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 CDCcrossmatch 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.

De novo glomerular diseases after renal transplantation:How is it different from recurrent glomerular diseases?

The glomerular diseases after renal transplantation can occur de novo,i.e.,with no relation to the native kidney disease,or more frequently occur as a recurrence of the original disease in the native kidney.There may not be any difference in clinical features and histological pattern between de novo glomerular disease and recurrence of original glomerular disease.However,structural alterations in transplanted kidney add to dilemma in diagnosis.These changes in architecture of histopathology can happen due to:(1) exposure to the immunosuppression specifically the calcineurin inhibitors(CNI);(2) in vascular and tubulointerstitial alterations as a result of antibody mediated or cellmediated immunological onslaught;(3) post-transplant viral infections;(4) ischemia-reperfusion injury; and(5) hyperfiltration injury.The pathogenesis of the de novo glomerular diseases differs with each type.Stimulation of B-cell clones with subsequent production of the monoclonal Ig G,particularly Ig G3 subtype that has higher affinity to the negatively charged glomerular tissue,is suggested to be included in PGNMID pathogenesis.De novo membranous nephropathy canbe seen after exposure to the cryptogenic podocyte antigens.The role of the toxic effects of CNI including tissue fibrosis and the hemodynamic alterations may be involved in the de novo FSGS pathophysiology.The well-known deleterious effects of HCV infection and its relation to MPGN disease are frequently reported.The new concepts have emerged that demonstrate the role of dysregulation of alternative complement pathway in evolution of MPGN that led to classifying into two subgroups,immune complex mediated MPGN and complement-mediated MPGN.The latter comprises of the dense deposit disease and the C3 GN disease.De novo C3 disease is rather rare.Prognosis of de novo diseases varies with each type and their management continues to be empirical to a large extent.

Recurrence of primary glomerulonephritis:Review of the current evidence

In view of the availability of new immunosuppression strategies,the recurrence of allograft glomerulonephritis(GN) are reported to be increasing with time post transplantation.Recent advances in understanding the pathogenesis of the GN recurrent disease provided a better chance to develop new strategies to deal with the GN recurrence.Recurrent GN diseases manifest with a variable course,stubborn behavior,and poor response to therapy.Some types of GN lead to rapid decline of kidney function resulting in a frustrating return to maintenance dialysis.This subgroup of aggressive diseases actually requires intensive efforts to ascertain their pathogenesis so that strategy could be implemented for better allograft survival.Epidemiology of native glomerulonephritis as the cause of end-stage renal failure and subsequent recurrence of individual glomerulonephritis after renal transplantation was evaluated using data from various registries,and pathogenesis of individual glomerulonephritis is discussed.The following review is aimed to define current protocols of the recurrent primary glomerulonephritis therapy.