The role of platelet activating factor in allergic respiratory disease.

1. Platelet activating factor (PAF) is an ether-linked phospholipid capable of eliciting many of the factors of the allergic response including bronchoconstriction, mucosal oedema, eosinophil infiltration and bronchial hyperresponsiveness. 2. A wide range of selective PAF receptor antagonists have now been described which have been reported to reduce many aspects of allergen-induced inflammatory responses in experimental animals. 3. Early clinical studies have indicated that some of these drugs are also effective PAF antagonists in man, but no controlled studies have been reported using these compounds in patients with allergic asthma. 4. The gingkolide mixture BN 52063 has recently been reported to inhibit allergen-induced cutaneous inflammation in man; a response which has certain pathological similarities to allergen-induced late-onset airways obstruction in the lung. 5. Therefore, drugs antagonizing the actions of PAF may well lead to a better understanding of and may be a novel therapeutic approach for allergic respiratory disorders.