Changes of Leukocyte Number and Distribution following Thermal Injury / 대한면역학회지

ABSTRACT

Regarding numerical changes of leukocytes involved in immune defects following thermal injury, a lot of controversial results have been reported. In this study, the changes of leukocyte number and distribution were examined and compared in spleen and lymph nodes of thermally injured mice. Mice (Balb/c) were anesthetized by intraqeritoneal injection of 2,2,2-tribromoethanol and thermally injured by immersion of hair-removed dorsal skin (15% total body surface) in a boiling water bath (96`C) for 7 seconds. Both of lymph node cell (LNC) and spleen cell (SPC) numbers decreased significantly at day 2 of injury and thereafter rebounded, but in a distinct pattern; 1) LNC numer returned to over normal level at day 6 and normalized again, whereas SPC number increased gradually over normal level and sustained until day 24 of injury. 2) Such increase of LNC and SPC number coincided with higher proportion of PMN and relative decline of lymphacytes, particularly CD3 T cells rather than slg' B cells, but such alteration was more significant in spleen. The changes of peripheral blood leukocyte (PBL) number was comparable to those of SPC. These data suggest that the cause of immune modulation in thermally injured mice acts systemically. In addition, it is noteworthy that reduction of lymphocyte and CD3 T cell proportions was due to relative increase of PMN number, not the decrease of absolute number of lymphocytes. Spontaneous recovery of injured mice in this study also implicates that increase of PMN number may be responsible for recovery from injury without infection. Finally, the CD4'/CD8' ratio of injured mice was lower only at day 2 ot injury, but not significantly, than that of control group. It is likely that contribution of Th/Ts ratio to immune defect after thermal injury should be determined together with other factors, such as injured body surface % and severity of injury.