Immunomodulation by histamine.

Blood histamine proved to be important for the immune homeostasis. By its direct action or by means of H-2 receptors it end or prevents the excessive immune response. Recent studies revealed changes in cell mediated immunity in subjects with atopia, with increased histaminemia and their obvious protection against cancer. In patients with cancer, hypogammaglobulinemia, AIDS, the depression of the immune responses was partly accounted for by the decrease of blood histamine and by the change of the number of H-2 receptors. Hence the attempt to treat these diseases with H-2 antagonists associated or not with histamine.