National Conference to Assess Antibody-Mediated Rejection in Solid Organ Transplantation

University of California, Los Angeles, Los Ángeles, California, United States
American Journal of Transplantation (Impact Factor: 5.68). 08/2004; 4(7):1033-41. DOI: 10.1111/j.1600-6143.2004.00500.x
Source: PubMed


The process of humoral rejection is multifaceted and has different manifestations in the various types of organ transplants. Because this process is emerging as a leading cause of graft loss, a conference was held in April 2003 to comprehensively address issues regarding humoral rejection.
Though humoral rejection may result from different factors, discussion focused on a paradigm caused by antibodies, typically against donor HLA antigens, leading to the term ‘antibody-mediated rejection’ (AMR). Conference deliberations were separated into four workgroups: The Profiling Workgroup evaluated strengths and limitations of different methods for detecting HLA reactive antibody, and created risk assessment guidelines for AMR; The Diagnosis Workgroup reviewed clinical, pathologic, and serologic criteria for assessing AMR in renal, heart and lung transplant recipients; The Treatment Workgroup discussed advantages, limitations and possible mechanisms of action for desensitization protocols that may reverse AMR; and The Basic Science Workgroup presented animal and human immunologic models for humoral rejection and proposed potential targets for future intervention. This work represents a comprehensive review with contributions from experts in the fields of Transplantation Surgery, Medicine, Pathology, Histocompatibility, Immunology, and clinical trial design. Immunologic barriers once considered insurmountable are now consistently overcome to enable more patients to undergo organ transplantation.

  • Source
    • "C4d deposition in PTC area has been regarded as a marker of ABMR for years [16, 17]. C4d-positive has been widely accepted as one of the diagnosis criteria [6, 18] and has contributed to the diagnosis and treatment of ABMR. However, as the recognition of a group of C4d-negative ABMR, C4d is no longer a reliable marker for ABMR diagnosis; thus, seeking a diagnosis marker that can distinguish C4d-negative ABMR is very important. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Background: Previous data showed that the predominance of intraglomerular T-bet or GATA3 is correlated with different mechanisms of rejection, suggesting that the ratio of T-bet/GATA3 might be used to distinguish antibody-mediated rejection (ABMR) and T-cell-mediated rejection (TCMR). Methods: We compared the intraglomerular T-bet/GATA3 ratio in ABMR and TCMR. The intragraft expression of T-bet and GATA3 was studied via immunohistochemistry. The correlation of the diagnosis of AMR with the ratio of T-bet/GATA3 was examined. Results: Both intraglomerular T-bet- and GATA3-expressing cells were increased during acute rejection. T-bet/GATA3>1 was strongly correlated with ABMR (93.3% versus 18.2%). The incidence of positive HLA-I/II antibodies and glomerulitis is significantly higher in T-bet/GATA3>1 group (P < 0.001, 0.013, resp.). The scores of peritubular capillary inflammation and glomerulitis were also higher in T-bet/GATA3>1 group (P = 0.052, P < 0.001, resp.). Nevertheless, T-bet/GATA3>1 is also correlated with C4d-negative ABMR and resistance to steroid treatment. Compared with C4d deposition, T-bet/GATA3>1 had a slight lower (90% versus 100%) specificity but a much higher (87.5% versus 68.8%) sensitivity. Conclusion: Our data suggested that intraglomerular predominance of T-bet over GATA3 might be used as diagnosis maker of ABMR in addition to C4d, especially in C4d-negative cases.
    Full-text · Article · Oct 2013 · Clinical and Developmental Immunology
  • Source
    • "Chronic AMR, which is characteristically seen as transplant glomerulopathy in kidney biopsies, is characterized by glomerular mesangial expansion and capillary basement membrane duplication or splitting, interstitial fibrosis/tubular atrophy, and/or fibrous intimal thickening in arteries. Sometimes, peritubular capillary basement membrane multilayering is also observed on electron microscopy [7] [13] [14]. Due to donor-specific antibodies, AMR leads to the activation of the classical complement pathway, resulting in impaired graft function [15]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Antibody-mediated rejection (AMR) is highly detrimental to the prolonged survival of transplanted kidneys. C4d has been regarded as a footprint of AMR tissue damage, and the introduction of C4d staining in daily clinical practice aroused an ever-increasing interest in the role of antibody-mediated mechanisms in allograft rejection. Despite the general acceptance of the usefulness of C4d in the identification of acute AMR, the data for C4d staining in chronic AMR is variable. The presence of C4d in the majority of the biopsies with features of chronic antibody-mediated rejection is reported, but this rejection without C4d staining is observed as well, suggesting that C4d is specific but not sensitive. Further studies on AMR with positive C4d staining in biopsy specimens are really important, as well as the study of novel routine markers that may participate in the pathogenesis of this process.
    Full-text · Article · Jul 2013 · Clinical and Developmental Immunology
  • Source
    • "B cell involvement is in general characterized by intragraft B cell infiltration, C4d deposition and circulating donor-specific antibodies (Barnett et al., 2011). In humans, about 5–7% of the kidney transplant patients develop acute humoral rejection (Takemoto et al., 2004). Therefore, we had a closer look into the detection of complement factor deposits and the circulation of donor-specific antibodies. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Mesenchymal stromal cells (MSC) have shown immunomodulatory and tissue repair potential including partial tolerance induction by pre-treatment of donor-specific cells in a rat heart transplantation model. Very recently, we could show that autologous MSC attenuated ischemia reperfusion injury in a highly mismatched donor-recipient rat kidney transplant model. Therefore, we investigated donor-specific MSC pre-treatment in this rat kidney transplantation model to study whether graft function could be improved, or if tolerance could be induced. Donor- and recipient-type MSC or PBS as a control were injected i.v. four days before kidney transplantation. Mycophenolate mofetil (MMF) immunosuppression (20 mg/kg body weight) was applied for 7 days. Kidney grafts and spleens were harvested between days 8-10 and analyzed by quantitative RT-PCR and immunohistology. In addition, creatinine levels in the blood were measured and serum was screened for the presence of donor-specific antibodies. Surprisingly, application of both donor- and recipient-specific MSC resulted in enhanced humoral immune responses verified by intragraft B cell infiltration and complement factor C4d deposits. Moreover, signs of inflammation and rejection were generally enhanced in both MSC-treated groups relative to PBS control group. Additionally, pre-treatment with donor-specific MSC significantly enhanced the level of donor-specific antibody formation when compared with PBS- or recipient-MSC-treated groups. Pre-treatment with both MSC types resulted in a higher degree of kidney cortex tissue damage and elevated creatinine levels at the time point of rejection. Thus, MSC pre-sensitization in this model impairs the allograft outcome. Our data from this pre-clinical kidney transplantation model indicate that pre-operative MSC administration may not be optimal in kidney transplantation and caution must be exerted before moving forward with clinical studies in order to avoid adverse effects.
    Full-text · Article · Jul 2012 · Frontiers in Immunology
Show more