A Sequential, Prospective Analysis of Immunologic Abnormalities and Infection Following Severe Thermal Injury

Abstract

A sequential, prospective analysis of humoral and cellular immune function was performed on 20 burn patients with injuries involving .gtoreq. 45% total body surface area. Infected patients had significantly worse neutrophil bactericidal activity against Staphylococcus aureus 502A than did noninfected patients. Chemotaxis of neutrophils correlated poorly with infection although chemotaxis was frequently abnormal. The opsonic index of serum was depressed early after the burn but returned to nearly normal values by the 4th to the 14th post-burn day. There was no difference between infected and noninfected patients. Serum levels of Ig[immunoglobulin]G, properdin and C3 [complement component 3] while initially low, remained within the normal range after the 9th post-burn day in both groups. Factor B levels rose rapidly during the first 3 wk after injury to more than double normal levels in many patients. Suggestive evidence for consumption of opsonic protein occurred with 5 of 19 episodes of bacteremia. The responsiveness of isolated lymphocytes to PHA [phytohemagglutinin] was normal. Patients'' sera significantly inhibited the responsiveness of normal lymphocytes to PHA. Analysis of immunologic profiles for individual patients indicates that abnormalities of neutrophil function are the most important acquired defect predisposing patients to the development of bacteremia following major thermal injury; abnormalities of opsonic action play a secondary but important role.