Immune deficiency – or immunodeficiency – disorders prevent the body from fighting infections and diseases. The presence of an immunodeficiency disorder also makes it easier for viruses and bacterial infections to take place.

An immunodeficiency disorder disrupts your body’s ability to defend itself against antigens (invaders). Immunodeficiency disorders can be categorized as either congenital or acquired.

A congenital, or primary, disorder is one you were born with. Acquired, or secondary, disorders are disorders you get later in life. Acquired disorders are more common than congenital disorders.

Congenital disorders include:
• X-linked agammaglobulinaemia (XLA)
• Common variable immunodeficiency (CVID)
• Severe combined immunodeficiency (SCID) • Alymphocytosis

Acquired disorders include:
• AIDS
• Cancers of the immune system, such as leukaemia
• Immune-complex diseases, such as viral hepatitis
• Multiple myeloma

Anything that weakens the immune system can lead to a secondary immunodeficiency disorder.
For example:
• Exposure to bodily fluids infected with HIV can cause AIDS.
• Removing the spleen can weaken the immune system.
• Aging can weaken the immune system.
• An insufficient amount of protein in the diet can reduce the strength of the immune system.
• Cancers and chemotherapy drugs can also weaken the immune system.

Diseases and conditions :
The following diseases and conditions are linked to immunodeficiency disorders:
• Ataxia-telangiectasia
• Chediak-Higashi syndrome
• Combined immunodeficiency disease
• Complement deficiencies
• DiGeorge syndrome
• Hypogammaglobulinemia
• Job syndrome
• Leukocyte adhesion defects
• Panhypogammaglobulinemia
• Bruton’s disease
• Congenital agammaglobulinemia
• Selective deficiency of IgA
• Wiskott-Aldrich syndrome

Symtoms :
A symptom of a weakened immune system is frequent or chronic illnesses, including pinkeye, sinus infections, colds, or diarrhoea. Recurrent pneumonia and yeast infections could also suggest an immune disorder.