Autoimmune lymphoproliferative syndrome (ALPS) is a rare disorder of the immune system caused by a mutation in the FAS gene. The objective of this study is to determine the efficacy of soquelitinib in reducing spleen volume or target lymph node volume in people with ALPS-FAS.

The purpose of this study is to evaluate whether Mozobil is safe and effective to treat neutropenia (low white blood cell count) in patients with WHIMS and to determine an appropriate treatment dose of Mozobil, within currently approved dosage levels.

The purpose of this study is to test samples from people with a Primary immunodeficiency disorders (PIDs) or people related to someone with a PID to find out what causes PIDs.

The purpose of this study is to see if a drug called empagliflozin can help people with severe congenital neutropenia (SCN).

The purpose of the protocol is to allow for patients, and relatives of patients, who may have the newly described autoimmune lymphoproliferative syndrome, to be evaluated at the NIH Clinical Center.

This study will explore the cause of immunodeficiency in common variable immunodeficiency (CVI) and other related immunodeficiency syndromes-IgA deficiency, hyper IgM syndrome, thymoma and agammaglobulinemia, hypogammaglobulinemia associated with Epstein-Barr infection, and others to better focus on how to correct the underlying defect.

The purposes of this study are to 1) identify the genes responsible for certain immune disorders, 2) learn about the medical problems they cause, and 3) learn how to predict who is likely to develop these disorders and what the risk is of passing them on to children.

The purpose of this study is to determine the biochemical and genetic causes of inherited immune diseases affecting lymphocyte homeostasis.

The purpose of this study is to improve understanding of GATA2 deficiency so there can be better diagnostic tests and treatments in the future.