The acute phase protein response in mice does not show tolerance to recurrent sterile inflammation

The response of acute phase proteins to repeated inflammatory stimuli was studied in BALB/c mice and Hylyne Dutch rabbits. Inflammation was produced by subcutaneous injections of turpentine/arachis oil twice weekly for three and a half weeks. Serum amyloid-P component (SAP) levels in the mice showed no significant decrease in the level of response following each injection and the pattern of response was the same in mice previously rendered tolerant to endotoxin. Haptoglobin levels in the rabbits also responded equally to repeated injections in two animals and showed a declining response in a third animal which became unwell during the experiment. The ability of experimental animals to continue to respond fully to repeated inflammatory stimuli supports the suggestion that the subnormal responses seen in certain chronic inflammatory conditions may reflect an underlying defect in the acute phase response rather than an adaptive change following chronic inflammation.