Animals.

LXR-deficient (Nhr1h3^−/− Nhr1h2^−/−) (LXR-DKO) mice on a mixed Sv129/C57BL/6 background were originally provided by David Mangelsdorf (University of Texas Southwestern) (51), and CD38-deficient mice (N-B6.129P2-Cd38 tm1Lnd) had been backcrossed to the C57BL/6 background for more than 10 generations. All mice were maintained under pathogen-free conditions in a temperature-controlled room and with a 12-h light-dark cycle in the animal facilities of the Universidad de Las Palmas de Gran Canaria (ULPGC) and Nationwide Children's Hospital (NCH)/Ohio State University (OSU). All animal studies were conducted in accordance with institutional participants' animal ethics research committees. WT and CD38-deficient mice (n = 5 per group) were euthanized, and blood was collected by cardiac puncture and stored in EDTA-coated tubes. Leukocyte counts were determined by using an Abacus JuniorVet hematologic counter (Diatron).