The Decrease in Peripheral Blood CD4+ T Cells Following Thermal Injury in Humans Can Be Accounted for by a Concomitant Decrease in Suppressor-inducer CD4+ T Cells As Assessed Using Anti-CD45R

Using single- and two-color fluorescence flow cytometry, 10 thermally injured human subjects were assessed over time for both percentages and absolute numbers of lymphocytes comprising peripheral blood lymphocyte subpopulations. The CD3+ lymphocyte percentage decreased significantly in the early postburn period, and this decrease could be accounted for entirely by a concomitant decrease in the CD4+ lymphocyte percentage. Further, the decline in CD4+ percentage was due to a specific decrease in the suppressor-inducer subset of CD4 as defined using anti-CD45R. No change in the helper-effector subset of CD4 was noted. The percentage of CD8+ lymphocytes did not change significantly at any time postburn nor did subsets of CD8 as defined using anti-CD11. Numerical changes in lymphocyte subsets were dominated by a general lymphopenia occurring on Day 4 following injury. However, suppressor-inducer (CD4+/CD45R+) T cells also decreased significantly on postburn Day 1. These results further elucidate phenotypic changes in immunoregulatory subsets following major injury and suggest a possible basis for depressed autologous mixed lymphocyte responsiveness of burn patient T cells, one of the functional immunologic defects associated with severe injury.