Support for PI

Learn More

Primary immunodeficiency (PI) diseases differ in many ways. Some types of PI are characterized by low levels of antibodies. Others involve defects in T cells, B cells, granulocytes or the complement system. Because of these differences, individuals with different types of PI are susceptible to different types of diseases.

Currently the World Health Organization lists over 150 different types of primary immunodeficiency.1 Different therapies are available for different types of PI. And healthy living habits can improve outcomes as well.

To learn about the most common types of PI, click the links below.

Stay Connected

Sign up for updates on news, resources, and events happening in the PI community.

Sign Up
Glossary Terms
Antibodies: A complex protein produced by the body to combat bacteria, virus, or other foreign antigens.
T cells: A white blood cell, processed in the thymus gland, which produces lymphokines and signals other lymphocytes to attack invading cells or foreign substances.
B cells: A small white blood cell, produced in the bone marrow, that develops into an antibody-producing plasma cell.
Complement System: Several interrelated proteins in the blood that work in conjunction with antibodies and are responsible for destroying bacteria, producing inflammation, and regulating immune reactions.
  1. Geha R, Notarangelo L, Casanova JL, Conley ME, Chapel ME, Fischer A, Hammerstrom L, Nonoyama S, Ochs H, Puck J, Roifman C, Seger R, Wedgwood J. Primary immunodeficiency diseases: an update from the International Union of Immunological Societies Primary Immunodeficiency Diseases Classification Committee Meeting. Journal of Allergy and Clinical Immunology 2007; 120(4):776-794.