The United States Immunodeficiency Network (USIDNET), in collaboration with the Clinical Immunology Society (CIS) and The Jeffrey Modell Foundation (JMF), has undertaken an effort to track what happens to infants who are identified at birth, or shortly after, as potentially having a primary immunodeficiency. The “Following Infants with Low Lymphocytes” program, “FILL” for short, allows us to collect important and specific medical information about the first year of life for these infants.

For more information about the FILL program, visit https://usidnet.org/fill/.