Impact of de novo donor-specific HLA antibodies detected by Luminex solid-phase assay after transplantation in a group of 88 consecutive living-donor renal transplantations.

De novo donor-specific HLA antibodies (DSA) after renal transplantation are known to be correlated with poor graft outcome and the development of acute and chronic rejection. Currently, data for the influence of de novo DSA in patient cohorts including only living-donor renal transplantations (LDRT) are limited. A consecutive cohort of 88 LDRT was tested for the occurrence of de novo DSA by utilizing the highly sensitive Luminex solid-phase assay for antibody detection. Data were analyzed for risk factors for de novo DSA development and correlated with acute rejection (AR) and graft function. Patients with de novo DSA [31 (35%)] showed a trend for inferior graft function [mean creatinine change (mg/dL/year) after the first year: 0.15 DSA (+) vs. 0.02 DSA (-) (P = 0.10)] and a higher rate of AR episodes, especially in case of de novo DSA of both class I and II [6 (55%), (P = 0.05)]. Antibody-mediated rejection (AMR) appeared in five patients and was significantly correlated with de novo DSA (P = 0.05). Monitoring for de novo DSA after LDRT may help to identify patients at risk of declining renal function. Especially patients with simultaneous presence of de novo DSA class I and class II are at a high risk to suffer AR episodes.

Monoclonal gammopathy-associated pauci-immune extracapillary-proliferative glomerulonephritis successfully treated with bortezomib.

Extracapillary-proliferative glomerulonephritis is a rare complication of multiple myeloma. Partial remission of kidney involvement with cyclophosphamide therapy has previously been described. We report the case of a 60-year-old male patient diagnosed with rapidly progressive glomerulonephritis associated with IgG kappa monoclonal gammopathy. His kidney biopsy revealed pauci-immune extracapillary-proliferative glomerulonephritis without cryoglobulinaemia. Treatment with the proteasome inhibitor bortezomib induced rapid clinical and histological remission of his kidney disease. The patient's renal function remained stable on bortezomib maintenance therapy. Our findings suggest that bortezomib is a promising therapeutic approach to ameliorate severe kidney damage in monoclonal gammopathy- and myeloma-associated pauci-immune extracapillary-proliferative glomerulonephritis.

Intrinsic proinflammatory signaling in podocytes contributes to podocyte damage and prolonged proteinuria.

Inflammation conveys the development of glomerular injury and is a major cause of progressive kidney disease. NF-κB signaling is among the most important regulators of proinflammatory signaling. Its role in podocytes, the epithelial cells at the kidney filtration barrier, is poorly understood. Here, we inhibited NF-κB signaling in podocytes by specific ablation of the NF-κB essential modulator (NEMO, IKKγ). Podocyte-specific NEMO-deficient mice (NEMO(pko)) were viable and did not show proteinuria or overt changes in kidney morphology. After induction of glomerulonephritis, both NEMO(pko) and control mice developed significant proteinuria. However, NEMO(pko) mice recovered much faster, showing rapid remission of proteinuria and restoration of podocyte morphology. Interestingly, quantification of infiltrating macrophages, T-lymphocytes, and granulocytes at day 7 revealed no significant difference between wild-type and NEMO(pko). To further investigate the underlying mechanisms, we created a stable NEMO knockdown mouse podocyte cell line. Again, no overt changes in morphology were observed. Translocation of NF-κB to the nucleus after stimulation with TNFα or IL-1 was sufficiently inhibited. Moreover, secretion of proinflammatory chemokines from podocytes after stimulation with TNFα or IL-1 was significantly reduced in NEMO-deficient podocytes and in glomerular samples obtained at day 7 after induction of nephrotoxic nephritis. Collectively, these results show that proinflammatory activity of NF-κB in podocytes aggravates proteinuria in experimental glomerulonephritis in mice. Based on these data, it may be speculated that immunosuppressive drugs may not only target professional immune cells but also podocytes directly to convey their beneficial effects in various types of glomerulonephritis.

Rituximab treatment for adults with refractory nephrotic syndrome: a single-center experience and review of the literature.

BACKGROUND/AIMS: Minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) are common causes of nephrotic syndrome (NS) in adults. However, induction of remission and sustained control of proteinuria is often difficult. Recently, B cell-directed therapy using the anti-CD20 antibody rituximab has been suggested as induction regimen in pediatric FSGS and MCD patients. Data on rituximab use in adults are still limited. METHODS: We report on rituximab use in five consecutively treated adult patients (mean age 42.2 ± 9.9 years) with FSGS or relapsing MCD (2 FSGS, 3 MCD) who failed to respond to standard immunosuppressive treatment. Median follow-up was 8 months (3-25). RESULTS: Rituximab induced complete remission in 2 MCD patients and partial remission in 3 patients. Proteinuria was reduced by 86.8% (42.9-95.2) 3 months and by 73.0% (60.1-95.5) 6 months after therapy. In 1 patient with severe FSGS, partial remission was not evident before 6 months after rituximab treatment. Relapses occurred in 2 patients. No severe adverse events related to rituximab were observed. CONCLUSION: Our findings suggest that B cell-directed therapies are novel treatment options for adults with refractory NS. Response to rituximab varied, with MCD patients exhibiting a faster and more pronounced response compared to FSGS patients.

Pilot study of extracorporeal removal of soluble fms-like tyrosine kinase 1 in preeclampsia.

BACKGROUND: Targeted therapies to stabilize the clinical manifestations and prolong pregnancy in preeclampsia do not exist. Soluble fms-like tyrosine kinase 1 (sFlt-1), an alternatively spliced variant of the vascular endothelial growth factor receptor 1, induces a preeclampsia-like phenotype in experimental models and circulates at elevated levels in human preeclampsia. Removing sFlt-1 may benefit women with very preterm (<32 weeks) preeclampsia. METHODS AND RESULTS: We first show that negatively charged dextran sulfate cellulose columns adsorb sFlt-1 in vitro. In 5 women with very preterm preeclampsia and elevated circulating sFlt-1 levels, we next demonstrate that a single dextran sulfate cellulose apheresis treatment reduces circulating sFlt-1 levels in a dose-dependent fashion. Finally, we performed multiple apheresis treatments in 3 additional women with very preterm (gestational age at admission 28, 30, and 27+4 weeks) preeclampsia and elevated circulating sFlt-1 levels. Dextran sulfate apheresis lowered circulating sFlt-1, reduced proteinuria, and stabilized blood pressure without apparent adverse events to mother and fetus. Pregnancy lasted for 15 and 19 days in women treated twice and 23 days in a woman treated 4 times. In each, there was evidence of fetal growth. CONCLUSIONS: This pilot study supports the hypothesis that extracorporeal apheresis can lower circulating sFlt-1 in very preterm preeclampsia. Further studies are warranted to determine whether this intervention safely and effectively prolongs pregnancy and improves maternal and fetal outcomes in this setting.