AUTOIMMUNE DISORDERS

The immune system comprises cellular, chemical and soluble protein components that collectively protect the body against foreign substances, including infectious agents and tumor cells, while avoiding responses to molecules that represent “self.” Autoimmunity arises when the immune system fails to distinguish self from non-self at the level of specific regions of cell-surface molecules or epitopes, recognized by two major immune effectors: B cells, which produce antibodies and T cells.

Autoimmune disorders encompass a heterogeneous group of conditions characterized by a dysregulated immune response in which immunological tolerance to self-antigens is lost, leading to the production of autoantibodies. 

These conditions are broadly classified into two major groups:
1. Organ-specific autoimmume diseases 
Organ-specific autoimmune diseases target defined tissues or organs. The autoantibodies, autoreactive immune cells and immune complexes involved vary according to the affected tissue. Examples: Type 1 Diabetes, Graves’ disease, Hashimoto’s thyroiditis.

2. Systemic autoimmune diseases
Systemic autoimmune diseases affect multiple tissues and physiological systems, creating widespread inflammation and activating autoreactive immune components. This chapter provides an overview of key autoimmune manifestations across different organ systems. Examples: Systemic lupuserythematosus (SLE), rheumatoid arthritis, scleroderma.

Autoimmune disorders are complex and multifactorial therefore, accurate, advanced and integrated diagnostic strategies are essential for reliable detection and clinically meaningful interpretation. 

The following are the key laboratory markers used to evaluate and diagnose autoimmune disorders:

•    Diagnosis of autoimmune disorders by ELISA