Activation of Complement System in Henoch-Schönlein Purpura Nephritis.

Introduction: We studied the association between Henoch-Schönlein purpura nephritis (HSPN) and complement system activation. Methods: We retrospectively reviewed the pathologic findings and medical records of 35 children and 12 adults with HSPN and compared the differences according to C4d positivity in three groups consisting of total 47 patients, 35 pediatric and 12 adult patients, respectively. C4d staining of renal biopsy was additionally performed at the time of diagnosis or retrospectively using archival biopsy material. Results: The overall rate of C4d positivity was 53.2%: 20 (57.1%) of the 35 children and five (41.7%) of the 12 adults. Among the groups there was no significant difference in the severity of proteinuria, renal function, presence of crescents or mesangial proliferation stratified by C4d positivity, unlike IgA nephropathy. Conclusions: We suggest that the activation of complement system is not correlated with the clinical or pathological severity of HSPN.

Clinical outcomes in pediatric patients with normal renal histopathology.

BACKGROUND: There have been some cases where abnormal histopathologic findings could not be found in the kidney could even with proper specimen collection through percutaneous renal biopsy (PRB) in accordance with its indication. We analyzed the incidence and clinical outcomes of children who showed normal histopathological findings in their PRBs. METHODS: The medical records of 552 pediatric subjects who underwent PRB between 2005 and 2016 were reviewed. Twenty-six subjects were excluded because allograft biopsy was performed in nine subjects, and the age at biopsy was greater than 18 years in 17 subjects. Finally, 526 subjects were enrolled in this study. RESULTS: Of the 526 pediatric patients, 32 (6.1%) showed no histopathological abnormalities in their PRBs. The male-to-female ratio of the patients was 1.9:1, and the mean ages at the first visit and at biopsy were 10.6 ± 4.1 and 11.4 ± 3.8 years, respectively. In accordance with the biopsy indications, recurrent gross hematuria showed the highest incidence rate, but combined hematuria and proteinuria had the lowest incidence rate regarding normal renal histopathology among all the subjects. At a mean follow-up of 35.5 ± 23.6 months, urinary abnormalities had improved in more than 50% of the subjects with normal renal histopathology, and none of the patients showed progression to end-stage renal disease or required rebiopsy due to symptom worsening during the follow-up period. CONCLUSION: The clinical outcomes of children with normal PRB histopathologic findings are generally good. Further studies to evaluate their long-term outcomes are needed.

Variation in clinical usefulness of biomarkers of acute kidney injury in young children undergoing cardiac surgery.

BACKGROUND: Acute kidney injury (AKI) is one of the most significant postoperative complications of pediatric cardiac surgery. Because serum creatinine has limitations as a diagnostic marker of AKI, new biomarkers including neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and interleukin-18 (IL-18) are being evaluated to overcome these limitations and detect AKI at an early stage after cardiac surgery. PURPOSE: This study aimed to investigate the clinical usefulness of these biomarkers in young children. METHODS: Thirty patients with congenital heart diseases who underwent cardiac surgery using cardiopulmonary bypass (CPB) were selected, and their urine and blood samples were collected at baseline and 6, 24, and 48 hours after surgery. Serum creatinine and blood urea nitrogen levels as well as NGAL, KIM-1, and IL-18 levels in urine samples were measured, and clinical parameters were evaluated. RESULTS: Of the 30 patients, 12 developed AKI within 48 hours after cardiac surgery. In the AKI group, 8 of 12 (66.6%) met AKI criteria after 24 hours, and urine KIM-1/creatinine (Cr) level (with adjustment of urine creatinine) peaked at 24 hours with significant difference from baseline level. Additionally, urine KIM-1/Cr level in the AKI group was significantly higher than in the non-AKI group at 6 hours. However, urine NGAL/Cr and IL-18/Cr levels showed no specific trend with time for 48 hours after cardiac surgery. CONCLUSION: It is suggested that urine KIM-1/Cr concentration could be considered a good biomarker for early AKI prediction after open cardiac surgery using CPB in young children with congenital heart diseases.

Renal involvement in children and adolescents with inflammatory bowel disease.

PURPOSE: The incidence of inflammatory bowel disease (IBD) is rapidly increasing, and several reports have described the renal complications of IBD. We sought to evaluate the clinical manifestations of renal complications in children with IBD in order to enable early detection and prompt treatment of the complications. METHODS: We retrospectively reviewed the medical records of 456 children and adolescents aged <20 years who had been diagnosed with IBD since 2000. We analyzed patient age, sex, medication use, IBD disease activity, and clinical manifestations of renal symptoms. RESULTS: Our study comprising 456 children with IBD included 299 boys (65.6%) and 157 girls (34.4%). The study included 346 children with Crohn disease and 110 children with ulcerative colitis. The incidence of kidney-related symptoms was 14.7%, which was significantly higher than that in normal children. We observed 26 children (38.8%) with isolated hematuria, 30 children (44.8%) with isolated proteinuria, and 11 children (16.4%) with hematuria and concomitant proteinuria. A renal biopsy was performed in 7 children. Histopathological examination revealed immunoglobulin A nephropathy in 5 children (71.4%). All children presented with mild disease and well-controlled disease activity of IBD. CONCLUSION: Children with IBD are more likely to show kidney-related symptoms than healthy children and adolescents are. Therefore, regular screening of urine and evaluation of renal function in such children are necessary for early detection of renal complications.