Complement activation products in plasma after heart transplantation in humans.
BACKGROUND
Complement activation has recently been implicated as a contributing factor to early and late allograft dysfunction in cardiac transplantation. The current study was designed to determine whether measurement of plasma complement fragments C4d and SC5b-9 would be useful in detecting acute rejection or accelerated graft atherosclerosis (AGA) in cardiac allograft recipients.


METHODS
We measured complement activation products, C4d (classical pathway) and SC5b-9 (terminal pathway), at the time of routine endomyocardial biopsy in heart transplant recipients. Ten patients in the immediate posttransplantation period (0-100 days) and 19 patients more than 6 months after transplantation were studied.


RESULTS
No correlation was found between plasma levels of complement activation fragments and the presence of biopsy-proven acute allograft rejection or AGA (assessed by coronary angiography). However, plasma C4d and SC5b-9 were significantly elevated in 9 of 10 and 7 of 10 patients, respectively, in the immediate posttransplantation period. This was followed by progressive decrease in the levels of C4d and SC5b-9 fragments during the first 4-6 weeks after transplantation.


CONCLUSIONS
We conclude that measuring plasma levels of fragments C4d and SC5b-9 is not a useful noninvasive method for detecting acute rejection or AGA after heart transplantation. However, this study provides further evidence that early complement activation after heart transplantation may play a pathogenic role in allograft injury.
Vallhonrat
H
H
Renal Unit, Massachusetts General Hospital, Boston 02114, USA.
Williams
W W
WW
Dec
G W
GW
Keck
S
S
Schoenfeld
D
D
Cosimi
A B
AB
Pascual
M
M
D003167:Complement Activation / Q000502:physiology*; D003181:Complement C4 / Q000032:analysis; D015935:Complement C4b; D003182:Complement C5 / Q000032:analysis; D050776:Complement C5b; D003165:Complement System Proteins / Q000378:metabolism*; D016027:Heart Transplantation; D006801:Humans; D010446:Peptide Fragments / Q000032:analysis / Q000097:blood*; D013997:Time Factors
D003181:Complement C4; D003182:Complement C5; D010446:Peptide Fragments; D015935:Complement C4b; C032261:complement C4d; D050776:Complement C5b; D003165:Complement System Proteins