Multicenter study on the genetics of glomerular diseases among southeast and south Asians: Deciphering Diversities - Renal Asian Genetics Network (DRAGoN).

Multinational studies have reported monogenic etiologies in 25%-30% of children with steroid-resistant nephrotic syndrome. Such large studies are lacking in Asia. We established Deciphering Diversities: Renal Asian Genetics Network (DRAGoN) and aimed to describe the genetic and clinical spectrums in Asians. We prospectively studied a cohort of 183 probands with suspected genetic glomerulopathies from South and Southeast Asia, of whom 17% had positive family history. Using multi-gene panel sequencing, we detected pathogenic variants in 26 (14%) probands, of whom one-third had COL4A4 or COL4A5 variants (n = 9, 5%). Of those with COL4A5 defects, only 25% had features suggestive of Alport syndrome. Besides traditional predictors for genetic disease (positive family history and extrarenal malformations), we identified novel predictors, namely older age (6.2 vs. 2.4 years; p = 0.001), hematuria (OR 5.6; 95% CI 2.1-14.8; p < 0.001), and proteinuria in the absence of nephrotic syndrome (OR 4.6; 95% CI 1.8-11.8; p = 0.001) at first manifestation. Among patients who first presented with proteinuria without nephrotic syndrome, the genetic diagnostic rates were >60% when a second risk factor (positive family history or extrarenal manifestation) co-existed. The genetic spectrum of glomerulopathies appears different in Asia. Collagen IV genes may be included in sequencing panels even when suggestive clinical features are absent.

Both the rituximab dose and maintenance immunosuppression in steroid-dependent/frequently-relapsing nephrotic syndrome have important effects on outcomes.

Rituximab is an effective treatment for steroid-dependent/ frequently-relapsing nephrotic syndrome (SDFRNS) in children. However, the optimal rituximab regimen remains unknown. To help determine this we conducted an international, multicenter retrospective study at 11 tertiary pediatric nephrology centers in Asia, Europe and North America of children 1-18 years of age with complicated SDFRNS receiving rituximab between 2005-2016 for 18 or more months follow-up. The effect of rituximab prescribed at three dosing levels: low (375mg/m2), medium (750mg/m2) and high (1125-1500mg/m2), with or without maintenance immunosuppression (defined as concurrent use of corticosteroids, mycophenolate motile or calcineurin inhibition at first relapse or for at least six months following the rituximab treatment) was examined. Among the 511 children (median age 11.5 year, 67% boys), 191, 208 and 112 received low, medium and high dose rituximab, respectively. Within this total cohort of 511 children, 283 (55%) received maintenance immunosuppression. Renal biopsies were performed in 317 children indicating the predominant histology was minimal change disease (74%). Without maintenance immunosuppression, low-dose rituximab had a shorter relapse-free period and a higher relapse risk (8.5 months) than medium (12.7 months; adjusted hazard ratio, 0.62) and high dose (14.3 months; adjusted hazard ratio, 0.50; all significant). With maintenance immunosuppression, the relapse-free survival in low-dose rituximab (14 months) was similar to medium (10.9 months; adjusted hazard ratio, 1.23) and high dose (12.0 months; adjusted hazard ratio, 0.92; all non-significant). Most adverse events were mild. Thus, children receiving low-dose rituximab without maintenance immunosuppression had the shortest relapse-free survival. Hence, both rituximab dose and maintenance immunosuppression have important effects on the treatment outcomes.

Persistent Dengue Infection in an Immunosuppressed Patient Reveals the Roles of Humoral and Cellular Immune Responses in Virus Clearance.

Detailed understanding of the roles of humoral and cellular immune responses in sterilizing dengue virus (DENV) infection in humans is required to inform effective vaccine development. We report an unusual case of persistent DENV infection in a lymphopenic renal transplant recipient who was therapeutically immunosuppressed to prevent organ rejection. Following resolution of symptomatic dengue, this patient remained positive for DENV3 RNA in the blood for 4 months and viruric up to 9 months post-infection despite demonstrable levels of serum neutralizing antibodies throughout this period. Full resolution of DENV infection instead coincided with recovery of CD8+ T cell counts during reversal from lymphopenia. Taken collectively, our observations suggest a role for cellular immunity in sterilizing DENV infection in humans. Any dengue vaccine should thus be able to induce both humoral and cellular immunity that respectively prevent symptomatic infection and enable effective viral clearance.

MeSsAGe risk score: tool for renal biopsy decision in steroid-dependent nephrotic syndrome.

BACKGROUND: A lack of consensus exists as to the timing of kidney biopsy in children with steroid-dependent nephrotic syndrome (SDNS) where minimal change disease (MCD) predominates. This study aimed at examining the applicability of a biomarker-assisted risk score model to select SDNS patients at high risk of focal segmental glomerulosclerosis (FSGS) for biopsy. METHODS: Fifty-five patients with SDNS and biopsy-proven MCD (n = 40) or FSGS (n = 15) were studied. A risk score model was developed with variables consisting of age, sex, eGFR, suPAR levels and percentage of CD8+ memory T cells. Following multivariate regression analysis, total risk score was calculated as sum of the products of odds ratios and corresponding variables. Predictive cut-off point was determined using receiver operator characteristics (ROC) curve analysis. RESULTS: Plasma suPAR levels in FSGS patients were significantly higher, while percentage of CD45RO+CD8+CD3+ was significantly lower than in MCD patients and controls. ROC analysis suggests the risk score model with threshold score of 16.7 (AUC 0.84, 95% CI 0.72-0.96) was a good predictor of FSGS on biopsy. The 100% PPV cut-off was >24.0, while the 100% NPV was <13.3. CONCLUSION: A suPAR and CD8+ memory T cell percentage-based risk score model was developed to stratify SDNS patients for biopsy and for predicting FSGS.

T Lymphocyte Activation Markers as Predictors of Responsiveness to Rituximab among Patients with FSGS.

BACKGROUND AND OBJECTIVES: Rituximab is used with variable success in difficult FSGS. Because B cell depletion significantly affects T cell function, we characterized T cell subsets in patients with FSGS to determine if an immunologic signature predictive of favorable response to rituximab could be identified. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Twenty-two consecutive patients with FSGS (median age =14.4 years old; range =6.2-25.0 years old) and age of onset of nephrotic syndrome 1-18 years old receiving rituximab for clinical indications between October of 2009 and February of 2014 were studied. Indications for rituximab were lack of sustained remission despite calcineurin inhibitors (CNIs) and mycophenolate in steroid-resistant patients and lack of steroid-sparing effect with cyclophosphamide and CNI or CNI toxicity in steroid-dependent patients. Exclusion criteria were infantile onset, known genetic mutations, and secondary causes. Rituximab (375 mg/m(2)) was given fortnightly up to a maximum of four doses. Immunologic subset monitoring was performed at baseline and regular intervals until relapse. Median follow-up duration postrituximab was 26.7 months (range =6.5-66.5 months). Baseline immunologic subsets were examined for association with rituximab response defined as resolution of proteinuria with discontinuation of prednisolone and CNI 3 months postrituximab. RESULTS: Twelve patients (54.5%) responded to rituximab. Mitogen-stimulated CD154(+)CD4(+)CD3(+) subset before rituximab was significantly lower in FSGS responders compared with nonresponders (54.9%±28.1% versus 78.9%±16.4%; P=0.03). IFN-γ(+)CD3(+) and IL-2(+)CD3(+) were similarly decreased in responders compared with nonresponders (0.6%±0.8% versus 7.5%±6.1%; P=0.003 and 0.2%±0.5% versus 4.0%±4.7%; P<0.01, respectively). Recovery of all three activation subsets occurred 6 months postrituximab treatment (CD154(+)CD4(+)CD3(+), 74.8%±17.2%; IFN-γ(+)CD3(+), 7.1%±7.7%; and IL-2(+)CD3(+), 7.9%±10.9%; P<0.01). Receiver-operating characteristic analysis using optimal cutoff values showed that activated CD154(+)CD4(+)CD3(+) <83.3% (area under the curve [AUC], 0.81; 95% confidence interval [95% CI], 0.61 to 1.00), IFN-γ(+)CD3(+)<2.5% (AUC, 0.90; 95% CI, 0.75 to 1.00), and IL-2(+)CD3(+)<0.3% (AUC, 0.78; 95% CI, 0.57 to 0.98) were good predictors of rituximab response. CONCLUSIONS: We have identified prognostic markers that define a subset of patients with FSGS bearing an immunologic signature representing hyporesponsiveness to T cell stimulation and therefore, who respond better to rituximab.

Recurrent white thrombi formation in hemodialysis tubing: a case report.

BACKGROUND: While the appearance of red clots in the dialyzer is a common phenomenon in every hemodialysis unit, the occurrence of white thrombi in the tubing is relatively rare. CASE PRESENTATION: We describe an adolescent male with recurrent white thrombi formation in the hemodialysis tubing. This patient had chronic renal failure from focal segmental glomerulosclerosis, but was no longer nephrotic at the time of the thrombi formation. He had a history of recurrent thrombosis of his vascular access. However, no pro-thrombotic risk factors could be identified. White particulate matter, measuring 1 to 3mm in size, and adherent to the arterial and venous blood tubing lines was found during the rinse back of a hemodialysis session. This was associated with a 60% decrease in his platelet count. Light microscopic examination of the deposits revealed the presence of platelet aggregates. He subsequently developed thrombosis of his arteriovenous graft six hours later. The white thrombi recurred at the next dialysis session, as well as six months later. These episodes occurred regardless of the type of dialysis machine or tubing, and appeared to resolve with an increase in heparin dose. CONCLUSION: Recurrent white thrombi formation can occur in the hemodialysis tubing of a patient with no identifiable pro-thrombotic factors. The white thrombi may be a harbinger of arteriovenous graft thrombosis and may be prevented by an increase in heparin dose.

Use of HF20 membrane in critically ill unstable low-body-weight infants on inotropic support.

BACKGROUND: Initiating continuous renal replacement therapy (CRRT) in infants exposes them to the dual hemodynamic challenges of high circuit extracorporeal volumes and potential membrane reactions, in the case of acrylonitrile AN69 membranes. The use of the new Prismaflex HF20 membrane in hemodynamically unstable low-body-weight infants on inotropic support has not been reported. TREATMENT: We describe the use of the HF20 (Gambro Lundia AB, Lund, Sweden) membrane in four low-body-weight infants (2.3 to 5.4 kg) with multi-organ dysfunction syndrome who were critically ill in the Pediatric Intensive Care Unit (PICU), hemodynamically unstable, and on inotropes. We were able to achieve target volume loss in all infants without compromising their hemodynamic status. Mean arterial pressures were maintained between 39 and 57 mmHg. The relatively low circuit volume of the HF20 set (60 ml) obviated the need for blood prime in the majority; however, when blood prime was required, there was no adverse reaction with the polyarylethersulfone (PAES) membrane. Solute clearance in these small infants was efficient with correction of metabolic acidosis and electrolyte abnormalities. Excellent circuit lifespan (56.3 ± 32.3 h) was observed. CONCLUSIONS: CRRT using the HF20 membrane is safe and hemodynamically well tolerated in high-risk, unstable low-body-weight infants with cardiac dysfunction on multiple inotropes.