Peripheral blood lymphocytes from thermal injury patients are defective in their ability to generate lymphokine-activated killer (LAK) cell activity

We have previously shown that natural killer (NK) cell activity against K562 tumor cells is severely depressed in thermal injury patients. In this study we have investigated whether the low NK cell activity present in peripheral blood lymphocytes (PBL) from thermal injury patients could be enhanced by in vitro culture with interleukin 2 (IL2) and whether PBL obtained from these patients could generate lymphokine-activated killer (LAK) cell activity against NK insensitive tumor targets. NK cell activity in PBL obtained from 12 different patients was greatly enhanced against K562 tumor cells after in vitro culture with IL2 for 3 days. In contrast, PBL obtained from these patients and incubated with IL2 had little to no cytotoxic activity when measured against a number of NK-insensitive tumor targets. The failure of PBL obtained from thermal injury patients to generate LAK cell activity was observed regardless of the culture time or the amount of IL2 added to the cultures. PBL from thermal injury patients demonstrated reduced proliferative responses to IL2 and, more importantly, contained suppressor cells which could inhibit the generation of LAK cell activity of normal PBL obtained from control individuals. These results clearly show that in some thermal injury patients NK cell activity can be enhanced by IL2 but these patients are defective in their ability to generate LAK cell activity.