Abstract
Prostaglandin E2 (PGE2)-mediated monocyte (M phi) suppressor activity and inadequate T-helper cell function represent the mechanistic keystones of trauma-induced impairment of cell-mediated immunity (CMI). In a prospective randomized trial, the immunorestorative potential of a combined therapy with the thymomimetic substance Thymopentin (TP-5; Timunox, Cilag GMBH, Sulzbach, FRG) and the cyclooxygenase inhibitor indomethacin (Indo) in 60 patients (mean age, 63 +/- 2 years) undergoing open heart surgery was studied. Perioperative immunologic screening was carried out on days -2, 3, 1, 5, and 7 and included the in vivo delayed type hypersensitivity (DTH) skin response, phenotyping for peripheral blood mononuclear cell (PBMC)-specific and nonspecific induction of lymphoproliferative responses, in vitro interleukin-2 (IL-2) synthesis, as well as the serum concentration of D-erythro-Neopterin (NPT) and of gamma interferon (gamma-IFN). The study protocol comprised three groups (n = 20): PA (Indo 150 mg administered intravenously on days 0 to 5), PB (TP-5 administered subcutaneously on days 0, 2, 4, and Indo), and PC (control). In contrast to PC, significant immunorestoration could be demonstrated in PB, as DTH scores on day 7, as well as proliferative responses in cell cultures were not depressed after operation (p less than 0.05). Cell-surface receptor expression for the CD3+, CD4+, and IL-2 receptor-positive (IL-2R+) lymphocyte subpopulations following surgery was reduced to 75% of baseline values in PC, while in PB, receptor protection for CD4+ and IL-2R+ subpopulations (more than 15% above baseline) was observed. Interleukin-2 synthesis (average baseline value, 0.7 + 0.08 U/mL) in cell cultures of PC was massively suppressed, with lymphokine concentrations in the supernatants never more than 0.27 +/- 0.05 U/mL. In PA cultures, IL-2 synthesis was impaired as well but not as precipitously as in PC. In contrast, in PB cultures, the average IL-2 production on consecutive postoperative days was never below baseline values. This study clearly demonstrates that the combined Indo/TP-5 therapy is superior to single Indo administration and can adequately preserve and/or restore intact M phi T-cell interaction and thus appears to be a feasible approach to maintain normal host defense activity in traumatized individuals.