Detection of antibodies in eluates of immunoadsorption causing humoural rejection in patients after solid organ transplantation.

The influence of antibodies (AB) against human leukocyte antigen (HLA) on antibody mediated rejection (AMR) is still discussed controversially. Here we demonstrate to what extent post transplant detected HLA-AB and non-HLA-AB against Angiotensin II type 1 receptor (AT1 R-AB), endothelin-1 type A receptor (ETA R-AB) and glycoprotein (GP) IIb/IIIa, Ia/IIa, Ib/IX affect the graft outcome. A total of 13 transplant recipients (9 kidneys and 4 hearts) suffering from AMR were analysed. Before immunoadsorption (IA) treatment HLA-AB (CDC) in sera were detected in 27% versus 39% in eluates and 46% versus 87% by using ELISA. We could not find any AB against GP in sera. In eluates, however, we could detect AB against GP: GP IIb/IIIa in 86% of all samples with titres from 1:1 to 1:32, GP Ib/IX (up to 1:32) in 76% and GP Ia/IIa with titres from 1:1 to 1:16 in 82%. Further we detected anti-endothelial cell antibodies (AECA) against receptors AT1 and ETA in sera before IA in 22%, after IA in 10% and in eluates in 42% of all samples. The antibody titres vary from 1:1 to 1:256. Our investigation pointed out, that AMR is still possible without detectable AB in serum and consolidates the hypothesis that clinical relevant non-HLA-AB and HLA-AB are partly fixed on the graft. IA is qualified to detach these fixed AB.