T cell receptor (TCR)-Vβ repertoire analysis of CD4+ T lymphocytes. Expansions of TCR-Vβ8 and TCR-Vβ22 were detected in the two older brothers affected by immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome, Y1 and Y2, respectively, reflecting the clinical picture of the two patients. All remaining TCR-Vβ were in the normal range. Grey bar: IPEX patient Y1; white bar: IPEX patient Y2; black bar: IPEX patient Y3.