This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Organ Transplant / Graft, Subject name: Pathology
All of the following regarding acute graft rejection are true, except: 
Select and explain. 
A. CD8+ T-cells directly destroy the graft, B. It is the principal cause of early graft failure, C. Preformed antibodies against graft are the main causative factor, D. Cytokines secreted by CD4+ T-cells cause inflammation which destroys the graft
C: Preformed antibodies against graft are the main causative factor
Answer: C: Preformed antibodies against graft are the main causative factor 
Explanation: Hyperacute rejection is mediated by preformed antibodies specific for antigens on graft endothelial cells. Acute graft rejection: It occurs within days or weeks after transplantation and is the principal cause of early graft failure. Divided into two types: In acute cellular rejection, CD8+ CTLs may directly destroy graft cells, or CD4+ cells secrete cytokines and induce inflammation, which damages the graft. In acute antibody-mediated (vascular, or humoral) rejection, antibodies bind to vascular endothelium and activate complement the classical pathway