Chemiluminescence response of human blood mononuclear cells to PHA and histamine

Phytohaemagglutinin (PHA) elicited a short early chemiluminescence (CL) response of human blood mononuclear cells with a maximum at 2.5 min. The magnitude of the CL production was a function of the PHA concentration used. The CL response could be dose-dependently inhibited by histamine. In the presence of mepyramine the action of histamine was more pronounced while a dose-dependent reversal of the inhibition was found by cimetidine.