Figure 4.

In this study, 6 patients were subjected to inhalational challenge with antigens to which they were known to be sensitive [5]. Simultaneous samples of blood were drawn from the brachial artery and from the antecubital vein. A representative patient is shown here. EHM is endogenous heparin-like material, measured with a functional anti-Xa assay after removing neutralizing substances from the heparin by adding low molecular weight dextran sulfate. After the 1 : 1000 spore challenge, there is an immediate rise in both the EHM material produced by exposing plasma to low molecular weight dextran (red line) and the material with heparin neutralizing substances intact when water, rather than dextran sulfate, was added to the plasma (blue line). A concurrent fall in FEV1 occurs along with the rise in heparin levels when the 1 : 1,000 antigen was inhaled. Similar findings occurred in 3 of the 6 patients.