NEUTROPHILS FROM PATIENTS AFTER BURN INJURY EXPRESS A DEFICIENCY OF THE OXIDASE COMPONENTS P47-PHOX AND P67-PHOX

Infection is a major cause of morbidity and mortality in patients afte r thermal injury. This predisposition to infections is related, in par t, to abnormal polymorphonuclear leukocyte (PMN) function and a dimini shed respiratory burst. To evaluate the biochemical basis for the defe ctive respiratory burst after major burns, the status of the oxidase e nzyme system and its components was investigated. PMNs were isolated f rom 24 patients with 12% to 62% burns. Oxidase activity of intact PMNs , measured as superoxide anion (O-2(-)) generation or oxygen consumpti on, was decreased in burn compared with healthy controls. Subcellular fractions from patient PMNs generated less O-2(-) in the sodium dodecy l sulfate cell-free system, and this was related to a diminished contr ibution by cytosol but not by plasma membrane. Subsequently, cytosol w as separated with CM-Sepharose, yielding two fractions; one contained the p47-phox and p67-phox (47/67 mix) and the other contained the rema ining cytosolic components (run through [RT]). Although the contributi on to oxidase activity made by RT from patient cytosol was similar to that of control, the activity of p47/67 mix from PMNs of burn patients was deficient. Quantitative assays using an immunoautoradiographic te chnique showed a consistent, but significant decrease in both p47-phox and p67-phox. The addition of purified or human recombinant p47-phox but not p67-phox corrected the diminished oxidase activity of cytosol from burn patients. Thus, decreased respiratory burst activity found i n PMNs from individuals with thermal injury was associated with a spec ific, quantitative deficiency of p47-phox. (C) 1996 by The American So ciety of Hematology.