Lack of evidence for human lymphokines with thrombocyte aggregating activity. An in vitro study

The ability of human lymphocytes to produce soluble mediator(s) with thrombocyte aggregating activity (TAA) was investigated in an in vitro technique. Isolated human mononuclear cells were stimulated with phytohaemagglutinin or purified protein derivative of tuberculin. The supernatants were investigated for lymphokine activity in a leucocyte migration inhibitory factor assay. Supernatants were then tested for their ability to aggregate human thrombocytes, and in contrast to the results of previous studies, we were not able to demonstrate any TAA. Most likely, lymphokines with TAA are not involved in the thrombotic processes seen in human cell-mediated immune inflammatory reactions.