STAT1 is required for IFNγ-induced oxygen consumption and regulates oxygen consumption via mitochondrial complex I. (A) OCR measured by Seahorse in primary human monocytes treated with media alone or IFNγ for 24 hours prior to the start of the assay (n = 5 technical replicates). (A) Primary monocytes from 2 healthy controls and 2 STAT1 GOF patients are represented in the composite tracing from 2 independent experiments with values normalized to the unstimulated healthy control samples run in the same experiment. (B) Primary monocytes from a healthy control were stimulated with media alone or IFNγ with or without rotenone (10 μM) treatment throughout stimulation. Data are representative of 3 independent experiments and summarized in the bar graphs with basal and PMA-stimulated OCR values normalized to the healthy control unstimulated samples run in the same experiment. Basal and PMA-stimulated OCR values from respective experiments are summarized in bar graphs, and data were analyzed by 2-way ANOVA with Sidak’s multiple comparisons test. Error bars are mean ± standard error of the mean. *P < .05, **P < .01, ***P < .001, ****P < .0001.