The Mechanism of the Creation of Immunological Diseases

J.t is well established thait both the an ti body de­ficiency and the reaction beru,een antigen and _ant.i­ hody cause many diseases Then there is antibody ·c1e­,ficiency the resulting disease is called antibody defi­ciency disease; and when the contact of antigen vih antibody produces the disease or the complex of anti­gen with antibody precipitates and causes tissue dama­ge the ,lesion is called hypersensitivity disease. These two groups 01[ diseases are coI!ectively called immuno­logic dise ses. The deficiency group is brought about by paucity or absence of B lymphocytes and T lym­phocytes. This absence is either congenital or acqui­red. The list of the diseases resulted from this de:ici­cncy is given.  The next group; the hypersensitivity diseases; are divided into four categories; according to ·the me­chanism by which arc produced.  THE FIRST TYPE; are the diseases which are produced by anaphylactic type of reaction. The best example of these arc : allergic asthma, allergic thinitis and angioneurntic edema. There is release of vasoc-tive substances from the ma;;t cells and platelet,; and this release is due to the contact of antigen with IgE which is :fixed on the surface of the target cells rspe­cial'ly the rnastocytes. These diseases can he recogni­zed by skin tests.  THF SECOND TYPE; arc the diseases resulted from cytolysis and inactivation. Cytolysis 1s exampli-:fied by red cells, white cells and pla,telets destructicn; and inactivation relates to insulip, intrinsic far.tor and coagulation factors, so by this mechanism many dis­Pases such as hemolytic anemia, thromhocytopeni:1. and leukopenia as well as diabetes mdlitus, pernici­ous anemia and coagulation defects arc produced. We can diagnose these diseases by Coombs tests and im­munofluorescent technices. THE THIRD TY.PE : is the type of diseases which arc produced by the combination o·f antigen and antibody; so called the toxic complex. This comp­lex is ,precipitated in the tissues and causes many dise­ases such as systemic lupus crythematosus, rheumatoid 2 rthritis polyarter,itis nodosa ancl glomeruloncphritis. There are diHercnt methods and tests to diagnose these diseases; namely the complement fixation te:t, the immunotluorescent tests, detection oantinuclear factors and L.E. cells as ,veil as tissue examinations.  THE FOURT,H TYPE: represents the diseases brought about by the reaction betveen sensitized lym­phocytes and the .functioning cells of all organs. These diseases are best cxamplified by autoimmune thyroi­dities, orchitis, parotitis derrnatomyositis and scelcro-­dcrma. This mechanism is be1i.eficial in the .fight o; the immune system against cancer cells. This type of reaction can be rcognized by im­munofluorcsccnt technics, tuberculin test and tissue biopsies.