Impaired IFN-α and IL-27 response in a STAT1-deficient patient. (A-B) PBMCs and NK cells from the patient and a healthy subject were stimulated in vitro for 24 hours with increasing amounts of IFN-α (1, 5, 100, 1000, 5000, 10 000, and 100 000 U/mL). Target gene expression was normalized against the housekeeping gene (β-2-microglobulin and GAPDH for PBMC and NK cells, respectively) and presented as n-fold increase over the expression in unstimulated cells from the healthy control. The experiments shown are representative of 4 independent experiments. Data are mean ± SE. *Significant difference in the response between the patient and control subject (P < .05). (C) PHA-T (2 × 10⁶/mL) were stimulated with IL-12 (200 ng/mL) or IFN-α (10⁴ U/mL) in the presence or the absence of anti-CD3 mAb (5 μg/mL) or with a combination of anti-CD3 and anti-CD28 mAb (5 μg/mL) for 24 hours in RPMI 1640 supplemented with IL-2 (1200 U/mL). Supernatants were collected after stimulation, and IFN-γ levels were evaluated by ELISA. (D) PBMCs from the patient and a healthy subject stimulated in vitro for 24 hours with IFN-α (10⁴ U/mL). Target gene expression was normalized to the housekeeping gene (β2M) expression and presented as n-fold of the expression in unstimulated cells from the healthy control. The experiments shown are representative of 4 independent experiments. Data are mean ± SE. *Significant difference in the response between the patient and control subject (P < .05). (E) NK cells from the patient and a healthy subject were cultured without IL-2 for 16 hours and then stimulated in vitro with the indicated doses of IL-27 for 24 hours. Target gene expression was normalized against the housekeeping gene (GAPDH) and presented as n-fold increase over the expression in unstimulated cells from the healthy control subject. The experiments shown are representative of 4 independent experiments. Data are mean ± SE. *Significant difference in the response between the patient and control subject (P < .05).