Effect of CD4+ and CD8+ cell depletion on wound healing

Background: Depression of the immune system can result in poor or delayed wound healing. Methods: Thymectomized rats were depleted of CD4(+) and CD8(+) lymphocytes by intraperitoneal injection of Medical Research Council Oxford (MRC OX)38 antibodies and MRC OX8. Significant depletion was demonstrated throughout the wound healing process by immunofluorescence studies of peripheral blood. Following depletion the rats underwent laparotomy incisions which were allowed to heal for 10 weeks. Differences in healing were demonstrated by analysing the wounds biomechanically by tensiometry to obtain values of ultimate strength, resilience, toughness, maximum extension and elastic constant. Results: Wounds of animals depleted of CD4(+) lymphocytes showed a significant decrease in ultimate strength, resilience and toughness. Wounds of animals depleted of CD8(+) lymphocytes showed a significant increase in ultimate strength, resilience and toughness. Conclusion: Wounds healed in the absence of T lymphocytes. However, the subsets have an opposing regulatory role, with CD4(+) lymphocytes upregulating and CD8(+) lymphocytes downregulating wound healing.