Impaired CTL cytotoxicity. Cytotoxicity of d7 PHA blasts assessed by anti-CD3-mediated redirected lysis on L1210 targets from the patient and 3 controls, including both parents. The percentage of CD8⁺ T cells among PHA blasts was not determined in this particular experiment, but was similar in patient and controls in 2 other PHA cultures, which were performed for different reasons.