Natural killer cells in renal allograft rejection.

Monoclonal antibody Anti Leu 7 has been used to enumerate peripheral blood NK cells in 20 renal allograft recipients. Blood was taken preoperatively and three times per week for the first month after transplantation; separated mononuclear cells were stained with Anti Leu 7 then analysed on a fluorescence activated cell sorter. Results were related to acute rejection episodes diagnosed clinically and confirmed by Trucut biopsy of grafts. A reduction in the number of Leu 7 positive cells occurred postoperatively. Nineteen out of 20 patients showed a rise in number of circulating NK cells during acute rejection episodes.