Which clinical history findings are characteristic of X-linked severe combined immunodeficiency (XSCID)?

Updated: Aug 11, 2020
  • Author: Francisco J Hernandez-Ilizaliturri, MD; Chief Editor: Emmanuel C Besa, MD  more...
  • Print
Answer

X-linked severe combined immunodeficiency (XSCID) is by far the most common form of SCID, accounting for almost 50% of cases. [16]  As the affected gene is located in the X chromosome (X13q band), the disease is limited to males. Because of a defective common gamma chain (a component of cytokine receptors for interleukin-2 [IL-2], IL-4, IL-7, IL-9, and IL-15), signal transduction cannot proceed normally, which results in SCID characterized by absent T and NK cells and dysfunctional B cells. The phenotype is T–B+NK–.

Infections begin in the first months of life, affecting the upper and lower respiratory tracts, gastrointestinal tract, and skin, whereas X-linked agammaglobulinemia (XLA) does not manifest clinically until the second half of an infant's first year of life. Persistent opportunistic infections with Candida albicans or P jirovecii and viral infections with varicella-zoster virus, CMV, and Epstein-Barr virus are common. The risk of GVHD is high in these patients because of their inability to reject foreign antigens


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!