FOXN1 mutation abrogates prenatal T-cell development in humans

I Vigliano, M Gorrese, A Fusco, L Vitiello… - Journal of medical …, 2011 - jmg.bmj.com
I Vigliano, M Gorrese, A Fusco, L Vitiello, S Amorosi, L Panico, MV Ursini, G Calcagno…
Journal of medical genetics, 2011jmg.bmj.com
Background The transcription factor FOXN1 is implicated in the differentiation of thymic and
skin epithelial cells, and alterations in it are responsible for the Nude/SCID phenotype.
During a genetic counselling programme offered to couples at risk in a community where a
high frequency of mutated FOXN1 had been documented, the identification of a human
FOXN1−/− fetus gave the unique opportunity to study T cell development in utero. Results
Total blockage of CD4+ T cell maturation and severe impairment of CD8+ cells were …
Background
The transcription factor FOXN1 is implicated in the differentiation of thymic and skin epithelial cells, and alterations in it are responsible for the Nude/SCID phenotype. During a genetic counselling programme offered to couples at risk in a community where a high frequency of mutated FOXN1 had been documented, the identification of a human FOXN1−/− fetus gave the unique opportunity to study T cell development in utero.
Results
Total blockage of CD4+ T cell maturation and severe impairment of CD8+ cells were documented. Evaluation of the variable-domain β-chain (Vβ) families' usage among T lymphocytes revealed that the generation of T cell receptor (TCR) diversity occurred to some extent in the FOXN1−/− fetus, although it was impaired compared with the control. A few non-functional CD8+ cells, mostly bearing TCRγδ in the absence of CD3, were found.
Discussion
FOXN1 is crucial for in utero T cell development in humans. The identification of a limited number of CD8+ cells suggests an extrathymic origin for these cells, implying FOXN1-independent lymphopoiesis.
jmg.bmj.com