Effect of Anticoagulants on Delayed Hypersensitivity Reactions

Abstract

Summary Administration of heparin or warfarin to sensitized guinea pigs resulted in diminution or prevention of delayed sensitivity reactions. This effect was found in animals sensitized either to a protein conjugate (DNP-BGG) or to a contact-sensitizing chemical (OCBC). Guinea pigs recovered quickly from the inhibitory effect of heparin, paralleling the return to normal of the coagulation time. The amount of heparin employed in these experiments did not result in depression of serum complement levels. The administration of chondroitin sulfate, a compound structurally similar to heparin but lacking its anticoagulant action, had no effect on contact sensitivity reactions. Heparin treatment of contact sensitive guinea pigs did not interfere with the capacity of their lymph node cells to transfer contact reactivity to normal recipients. Heparin failed to inhibit nonimmunologic inflammatory reactions elicited by bovine fibrinogen or poly-l-lysine, although these reactions bore some gross and histologic resemblance to delayed reactions. The inhibition of dermal hypersensitivity reactions (DNP-BGG) by heparin was not accompanied by an interference with the booster effect of the skin test on the production of circulating anti-DNP antibodies. It is concluded that heparin and warfarin exert their inhibitory effect on delayed reactivity through some action on the coagulation mechanism which probably results either in the prevention of accumulation of immunologically nonspecific inflammatory cells or somehow blocks the triggering events initiated by interaction of antigen with sensitized cells.