Histamine-induced inhibition of lymphocyte proliferation and lysosomal enzyme release from polymorphs may not be mediated via H1- or H2-receptors.

Histamine, selective histamine H1- and H2-receptor agonists, and chemical analogues of these compounds lacking activity at histamine receptors, were tested as inhibitors of phytohaemagglutinin-induced human lymphocyte proliferation and zymosan-induced release of lysosomal enzymes from human polymorphs. No correlation was found between their inhibitory potency in these systems and their relative activity at histamine H1- or H2-receptors.