7.5
#7-OR
ANTI-MICA ALLO-ANTIBODIES IN SERA FROM HEART ALLOGRAFT RECIPIENTS AT RISK OF TRANSPLANT-ASSOCIATED CORONARY ARTERY DISEASE.
Yizhou Zou MD 1, Zhengnan Wang BSN 1, Bhavna Lavingia CHS 1, Jason Crumpton BS 1, W. Steves Ring MD 2, Clyde Yancy MD 1 and Peter Stastny MD 1. 1 Internal Medicine, Univ of TX Southwestern Medical Center and 2 Surgery, Univ of TX Southwestern Medical Center, Dallas, TX .
MHC class I-related chain A (MICA) are HLA-related, polymorphic glycoproteins expressed on the surface of human endothelial cells, epithelial cells and fibroblasts. Anti-MICA allo-antibodies were detected in serum from some kidney graft recipients in previous studies. Development of accelerated transplant-related coronary artery disease (CAD) is a major obstacle to long-term survival of cardiac allografts. The aim of the present study was to investigate whether MICA antibodies are associated with CAD after cardiac transplantation. Polystyrene microspheres were bound with soluble recombinant of MICA*01, MICA*02, MICA*04, MICA*08 or MICA*09 produced from insect cells. Luminex flow cytometry was used to determine MICA allele-specific antibodies in sera from 100 cardiac transplant recipients before and after transplantation. Sera from normal subjects (n = 18) were used to set a threshold for this assay. 27% of cardiac recipients were detected to have anti-MICA antibodies. Of 27 cardiac recipients who produced anti-MICA antibodies, 9 (33.3%) developed CAD compared to 13.7% among MICA antibody negative recipients (n=73) (X2=4.9374, P<0.05). If we count together cardiac recipients with CAD and/or with more than one episode of acute rejection per year (n=30), 43.3% of them were producing MICA antibodies. While only 20% of recipients who had not developed CAD or rejection episodes developed MICA antibodies (X2=5.8008, P<0.025). Our data demonstrates that patients who developed anti-MICA antibodies were at increased risk of developing CAD, suggesting MICA may be a target molecule in allograft rejection.