Spontaneous lymphocyte activity: an important but neglected component of the immunologic profile of the thermally injured patient.

Controversy exists over whether lymphocyte mitogenic activity decreases after thermal injury, as well as whether the decreased activity is of clinical significance. Therefore to characterize the pattern of postburn lymphocyte dysfunction, the rates of the patient's spontaneous (SBT) and stimulated (mitogen phytohemagglutinin) lymphocyte blastogenesis were measured and correlated with the biologic effect of the patient's serum and lymphokines on control mononuclear cell blastogenesis. The SBT increased after thermal injury (p less than 0.01) in contrast to the mitogenic-induced blastogenic response, which was either normal or decreased depending on the mechanics of data analysis. The level of SBT elevation but not stimulated lymphocyte activity would identify patients who had sepsis (p less than 0.05). The changes in lymphocyte activity could not be explained by the presence of circulating serum mediators or the biologic effect of soluble mononuclear cell products (lymphokines). The results of these experiments clearly document that after thermal injury lymphocytes are being activated in vivo even when the patient's serum is suppressive and the phytohemagglutinin-stimulated activity is depressed. Therefore the level of SBT must be taken into consideration when lymphocyte function is evaluated after thermal injury.