Posterior Reversible Encephalopathy Syndrome in Organ Transplantation.

Posterior reversible encephalopathy syndrome encompasses a spectrum of disorders with a constellation of clinical symptoms and neuroradiological features. It is commonly encountered in organ transplant where it poses a challenge in the diagnosis and treatment in the absence of strong evidence. The underlying pathophysiology of posterior reversible encephalopathy syndrome is the loss of cerebral autoregulation following elevated blood pressure and/or endothelial dysfunction. It is more likely to happen in patients treated with cyclosporine versus with tacrolimus. Posterior reversible encephalopathy syndrome manifests as headache, visual disturbances, seizure, and abnormal mentation. The characteristic radiological features are the result of posterior- circulation vasogenic edema secondary to blood-brain barrier disruption. Treatment varies based on the etiology of the condition. In addition to the symptomatic management of hypertension and seizure disorders, switching or replacing the calcineurin inhibitor with another immunosuppressant or decreasing the dose of the calcineurin inhibitor is the key in calcineurin inhibitor-associated posterior reversible encephalopathy syndrome. Here, we have reviewed the terminology, pathogenesis, clinical features, diagnosis, and treatment of posterior reversible encephalopathy syndrome with special reference to its presence in the posttransplant period.

Human leukocyte antigen typing and crossmatch: A comprehensive review.

Renal transplantation remains the best option for patients suffering from end stage renal disease (ESRD). Given the worldwide shortage of organs and growing population of patients with ESRD, those waitlisted for a transplant is ever expanding. Contemporary crossmatch methods and human leukocyte antigen (HLA) typing play a pivotal role in improving organ allocation and afford better matches to recipients. Understanding crossmatch as well as HLA typing for renal transplantation and applying it in clinical practice is the key step to achieve a successful outcome. Interpretation of crossmatch results can be quite challenging where clinicians have not had formal training in applied transplant immunology. This review aims to provide a worked example using a clinical vignette. Furthermore, each technique is discussed in detail with its pros and cons. The index case is that of a young male with ESRD secondary to Lupus nephritis. He is offered a deceased donor kidney with a 1-0-0 mismatch. His complement dependent cytotoxicity (CDC) crossmatch reported positive for B lymphocyte, but flow cytometry crossmatch (FCXM) was reported negative for both B and T lymphocytes. Luminex-SAB (single antigen bead) did not identify any donor specific antibodies (DSA). He never had a blood transfusion. The positive CDC-crossmatch result is not concordant with DSA status. These implausible results are due to underlying lupus erythematosus, leading to false-positive B-lymphocyte crossmatch as a result of binding immune complexes to Fc-receptors. False positive report of CDC crossmatch can be caused by the underlying autoimmune diseases such as lupus erythematosus, that may lead to inadvertent refusal of adequate kidney grafts. Detailed study of DSA by molecular technique would prevent wrong exclusion of such donors. Based on these investigations this patient is deemed to have "standard immunological risk" for renal transplantation.