Procoagulant activity in renal transplant recipients.

Procoagulant activity (PCA) of leukocytes of renal transplant recipients was studied. This material, which activates coagulation, has previously been shown to be released from macrophages after they interact with mitogen-stimulated or antigen-stimulated T lymphocytes. Under endotoxin-free conditions, PCA of peripheral blood leukocytes, incubated for 90 min in tissue culture, was elevated in postoperative transplant recipients and in many transplant patients tested around the time of a rejection episode. The response to lipopolysaccharide added during culture was also increased in these populations. The PCA response was factor-VII-dependent when tested with washed peripheral blood mononuclear cells (PBMC), but was factor-VII-independent when tested with unwashed PBMC in their original culture medium. The results indicate a possible link between immunologic events and coagulation in transplant recipients.