Immunosuppression follows systemic T lymphocyte activation in the burn patient

A general consensus that thermal injury affects T lymphocyte function adversely is supported particularly by the observation that burned patients’ lymphocytes secrete reduced levels of biologically active IL‐2 in vitro. In the same patients, however, high serum concentrations of the low‐affinity IL‐2 receptor (IL2Rα), a product of an IL‐2‐activated gene, have been observed. In this study a significant proportion of patients also demonstrated over‐physiological levels (from 2 to 500 U/ml) of serum IL‐2 ascertained by immunoassay. Increases in serum IL‐2 content correlated significantly (P < 002) with those of serum IL‐2Rα during the first week post‐burn. Later, serum IL‐2Rα levels continued to increase up to 30 days while IL‐2 eventually declined. Thus, augmented secretion of IL‐2Rα appears related to the high serum IL‐2 content. Therefore refractoriness to further immune stimulation may be due to early activation of the lymphoid system, rather than to an intrinsic incapacity of T lymphocytes for generating sequential responses.