Inhibition of histamine release from human granulocytes by ions of the rare earth elements lanthanum and cerium.

: The influence of the ATPase inhibitors, lanthanum or cerium, on histamine release in basophils and mast cells was studied. Both compounds inhibited IgE- or A23187-induced histamine release. To exclude a general inhibition of calcium-dependent reactions in the cell, we tested the influence of these compounds on phagocytosis and superoxide production of neutrophil granulocytes. Phagocytosis of Candida albicans was inhibited partially, superoxide generation, measured by the INT test after stimulation with zymosan or aggregated gamma globulin, was not affected. Because of the inhibitory effect of lanthanum or cerium compounds on membrane ATPase and immunological function of epidermal Langerhans cells we propose that these compounds may be used in the treatment of atopic eczema, where both histamine-releasing mast cells and IgE-bearing Langerhans cell play a pathogenetically important role.