THE EFFECTS OF PROLONGED CARDIOPULMONARY BYPASS ON CELL-MEDIATED-IMMUNITY

Studies of T-cell subsets (CD3+, CD4+, CD8+, CD8+ CD57+ cells), lympho cyte response to concanavalin A (Con A), phytohaemoagglutinin (PHA) an d the alterations of white cell membranes shown by scanning electronic microscope (SEM) in 51 patients who underwent cardiac operation were performed. Out of these 51 unselected patients, for 16, duration of CP B was less-than-or-equal-to 110 min (group A), while for the other 35 (group B) it was prolonged (> 110 minutes). Although variations of the lymphocyte subset observed between groups A and B were slighly signif icant (p < 0.05 before CPB and on postoperative day 7), the T-cell rea ctivity in group B in comparison to that of group A did not normalize by postoperative day 7 regardless of stimulation with PHA or with Con A. With the use of the SEM, the folded aspect of lymphocyte surface de creased after surgery in about 71 % (group A) and 78 % (group B) of th e observed cells. The outcome of the immunological effects given by ou r studies could have been due to an elongated CPB even if there need t o be taken into consideration multifactorial influences, i.e. biologic al, pharmacological and hormonal hypotheses, and rapid changes in CPB- micro-enrivonment.