FILL Program

FILL Program

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.

The FILL program’s online space allows for both patients and physicians to take action.


Clinical Immunology Society

Jeffrey Modell Foundation

Immune Deficiency Foundation

FILL Program Statistics


Patient Participation

For parents who would like to enroll their infants in the FILL project but do not have access to a USIDNET enrolling center, you can use this website to enroll your child through an IRB-approved online consent form. The USIDNET team will take care of the rest!

Would you like to enroll your child in the FILL Program?

Click Here if you are a parent

Enrollment Centers & Physicians

Physicians at active USIDNET enrolling centers can enter their FILL-related data on consented patients using a streamlined, targeted data entry form. You can use your USIDNET username and password to access your FILL patients and enter and update their data right from this website.

Click Here if you are a physician with FILL data to enter