A comparison of the effects of hydrocortisone on peritoneal inflammatory exudates, the tuberculin reaction and contact sensitivity-to DNFB in the guinea pig.

Hydrocortisone acetate, injected subcutaneously in five doses in a depot producing vehicle, causes prolonged suppression of the ability of guinea pigs to produce a chronic inflammatory reaction in the peritoneal cavity and also of the tuberculin reaction. This suppression of the tuberculin reaction persists for at least 65 days after the last dose of hydrocortisone. Suppression of both peritoneal exudate and the tuberculin reaction was associated with a preferential depletion of macrophages at the reaction site. A similar regime had no effect on the ability of guinea pigs to manifest contact sensitivity reactions to 2,4-dinitrofluorobenzene although there was a similar drop in macrophages in the lesion. It appears that the effect of hydrocortisone on delayed hypersensitivity reactions is not directly related to the functional contribution of macrophages in the inflammatory reactions, and may be related to the site of the inflammatory reaction in the skin.