Immunohistochemical study of the cells infiltrating human renal allografts by the ABC and the IGSS method using monoclonal antibodies.

Sixty renal allograft tissues obtained from 29 patients were stained with hematoxylin and eosin. These tissues were histologically classified into 4 patterns according to the distribution pattern of the infiltrating cells: normal, focal, focal-diffuse, and diffuse types. Clinical signs of acute rejection were observed in 88% of the patients with the diffuse type infiltration, and 83% of those with the focal-diffuse type infiltration but in only 13% of those with the focal type infiltration. Twenty-four renal allografts were analyzed by the ABC and the IGSS methods using monoclonal antibodies. The number of T cells (Leu 1) accounted for about 80% of the total number of infiltrating cells; 2-8% of the cells were B cells (Leu 12); about 10% were NK/K cells (Leu 7); and 4-6% were monocytes/macrophages (Leu M3). As to helper/inducer T cell (Leu3a) and killer/suppressor T cell (Leu2a), which are T lymphocyte subsets, there were more Leu3a- than Leu2a-positive cells in focal type tissue, but there were more Leu2a- than Leu3a-positive cells in focal-diffuse and diffuse type tissue. In most cases that developed clinical signs of acute rejection, there were more Leu2a- than Leu3a-positive cells. The Leu3a/Leu2a ratio in most of the AZA-administered cases dropped immediately after the transplantation and maintained a low value, but in the CSA-administered cases it decreased gradually post-transplant.