LYMPHOCYTE SUBSET RESPONSES TO TRAUMA AND SEPSIS

One hundred five trauma patients admitted to three trauma centers with Injury Severity Scores of 20 or greater had lymphocyte phenotypic subsets characterized throughout their hospital course. Total lymphocytes, pan-T (CD2), helper T (CD4), suppressor T (CD8), pan B (CD20), and DR expressing lymphocytes were quantitated by monoclonal antibodies and flow cytometric analysis. Results were analyzed between three patient groups: uninfected, uneventful recovery (n = 64); major infection (n = 26); and dead (n = 15; 7 with sepsis). A significant lymphopenia, maximal at 3 days, occurred in the first postinjury week compared with controls (p < 0.05), which recovered over the study period. A hierarchical distribution was found between the three outcome groups with the lowest numbers of several lymphocyte phenotypes in those who died. T helper and suppressor cells were similarly affected, but lowest in patients destined to develop infection or die. The helper-suppressor ratio, however, was similar in all three outcome groups. Therefore, modulation early after injury aimed at restoring these subsets may reduce the risk of subsequent infection.