Early acute microvascular kidney transplant rejection in the absence of anti-HLA antibodies is associated with preformed IgG antibodies against diverse glomerular endothelial cell antigens

International audienceBACKGROUND: Although anti-HLA antibodies (Abs) cause most antibody-mediated rejections of renal allografts, non-anti-HLA Abs have also been postulated to contribute. A better understanding of such Abs in rejection is needed.METHODS: We conducted a nationwide study to identify kidney transplant recipients without anti-HLA donor-specific Abs who experienced acute graft dysfunction within 3 months after transplantation and showed evidence of microvascular injury, called acute microvascular rejection (AMVR). We developed a crossmatch assay to assess serum reactivity to human microvascular endothelial cells, and used a combination of transcriptomic and proteomic approaches to identify non-HLA Abs.RESULTS: We identified a highly selected cohort of 38 patients with early acute AMVR. Biopsy specimens revealed intense microvascular inflammation and the presence of vasculitis (in 60.5%), interstitial hemorrhages (31.6%), or thrombotic microangiopathy (15.8%). Serum samples collected at the time of transplant showed that previously proposed anti-endothelial cell Abs-angiotensin type 1 receptor (AT1R), endothelin-1 type A and natural polyreactive Abs-did not increase significantly among patients with AMVR compared with a control group of stable kidney transplant recipients. However, 26% of the tested AMVR samples were positive for AT1R Abs when a threshold of 10 IU/ml was used. The crossmatch assay identified a common IgG response that was specifically directed against constitutively expressed antigens of microvascular glomerular cells in patients with AMVR. Transcriptomic and proteomic analyses identified new targets of non-HLA Abs, with little redundancy among individuals.CONCLUSIONS: Our findings indicate that preformed IgG Abs targeting non-HLA antigens expressed on glomerular endothelial cells are associated with early AMVR, and that cell-based assays are needed to improve risk assessments before transplant

NIR Spectroscopy of Selected Iron (II) and Iron (III) Sulphates

A problem exists when closely related minerals are found in paragenetic relationships. The identification of such minerals cannot be undertaken by normal techniques such as X-ray diffraction. Vibrational spectroscopic techniques may be applicable especially when microtechniques or fibre-optic techniques are used. NIR spectroscopy is one technique which can be used for the identification of these paragenetically related minerals and has been applied to the study of selected iron(II) and iron(III) sulphates. The Near–IR spectral regions may be conveniently divided into four regions (a) the high wavenumber region > 7500 cm-1 (b) the high wavenumber region between 6400 and 7400 cm-1 attributed to the first overtone of the fundamental hydroxyl stretching mode (c) the 5500-6300 cm-1 region attributed to water combination modes of the hydroxyl fundamentals of water, and (d) the 4000-5500 cm-1 region attributed to the combination of the stretching and deformation modes of the iron(II) and iron(III) sulphates. The minerals containing iron(II) show a strong, broad band with splitting, around 11000-8000 cm-1 attributed to 5T2g --> 5Eg transition. This shows the ferrous ion has distorted octahedral coordination in some of these sulphate minerals. For each of these regions, the minerals show distinctive spectra which enable their identification and characterisation. NIR spectroscopy is a less used technique which has great application for the study of minerals, particularly minerals which have hydrogen in the structure either as hydroxyl units or as water bonded to the cation as is the case for iron(II) and iron(III) sulphates. The study of minerals on planets is topical and NIR spectroscopy provides a rapid technique for the distinction and identification of iron(II) and iron(III) sulphates minerals

Subarachnoid anesthesia in sedated calves undergoing umbilical surgery: Comparison of procaine 2% and lidocaine 2% associated with xylazine 2%

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Nouvelle lecture des phases de la dernière déglaciation dans le Loch Sunart (Nord-Ouest Ecosse) basée sur des traceurs géochimiques

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Nouvelle lecture des phases de la dernière déglaciation dans le Loch Sunart (Nord-Ouest Ecosse) basée sur des traceurs géochimiques

International audienc

Nouvelle lecture des phases de la dernière déglaciation dans le Loch Sunart (Nord-Ouest Ecosse) basée sur des traceurs géochimiques

International audienc

Nouvelle lecture des phases de la dernière déglaciation dans le Loch Sunart (Nord-Ouest Ecosse) basée sur des traceurs géochimiques

International audienc