AUTOIMMUNITY

INTRODUCTION: The purpose of the immunological response is to protect the host and to discriminate between what is self and what is non-self for the host. The primary means by which the immune system recognises foreign antigens is through comparison with self major histocompatibility complex (MHC) determinants. Therefore, MHC serves as a yardstick against which foreign determinants can be measured. This implies that a mechanism exists in the host which can recognise its own self-antigens. At the same time mounting an immune response against self-antigens shall be devastating.

ORIGIN OF AUTOIMMUNITY: Recognition of self-determinants is normal and occurs during the generation of nearly all immune responses, whereas immunologic reactivity against self determinants can lead to autoimmune disease. The emergence of autoimmune disease is postulated to be due to mutation of a non-self reactive lymphocyte into self-reactive one, the activation of previous tolerant helper T cell or the inhibition of suppressor T cells.

CRITERIA FOR AUTOIMMUNE DISEASE: The disease must fulfil following criteria before it can be called as autoimmune disease.

a) The autoimmune response must be regularly associated with the disease.

b) A replica of the disease must be inducible in laboratory animals.

c) Immunopathologic changes in the natural and experimental diseases should parallel each other.

d) Transfer of autoimmune illness should be possible by the transfer of serum or lymphoid cells from the diseased individual to a normal recipient.

RELATIONSHIP OF HLA TYPES AND AUTOIMMUNE DISEASES: On the basis of various studies in animals, it has been shown that a relationship exists between MHC and autoimmune diseases. A link between HLA types and autoimmune diseases has been suggested by studies in families and population with disease vis a vis normal healthy subjects.

RELATED;

1. THE MAJOR HISTOCOMPATIBILITY COMPLEX

2. THE HUMAN LEUKOCYTE ANTIGEN

3. AUTOIMMUNE DISEASES

4.  ADAPTIVE IMMUNITY

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