Enhancement of delayed hypersensitivity in guineapigs by H2-receptor antagonist

Abstract

Summary Guinea‐pigs have been sensitized with dinitrochlorobenzene (DNCB) to produce type IV‐reactions. The reactions spontaneously faded in the untreated animals. In contrast, in the group treated with cimetidine, the reaction remained essentially unchanged. Cimetidine thus caused an augmentation by preventing the spontaneous fading. The enhancement of the type IV‐reaction by cimetidine is possibly caused by supression of regulatory T‐lymphocytes through their H2‐receptors. The histamine content of the sensitized and challenged sites increased both in the untreated and cimetidine‐treated groups.

Letters to the Editor

“…There is still a great deal unknown about how cimetidine influences immune responsiveness. It has been shown to prevent the spontaneous fading of delayed hypersensitivity to DNCB in guinea pigs 2 . In addition to prevention of the spontaneous fading of delayed hypersensitivity to DNCB, cimetidine appears to have some success in reversing acquired tolerance to DNCB 3,4 .…”