Pre- and posttransplant monitoring of alloantibodies by complement-dependent cytotoxicity and luminex methodologies in liver transplantation

Human Leukocyte Antigen Sensitization in Solid Organ Transplantation: A Primer on Terminology, Testing, and Clinical Significance for the Apheresis Practitioner

The human leukocyte antigen (HLA) system is an important immunologic barrier that must be considered for successful solid organ transplantation. Formation of donor-specific HLA antibodies in solid organ transplantation is an important cause of allograft injury and may contribute to recipient morbidity and mortality. Therapeutic plasma exchange is often requested to lower HLA antibody levels prior to or after transplantation and for management of HLA antibodies in the context of organ rejection. In this review, we summarize the current terminology, laboratory testing, and clinical significance of HLA sensitization in the solid organ transplant population. Furthermore, to illustrate applications of HLA testing in clinical practice, we summarize our own lung and kidney institutional protocols for managing HLA antibodies in the peri-transplant setting.

Behaviour of non-donor specific antibodies during rapid re-synthesis of donor specific HLA antibodies after antibody incompatible renal transplantation

BACKGROUND

HLA directed antibodies play an important role in acute and chronic allograft rejection. During viral infection of a patient with HLA antibodies, the HLA antibody levels may rise even though there is no new immunization with antigen. However it is not known whether the converse occurs, and whether changes on non-donor specific antibodies are associated with any outcomes following HLA antibody incompatible renal transplantation.

METHODS

55 patients, 31 women and 24 men, who underwent HLAi renal transplant in our center from September 2005 to September 2010 were included in the studies. We analysed the data using two different approaches, based on; i) DSA levels and ii) rejection episode post transplant. HLA antibody levels were measured during the early post transplant period and corresponding CMV, VZV and Anti-HBs IgG antibody levels and blood group IgG, IgM and IgA antibodies were quantified.

RESULTS

Despite a significant DSA antibody rise no significant non-donor specific HLA antibody, viral or blood group antibody rise was found. In rejection episode analyses, multiple logistic regression modelling showed that change in the DSA was significantly associated with rejection (p = 0.002), even when adjusted for other antibody levels. No other antibody levels were predictive of rejection. Increase in DSA from pre treatment to a post transplant peak of 1000 was equivalent to an increased chance of rejection with an odds ratio of 1.47 (1.08, 2.00).

CONCLUSION

In spite of increases or decreases in the DSA levels, there were no changes in the viral or the blood group antibodies in these patients. Thus the DSA rise is specific in contrast to the viral, blood group or third party antibodies post transplantation. Increases in the DSA post transplant in comparison to pre-treatment are strongly associated with occurrence of rejection.