Suppressive serum, suppressor lymphocytes, and death from burns.

Both suppressor lymphocytes and serum immunosuppressive factors have been found in patients who have had major thermal burns, and may inhibit host resistance to the bacteria invariably present in burn wounds. However, the relationship and clinical importance of these two manifestations of impaired immune reactivity are poorly understood. Eighteen patients (aged 20-84 years) with full thickness burns of varying severity have been studied, and the clinical course related to the presence of nonspecific immunosuppressive serum and circulating suppressor lymphocytes. Serum factors capable of suppressing the phytohemagglutinin (PHA) response of normal lymphocytes usually appeared early and were detected in 15 of the 18 patients at some time during the illness. Thirteen of these patients developed systemic infection. Depression of the PHA response of peripheral blood lymphocytes was much less common and was associated with this finding died. No patients who did not have severe depression of the lymphocyte response to PHA died. Nonadherent leukocyte (NA leukocyte) populations exhibiting a depressed PHA response were capable of suppressing the PHA response of normal human lymphocytes and, therefore, contained suppressor cells.