND OBJECTIVES: One way to measure arterial stiffness is the ambulatory arterial stiffness index (AASI), which is the relationship between diastolic and systolic ambulatory blood pressure (BP) over 24-hours. METHODS: We studied the difference in AASI between obese and lean children. AASI was calculated from 24- hour ambulatory blood pressure monitoring in 53 obese children (33 girls) and compared with age-matched 42 healthy subjects (20 girls). Hypertension was defined according to the criteria of the American Heart Association. To evaluate inflammation, the blood level of high-sensitive C-reactive protein was measured. RESULTS: The mean age was 10.6 ± 2.83 years in obese children and 11.3 ± 3.17 years in healthy subjects. Hypertension was determined in three (5.6%) obese children. The median heart rate-SDS, pulse pressure and blood pressure values did not differ between the two groups. The mean AASI was significantly higher in obese children compared to healthy subjects (0.42 ± 0.15 vs. 0.29 ± 0.18, p < 0.001). AASI significantly correlated with nighttime SBP-SDS, nighttime SBP-load, systolic and diastolic nocturnal dipping, with no independent predictor. CONCLUSION: This study confirms that AASI is increased in obese children. AASI calculation is a useful, costeffective, and an easy method to evaluate arterial stiffness. Early detection of increased arterial stiffness can help clinicians come up with preventive measures in the management of patients.