Cytokine production by CARD9-deficient leukocytes and by the patient’s CD34⁺ hematopoietic stem cells following CARD9 transduction. Leukocytes from the patient and a control subject were incubated overnight with the indicated stimuli. Culture supernatants were collected and the concentrations of IL-6 and IL-1β by (A-B) PBMCs or (D) IL-8 by neutrophils were assessed by ELISA. To examine the effect of mutated CARD9 on cytokine production, a human wild-type CARD9 complementary DNA (cDNA) was cloned into a lentiviral expression vector. (C) Following transduction, macrophage-CSF–cultured BM-derived monocytic cells of the patient and healthy controls were stimulated with C albicans or S aureus, and the production of IL-6 was assessed by ELISA. Results represent 2 experiments in triplicate from different BM aspirates of the patient and from healthy controls. Results are means ± SEM of measurement from 4 to 6 independent experiments; *P < .01; **P < .001.