Scoring of skin rejection in a swine composite tissue allograft model.
BACKGROUND
For the first time, we define and correlate visual and histologic grading systems of composite tissue allograft (CTA) skin rejection in a large-animal model and determine the utility of these grading systems for early diagnosis and monitoring of rejection.


METHODS
Sixteen pairs of outbred swine underwent transplant of a forelimb osteomyocutaneous free flap. Group I (n = 6) did not receive immunosuppressive therapy. Group II (n = 10) received oral cyclosporin A, mycophenolate mofetil, and prednisone. The flap was visually inspected and protocol skin biopsies were taken at frequent intervals over a 90-day period. Visual Grades 0 (no rejection) to 4 (severe rejection) were assigned based on skin color, bleeding from biopsy site, and blister formation. Histologic Grades 0 to 4 were assigned based on the degree of vasculitis, folliculitis, dermal inflammation, and epidermal degeneration present.


RESULTS
All Group I animals progressively rejected their graft by Day 7. Group II grafts survived from 19 and 90 days; 93% of 115 biopsy specimens were read to be within +/-1 histologic score of their assigned flap visual grade. Visual assessment carried an 8% false positive and 39% false negative rate with regard to biopsy-proven rejection. However, 81% of missed rejection specimens were histologic Grade 1. Biopsy, when visually indicated, would detect all rejection episodes when histologically Grade 1 or 2 and still potentially reversible.


CONCLUSIONS
Visual scoring of CTA skin serves as a useful tool for initially detecting rejection, but repeated histologic evaluation is necessary for monitoring the subsequent course of the graft.
Zdichavsky
M
M
Divisions of Plastic and Reconstructive Surgery and Hand Surgery of the Department of Surgery, University of Louisville School of Medicine, Louisville, Kentucky, 40292, USA.
Jones
J W
JW
Ustuner
E T
ET
Ren
X
X
Edelstein
J
J
Maldonado
C
C
Breidenbach
W
W
Gruber
S A
SA
Ray
M
M
Barker
J H
JH
D000818:Animals; D001706:Biopsy; D016572:Cyclosporine / Q000627:therapeutic use; D005188:False Negative Reactions; D005552:Forelimb / Q000601:surgery; D006084:Graft Rejection / Q000473:pathology*; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D009173:Mycophenolic Acid / Q000031:analogs & derivatives / Q000627:therapeutic use; D011241:Prednisone / Q000627:therapeutic use; D012867:Skin / Q000473:pathology; D016038:Skin Transplantation; D013524:Surgical Flaps; D013552:Swine
D007166:Immunosuppressive Agents; D016572:Cyclosporine; D009173:Mycophenolic Acid; D011241:Prednisone