Purpose: Thin glomerular basement membrane nephropathy (TBMN) is, along with the IgA nephropathy, the most common cause of asymptomatic hematuria in Korean children. TBMN is usually a benign renal disease not requiring treatment and is associated with a good prognosis, but some cases hematuria is indicative of a state of progressive renal insufficiency. We aimed to retrospectively evaluate clinical manifestations and renal prognosis of patients with TBMN. Methods: Among the 428 renal biopsies performed on children at Yeungnam University Hospital between January 2000 and February 2017, 167 patients were diagnosed as having TBMN. We retrospectively investigated 167 pediatric patients and identified 59 children with follow-up duration >3 years. Results: Among 59 patients, there were 33 boys and 26 girls. Mean age of onset of hematuria was $7.18{\pm}2.64$ years, and mean time from onset of disease until a renal biopsy was performed was $2.48{\pm}2.10$ years. There were no clinical features or laboratory findings among studied children to indicate decreased renal function during follow-up; however, one case progressed to chronic kidney disease (CKD) due to an unknown cause. There were seven patients among these related a positive family history of hematuria or renal insufficiency. Concluson: Although almost all patients had normal renal functions during follow-up, there were one patient who progressed to CKD and seven patients with family history of hematuria or renal insufficiency. Moreover, four among the 428 patients over 17 years underwent repeat renal biopsies, which showed results different from their earlier biopsies.Thus, large-scales studies may be required to determine long-term prognosis of TBMN in children, and further evaluation for Alport syndrome in TBMN cases is essential.

Purpose: Renal ultrasonography has been widely used in children with renal disease. However, the relationship of renal echogenicity with renal pathology and function in children is not well known. Method: Ultrasound examination was performed in 75 patients undergoing renal biopsy for suspected renal disease in Konkuk University Medical Center from August 2005 to November 2015. We compared renal echogenicity to pathologic findings and renal function. Renal echogenicity was scored as 0 to 2 by comparing adjacent liver echogenicity. Three histologic characteristics were evaluated: glomerular changes, interstitial infiltration or fibrosis, and tubular atrophy. These were graded as 0 to 3, according to increasing severity. Laboratory results included urine albumin excretion and estimated glomerular filtration rate (eGFR). Results: Among pathologic findings, renal echogenicity revealed a positive correlation with interstitial infiltration or fibrosis (r=0.259, P=0.025), and with tubular atrophy (r=0.268, P=0.02). Renal echogenicity and glomerular changes were not correlated. Renal echogenicity showed a positive correlation with microalbuminuria (r=0.283, P=0.014), but a negative correlation with eGFR (r=-0.352, P=0.002). Conclusion: Increased renal echogenicity suggested severe interstitial infiltration or fibrosis and tubular atrophy among the pathologic findings. Moreover, increased echogenicity is correlated with increased urine albumin excretion and decreased eGFR. Echogenicity on ultrasonography is useful for determining the status of renal pathology and function.

Proteinuria is common in pediatric and adolescent patients. Proteinuria is defined as urinary protein excretion at levels higher than $100-150mg/m^2/day$ in children. It can be indicative of normal or benign conditions as well as numerous types of severe underlying renal or systemic disease. The school urine screening program has been conducted in Korea since 1998. Since then, numerous patients with normal or benign proteinuria as well as early stage renal diseases have been referred to the hospital. Benign proteinuria includes orthostatic proteinuria and transient proteinuria. Most causes of proteinuria can be categorized into 3 types: 1) overflow, 2) tubular, and 3) glomerular. Although treatment should be directed at the underlying cause of the proteinuria, prompt evaluation, diagnosis, and long-term monitoring of these pediatric patients can prevent potential progression of the underlying disease process. This article provides an overview of proteinuria: its causes, methods of assessment, and algorithmic suggestions to differentiate benign from pathologic renal disease.

Purpose: To investigate differences in clinical features, blood/urinary findings, and prognosis in different age groups of patients with Henoch-$Sch{\ddot{o}}nlein$ purpura (HSP). Methods: A total of 469 patients with HSP were analyzed retrospectively from June 2003 to February 2016. We classified patients into child or adult groups based on their age. Results: The adult group had more patients with anemia (child vs. adult; 7.5% vs. 16.4%), and higher immunoglobulin A (IgA) (30.0% vs. 50.0%) levels, C-reactive protein (34.2% vs. 54.0%) and uric acid (3.1% vs. 12.1%) levels than the child group. The child group was highly positive for Mycoplasma pneumoniae immunoglobulin M (IgM) (34.4%). More patients in the child group presented with high levels of antistreptolysin O (24.7% vs. 2.9%) and high C4 (11.5% vs. 4.2%). Low C3 (1.1% vs. 10.2%) levels, and renal involvement with gross hematuria (8.6% vs. 21.5 %), nonnephrotic proteinuria (1.1% vs. 11.2%), and nephrotic syndrome (1.1% vs. 6.0%) were common in the adult group. Adults also had poorer renal outcomes [persistent hematuria/proteinuria (10.5% vs. 32.8%), and chronic kidney disease (0% vs. 11.2%)] than the child group. Risk factors for renal involvement such as older age and higher level of uric acid were only found in the child group. The risk factors for poor renal outcome were nephrotic syndrome in the child group and gross hematuria in the adult group. Conclusion: In this study, child and adult groups presented with different clinical manifestations of HSP. We found that risk factors for renal involvement included age and high uric acid level in the child group. Moreover, nephrotic syndrome in the child group and gross hematuria in the adult group increased the risk of poor renal outcome.

Purpose: Kidney transplantation (KT) is an ideal treatment for pediatric patients with end-stage renal disease (ESRD). We report the clinical outcomes of pediatric ESRD patients who underwent KT in a single regional center. Methods: We retrospectively investigated the medical records of 60 pediatric patients who were diagnosed with ESRD and underwent KT in our hospital between January 1985 and June 2016. Results: A total of 60 children and adolescents (40 male, 20 female; mean age, $13.86{\pm}4.26$ years) were included in this study. Six patients (10.0%) underwent KT immediately after receiving the diagnosis of ESRD, while the others underwent KT after dialysis treatment (mean period of dialysis, $368.7{\pm}4,41.8$ days). The mean donor age (50 living-related [83.3%], 10 deceased [16.7%]) was $40.0{\pm}12.85$ years and the male:female ratio was 1.07:1. The most common cause of ESRD was chronic glomerulonephritis. The overall survival rates at 1, 3, and 5 years after KT were 98%, 98%, and 96%, respectively, while the graft survival rates at 1, 3, and 5 years were 93%, 86%, and 68%, respectively. Children who underwent KT before 10 years of age had better monthly growth rates than those who underwent KT later than 10 years of age. Conclusions: KT is performed less frequently in children than in adults, but causes of ESRD vary and clinical outcomes after KT greatly affect the growth and development of pediatric patients. Therefore, further analysis and monitoring of clinical progression after KT in pediatric ESRD patients are necessary.

Purpose: To investigate the frequency, presentation, management, and outcome of cytomegalovirus (CMV) infection in pediatric patients who underwent renal transplantation. Methods: We performed a retrospective chart review of 70 patients under the age of 18, who underwent renal transplantation between January 1990 and November 2014. A diagnosis of CMV infection was based on serology, molecular assays, antigenemia assays, and culture. CMV infection was defined as detection of virus and CMV disease was diagnosed when clinical signs and symptoms were present. Results: The number of patients with CMV infection was 18 (25.7% of renal transplant recipients). Twelve were male (66.7%), and the $mean{\pm}standard$ deviation (SD) age at infection was $13.3{\pm}3.9$ years. Median time of infection after renal transplantation was 4 months (range 1.0-31.0 months). Pretransplantation CMV status in the infected group was as follows: donor (D)+/recipient (R)+, 11 (61.1%); D+/R-, 7 (38.9%); D-/R+, 0; and D-/R- 0. Nine patients had CMV disease with fever, leukopenia, thrombocytopenia, or organ involvement such as enteritis, hepatitis, and pneumonitis. The age of disease occurrence was $13.1{\pm}3.9$ years and the median time to disease onset after renal transplantation was 8 months (range 1.0-31.0). Immunosuppressive agents were reduced or discontinued in 14 patients (77.8%), antiviral agents were used in 11 patients (61.1%), and all patients with CMV infection were controlled. Conclusions: A quarter of the patients had CMV infection about 4 months after renal transplantation. CMV infection was successfully treated with reduction of immunosuppressants or with antiviral agents.

Purpose: The American Society for Apheresis provides clinical guidelines for therapeutic apheresis in adults, but there are no guidelines for children. This study aimed to analyze the effect of therapeutic plasma exchange (TPE) in pediatric patients with various kidney diseases in Korea. Methods: We retrospectively reviewed the data of 16 children (up to 18 years of age) who were admitted to Severance Children's Hospital with refractory kidney disease. All patients received TPE between 1994 and 2016. Clinical and laboratory characteristics such as age, weight, sex, change in blood urea nitrogen (BUN), and creatinine level before and after TPE, and complications after TPE were analyzed. Results: The mean age and weight of the 16 patients at the time of TPE was $11.3{\pm}4.0$ years and $34.6{\pm}17.5$ kg, respectively. The BUN level was 35.4 mg/dL before TPE and significantly decreased to 21.5 mg/dL (P=0.025) at 1 week and 20.5 mg/dL (P= 0.01) at 1 month after TPE. The creatinine level significantly decreased from 1.20 mg/dL before TPE to 0.90 mg/dL (P=0.02) at 1 week after TPE. Four complications (hypovolemia, anemia, hypocalcemia, and thrombocytopenia) were reported, but were not fatal. Conclusion: Our findings suggest that TPE is an effective therapeutic modality in children with refractory kidney disease and can be indicated for the treatment of various kidney diseases.

Purpose: Virus-associated rhabdomyolysis is very rare. We report 15 patients with rhabdomyolysis caused by various viruses. Methods: Fifteen patients who were diagnosed with rhabdomyolysis and a viral infection were included in this study. Clinical, laboratory, and radiologic findings were evaluated through retrospective chart reviews. Results: Chief complaints were severe bilateral lower leg pain and leg weakness. The median age was 5.7 years. The male:female ratio was 2:5. The viral infections were caused by influenza virus B, parainfluenza virus, and rhinovirus. One patient with influenza virus B had coinfection with coronavirus. Median initial laboratory values and ranges were as follows: serum creatinine, 0.4 (0.1-0.5) mg/dL; serum aspartate transaminase, 124 (48-1,098) IU/L; serum alanine transaminase, 30 (16- 1,455) IU/L; serum creatine kinase, 2,965 (672-16,594) IU; serum lactate dehydrogenase, 400 (269-7,394) IU/L; serum myoglobin, 644 (314-3,867) ng/mL; urine myoglobin, 3 (3-10,431) ng/mL. All patients recovered without complications. Conclusion: This is the first report of the simultaneous occurrence of rhabdomyolysis caused by various viruses. This is also the first report of rhinovirus-associated rhabdomyolysis.

Purpose: The American Academy of Pediatrics provides guidelines for managing febrile urinary tract infection (UTI) in infants and children 2-24 months old, but little guidance is offered regarding UTIs in those younger than 8 weeks of age. The definition of UTI is unclear and whether to proceed with micturating cystourethrography (MCUG) or $^{99m}$technetium-dimercaptosuccinic acid (DMSA) scintigraphy scan in this age group is controversial. Methods: We retrospectively analyzed 29 neonates and infants younger than 2 months of age who underwent late DMSA scans 9 months following the first episode of febrile or symptomatic UTI between July 2009 and June 2016. Results: In total, 192 children aged 0-24 months underwent ultrasound and DMSA scans (MCUG in 174/192). Neonates and infants younger than 2 months of age were significantly less likely to develop fever, and had a lower fever peak, shorter duration of fever before admission and after starting antibiotics, longer hospitalization period, lower C-reactive protein, and greater incidence of nonEscherichia coli infection. There was no difference in pyuria response at diagnosis. The prevalence rates of an ultrasound abnormality (28%), vesicoureteral reflux (28%), UTI recurrence (38%), and renal scarring (10%) in infants younger than 8 weeks of age were similar to those in children 2-24 months old. Conclusion: Neonates and infants younger than 2 months of age with UTI warrant special consideration because the fever response used for diagnosis in older children may be absent or blunted. Clinical guideline is needed for the diagnosis and management of UTI in this age group.

Purpose: The aim of this study was to analyze the incidence and microbiological characteristics of urinary tract infection in infants aged younger three months and to compare with other infection with positive urine culture. Methods: We retrospectively reviewed the medical records of 425 infants with a tympanic temperature >$37.6^{\circ}C$, aged younger than three months, who were admitted to Cheil General Hospital in Seoul, Korea, from January 2013 to December 2016. Demographic and clinical features, laboratory findings, respiratory virus PCR and the pathogens of a urine culture were analyzed. Results: A total of 88 infants (63 males, 25 females) had urinary pathogens detected in the urine culture test. The incidence of UTI in febrile infants aged younger 3 months was 11%. The most common pathogen which causes UTI was E. coli as same as in previous studies. They were divided into a UTI group (n=48) and a non-UTI group (n=40). In comparison of both group, leukocytosis, C-reactive protein level, Absolute neutrophil count level, peak temperature is statistically significant. In both group, there were co-infections with viral pathogens in some cases, and the odd ratio of non-UTI group with viral infection was 3.28. Conclusion: The study determined the incidence and pathogen of UTI in febrile infants, aged younger three months. E. coli was responsible for the majority UTI. There were some viral co-infections in febrile infants with bacteriuria and incidence was higher in non-UTI group. WBC count, ANC count and CRP level were the differentiating factors of UTI from non-UTI group.

Purpose: This study aimed to evaluate the relationships between 99mTecnicium-dimercaptosuccinic acid (DMSA) scan findings and clinical parameters including age and fever duration. Methods: The positive rates for abnormal DMSA scans were analyzed according to the age of patients, fever duration prior to admission, and total fever duration. DMSA scan findings were divided into 3 categories: single defect, multifocal defects, and discrepant defects. We evaluated the detection rates of vesicoureteral reflux according to DMSA scan lesions. Results: Among a total 320 cases, 141 (44.1%) had abnormal DMSA scans. The infant group (0-1 year of age) had a shorter total fever duration, and a lower C-reactive protein (CRP) value and DMSA positive rate (39.8% vs. 60.6%, P=0.002) compared to children group (2-15 years of age). Patients with abnormal scans had a longer total fever duration and higher CRP compared to those with normal scans. The positivity rate of abnormal scans did not differ between the patients with a short fever duration prior to admission of ${\leq}2$ days and those with longer fever duration of ${\geq}3$ days. However, patients with longer total fever duration had a higher rate of abnormal DMSA scans (P=0.02). Among cases with a single defect, multifocal defects, and discrepant defects, vesicoureteral reflux was observed in 22.4%, 60% and 70.6% of cases, respectively (P=0.004). Conclusion: Although DMSA scan has limitations in early diagnosis, DMSA scan findings may aid in the prediction of the severity of systemic inflammation and detection of vesicoureteral reflux.

Purpose: The aim of this study was to determine the clinical characteristics, frequency of renal abnormalities and benefits of a top-down approach in children with their first febrile urinary tract infection (UTI). Methods: We reviewed 308 patients retrospectively who were admitted to Yeungnam University Hospital and were treated for their first febrile UTI from February 2006 to December 2013. We performed a comparative analysis of laboratory findings and results of imaging techniques including a Tc-99m dimercaptosuccinic acid (DMSA) renal scan. Results: Among the patients, 69% (213/308) were males, and 90% (277/308) had their first UTI episode during infancy. A DMSA renal scan was performed on all patients, and showed positive findings in 60% (184/308) of cases. Laboratory indices of inflammation were significantly higher in the DMSA-positive group (P< 0.05). There was a statistically significant difference in the age distribution between the two groups. In the DMSA-positive group, 165 patients underwent voiding cystourethrography (VCUG), and 58 (35%) cases demonstrated vesicoureteral reflux. In total, 110 patients in the DMSA-positive group, underwent repeat scanning at 6 months; 33 children (30%) demonstrated static scarring, but 77 (70%) had improved completely. The concordance of the ultrasonography (US) and VCUG was low. Older patients had more renal scarring. Conclusion: DMSA is a sensitive method for assessing the severity of inflammation and kidney injury. However, the ability of US to predict renal parenchymal damage was limited. A top-down approach in children with their first febrile UTI showed significant value.

Purpose: The aim of this study was to determine the prevalence of antibiotic susceptibility and resistance of Escherichia coli in urinary tract infections (UTIs) in children. Methods: We retrospectively reviewed the clinical records of 212 inpatients aged 18 years or younger with UTIs treated at the Pediatric Department of Dongguk University Gyeongju Hospital between January 2008 and December 2016. For comparison, patients were divided into three groups according to age as follows: group 1, ${\leq}1$ month; group 2, >1 month to ${\leq}12$ months; and group 3, ${\geq}13$ months. The antibiotic resistance rates from January 2008 to December 2012 (study period 1) and from January 2013 to December 2016 (study period 2) were analyzed statistically by group. Results: As the patient age increased, the antibiotic resistance rate to ampicillin (P=0.013), levofloxacin (P=0.050), piperacillin/tazobactam (TZP) (P<0.001), and trimethoprim/sulfamethoxazole (P=0.002) increased. The frequency of extended spectrum beta-lactamase producing E. coli showed a significant difference from 5 cases (4.6%) in study period 1 and 16 cases (15.8%) in study period 2 (P=0.007). The antibiotic resistance rate of E. coli was compared between the two time periods and we found that the antibiotic resistance rate to cefotaxime was significantly increased from 5.4% to 16.8% (P=0.008) and that to TZP was significantly decreased from 40.5% to 7.9% (P<0.001). Conclusion: Over the past 9 years, the resistance rate to cefotaxime has increased but the resistance rate to TZP has decreased. Thus, it is important to continue to investigate the antibiotic resistance rates of bacteria in the community.

Purpose: Extended-spectrum ${\beta}$-lactamase-producing bacteria-induced urinary tract infections are increasing and require more potent antibiotics such as carbapenems. We evaluated the clinical significance of extended-spectrum ${\beta}$-lactamase -urinary tract infection in children younger than 5 years to select proper antibiotics and determine prognostic factors. Differences were compared between age groups. Methods: We retrospectively studied 288 patients with their first febrile urinary tract infection when they were younger than 5 years. Patients were divided into extended-spectrum ${\beta}$-lactamase-positive and extended-spectrum ${\beta}$-lactamasenegative urinary tract infection groups. Clinical characteristics and outcomes were compared between the groups; an infant group was separately analyzed (onset age younger than 3 months). Results: Extended-spectrum ${\beta}$-lactamase urinary tract infection occurred in 11 % patients who had more frequent previous hospitalization (P=0.02) and higher recurrence rate (P=0.045). During the antimicrobial susceptibility test, the extended-spectrum ${\beta}$-lactamase-positive urinary tract infection group showed resistance to third-generation cephalosporins; however, 98% patients responded clinically. In the infant group, extended-spectrum ${\beta}$-lactamase-positive urinary tract infection occurred in 13% patients and was associated with a longer pre-onset hospitalization history (P=0.002), higher C-reactive protein level (P=0.04), and higher recurrence rate (P=0.02) than that in the older group. Conclusion: Extended-spectrum ${\beta}$-lactamase urinary tract infection requires more attention because of its higher recurrence rate. The antimicrobial susceptibility test demonstrated resistance to third-generation cephalosporins, but they can be used as first-line empirical antibiotics because of their high clinical response rate. Aminoglycosides can be second-line antibiotics before starting carbapenems when third-generation cephalosporins do not show bactericidal effects for extended-spectrum ${\beta}$-lactamase urinary tract infection.

Purpose: This study aimed to investigate clinical and radiological factors that may predict high-grade vesicoureteral reflux (VUR) in patients with febrile urinary tract infection (UTI). Methods: We retrospectively analyzed medical records of 446 patients diagnosed with febrile UTI from March 2008 to February 2017. All patients underwent renal-bladder ultrasonography (RBUS), 99mTc dimercaptosuccinic acid (DMSA) renal scan, and voiding cystourethrography (VCUG), and were divided in to 3 groups: a high-grade VUR group (n=53), a low-grade VUR group (n=28), and a group without VUR (n=365). Results: The recurrence and non-Escherichia coli infection rates in febrile UTI were significantly higher in the high-grade VUR group than in the other two groups (P<0.05). RBUS showed that hydronephrosis and ureter dilatation were more frequent in the high-grade VUR group than in the other groups (P<0.05). In the high-grade VUR group, a renal cortical defect was more likely to appear as multiple defects, and the difference in bilateral renal scan uptake between both kidneys was larger than in the other two groups (P<0.001). Conclusion: Recurrent UTI, non-E. coli UTI, abnormal findings on RBUS such as hydronephrosis and ureter dilatation, and abnormal findings in the DMSA renal scan such as multiple renal cortical defects and greater uptake difference were associated with high-grade VUR. VCUG should be selectively performed when RBUS and/or DMSA renal scan reveal significant abnormalities.

Purpose: To evaluate changes in quality of life (QoL) in patients with neurogenic bladder treated with clean intermittent catheterization (CIC), who changed from a multiple use catheter (MUC) to single use catheter (SUC). Methods: The Modified Intermittent Self-Catheterization Questionnaire (mISC-Q) was used to determine potential changes in patients' QoL as a result of switching from MUC to SUC. The mISC-Q consists of questions within four categories: ease of use, convenience, discreetness, and symptomatic benefit. Answers were graded as Strongly agree (+2), Agree (+1), Not sure (0), Disagree (-1), and Strongly disagree (-2). Overall patient QoL, as well as by sex, disease (presence of augmentation cystoplasty), and catheterization route (via urethra or urinary diversion), were analyzed. Results: Thirty-eight patients (21M:17F; mean age: $21.7{\pm}5.3y$) submitted questionnaires. For ease of use, SUC was significantly better than MUC (score: 0.364, P=0.002) in all patients. Patients with catheterization via the urethra showed significant favor for SUC in ease of use (score: 0.512, P<0.001) and convenience (score: 0.714, P=0.011), but patients with catheterization via the abdominal stoma of urinary diversion gave negative scores in all categories, though no categories were significant. Conclusion: This study suggested that changing from MUC to SUC may lead to improvements in QoL, especially regarding ease of use. This benefit was clearly found in patients with catheterization via urethra rather than abdominal stoma of urinary diversion.

Giant hydronephrosis (GH) is a rare urological entity and usually presents with more than a liter of fluid in the collecting system. It may mimic a progressive and benign abdominal cystic tumor. We report a case of GH in an 11-year-old obese boy who presented with abdominal distension and dyspnea on exercise. Hydronephrosis was caused by ureteropelvic junction obstruction, with 2,300 mL of fluid in the collecting system. Diagnostic and therapeutic features of this case are discussed, with reference to current literature.

Orthostatic or postural proteinuria is the most common cause of asymptomatic proteinuria in children. As orthostatic proteinuria (OP) is a benign disease with relatively good prognosis, it has no specific management, and patients only need to be observed. However, if OP shows a persistently high level of proteinuria, in theory, glomerular changes can occur. An 11-year-old girl was referred to the hospital due to asymptomatic proteinuria and was diagnosed as having OP based on the results of clinical and laboratory examinations, urinalysis, and protein/creatinine (TP/Cr) ratio at both supine and erect positions. During follow-up observation, the 24-hour TP/Cr ratio was persistently higher than 1.5 mg/mg for 2 years. We performed renal biopsy, which showed mesangial proliferative glomerular lesions with focal effacement of the podocyte foot processes, but without immune depositions. OP can be accompanied by glomerular lesions if moderate to severe proteinuria persists.

Systemic lupus erythematosus (SLE) is characterized by various symptoms and multi-organ involvement. Hypophosphatemia has been described in several diseases accompanied with systemic inflammation. However, hypophosphatemia has rarely been described in SLE patients, especially in those without nephritis. We report the case of a 13-year-old girl with SLE who developed hypophosphatemia without renal involvement. Her hypophosphatemia was caused by renal loss of phosphorus and persisted for 7 months. It improved as her complement levels increased. Therefore, hypophosphatemia may be related to disease activity in SLE patients.

C3 glomerulopathy (C3G) is a recently defined pathological entity characterized by C3 accumulation with absent or scant immunoglobulin deposition, leading to variable glomerular inflammation. The clinical presentation of patients with C3G is highly variable, as they may present with symptoms ranging from microscopic or mild proteinuria to full-blown nephrotic syndrome, with or without renal impairment. However, there is no consensus recommendation for specific treatment in children with C3G. Recently, new therapies have been suggested to target complement pathways, owing to an improvement in the understanding of the pathogenesis of C3G. C3G complement blockade with eculizumab, a monoclonal antibody targeted against complement C5, inhibits activation of the alternative complement pathway. We could not use eculizumab owing to its high price; thus, we administered oral prednisolone and mycophenolate mofetil (MMF). MMF was replaced with cyclosporine because proteinuria persisted, with a consistently low serum C3 level; we tapered off the prednisolone because of a Cushingoid appearance and amenorrhea. Thereafter, proteinuria improved, and the serum C3 level returned to normal. Thus, we report the effectiveness of cyclosporine in a patient with C3G and an inadequate response to prednisolone and MMF, who was detected via school urinary screening.

Focal segmental glomerulosclerosis (FSGS) in children, which is a kind of nephrotic syndrome showing steroid resistance, usually progresses to a substantial number of end stage renal disease (ESRD). Although the pathogenesis of primary FSGS is unclear, several recent studies have reported that FSGS is associated with circulating immune factors such as soluble urokinase-type plasminogen activator receptor (suPAR) or anti-CD40 autoantibody. We report a successfully treated case of a 19-year-old female patient who experienced a recurrence of primary FSGS. After the diagnosis of FSGS, the patient progressed to ESRD and received a kidney transplantation (KT). Three days later, recurrence was suspected through proteinuria and hypoalbuminemia. She has been performed plasmapheresis and high dose methylprednisolone pulse therapy and shown remission status without increasing proteinuria for four years after KT. In conclusion, strong immunosuppressive therapy may be helpful for a good prognosis of recurrent FSGS, suppressing several immunologic circulating factors related disease pathogenesis.