Aspects of Immunology
A patient's guide to autoimmunity
|In the immune
response, there is an activation of various immune cells, which transmit
messages to each other via chemicals called cytokines. The immune
process, when directed against self, is called autoimmunity and is the
fundamental cause of most inflammatory rheumatic diseases.
In this model, foreign matter known as antigens are identified by cells called antigen presenting cells, especially macrophages, which consume these particles (A), and process them, before displaying them on their surface (B), to immune cells called lymphocytes (C). In order for these lymphocytes to be activated, the antigens must be recognized as foreign, and are presented to the lymphocyte in association with a genetic surface marker. Therefore for the reaction to take place, both a gene marker and the foreign particle are required. Genetic markers are identified in several diseases. The B27 gene n chromosome 6 is associated with Ankylosing spondylitis, and the DR4 gene has associations with Rheumatoid arthritis. The lymphocyte then makes cytokines which activate more and more lymphocytes in a progressive cascade, to multiply and spread the message. The resulting response includes the development of antibodies to the original offending agent / antigen.
Figure 1 - the immune response
this in a simple way related to a joint....
The joints are lined by a thin tissue
called the synovium. This tissue consists of millions of genetically
determined molecules in certain sequences - determined by inheritance.
For illustrative purposes, we can draw in the diagram of the joint, a
sequence of molecules in the synovium as shown in (A). This genetic
marker is an intrinsic part of the normal tissue of that
Figure 2 - Molecular mimicry and autoimmunity
|What follows is an ongoing attack on one's own tissue...in this case the joints, and the consequence is an arthritis.|
|HLA - the basics
Tumour necrosis factor
|Back to arthritis index page
Back to drdoc on-line home page