PROCOAGULANT ACTIVITY OF PPD-STIMULATED HUMAN-LYMPHOCYTES AFTER CRYOPRESERVATION

Objective: Human mononuclear cells from a previously sensitized donor generate procoagulant activity (PCA) following stimulation with purifi ed protein derivative (PPD). Lymphocytes of tuberculous pleural effusi ons are also highly responsive to PPD stimulation. We examined the inf luence of cryopreservation on lymphocytes following stimulation with P PD. Design: Peripheral blood lymphocytes of 5 healthy PPD skin test po sitive subjects were incubated with either PPD, thromboplastin, or con canavalin A (Con A) at concentrations of 0, 1, and 10 mu g/ml. PCA was determined by measuring the recalcification time. Tests were repeated following cryopreservation for 4 weeks, Results: Incubation of fresh lymphocytes led to a dose dependent shortening of recalcification time : PPD (0-1-10 mu g/ml: 100-84-65%), thromboplastin (0-1-10 mu g/ml: 10 0-85-62%), and Con A (0-1-10 mu g/ml: 100-85-42%). These results were highly reproducible when tests were repeated 6 weeks later. Cryopreser vation did not significantly affect the expression of PCA following in cubation with PPD and with thromboplastin. In contrast, cryopreservati on significantly diminished the degree of Con A generated PCA. Conclus ion: Cryopreservation and storage of human lymphocytes is possible wit hout alteration of PCA expression following their incubation with PPD or thromboplastin.