Since the early 1960's, the Committee on Primary Immunodeficiency Diseases has met every two or three years in various parts of the world to define and classify the Primary Immunodeficiency Diseases. The resulting report not only provides vital information to the medical community, but is also used by various governments to help determine health care policy.

The Jeffrey Modell Foundation, since the mid 1990's, has been honored to have been asked to help organize these meetings. The symposium in Jackson Hole, Wyoming in June was the latest in recently held meetings in Budapest, Hungary (2005) ; Sintra, Portugal (2003) ; Bristol, England; Baden Bei Wein, Austria and Lucerne, Switzerland. The next WHO/IUIS Expert Meeting is expected to be held in 2009.