Application of immunoapheresis for delaying hyperacute rejection during isolated xenogeneic pig liver perfusion.
BACKGROUND
Extracorporeal liver perfusion in hepatic coma, used to eliminate toxic metabolites causing hepatic encephalopathy, is limited by the antibody (Ab) and complement-mediated hyperacute rejection of discordant xenografts. Thus, the efficacy of highly selective immunoadsorption columns to deplete xenoreactive human anti-porcine antibodies before ex vivo liver perfusion was examined in this study.


METHODS
Eighteen domestic pigs were hepatectomized according to standard techniques. The livers were ex vivo perfused for 4 hr. The perfusion protocol closely followed the physiological conditions of a human liver. Parameters of liver function and damage were analyzed. Three groups were formed differing in the treatment of the perfusate. As basic control, livers were perfused with heparinized human blood (group 1; n=6). Immunoapheresis was applied in group 3 (n=6). Immunoapheresis was performed using Ig Therasorb columns consisting of sheep-anti-human IgG Abs covalently coupled to Sepharose CL-4B. Additionally, the effect of pure Sepharose CL-4B without immobilized Ab was tested in group 2 (n=6).


RESULTS
The use of Ig Therasorb 100 columns in group 3 resulted in a reduction of IgG, IgM, and IgA in the order of 95.0%, 72.3%, and 81.5%, respectively. In group 2, IgG, IgM, and IgA were lowered by 30% to 39%. Determination of liver-specific enzymes and tolerance tests revealed a significant reduction of cellular damage and functional restrictions in group 3 compared with the control groups.


CONCLUSIONS
Immunoapheresis conducted according to this protocol appears to be an effective approach for delaying antibody-mediated hyperacute xenogeneic rejection.
Pascher
A
A
Institute for Surgical Research, Klinikum Grosshadern, Ludwig Maximilians University Munich, Germany.
Poehlein
C
C
Stangl
M
M
Hoebel
G
G
Thiery
J
J
Mueller-Derlich
J
J
Hammer
C
C
D000208:Acute Disease; D000641:Ammonia / Q000097:blood; D000818:Animals; D000910:Antibodies, Heterophile / Q000302:isolation & purification*; D001781:Blood Component Removal / Q000379:methods*; D003176:Complement C3 / Q000032:analysis; D003181:Complement C4 / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D004798:Enzymes / Q000097:blood; D005112:Extracorporeal Circulation; D005690:Galactose / Q000032:analysis; D005693:Galactosemias; D006084:Graft Rejection / Q000517:prevention & control*; D006501:Hepatic Encephalopathy / Q000628:therapy*; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007773:Lactates / Q000097:blood; D008099:Liver; D008111:Liver Function Tests; D010477:Perfusion; D012756:Sheep; D013552:Swine; D014183:Transplantation, Heterologous
D000910:Antibodies, Heterophile; D003176:Complement C3; D003181:Complement C4; D004798:Enzymes; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007773:Lactates; D000641:Ammonia; D005690:Galactose