Efficacy of combined rituximab and daratumumab treatment in posttransplant recurrent focal segmental glomerulosclerosis.

Focal segmental glomerulosclerosis (FSGS) is one of the leading causes of kidney failure and it is characterized by a high rate of recurrence after kidney transplant. Moreover, FSGS recurrence is worsened by an increased risk of graft failure. Common therapies for FSGS recurrence mostly consist of plasma exchange treatments, also for prolonged time, and rituximab, with variable efficacy. We report 5 cases of early FSGS recurrence after kidney transplant, resistant to plasma exchange and rituximab treatment that subsequently resolved after combined therapy with rituximab and daratumumab. All cases were negative for genetic FSGS. The combined treatment induced a complete response in all the cases and was well tolerated. We also performed a comprehensive flow cytometry analysis in 2 subjects that may suggest a mechanistic link between plasma cells and disease activity. In conclusion, given the lack of viable treatments for recurrent FSGS, our reports support the rationale for a pilot trial testing the safety/efficacy profile of combined rituximab and daratumumab in posttransplant FSGS recurrence.

Anti-glutathione S-transferase theta 1 antibodies correlate with graft loss in non-sensitized pediatric kidney recipients.

Introduction: Immunity to Human leukocyte antigen (HLA) cannot explain all cases of ABMR, nor the differences observed in the outcome of kidney recipients with circulating DSAs endowed with similar biologic characteristics. Thus, increasing attention has recently been focused on the role of immunity to non-HLA antigenic targets. Methods: We analyzed humoral auto- and alloimmune responses to the non-HLA antigen glutathione S-transferase theta 1 (GSTT1), along with development of de novo (dn)HLA-DSAs, in a cohort of 146 pediatric non-sensitized recipients of first kidney allograft, to analyze its role in ABMR and graft loss. A multiplex bead assay was employed to assess GSTT1 antibodies (Abs). Results: We observed development of GSTT1 Abs in 71 recipients after transplantation, 16 with MFI > 8031 (4th quartile: Q4 group). In univariate analyses, we found an association between Q4-GSTT1Abs and ABMR and graft loss, suggesting a potential role in inducing graft damage, as GSTT1 Abs were identified within ABMR biopsies of patients with graft function deterioration in the absence of concomitant intragraft HLA-DSAs. HLA-DSAs and GSTT1 Abs were independent predictors of graft loss in our cohort. As GSTT1 Ab development preceded or coincided with the appearance of dnHLA-DSAs, we tested and found that a model with the two combined parameters proved more fit to classify patients at risk of graft loss. Discussion: Our observations on the harmful effects of GSTT1Abs, alone or in combination with HLA-DSAs, add to the evidence pointing to a negative role of allo- and auto-non-HLA Abs on kidney graft outcome.

A UHPLC-MS/MS Method for Therapeutic Drug Monitoring of Aciclovir and Ganciclovir in Plasma and Dried Plasma Spots.

The role of therapeutic drug monitoring (TDM) of valaciclovir (VA)/aciclovir (A) and valganciclovir/ganciclovir (VG/G) in critically ill patients is still a matter of debate. More data on the dose-concentration relationship might therefore be useful, especially in pediatrics where clinical practice is not adequately supported by robust PK studies. We developed and validated a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) micro-method to simultaneously quantify A and G from plasma and dried plasma spots (DPS). The method was based on rapid organic extraction from DPS and separation on a reversed-phase C-18 UHPLC column after addition of deuterated internal standards. Accurate analyte quantification using SRM detection was then obtained using a Thermo Fisher Quantiva triple-quadrupole MS coupled to an Ultimate 3000 UHPLC. It was validated following international (EMA) guidelines for bioanalytical method validation and was tested on samples from pediatric patients treated with A, VG, or G for cytomegalovirus infection following solid organ or hematopoietic stem cell transplantation. Concentrations obtained from plasma and DPS were compared using Passing-Bablok and Bland-Altman statistical tests. The assay was linear over wide concentration ranges (0.01-20 mg/L) in both plasma and DPS for A and G, suitable for the expected therapeutic ranges for both Cmin and Cmax, accurate, and reproducible in the absence of matrix effects. The results obtained from plasma and DPS were comparable. Using an LC-MS/MS method allowed us to obtain a very specific, sensitive, and rapid quantification of these antiviral drugs starting from very low volumes (50 µL) of plasma samples and DPS. The stability of analytes for at least 30 days allows for cost-effective shipment and storage at room temperature. Our method is suitable for TDM and could be helpful for improving knowledge on PK/PD targets of antivirals in critically ill pediatric patients.

Post-transplant de novo non donor-specific HLA antibodies are not associated with poor graft outcome in non-sensitized pediatric recipients of kidney transplantation.

While de novo donor-specific HLA antibodies (dnDSAs) have a detrimental impact on kidney graft outcome, the clinical significance of de novo non donor-specific antibodies (dnNDSAs) is more controversial. We retrospectively evaluated for Ab development and characteristics of dnNDSAs serially collected post-transplant sera and, when available, graft biopsy eluates, from 144 non-sensitized, primary pediatric kidney recipients, consecutively transplanted at a single center between 2003 and 2017, using HLA class I and class II single-antigen flow-bead assays (SAB). The results were compared with clinical-pathologic data from HLA antibody negative and HLA dnDSA-positive patients. Forty-five out of 144 patients developed dnNDSAs (31%). Among the dnNDSA-positive patients, 86% displayed one or more class I/II antibodies recognizing antigens included in the CREG/shared epitope groups that also comprise the mismatched donor HLA antigens. Despite potential pathogenicity, as suggested by their occasional presence within the graft, dnNDSAs displayed significantly lower MFI, and limited complement binding and graft homing properties, when compared with dnDSAs. In parallel, the graft survival probability was significantly lower in patients with dnDSA than in those with dnNDSA or without HLA antibodies (p < 0.005). Indeed, the dnNDSA-positive patients remaining dnDSA-negative throughout the posttransplant period did not develop clinical antibody mediated rejection and graft loss, and maintained good graft function at a median follow-up of 9 years. The biological characteristics of dnNDSAs may account for the low graft damaging capability when compared to dnDSAs.

Plasma DNA Profile Associated with DNASE1L3 Gene Mutations: Clinical Observations, Relationships to Nuclease Substrate Preference, and In Vivo Correction.

Plasma DNA fragmentomics is an emerging area in cell-free DNA diagnostics and research. In murine models, it has been shown that the extracellular DNase, DNASE1L3, plays a role in the fragmentation of plasma DNA. In humans, DNASE1L3 deficiency causes familial monogenic systemic lupus erythematosus with childhood onset and anti-dsDNA reactivity. In this study, we found that human patients with DNASE1L3 disease-associated gene variations showed aberrations in size and a reduction of a "CC" end motif of plasma DNA. Furthermore, we demonstrated that DNA from DNASE1L3-digested cell nuclei showed a median length of 153 bp with CC motif frequencies resembling plasma DNA from healthy individuals. Adeno-associated virus-based transduction of Dnase1l3 into Dnase1l3-deficient mice restored the end motif profiles to those seen in the plasma DNA of wild-type mice. Our findings demonstrate that DNASE1L3 is an important player in the fragmentation of plasma DNA, which appears to act in a cell-extrinsic manner to regulate plasma DNA size and motif frequency.

An Update on Antibodies to Necleosome Components as Biomarkers of Sistemic Lupus Erythematosus and of Lupus Flares.

Systemic lupus erythematosus (SLE) is an autoimmune disease with variable clinical expression. It is a potentially devastating condition affecting mostly women and leading to clinically unpredictable outcomes. Remission and flares may, in fact, alternate over time and a mild involvement limited to few articular sites may be followed by severe and widespread organ damage. SLE is the prototype of any autoimmune condition and has, for this reason, attracted the interest of basic immunologists. Therapies have evolved over time and clinical prognosis has, in parallel, been improved. What clinicians still lack is the possibility to use biomarkers of the disease as predictors of outcome and, in this area, several studies are trying to find solutions. Circulating autoantibodies are clearly a milestone of clinical research and the concrete possibility is to integrate, in the future, classical markers of activation (like C3) with target organ autoantibodies. Anti-dsDNA antibodies represent a basic point in any predictive attempt in SLE and should be considered the benchmark for any innovative proposal in the wide field of target organ pathologies related to SLE. DNA is part of the nucleosome that is the basic unit of chromatin. It consists of DNA wrapped around a histone octamer made of 2 copies each of Histone 2A, 2B, 3, and 4. The nucleosome has a plastic organization that varies over time and has the potential to stimulate the formation of antibodies directed to the whole structure (anti-nucleosome) or its parts (anti-dsDNA and anti-Histones). Here, we present an updated review of the literature on antibodies directed to the nucleosome and the nucleosome constituents, i.e., DNA and Histones. Wetriedto merge the data first published more than twenty years ago with more recent results to create a balanced bridge between old dogma and more recent research that could serve as a stimulus to reconsider mechanisms for SLE. The formation of large networks would provide the chance of studying large cohorts of patients and confirm what already presented in small sample size during the last years.

Failure to remove de novo donor-specific HLA antibodies is influenced by antibody properties and identifies kidney recipients with late antibody-mediated rejection destined to graft loss - a retrospective study.

Current research is focusing on identifying bioclinical parameters for risk stratification of renal allograft loss, largely due to antibody-mediated rejection (AMR). We retrospectively investigated graft outcome predictors in 24 unsensitized pediatric kidney recipients developing HLA de novo donor-specific antibodies (dnDSAs), and treated for late AMR with plasmapheresis + low-dose IVIG + Rituximab or high-dose IVIG + Rituximab. Renal function and DSA properties were assessed before and longitudinally post treatment. The estimated GFR (eGFR) decline after treatment was dependent on a negative % eGFR variation in the year preceding treatment (P = 0.021) but not on eGFR at treatment (P = 0.74). At a median follow-up of 36 months from AMR diagnosis, 10 patients lost their graft. Altered eGFR (P < 0.001) and presence of C3d-binding DSAs (P = 0.005) at treatment, and failure to remove DSAs (P = 0.01) were negatively associated with graft survival in the univariable analysis. Given the relevance of DSA removal for therapeutic success, we analyzed antibody properties dictating resistance to anti-humoral treatment. In the multivariable analysis, C3d-binding ability (P < 0.05), but not C1q-binding, and high mean fluorescence intensity (P < 0.05) were independent factors characterizing DSAs scarcely susceptible to removal. The poor prognosis of late AMR is related to deterioration of graft function prior to treatment and failure to remove C3d binding and/or high-MFI DSAs.

De Novo Donor-Specific HLA Antibodies Developing Early or Late after Transplant Are Associated with the Same Risk of Graft Damage and Loss in Nonsensitized Kidney Recipients.

De novo posttransplant donor-specific HLA-antibody (dnDSA) detection is now recognized as a tool to identify patients at risk for antibody-mediated rejection (AMR) and graft loss. It is still unclear whether the time interval from transplant to DSA occurrence influences graft damage. Utilizing sera collected longitudinally, we evaluated 114 consecutive primary pediatric kidney recipients grafted between 2002 and 2013 for dnDSA occurrence by Luminex platform. dnDSAs occurred in 39 patients at a median time of 24.6 months. In 15 patients, dnDSAs developed within 1 year (early-onset group), while the other 24 seroconverted after the first posttransplant year (late-onset group). The two groups were comparable when considering patient- and transplant-related factors, as well as DSA biological properties, including C1q and C3d complement-binding ability. Only recipient age at transplant significantly differed in the two cohorts, with younger patients showing earlier dnDSA development. Late AMR was diagnosed in 47% of the early group and in 58% of the late group. Graft loss occurred in 3/15 (20%) and 4/24 (17%) patients in early- and late-onset groups, respectively (p = ns). In our pediatric kidney recipients, dnDSAs predict AMR and graft loss irrespective of the time elapsed between transplantation and antibody occurrence.

Posttransplant soluble B-cell activating factor kinetics in pediatric recipients of first kidney allograft.

BACKGROUND: Development of de novo donor-specific antibodies (dnDSA) is associated with late or chronic antibody-mediated rejection (CAMR) and poor graft outcome in low-risk kidney transplant recipients. High-level soluble B-cell activating factor (sBAFF) was observed in kidney recipients at higher risk of developing dnDSA. METHODS: We longitudinally analyzed sBAFF levels in 81 consecutive primary pediatric kidney recipients monitored for de novo human leukocyte antigen (HLA) antibody (Ab) occurrence to gain insight into the events conditioning B-cell activation posttransplant and to analyze the usefulness of paired DSA-sBAFF monitoring in this clinical setting. RESULTS: At a median follow-up of 65 months, 23 patients (28%) developed dnDSA, with 13 of 23 developing CAMR. Irrespective of HLA Ab status, sBAFF levels progressively increased in all patients in the first posttransplant year, thereafter reaching a plateau. sBAFF levels were influenced by the degree of HLA class I antigen match and donor age. Despite higher levels of sBAFF in HLA Ab-positive patients (median and 95% confidence interval sBAFF in DSA+non-DSA patients: 568, 534-608 pg/mL vs. 502, 422-548 pg/mL in Ab-negative patients; P<0.05), we found that sBAFF monitoring could not predict DSA development by a time to event longitudinal analysis. Moreover, sBAFF kinetics up to CAMR onset could not anticipate CAMR development in the DSA cohort. CONCLUSION: Our findings provide evidence of early posttransplant B-cell activation even in unsensitized recipients of first kidney allograft. The significance of this activation, likely induced by exposition to the allograft, is yet unclear.

DQ molecules are the principal stimulators of de novo donor-specific antibodies in nonsensitized pediatric recipients receiving a first kidney transplant.

Data on the different HLA-antibody (Ab) categories in pediatric kidney recipients developing de novo donor-specific Abs (DSA) after transplantation are scarce. We retrospectively evaluated 82 consecutive nonsensitized pediatric recipients of a first kidney graft for de novo HLA Ab occurrence and antigen specificity. At a median follow-up of 6 years, 29% of patients developed de novo DSA, while 45% had de novo non-DSA. DSA appeared at 25-month median time post-transplant and were mostly directed toward HLA-DQ antigens. Considering each HLA antigen, the estimated rate of DQ DSA (7.55 per 100 person-years) was much higher than the rates observed for non-DQ DSA. The HLA-DQ Ab recognized determinants of the DQß chain in 70% of cases, α chain in 25% of cases, and both chains in one patient. Non-DSA peaked earlier than DSA, and were largely directed against HLA class I specificities that belonged to HLA-A- and HLA-B-related cross-reacting epitope groups (CREG) in 56% of cases. Our results indicate a need for evaluating HLA-DQ compatibilities in kidney allocation, in order to minimize post-transplant development of de novo DSA, known to be responsible for antibody-mediated rejection and graft loss.

Rituximab is a safe and effective long-term treatment for children with steroid and calcineurin inhibitor-dependent idiopathic nephrotic syndrome.

In children with idiopathic nephrotic syndrome, rituximab can maintain short-term remission with withdrawal of prednisone and calcineurin inhibitors. Long-term effects including the number of repeated infusions to maintain remission are unknown. To test this, we treated 46 consecutive children with idiopathic nephrotic syndrome lasting for at least 1 year (mean 6.3 years), maintained in remission with oral prednisone and calcineurin inhibitors. They received 1-5 rituximab courses during a median follow-up of 3 years. Oral agents were tapered after each infusion, and completely withdrawn within 45 days. Rituximab was well tolerated. Six-month probabilities of remission were 48% after the first infusion and 37% after subsequent infusions. One- and 2-year-remission probabilities were, respectively, 20 and 10%. Median time intervals between complete oral-agent withdrawal and relapse were 5.6 and 8.5 months, respectively, following the first and subsequent courses. The time to reconstitution of CD20 cells correlated with the duration of remission, but was not associated with variation in FcyR, CD20, or SMPDL-3B polymorphisms. Podocyte Src phosphorylation was normal. Thus, rituximab can be safely and repeatedly used as a prednisone and calcineurin inhibitor-sparing therapy in a considerable proportion of children with dependent forms of idiopathic nephrotic syndrome. Further study is needed to identify patients who will benefit most from rituximab therapy.

Rituximab in children with resistant idiopathic nephrotic syndrome.

Idiopathic nephrotic syndrome resistant to standard treatments remains a therapeutic dilemma in pediatric nephrology. To test whether the anti-CD20 monoclonal antibody rituximab may benefit these patients, we conducted an open-label, randomized, controlled trial in 31 children with idiopathic nephrotic syndrome unresponsive to the combination of calcineurin inhibitors and prednisone. All children continued prednisone and calcineurin inhibitors at the doses prescribed before enrollment, and one treatment group received two doses of rituximab (375 mg/m(2) intravenously) as add-on therapy. The mean age was 8 years (range, 2-16 years). Rituximab did not reduce proteinuria at 3 months (change, -12% [95% confidence interval, -73% to 110%]; P=0.77 in analysis of covariance model adjusted for baseline proteinuria). Additional adjustment for previous remission and interaction terms (treatment by baseline proteinuria and treatment by previous remission) did not change the results. In conclusion, these data do not support the addition of rituximab to prednisone and calcineurin inhibitors in children with resistant idiopathic nephrotic syndrome.

Short-term effects of rituximab in children with steroid- and calcineurin-dependent nephrotic syndrome: a randomized controlled trial.

BACKGROUND AND OBJECTIVES: Prednisone and calcineurin inhibitors are the mainstay therapy of idiopathic nephrotic syndrome (INS) in children. However, drug dependence and toxicity associated with protracted use are common. Case series suggest that the anti-CD20 monoclonal antibody rituximab (RTX) may maintain disease remission. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This open-label randomized controlled trial was powered to show that a strategy based on RTX and lower doses of prednisone and calcineurin inhibitors was noninferior to standard doses of these agents in maintaining 3-month proteinuria as low as baseline or up to 1 g/d greater (noninferiority margin). Participants were stratified by the presence of toxicity to prednisone/calcineurin inhibitors and centrally assigned to add RTX (Mabthera, 375 mg/m(2) intravenously) to lower doses of standard agents or to continue with current therapy alone. The risk of relapse was a secondary outcome. RESULTS: Fifty-four children (mean age 11 ± 4 years) with INS dependent on prednisone and calcineurin inhibitors for >12 months were randomized. Three-month proteinuria was 70% lower in the RTX arm (95% confidence interval 35% to 86%) as compared with standard therapy arm (intention-to-treat); relapse rates were 18.5% (intervention) and 48.1% (standard arm) (P = 0.029). Probabilities of being drug-free at 3 months were 62.9% and 3.7%, respectively (P < 0.001); 50% of RTX cases were in stable remission without drugs after 9 months. CONCLUSIONS: Rituximab and lower doses of prednisone and calcineurin inhibitors are noninferior to standard therapy in maintaining short-term remission in children with INS dependent on both drugs and allow their temporary withdrawal.

Nephrectomy for multicystic dysplastic kidney and renal hypodysplasia in children: where do we stand?

OBJECTIVES: Little is reported in literature regarding correct management of benign lesions of the kidney. The aim of our study is to present a series of total and partial nephrectomies performed in the last 5 years and to discuss indications. MATERIALS AND METHODS: Patients with benign lesions who underwent nephrectomy and partial nephrectomy at our institution in the period 2003-2008 were retrospectively included in the study. Notes were carefully reviewed and demographic data, symptoms onset, preoperative diagnosis, investigations, medical and/or surgical treatment, postoperative complications and definitive histological reports were collected. RESULTS: Forty procedures were performed. Twelve patients were preoperatively diagnosed of having multicystic dysplastic kidney (MCDK), which was confirmed in 10, whereas the remaining 28 patients of having severe dysplasia or hypodysplasia. Thirty-four patients underwent total nephrectomy, six underwent partial nephrectomy. Histopathological analysis confirmed segmental or complete abnormalities of the involved kidney in all cases. No malignancies were detected. DISCUSSION: Our study confirmed the extremely low malignancy rate of MCDK and hypodysplastic kidneys. The 20% mismatch of pre- and post-operative diagnosis suggests a common aetiology and shared therapeutic strategies for MCDK and hypodysplasia. At present, there is no consensus regarding correct indications for nephrectomy in paediatric age. As nephrectomy seems not to provide any advantage over preservation, but surgical and anesthesiological risks, we should be prudent in preserving every asymptomatic poorly or non-functioning kidneys maintaining a strict follow-up. Randomised controlled studies on larger multicentric series are strongly warranted to define this topic.

Autoimmunity in membranous nephropathy targets aldose reductase and SOD2.

Glomerular targets of autoimmunity in human membranous nephropathy are poorly understood. Here, we used a combined proteomic approach to identify specific antibodies against podocyte proteins in both serum and glomeruli of patients with membranous nephropathy (MN). We detected specific anti-aldose reductase (AR) and anti-manganese superoxide dismutase (SOD2) IgG(4) in sera of patients with MN. We also eluted high titers of anti-AR and anti-SOD2 IgG(4) from microdissected glomeruli of three biopsies of MN kidneys but not from biopsies of other glomerulonephritides characterized by IgG deposition (five lupus nephritis and two membranoproliferative glomerulonephritis). We identified both antigens in MN biopsies but not in other renal pathologies or normal kidney. Confocal and immunoelectron microscopy (IEM) showed co-localization of anti-AR and anti-SOD2 with IgG(4) and C5b-9 in electron-dense podocyte immune deposits. Preliminary in vitro experiments showed an increase of SOD2 expression on podocyte plasma membrane after treatment with hydrogen peroxide. In conclusion, our data support AR and SOD2 as renal antigens of human MN and suggest that oxidative stress may drive glomerular SOD2 expression.

Cyclosporin and organ specific toxicity: clinical aspects, pharmacogenetics and perspectives.

Cyclosporine (CsA) has considerably modified the graft survival in solid organ and bone marrow transplantations. It is also the treatment of choice in chronic diseases such as steroid resistance and/or dependence nephrotic syndrome and autoimmune-diseases, especially in those cases that require long term treatments. Renal toxicity is the major adverse effect of chronic CsA administration. Deterioration of renal function and renal histopathology are the basic elements of the diagnosis. Overall, available studies suggest a good degree of safety related to appropriate drug dosages even if they require an adequate degree of surveillance in case of rapid changes of renal functions and long term evaluation of renal pathology. CsA neurotoxicity is the second major problem that seems underestimated especially in case of subtle manifestations in children. The full blown picture of the acute form is characterized by convulsion and sudden alteration of mental function that are reversible upon drug withdrawal. The diagnosis is based on typical CT and MRI aspects of extensive bilateral white-matter abnormalities in the occipital region of the brain that mimics the posterior encephalopathy syndrome. Prospective evaluations of drug tolerance include renal histology in case of chronic renal toxicity and neuro-imaging to identify and block acute neurotoxicity.