Complement Fragment C4d and C3d Deposition in Pediatric Heart Receipients With a Positive Crossmatch

C3d deposition was universally present after heart transplantation with a CDC+ donor/recipient crossmatch. C4d deposition and pericapillary macrophage infiltration were found with some, but not all, episodes of rejection. Further study is needed to understand the significance of the presence of complement fragments and pericapillary macrophage infiltration in these endomyocardial biopsies.