IgA nephropathy associated with ankylosing spondylitis is not controlled by infliximab therapy.

The association between seronegative spondyloarthro- pathies and IgA nephropathy is well documented, mainly in cases of ankylosing spondylitis (AS). However, although these diseases have been associated, the physiopathological links between each other appear unclear. Anti-TNFalpha agents have transformed the outcome of axial forms of AS resistant to conventional anti-inflammatory therapies. Infliximab, a monoclonal anti-TNFalpha antibody, has greatly improved the evolution of AS although several adverse events have been described. On the other hand, infliximab has been demonstrated to reduce renal symptoms associated with chronic inflammatory rheumatological diseases, such as amyloid A (AA) amyloidosis, but few data are available on its efficacy in controlling IgA nephropathy associated with AS [1,2]. We report here a case of IgA nephropathy associated with AS that became symptomatic, whereas infliximab therapy efficiently controlled the rheumatological disease. This suggests that even though infliximab therapy effectively controls rheumatological manifestations, it may not be able to prevent IgA nephropathy associated with AS. Thus, this case report illustrates the complexity of the physiopathology of both diseases.

Falsely elevated whole blood tacrolimus concentrations due to interference in an affinity column-mediated immunoassay method on Xpand dimension.

The whole blood concentration of tacrolimus is required for therapeutic drug monitoring of this immunosuppressive drug. Abnormal tacrolimus levels affect its efficacy or toxicity, leading to changes in its dosage. Here, we report analytical interference in the affinity column-mediated immunoassay tacrolimus method on the Xpand autoanalyzer in a kidney transplant human immunodeficiency virus-infected patient. Tacrolimus concentrations obtained by affinity column-mediated immunoassay are 3- to 7-fold higher than measurements with the enzyme multiplied immunoassay technique assay. The cause of this interference remains unknown. However, it would be necessary to identify this type of interference to measure tacrolimus concentration with another method to avoid analytical error, which may lead to a poor clinical outcome.

The blockade of T-cell co-stimulation as a therapeutic stratagem for immunosuppression: Focus on belatacept.

The development of immunosuppressive drugs has in recent years been focused on prevention of acute rejection. This has led to an increase in one-year allograft survival. However, these drugs have non-immune effects which contribute to the high incidence of late graft loss, as a consequence of chronic allograft nephropathy, and the death of patients. As an immune-specific alternative to conventional immunosuppressants, new biotechnology tools have been developed; they target the costimulation signal of T-cell activation, particularly by the "classical" B7/CD28 and CD40/CD40L pathways. Here, we review the limitations of current immunosuppressive protocols, the benefits of classical B7/CD28 costimulation blockade, and the first large-scale clinical application of this strategy to human transplantation with belatacept. We will also consider novel costimulatory molecules of the B7/CD28 and TNF/TNF-R families, which appear to be important for the functions of memory and effector T-cells.

Extracellular calpains increase tubular epithelial cell mobility. Implications for kidney repair after ischemia.

Calpains are intracellular Ca2+-dependent cysteine proteases that are released in the extracellular milieu by tubular epithelial cells following renal ischemia. Here we show that externalized calpains increase epithelial cell mobility and thus are critical for tubule repair. In vitro, exposure of human tubular epithelial cells (HK-2 cells) to mu-calpain limited their adhesion to extracellular matrix and increased their mobility. Calpains acted primarily by promoting the cleavage of fibronectin, thus preventing fibronectin binding to the integrin alphavbeta3. Analyzing downstream integrin effects, we found that the cyclic AMP-dependent protein kinase A pathway was activated in response to alphavbeta3 disengagement and was essential for calpain-mediated increase in HK-2 cell mobility. In a murine model of ischemic acute renal failure, injection of a fragment of calpastatin, which specifically blocked calpain activity in extracellular milieu, markedly delayed tubule repair, increasing functional and histological lesions after 24 and 48 h of reperfusion. These findings suggest that externalized calpains are critical for tubule repair process in acute renal failure.