Highly Variable Sialylation Status of Donor-Specific Antibodies Does Not Impact Humoral Rejection Outcomes.

Clinical outcome in antibody-mediated rejection (AMR) shows high inter-individual heterogeneity. Sialylation status of the Fc fragment of IgGs is variable, which could modulate their ability to bind to C1q and/or Fc receptors. In this translational study, we evaluated whether DSA sialylation influence AMR outcomes. Among 938 kidney transplant recipients for whom a graft biopsy was performed between 2004 and 2012 at Lyon University Hospitals, 69 fulfilled the diagnosis criteria for AMR and were enrolled. Sera banked at the time of the biopsy were screened for the presence of DSA by Luminex. The sialylation status of total IgG and DSA was quantified using Sambucus nigra agglutinin-based chromatography. All patients had similar levels of sialylation of serum IgGs (~2%). In contrast, the proportion of sialylated DSA were highly variable (median = 9%; range = 0-100%), allowing to distribute the patients in two groups: high DSA sialylation (n = 44; 64%) and low DSA sialylation (n = 25; 36%). The two groups differed neither on the intensity of rejection lesions (C4d, ptc, and g; p > 0.05) nor on graft survival rates (Log rank test, p = 0.99). in vitro models confirmed the lack of impact of Fc sialylation on the ability of a monoclonal antibody to trigger classical complement cascade and activate NK cells. We conclude that DSA sialylation status is highly variable but has not impact on DSA pathogenicity and AMR outcome.

Endothelial chimerism and vascular sequestration protect pancreatic islet grafts from antibody-mediated rejection.

Humoral rejection is the most common cause of solid organ transplant failure. Here, we evaluated a cohort of 49 patients who were successfully grafted with allogenic islets and determined that the appearance of donor-specific anti-HLA antibodies (DSAs) did not accelerate the rate of islet graft attrition, suggesting resistance to humoral rejection. Murine DSAs bound to allogeneic targets expressed by islet cells and induced their destruction in vitro; however, passive transfer of the same DSAs did not affect islet graft survival in murine models. Live imaging revealed that DSAs were sequestrated in the circulation of the recipients and failed to reach the endocrine cells of grafted islets. We used murine heart transplantation models to confirm that endothelial cells were the only accessible targets for DSAs, which induced the development of typical microvascular lesions in allogeneic transplants. In contrast, the vasculature of DSA-exposed allogeneic islet grafts was devoid of lesions because sprouting of recipient capillaries reestablished blood flow in grafted islets. Thus, we conclude that endothelial chimerism combined with vascular sequestration of DSAs protects islet grafts from humoral rejection. The reduced immunoglobulin concentrations in the interstitial tissue, confirmed in patients, may have important implications for biotherapies such as vaccines and monoclonal antibodies.

[CARDIORENAL SYNDROME: DIAGNOSTIC AND THERAPEUTIC APPROACHES]. / Syndrome cardio-rénal : prise en charge diagnostique et thérapeutique. Insuffisance cardiaque : un pronostic vital en jeu dès le début de l'atteinte rénale.

Kidney dysfunction during congestive heart failure, although frequent, is often neglected. Yet, it represents a life-threatening condition, oven when the kidney dysfunction is moderate. The initial approach involvus strict application of recommendations, cardiologic and nephrologic joined management and close follow-up involving patient's general practitioner. Cases of true diuretics resistance are infrequent and late. Yet, it represents a significant turning point. Mortality is high, with a major individual unpredictability. A multidisciplinary approach is needed, which has to take into account patient's preferences. Several treatments may be discussed and are sometimes joined: cardiac transplantation, water and salt extraction (using ultrafiltration, hemodialysis or peritoneal dialysis), vasoconstrictive drugs, ventricular assistance devices and palliative care. Water and salt extraction techniques seem to space out hospitalizations and to provide symptomatic relief even though no benefit on patient survival has been demonstrated to date. The need for randomized clinical trials is mandatory.

Recent advances in renal transplantation: antibody-mediated rejection takes center stage.

Overlooked for decades, antibodies have taken center stage in renal transplantation and are now widely recognized as the first cause of allograft failure. Diagnosis of antibody-mediated rejection has considerably improved with identification of antibody-mediated lesions in graft biopsies and advances made in the detection of circulating donor-specific antibodies. Unfortunately, this progress has not yet translated into better outcomes for patients. Indeed, in the absence of a drug able to suppress antibody generation by plasma cells, available therapies can only slow down graft destruction. This review provides an overview of the current knowledge of antibody-mediated rejection and discusses future interesting research directions.

[Physical activity and chronic kidney disease: an update in 2013?]. / Activité physique et maladie rénale chronique : quelles relations en 2013 ?

The practice of physical activity is now a subject of special attention in public health. Indeed, the expected benefits in terms of cardiovascular morbidity and mortality suggest that all physicians should promote it. However, there are few data on the impact of physical activity on the health of patients with chronic kidney disease before the dialysis stage. This review focuses on the relationship between chronic kidney disease and the practice of physical activity. Different tools to assess the level of physical activity helped to highlight a marked deterioration in physical capacity of patients with chronic kidney disease, including during the earliest stages. Although there is currently no specific recommendations regarding the practice of physical activity in patients with renal impairment, it seems desirable to promote it in an appropriate way, based on what is currently advocated for cardiovascular prevention in the general population.

[Atypical obstruction during a hemodialysis catheter replacement]. / Obstacle atypique lors d'un changement de cathéter d'hémodialyse.

We followed a 60-year-old woman in our department for a vascular chronic kidney disease. The peritoneal dialysis was stopped because of a Candida albicans catheter infection. As the patient refused the arterio-venous fistula creation, we have placed a central venous catheter (Medcomp 32cm). Because the instability of the cuff, we decided to remove and change it by another one (Quinton 40cm). The discovery of an important cylindrical calcification has complicated the manipulation requiring tranquility and agility. The finding of a massive calcification is uncommon and confirms the major risk of calcification in chronic kidney disease patients.