Although heparin is used as an anticoagulant, its biologic function remains unclear. Substantial evidence exists that suggests it may modulate many aspects of immune function and inflammation. We demonstrated, in a double-blind, placebo-controlled, crossover study involving 10 allergic subjects, that a small dose of heparin (25 U/kg) administered intravenously 10 min before challenge reduced the acute cutaneous reaction to 10 allergens and histamine from a group-average sum of mean (+/- SD) wheal diameters at a baseline of 29.9 +/- 10 mm and after normal saline placebo (29.5 +/- 10.7 mm) to after heparin (14.4 +/- 10.4 mm) (p < 0.02, Wilcoxon's signed rank test). In 15 subjects with asthma and dust mite allergy, nebulized heparin 20,000 units administered in a double-blind, placebo-controlled, crossover fashion 10 min before challenge inhibited the bronchospasm induced by inhaled dust mite extract. Log2 of the provocative dose of mite extract causing a 20% fall in FEV1 at baseline was 4.1 +/- 1.5 protein nitrogen units (PNU); after normal saline it was 4.5 +/- 2.0 PNU, and after heparin it was 5.1 +/- 2.5 PNU (p = 0.04). These data suggest heparin may have an inhibitory role in acute mast-cell-mediated allergic inflammation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.