After restimulation, AIRE−/− splenocytes showed significantly more CD62Llow cells than AIRE+/+ splenocytes (Fig. 4C+ B16F10) suggesting that CD4+ and to a lesser degree CD8+ T lymphocytes are activated after tumour challenge in AIRE−/− mice presumably because of less efficient thymic clonal deletion in the absence of AIRE. This evidence concerns the gene CD4 and neoplasm.