This kidney was removed because of acute transplant rejection. Note the swollen and hemorrhagic appearance of this entire kidney47 Seen here is acute tubulointerstitial cellular rejection of a renal transplant. This can occur days to months to years following transplantation. Both CD4 and CD8 lymphocytes participate in this rejection reaction. The cyclosporine given to counteract the rejection may lead to nephrotoxicity with similar changes as well.