title: Histamine potently suppresses human IL-12 and stimulates IL-10 production via H2 receptors.
abstract: IL-12 and IL-10, respectively, stimulate Th1 and Th2 immune responses. The development of some allergic reactions, infections, and tumors are associated with excessive histamine production and a shift toward Th2 responses. Here we address the possibility that this association is causally linked, at least in part, to modulation of IL-12 and IL-10 production by histamine. We report that histamine dose-dependently inhibited the secretion of human IL-12 (p70) and increased the production of IL-10 in LPS-stimulated whole blood cultures. These effects of histamine were antagonized by cimetidine, an H2 receptor antagonist, but not by selective H1 and H3 receptor blockers, and were mimicked by an H2 receptor agonist. The effects of histamine on IL-12 and IL-10 secretion were independent of endogenous secretion of IL-10 or exogenous addition of IL-12, while Ro 20-1724, a phosphodiesterase inhibitor, potentiated the effects of histamine on IL-12 and IL-10 production, implicating cAMP in its actions. Similar modulatory effects of histamine on IL-12 and IL-10 production, which were reversed by the H2 antagonist cimetidine, were observed in PBMC and isolated monocytes stimulated by Staphylococcus aureus Cowan strain 1 and LPS, respectively. Thus, histamine, via stimulation of H2 receptors on peripheral monocytes and subsequent elevation of cAMP, suppresses IL-12 and stimulates IL-10 secretion, changes that may result in a shift of Th1/Th2 balance toward Th2-dominance. This may represent a novel mechanism by which excessive secretion of histamine potentiates Th2-mediated allergic reactions and contributes to the development of certain infections and tumors normally eliminated by Th1-dependent immune mechanisms.
authors.affiliation: Arthritis and Rheumatism Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, Bethesda, MD 20892, USA. ElenkovI@cc1.nichd.nih.gov
authors.forename: I J
authors.initials: IJ
authors.lastname: Elenkov
authors.forename: E
authors.initials: E
authors.lastname: Webster
authors.forename: D A
authors.initials: DA
authors.lastname: Papanicolaou
authors.forename: T A
authors.initials: TA
authors.lastname: Fleisher
authors.forename: G P
authors.initials: GP
authors.lastname: Chrousos
authors.forename: R L
authors.initials: RL
authors.lastname: Wilder
mesh_terms: D000328:Adult; D002478:Cells, Cultured; D002927:Cimetidine / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology; D017259:Dimaprit / Q000494:pharmacology; D004357:Drug Synergism; D005260:Female; D006632:Histamine / Q000097:blood / Q000502:physiology*; D017442:Histamine Agonists / Q000494:pharmacology; D006635:Histamine H2 Antagonists / Q000494:pharmacology; D006801:Humans; D016753:Interleukin-10 / Q000096:biosynthesis* / Q000097:blood / Q000494:pharmacology; D018664:Interleukin-12 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis* / Q000097:blood; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D011970:Receptors, Histamine H2 / Q000097:blood / Q000187:drug effects / Q000502:physiology*; D018417:Th1 Cells / Q000378:metabolism; D018418:Th2 Cells / Q000378:metabolism
chemical_list: D017442:Histamine Agonists; D006635:Histamine H2 Antagonists; D008070:Lipopolysaccharides; D011970:Receptors, Histamine H2; D016753:Interleukin-10; D018664:Interleukin-12; D002927:Cimetidine; D006632:Histamine; D000242:Cyclic AMP; D017259:Dimaprit