An increase in the susceptibility of burned patients to infectious complications due to impaired production of macrophage inflammatory protein 1α¹

Sepsis is a major mortality concern with burned patients, who have an increased susceptibility to infectious complications. PBMC from 41 of 45 severely burned patients (91%) failed to produce macrophage inflammatory protein 1α (MIP-1α) in cultures, while 2355-6900 pg/ml MIP-1α were produced by healthy donor PBMC, stimulation with anti-human CD3 mAb. Healthy chimeras (SCID mice inoculated with healthy donor PBMC) treated with anti-human MIP-1α mAb and patient chimeras (SCID mice reconstituted with burned patient PBMC) were susceptible (0% survival) to infectious complications induced by well-controlled cecal ligation and puncture. In contrast, patient chimeras treated with human recombinant MIP-1α and healthy chimeras were resistant (∼77-81% survival). Similarly, after anti-mouse CD3 mAb stimulation, splenic mononuclear cells from burned mice (6 h to 3 days after thermal injury) did not produce significant amounts of MIP-1α in their culture fluids. Normal mice treated with anti-murine MIP-1α mAb and burned mice were susceptible to cecal ligation- and puncture-induced infectious complications, while burned mice treated with murine recombinant MIP-1α and normal mice were resistant. Burned patients seemed to be more susceptible to infectious complications when the production of MIP-1α was impaired.