Highly active effect of alpha interferon in blocking the cutaneous delayed hypersensitivity

A group of 13 patients with contact dermatitis to various chemical compounds such as potassium dichromate, nickel sulphate, formaldehyde and balsam of Peru, was investigated by patch test and by the agreement between the history of disease and the patch test, the specific allergen involved in each special case could be demonstrated. Two-three days after the first patch test three normal skin areas were chosen. The first area was intradermally infiltrated with alpha-2a Interferon (IFN) (100,000 I.U. in 1 ml), the second area was infiltrated with saline and the third area, considered as control, did not receive any treatment. Once more the corresponding allergen was applied into the skin in a second patch-test. After 48 hours in the IFN infiltrated area, only the delayed contact hypersensitivity become negative thus proving that alpha-2a IFN behaves as an efficient inhibitor of these immune effector reactions. Since the lymphocytes involved in the delayed type hypersensitivity reactions (in our case contact dermatitis) belong to the T helper line, i.e., are CD-4 positive cells we conclude that alpha-2a IFN in vivo is an efficient inhibitor of the activation of these cells. This effect achieved by any CD-4(+) DTH clones does not depend on their antigenic specificity. Some clinical trials are now in progress in our laboratory to turn to account this important biological effect in the clinical practice as an efficient inhibitor in skin contact dermatitis.