Human IL-2 receptor alpha chain deficiency

Pediatr Res. 2000 Jul;48(1):6-11. doi: 10.1203/00006450-200007000-00004.


Profound cellular immunodeficiency occurs as the result of mutations in proteins involved in both the differentiation and function of mature lymphoid cells. We describe here a novel human immune aberration arising from a truncation mutation of the IL-2 receptor alpha chain (CD25), a subunit of the tripartite high-affinity receptor for IL-2. Decreased numbers of peripheral T cells displaying abnormal proliferation but normal B-cell development characterize this immunodeficiency. Extensive lymphocytic infiltration of tissues, including lung, liver, gut, and bone, is observed, accompanied by tissue atrophy and inflammation. Although mature T cells are present, the absence of CD25 does affect the differentiation of thymocytes. Although displaying normal development of CD2, CD3, CD4, and CD8 expression, CD25-deficient cortical thymocytes do not express CD1. Furthermore, they fail to down-regulate levels of bcl-2 and, subsequently, apoptosis in the thymus is markedly reduced, resulting in expansion of autoreactive clones in multiple tissues.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antigens, CD / genetics
  • Apoptosis / genetics
  • B-Lymphocytes / immunology*
  • B-Lymphocytes / pathology
  • Child, Preschool
  • Consanguinity
  • Gene Deletion
  • Humans
  • Immunologic Deficiency Syndromes / genetics*
  • Immunologic Deficiency Syndromes / immunology
  • Liver / immunology
  • Liver / pathology
  • Lung / immunology
  • Lung / pathology
  • Male
  • Molecular Sequence Data
  • Protein Subunits
  • Receptors, Interleukin-2 / deficiency*
  • Receptors, Interleukin-2 / genetics*
  • Reference Values
  • Reverse Transcriptase Polymerase Chain Reaction
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / pathology
  • Thymus Gland / cytology
  • Thymus Gland / immunology
  • Thymus Gland / pathology


  • Antigens, CD
  • Protein Subunits
  • Receptors, Interleukin-2