DNTs predict defective Fas-mediated apoptosis. Twelve patients with Evans syndrome were screened for ALPS with DNTs by FACS and then evaluated for ALPS by in vitro testing for defective Fas-mediated apoptosis. ▪ indicates patients with defective Fas-mediated apoptosis (consistent with ALPS); □, patients with normal apoptosis (not consistent with ALPS). The ordinate depicts percentage of DNTs and the bold line the cutoff for an elevated result (2.6%; solid horizontal line). All patients except one (number 5) with elevated DNTs had defective Fas-mediated apoptosis. All patients with normal DNTs had normal apoptosis.