Susceptibility to bacterial sepsis. Accurate measurement by the delayed-type hypersensitivity skin test score

To test the hypothesis that any alteration in the delayed-type hypersensitivity (DTH) skin test response (not necessarily total anergy) reflects increased susceptibility to bacterial sepsis, male Sprague-Dawley rats presensitized to keyhole-limpet hemocyanin were subjected to a 30% full-thickness scald burn. Susceptibility to bacteria was assessed by the intradermal injection of Staphylococcus aureus 502A. The DTH response decreased following burn injury from 6.6 to 3.9 mm on days 2 and 8. Skin abscess size increased from 5.8 to 9.3 mm on day 2 and 8.9 mm on day 8. There was a significant inverse correlation between DTH skin test score and abscess size. Histologically there was no difference in the overall leukocyte accumulation in the abscess or the DTH reaction between the two groups, yet the overall size of the abscess was greater and the swelling of the dermis in the DTH response was less in the burned rats.