Increased spontaneous, tumor necrosis factor receptor- and CD95 (Fas)-mediated apoptosis in cord blood T-cell subsets from Turner's syndrome.

Increased spontaneous as well as TNF-alpha-induced and CD95-mediated apoptosis were observed in CD4+ and CD8+ T cells from the cord blood of a patient with Turner's syndrome as compared to normal cord blood. Increased apoptosis was associated with an increased expression of TNFR-1, TNFR-2, and CD95L and decreased expression of cIAP1 and FLIP(L). No significant difference was observed in the expression of Bcl-2 family members (Bcl-2, Bax) between Turner's syndrome cord blood and normal cord blood lymphocytes. This study demonstrates that increased apoptosis of T-cell subsets in Turner's syndrome occurs via the death receptor pathway and may play a role in the pathogenesis of immunological defects associated with Turner's syndrome.