Inhibition of chemical mediator release from human leukocytes and lung in vitro by a novel antiallergic agent, KB-2413.

The effect of KB-2413 on IgE-mediated histamine and LTC4 release from leukocytes obtained from asthmatic patients who were sensitive to mites, and from human lung tissues passively sensitized with IgE myeloma serum was studied. KB-2413 inhibited the IgE-mediated chemical mediator release concentration dependently at a range of 10(-4) to 3 x 10(-3) M. KB-2413 did not enhance histamine release at a higher concentration unlike ketotifen. These findings suggest that the inhibitory effect of KB-2413 on the release of chemical mediators contributes to the anti-allergic activity of this compound.