Primary immunodeficiency disease

Primary immunodeficiency disease (PIDD), also known as primary immune disorder or primary immunodeficiency, is a group of more than 400 rare, chronic disorders in which part of the body's immune system is missing or functions improperly.

Overview

PIDDs are present at birth, although symptoms may not appear until later in life. They are caused by genetic defects that disrupt the normal development and function of the immune system. This can lead to an increased susceptibility to infection, autoimmune disease, and malignancy.

Types

There are several types of PIDDs, each affecting a different part of the immune system. These include:

• B cell (antibody) deficiencies: The most common type of PIDD, these deficiencies occur when the body does not produce enough antibodies to fight off infection.
• T cell deficiencies: These deficiencies occur when the body does not produce enough T cells, which are responsible for recognizing and killing infected cells.
• Combined immunodeficiencies: These occur when both B and T cells are affected.
• Phagocytic function deficiencies: These occur when the body's phagocytes (cells that ingest bacteria) do not function properly.
• Complement deficiencies: These occur when the body's complement system (a part of the immune system that enhances the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism) does not function properly.

Diagnosis

Diagnosis of PIDDs typically involves a series of tests to evaluate the function of the immune system. These may include blood tests, genetic testing, and immunological tests.

Treatment

Treatment for PIDDs depends on the specific type and severity of the disorder. It may include antibiotic therapy to prevent and treat infections, immunoglobulin therapy to replace missing or non-functioning antibodies, and in severe cases, stem cell transplantation.

See also

• Secondary immunodeficiency
• Autoimmune disease
• Immunology