Characterizing T Cells in SCID Patients Presenting with Reactive or Residual T Lymphocytes

Table 2

Suggested immunological distinctions between SCID patients presenting with residual T lymphocytes of different origins.

Origin of patient’s cells	Allo-reactive T cells	Auto-reactive T cells	Residual T cells
SCID phenotype	Transplacentally acquired maternal lymphocytes	Omenn	MHC-II deficiency
Autoimmunity	+	+++	−
Eosinophilia	±	+	−
Lymphocyte count	Normal	Normal	Normal
Lymphocyte subset	Inconsistent, based on the TCR clonality	Inconsistent, based on the TCR clonality	Usually CD4/CD8 reverse ratio
Immunoglobulin levels	Low	Low	Low
Lymphocytes response to mitogens	Low	Low	Normal
TREC	UD	UD	Normal
TCR-V𝛽 repertoire	Skewed, restricted	Monoclonal	Polyclonal
Treg cells	High	Inconsistent	Normal

UD: undetectable, TCR: T cell receptor, TREC: TCR excision circles, Treg: regulatory T cells.