The role of the Lewis antigen system in renal transplantation and allograft rejection

A positive complement dependent cytotoxicity immunoglobulin G crossmatch due to auto-antibodies with a negative luminex bead assays in a renal transplant recipient: A Diagnostic dilemma

Transplant recipients are always at a risk of developing anti-human leukocyte antigen (HLA) antibodies due to prior sensitizing events such as blood transfusions, multiple pregnancies, or transplantation. Unexpected positive outcomes can be seen in complement dependent cytotoxicity (CDC) based assays due to underlying autoimmune disorders or pharmacological treatment (rituximab/intravenous immunoglobulin/anti-thymocyte globulin administration), therefore, limiting its value. CDC based assay results strongly depend on the vitality of the donor lymphocytes, highlighting another major limitation of this assay. Thus, as an alternative approach, solid phase based crossmatch assays were introduced which function independently of the cell quality and have higher sensitivity and specificity in detecting anti-HLA antibodies. We describe a case where the patient awaiting renal transplantation from living related donor was evaluated by pretransplant histocompatibility testing for the detection of anti-HLA antibodies. The histocompatibility testing revealed positive CDC anti-human globulin and flow crossmatch along with negative Luminex based assays (HLA antibody screen, luminex crossmatch, and luminex single bead assay). Detailed histocompatibility workup revealed immunoglobulin G autoantibodies which were complement activating and lympocytoxic in nature.

Role of ABO and Lewis blood group antigens in donor-recipient compatibility of corneal transplantation rejection

PURPOSE

There are conflicting results regarding the role of human leukocyte antigen (HLA) matching and ABO compatibility in corneal graft rejection for low- and high-risk patients. Lewis blood group antigens could be an important histocompatibility system. Beneficial effects of Lewis antigens matching have been reported in renal transplantation, but its effect is still unknown in corneal allografting.

METHODS

Between 1987 and 1993, ABO, Lewis and HLA phenotypes were determined in 697 consecutive grafts of corneal transplantations. The effect of Lewis matching on corneal endothelial rejection was evaluated over a 3-year period. Data analysis was done by plotting survival curves with the Kaplan-Meier method for survivorship data and performing statistical analysis with the log-rank test (Mantel-Haenszel test) for curve comparison.

RESULTS

In vascularized recipients, the ABO, Lewis, and HLA systems did not influence the graft outcome. However, for the unvascularized recipients, the endothelial 3-year rejection rate was significantly lower for both Lewis compatible patients (84% vs. 68%; log rank = 0.03) and HLA compatible patients (86% vs 72%; log rank = 0.001), but not for the ABO-matched patients (82% vs. 79%; log rank = 0.56).

CONCLUSIONS

The authors' study suggests that Lewis antigens and HLA matching could positively influence corneal graft survival for the unvascularized recipients, but it did not seem to have any effect in vascularized recipients.

Immunoaffinity isolation of the Lewis blood group antigens

Extraction, followed by immunoaffinity chromatography on a column of immobilized antibodies is described for the isolation of the Lewis blood group antigens. These affinity-isolated antigens are suitable in organ transplant immunology laboratories for screening potential donors and recipients for mismatch at the Lewis antigen loci.

Organ transplantation and the immune response gene. Clinical correlations and donor requirements

Major gains have been made in the area of clinical organ transplantations due to recent studies concerning the human histocompatibility locus (HLA). These basic science findings, along with developments in clinical pharmacology have allowed for a much broader use of donor sources, and a significant prolongation in clinical life span for these transplantation recipients.