Table 1

Classification of severe combined immunodeficiency

SyndromeT cellsB cellsNK cellsInheritance
The hallmark of severe combined immunodeficiency is an absence of mature T cells. Further delineation is marked by the presence or absence of B and natural killer cells, inheritance pattern, and the genetic molecular defect, where known.
ADA, adenosine deaminase; BCR, B cell receptor; CγC, interleukin 2 receptor common γ chain; GvDH, graft versus host disease; IL7Rα, the α chain of the interleukin 7 receptor; JAK3, Janus associated kinase 3; MFE, maternofetal lymphoid engraftment; MHC, major histocompatibility complex; NK, natural killer; RAG, recombination activating genes; TCR, T cell receptor.
Reticular dysgenesisAR
ADA deficiencyAR
RAG 1, 2 deficiency+AR
TCR + BCR recombination gene deficiency+AR
CγC deficiency+XL
JAK3 deficiency+AR
IL7Rα deficiency++AR
Omenn's syndrome++AR
ZAP-70 kinase deficiencyCD4+++AR
CD4+ lymphopeniaCD8+++AR
MHC II deficiencyCD8+++AR
p56lck deficiencyCD8+++AR
Non-host T cells (MFE or transfusion GvHD)++/−+/−