Seen here is acute tubulointerstitial cellular rejection of a renal transplant. Note the extensive inflammatory cell infiltrates in the interstitium.The glomerulus at the lower left is not involved. This form of rejection can occur days to months to years following transplantation. Both CD4 and CD8 lymphocytes participate in this rejection reaction. The immunosuppressive drugs such as cyclosporine given to counteract the rejection may lead to nephrotoxicity with similar changes as well.