CHAPTER 27. DRUGS AFFECTING THE IMMUNE SYSTEM

In this Chapter:

27.1. Antiallergic drugs. Immunosuppressants

27.1.1. Antihistamines (blockers of histamine Η₁-receptors)

27.2. Immunostimulators (immunomodulators)

27.1. ANTIALLERGIC DRUGS. IMMUNOSUPPRESSANTS

Pathologically excessive immune responses to an antigen that cause damage to the tissues of a sensitized macroorganism are called allergic (hypersensitivity) reactions. Such conditions are relatively common.

Two mechanisms of immunogenesis participate in the development of different types of allergic reactions - humoral, that occurs due to antibody production, and the cellular one that involves many immunocompetent cells. Immune response is known to be formed via the interaction between phagocytes, regulatory lymphocytes (T-helpers and T-suppressors), effector lymphocytes (cytotoxic T-cells, antibody producing B-cells) and a number of other cells (including mast cells). Lymphocytes, activated by the antigen, as well as monocytes and macrophages produce biologically active peptide compounds which regulate and intensify the immune response. This group of substances is called cytokines¹. Cytokines produced by lymphocytes are often called lymphokines.

Cytokines play the most important role in the regulation of immunocompetent cell interaction and, thus, in the development of the immune response. They also have a great influence on the course of inflammatory process; they pos-

¹ The following substances are related to cytokines: interferons (α, β, γ); colony stimulating factors (granulocyte-macrophage, granulocyte, macrophage); factor influencing macrophages (migration inhibitory factor - MIF); cytotoxines (tumor necrosis factor; lymphotoxin). See also erythropoetin (Chapter 18).

sess antiproliferating, antimicrobial and antitumor properties. The main groups of cytokines are presented in the Table 27.1.