[Perspectives on immunologic damage].

The most important steps followed by the science of Immunology since the end of last century to attain the knowledge on the subpopulations of T and B lymphocytes are summarized. General immunologists observed that the immune response could have adverse effects to the host. First, it was the observation of anaphylaxis and the reaction to tuberculin; next, the term hypersensitivity was coined and finally, four different mechanisms of the immunologic harm were characterized. Through the last years, a fifth hypersensitivity mechanism has been proposed where of the function of the cells having membrane receptors are damaged and against which, autoantibodies are formed. This autoimmune response may block or may stimulate the receptors. The author analyses the perspectives had by this mechanism of "cellular function altered by autoantibodies against membrane receptors". An important tissular damage does not exist like in the other hypersensitivity mechanisms, but there is rather a change in the biological activity of a tissue, due to the fact that several of its receptors become blocked or are stimulated.