EARLY IL-2 SIL-2R SURGE FOLLOWING SURGERY LEADS TO TEMPORARY IMMUNE REFRACTORINESS/

High serum level of immunoreactive but not biologically active IL-2 wa s detected 1 day after surgery in patients undergoing major operation (abdominal, open-heart), in proportion to the tissue injury caused by surgical trauma. IL-2 values were highest in those patients who underw ent open-heart surgery and received blood transfusions, In all patient s they declined in the third and fourth post-operative days. Elevated serum levels of soluble IL-2 receptors (sIL-2R) were already present 1 day after operation, and peaked in the third and fifth post-operative days after mitogen triggering. Blood lymphocytes derived from operate d patients secreted reduced amounts of both IL-2 and sIL-2R compared w ith control lymphocytes. The extent and duration of this reduction wer e also proportional to the tissue trauma and were affected by blood tr ansfusions. Based on these data we suggest that early post-operative s ystemic immunological activation (appearance of IL-2 in the serum) is followed by elevation of sIL-2R, which then interferes with IL-2-depen dent immunity. Blood lymphocytes are probably not involved in the post -operative immunological activation. The trigger for and the site of I L-2/sIL-2R synthesis are not yet clear.