Objective:To explore the efficacy and its related factors of rituximab (RTX) in the treatment of children with frequently relapsing nephrotic syndrome/steroid-dependent nephrotic syndrome (FRNS/SDNS).Methods:It was a single-center retrospective study. The clinical data of FRNS/SDNS children first treated with RTX in the First Affiliated Hospital of Sun Yat-sen University from November 1, 2016 to September 1, 2023 were collected. The number of relapse within 1 year before and after RTX treatment, the time to first relapse after RTX treatment, and the time to B-cell reconstitution were analyzed. At the first treatment, a single dose of RTX was given at 375 mg/m 2, with a maximum dose of 500 mg, once a week, for 1 to 4 doses. The count of CD19 + lymphocytes in the peripheral blood of the children was continuously monitored. If B-cell reconstruction was performed, the decision on whether to proceed to the next course of RTX treatment was made based on clinical manifestations. Kaplan-Meier method was used to analyze relapse-free survival rate after receiving RTX. Cox proportional hazards regression model was used to analyze the related factors of relapse after RTX treatment. Results:A total of 98 FRNS/SDNS children receiving RTX treatment were enrolled, including 75 males (76.5%). The age at onset was 4.0 (1.9, 7.1) years and age of receiving RTX was 11.3 (8.5, 13.5) years. There were 90 children (91.8%) achieving complete remission, while 8 patients (8.2%) did not respond to RTX treatment, and 3 patients (3.1%) progressed to end-stage kidney disease after receiving RTX. The relapse-free survival rates at 6 months and 1 year after RTX treatment were 83.3% (75/90) and 57.9% (22/38), respectively. The frequency of relapse 1 year after RTX treatment decreased compared to 1 year before RTX treatment ( Z=-7.398, P<0.001). Compared with children without relapse during the period of B-cell depletion, relapsed children had a higher number of relapse within one year after RTX treatment ( Z=5.246, P<0.001). The time to first relapse after RTX treatment was 8.3 (4.6, 13.9) months in 51 relapse patients. Compared with children receiving 1 dose of RTX in the first course, those receiving 2 or more doses had a longer time to the first relapse ( Z=2.983, P=0.003). There was no statistically significant difference in time to the first relapse between children who received mycophenolate mofetil therapy after RTX treatment and those who didn't ( P>0.05). The reconstruction time of B cells after the first course of RTX was 6.9 (5.3, 9.0) months. Compared to children receiving one dose of RTX in the first course, those receiving two or more doses had a longer B-cell reconstitution time ( Z=2.739, P=0.006). There was no statistically significant difference in B-cell reconstitution time between children who received mycophenolate mofetil therapy after RTX treatment and those who didn't ( P>0.05). Univariate Cox regression analysis showed that recurrence after calcineurin inhibitor (CNI) treatment before RTX treatment and the number of recurrence in one year before RTX treatment were correlated factors of recurrence after RTX treatment (both P<0.05). Multivariate Cox regression analysis showed that recurrence after CNI treatment before RTX treatment was an independent correlated factor of relapse after RTX therapy ( HR=3.496, 95% CI 1.245-9.818, P=0.018). Infusion reactions occurred in 10 patients (10.2%) and infections were observed in 24 patients (24.5%) during B cell depletion. No serious adverse events occurred. Conclusions:RTX is well tolerated and effective in treating FRNS/SDNS. Recurrence after CNI treatment before RTX treatment may be an independent related factor of relapse after RTX treatment.

Objective:To explore the efficacy and its related factors of rituximab (RTX) in the treatment of children with frequently relapsing nephrotic syndrome/steroid-dependent nephrotic syndrome (FRNS/SDNS).Methods:It was a single-center retrospective study. The clinical data of FRNS/SDNS children first treated with RTX in the First Affiliated Hospital of Sun Yat-sen University from November 1, 2016 to September 1, 2023 were collected. The number of relapse within 1 year before and after RTX treatment, the time to first relapse after RTX treatment, and the time to B-cell reconstitution were analyzed. At the first treatment, a single dose of RTX was given at 375 mg/m 2, with a maximum dose of 500 mg, once a week, for 1 to 4 doses. The count of CD19 + lymphocytes in the peripheral blood of the children was continuously monitored. If B-cell reconstruction was performed, the decision on whether to proceed to the next course of RTX treatment was made based on clinical manifestations. Kaplan-Meier method was used to analyze relapse-free survival rate after receiving RTX. Cox proportional hazards regression model was used to analyze the related factors of relapse after RTX treatment. Results:A total of 98 FRNS/SDNS children receiving RTX treatment were enrolled, including 75 males (76.5%). The age at onset was 4.0 (1.9, 7.1) years and age of receiving RTX was 11.3 (8.5, 13.5) years. There were 90 children (91.8%) achieving complete remission, while 8 patients (8.2%) did not respond to RTX treatment, and 3 patients (3.1%) progressed to end-stage kidney disease after receiving RTX. The relapse-free survival rates at 6 months and 1 year after RTX treatment were 83.3% (75/90) and 57.9% (22/38), respectively. The frequency of relapse 1 year after RTX treatment decreased compared to 1 year before RTX treatment ( Z=-7.398, P<0.001). Compared with children without relapse during the period of B-cell depletion, relapsed children had a higher number of relapse within one year after RTX treatment ( Z=5.246, P<0.001). The time to first relapse after RTX treatment was 8.3 (4.6, 13.9) months in 51 relapse patients. Compared with children receiving 1 dose of RTX in the first course, those receiving 2 or more doses had a longer time to the first relapse ( Z=2.983, P=0.003). There was no statistically significant difference in time to the first relapse between children who received mycophenolate mofetil therapy after RTX treatment and those who didn't ( P>0.05). The reconstruction time of B cells after the first course of RTX was 6.9 (5.3, 9.0) months. Compared to children receiving one dose of RTX in the first course, those receiving two or more doses had a longer B-cell reconstitution time ( Z=2.739, P=0.006). There was no statistically significant difference in B-cell reconstitution time between children who received mycophenolate mofetil therapy after RTX treatment and those who didn't ( P>0.05). Univariate Cox regression analysis showed that recurrence after calcineurin inhibitor (CNI) treatment before RTX treatment and the number of recurrence in one year before RTX treatment were correlated factors of recurrence after RTX treatment (both P<0.05). Multivariate Cox regression analysis showed that recurrence after CNI treatment before RTX treatment was an independent correlated factor of relapse after RTX therapy ( HR=3.496, 95% CI 1.245-9.818, P=0.018). Infusion reactions occurred in 10 patients (10.2%) and infections were observed in 24 patients (24.5%) during B cell depletion. No serious adverse events occurred. Conclusions:RTX is well tolerated and effective in treating FRNS/SDNS. Recurrence after CNI treatment before RTX treatment may be an independent related factor of relapse after RTX treatment.

Wiskott-Aldrich syndrome (WAS) is a rare X-linked recessive genetic disorder characterized by thrombocytopenia, eczema, recurrent infections, and susceptibility to autoimmune diseases. The renal complication of WAS is mainly manifested as IgA nephropathy. Membranous nephropathy (MN) in children mostly has secondary factors, and its occurrence is related to immune disorders. This paper reports a case of WAS in an infant with bleeding tendency and recurrent infections, complicated with nephrotic syndrome during the course, confirmed as MN by pathological examination. After treatment with glucocorticoids, tacrolimus and hematopoietic stem cell transplantation, nephrotic syndrome was manifested as steroid-resistant and partially sensitive to tacrolimus. Proteinuria continued to relieve 3 months after hematopoietic stem cell transplantation and renal function remained stable. WAS complicated with MN is extremely rare, and its renal prognosis is still unclear, which deserves the attention of clinicians.

Objective:To explore clinicopathological features and prognosis of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) in children induced by antithyroid drugs.Methods:The clinicopathological features, treatment and prognosis of 3 children with AAV induced by antithyroid drugs in the Department of Pediatric Nephrology and Rheumatology of the First Affiliated Hospital of Sun Yat-sen University were analyzed retrospectively, and the literatures were reviewed.Results:(1) Among the 3 cases, there were 2 females and 1 male, whose ages were 12.6, 13.9 and 13.1 years old, respectively. All patients had medication history of propylthiouracil (PTU) and/or methimazole (MMI) before onset. Initial manifestation was pallor and renal involvements with nephrotic proteinuria, hematuria and renal function abnormality, while 2 of them had hypertension. Extrarenal manifestations were also presented: case 1 presented with rash, arthralgia and cardiac insufficiency; case 2 had brain involvement with repeated convulsions; case 3 presented with arthralgia and lung involvement. They were all tested positive for p-ANCA and MPO-ANCA. Initial renal histopathology of the 3 cases were consistent with ANCA-associated glomerulonephritis, which were classified into sclerosis, crescentic and mixed class respectively. After 8 months of treatments, repeated renal biopsy of case 3 had demonstrated progression to sclerosis class. Antithyroid drugs (PTU or MMI) were discontinued in 3 cases, and the children were all treated with corticosteroid combined with intravenous pulse cyclophosphamide therapy. Plasma exchange was performed in case 2 and case 3 due to rapidly progressive glomerulonephritis and disease recurrence (suspected pulmonary hemorrhage), respectively. Case 3 was treated with rituximab combined with mycophenolate mofetil after recurrence. The extrarenal symptoms relieved quickly after treatments in all cases. P-ANCA and MPO-ANCA became negative in case 1 and case 2 after 6 months of treatments but they were persistently positive in case 3. Three cases were followed up for 24 months, 10 months and 12 months, respectively: case 1 develop chronic kidney disease (CKD) stage 2 with normal urinalysis; case 2 develop CKD stage 5 and had sudden death at home at 10-month follow-up; case 3 develop CKD stage 4 with nephrotic proteinuria and microscopic hematuria. (2) There were totally 30 pediatric cases with AAV induced by PTU and MMI, including 27 reported cases in the literature and 3 cases in this study. Symptoms of AAV appeared in children after an average administration of (37.5±4.0) months of PTU (range from one month to 96 months and 8 months of MMI alone). Kidney (28 cases, 93.3%) and lung (12 cases, 40.0%) were commonly involved, while brain (2 cases, 6.7%) was rarely involved. The pathological changes of kidney were crescent nephritis (5/23) and necrotizing pauci-immune complex nephritis (11/23). The total remission rate was 93.3% (28/30) after antithyroid drugs withdrawal and treatment with corticosteroids and immunosuppressive therapy, however, there were still severe cases with progression to CKD stage 5, and death. (3) Thirty cases were divided into complete response group ( n=19) and incomplete response group ( n=11) according to the treatment response. Compared with complete response group, the proportions of massive proteinuria (8/11 vs 5/19), fibrinoid necrosis (7/9 vs 4/14), deposition of immune complex in renal tissues (6/9 vs 2/14) and administration of immunosuppressants (10/11 vs 5/19), and degree of tubular atrophy (0/1/2/3 grade, 2/4/2/1 vs 9/5/0/0) in incomplete response group were higher (all P<0.05). Conclusions:PTU and MMI can both induce AAV in children, and AAV may occur after short-term course of administration. Kidney and lung are commonly involved while brain involvement is rarely seen. Timely withdrawal of antithyroid drugs and proper treatments with corticosteroids and immunosuppressants can result in high remission rate, though there are still some severe cases. Nephrotic-range proteinuria, renal fibrinoid necrosis, immune-complex deposition and tubular atrophy may be the risk factors of AAV for poor prognosis.

Objectives:To analyze the clinical characteristics, treatment effectiveness and long-term prognosis of childhood-onset lupus nephritis (LN), and to explore the risk factors for progression to end-stage renal disease (ESRD).Methods:In this retrospective study, the clinical data including general conditions, clinical manifestations, laboratory examinations, treatment, following up (till December 31st, 2020) and prognosis of 343 children with LN who were treated and followed up in the First Affiliated Hospital of Sun Yat-sen University from January 1, 2003 to December 31, 2019 were analyzed. Complete remission rates were compared between different pathological types according to renal biopsies and flare rates were compared between complete remission group and partial remission group according to the treatment effectiveness after 6 months of induction treatment. To investigate the risk factors of ESRD, the prognosis of flare and non-flare cases, and of cases with normal and elevated serum creatinine levels at baseline, was compared. Chi-squared tests were used for comparison between groups, and cumulative survival rate and renal survival rates were calculated by Kaplan-Meier survival analysis. Risk factors for ESRD were analyzed by COX regression model.Results:Among the 343 children, 68 were males (19.8%) and 275 were females (80.2%) with a median age of 13.0 (11.0, 16.0) years. Regarding the renal symptoms, 305 (88.9%) children had proteinuria and 245 (71.4%) had hematuria; while for extra-renal manifestations, 273 (79.6%) had anemia, 183 (53.4%) had rashes and 165 (48.1%) had fever. A total of 212 (61.8%) children had severely active SLE at initial presentation. After 6 months of induction treatment, the complete remission rate was 63.8% (219/343) and the partial remission rate was 27.1% (93/343). The complete remission rate was significantly higher in type Ⅰ and type Ⅱ LN compared to type Ⅳ LN (10/12 vs. 82/135 (60.7%), χ2 =3.936, P=0.047). One hundred and ten children who achieved remission, including complete remission and partial remission, experienced renal flare with a flare rate of 35.3% and a mean time to flare was (43.2±28.4) months. There was no significant difference in flare rates between complete and partial remission group (36.1% (79/219) vs. 33.3% (31/93), χ2=3.394, P=0.065). The follow-up time of all the children was 60.4 (32.3, 100.9) months. During the follow-up period, 15 children died and the cumulative survival rates at 3, 5 and 10 years were 97.2%, 96.4% and 93.3%, respectively; 14 children progressed to ESRD and the cumulative renal survival rates at 3, 5, and 10 years were 99.2%, 97.1%, and 93.4%, respectively. COX multivariate analysis demonstrated that elevated serum creatinine at baseline, nephritic flare and nephrotic flare were independent risk factors for progression of ESRD ( hazard ratio (HR)=3.575, 21.550 and 8.590, 95% CI 1.127-11.341, 2.394-194.027 and 1.042-70.823, P=0.031, 0.006, and 0.046, respectively). Conclusions:Children with LN are characterized by high SLE disease activity and multi-system involvement at onset. After 6 months of induction treatment, most of LN children could achieve clinical remission but some would experience renal flare. Nephritic flare, nephrotic flare and elevated serum creatinine at onset are independent risk factors for the progression of ESRD in children with LN.

Objective To analyze the relationship between the serum B-cell activating factor (BAFF) levels and clinical characters and pathological features in children with lupus nephritis (LN). Methods ELISA was used to detect the serum BAFF (sBAFF) levels of the 54 LN children diagnosed in the First Affiliated Hospital, Sun Yat-sen University during October 1, 2014 to December 31, 2016 and with complete clinical data. According to whether glucocorticoid or immunosuppressive agents has been used at their first admission, patients were divided into treated group (n=44) and non-therapy group (n=10). According to the renal response after induction treatment for 6 months, patients were divided into remission group (n=20) and non-response group (n=34). According to whether there was renal recurrence, they were divided into recurrence group (6 cases) and non-recurrence group (48 cases). According to renal biopsy, patients were divided into class-Ⅲ, class-Ⅳ and class-Ⅴ group. Another 15 healthy children were taken as a control group. The correlations between sBAFF and clinical manifestation, laboratory examination, renal biopsy and clinical outcome were analyzed. Results (1) Compared with the control group, the sBAFF was significantly increased in LN group (t=3.821, P<0.001). Compared with the non- neuropsychiatric systemic lupus erythematosus (NPSLE) group, sBAFF was significantly increased in NPSLE group (t=2.202, P=0.032). (2) Compared with that in treated group, sBAFF was significantly higher in untreated group (LSD - t=2.309, P=0.025). Compared with non-response group, sBAFF was significantly decreased in response group (LSD-t=2.035, P=0.046). (3) No significant difference was observed between class-Ⅲ, class-Ⅳ and class-Ⅴpathological classification group (F=1.080, P=0.459). sBAFF in LN children was not significantly correlated with the active index (AI) or chronic index (CI) of Austin index (r=-0.273, P=0.063; r=0.150, P=0.314). (4) In LN children, sBAFF has positive correlation with ESR and IgG level (r=0.289, P=0.036; r=0.340, P=0.017) and negative correlation with WBC (r=-0.337, P=0.013). Multiple linear regression model showed that serum IgG level (β'=0.517, P=0.001) and renal response (β'=-0.271, P=0.037) were independent influencing factors of sBAFF level. Conclusions Renal remission and serum IgG levels in LN children are influencing factors of sBAFF levels. sBAFF is helpful to clinical assessment on renal response of LN children.

Objective To investigate the clinical, pathological features and risk factors of hyperuricemia in children with IgA nephropathy (IgAN). Methods A retrospective study of 269 primary IgAN children diagnosed between January 1, 2006 to December 31, 2017 at the Children Kidney Disease Center, the First Affiliated Hospital of Sun Yat-sen University, was performed in the hyperuricemia group (uric acid>350 μmol/L) and the normal uric acid group. The clinical and pathological characteristics were analyzed, and the risk factors of hyperuricemia were analyzed by using multivariate logistic regression analysis. Results There were 185 males and 84 females in the 269 IgAN children with age of (9.2 ± 3.1) years old, among whom there were 70 patients (26.0％) accompanied by hyperuricemia. Clinical indicators such as hypertension, urea nitrogen, serum creatinine, blood lipids, urinary protein in hyperuricemia group were higher than those in normal uric acid group (all P<0.05), while estimated glomerular filtration rate, serum total protein and albumin were less (all P<0.05). There were 58 patients (23.0％) and 12 patients (70.5％) associated with hyperuricemia among IgAN children with CKD 1-2 and CKD 3-5. The proportion of hyperuricemia in CKD stage 3-5 IgAN children was statistically higher than that in normal uric acid group (P<0.01). The hyperuricemia group had a higher proportion of Lee IV and V grade, and a lower proportion of the Lee III grade than the normal uric acid group (all P<0.05). According to the Oxford pathological classification score, there was no significant difference in total scores of renal lesions, glomerular score, and tubulointerstitial score between the two groups (all P>0.05). According to the Katafuchi semi-quantitative score, there was no significant difference in the total scores of renal lesions, glomeruli, and tubulointerstitial scores (all P>0.05), while the hyperuricemia group had higher renal vascular scores than the normal uric acid group (P<0.01). Multivariate logistic regression analysis showed that hypertension (OR=12.596, 95％CI 1.778-89.243, P=0.011), higher total cholesterol (OR=1.192, 95％CI 1.064-1.336, P=0.002), higher urea nitrogen (OR=1.273, 95％CI 1.104-1.468, P=0.001), proteinuria 3+(OR=1.875, 95％CI 1.309-2.684, P=0.001), proteinuria 4+(OR=1.627, 95％CI 1.241-2.134, P<0.001) and CKD stage 3 (OR=3.355, 95％CI 1.376-8.181, P=0.008) were the risk factors of hyperuricemia in children with IgAN. Conclusions Twenty-six percent IgAN children patients are accompanied by hyperuricemia, and their clinical parameters and pathological changes are more severe than those in normal uric acid group. Hypertension, higher total cholesterol, higher urea nitrogen, proteinuria 3+/4+and CKD stage 3 are the risk factors of hyperuricemia in children with IgAN.