List of primary immunodeficiencies

Overview of primary immunodeficiencies

Classification
External resources

Overview

Primary immunodeficiencies (PIDs) are a group of over 400 rare, chronic disorders in which part of the body's immune system is missing or functions improperly. These conditions are usually genetic and present at birth, although they may not be diagnosed until later in life. Individuals with PIDs are more susceptible to infections, autoimmune disorders, and certain types of cancer.

Classification

Primary immunodeficiencies are classified based on the part of the immune system that is affected. The main categories include:

Antibody Deficiencies

Antibody deficiencies are the most common type of PID. They involve defects in B cells, which are responsible for producing antibodies. Examples include:

• X-linked agammaglobulinemia (XLA)
• Common variable immunodeficiency (CVID)
• Selective IgA deficiency

Combined Immunodeficiencies

These involve defects in both B and T cells, leading to severe immune dysfunction. Examples include:

• Severe combined immunodeficiency (SCID)
• Wiskott-Aldrich syndrome
• Ataxia-telangiectasia

Phagocytic Cell Deficiencies

These disorders affect the ability of phagocytes to engulf and destroy pathogens. Examples include:

• Chronic granulomatous disease (CGD)
• Leukocyte adhesion deficiency

Complement Deficiencies

These involve defects in the complement system, which helps antibodies and phagocytic cells clear pathogens. Examples include:

• C1 inhibitor deficiency
• C3 deficiency

Other Well-Defined Immunodeficiency Syndromes

This category includes a variety of syndromes with specific genetic causes. Examples include:

• Hyper-IgM syndrome
• DiGeorge syndrome

Diagnosis

Diagnosis of primary immunodeficiencies typically involves a combination of clinical evaluation, family history, and laboratory tests. Common tests include:

• Complete blood count (CBC)
• Immunoglobulin levels
• Specific antibody response tests
• Genetic testing

Management

Management of PIDs often involves:

• Immunoglobulin replacement therapy
• Antibiotic prophylaxis
• Hematopoietic stem cell transplantation
• Gene therapy (in some cases)

Prognosis

The prognosis for individuals with primary immunodeficiencies varies widely depending on the specific disorder and the availability of treatment. Early diagnosis and appropriate management can significantly improve outcomes.

Related pages

• Immune system
• Autoimmune disease
• Infectious disease

Genetic Immunodeficiencies