NLRP3 and Sepsis: When sepsis evaluation is negative in a neonate with multisystem involvement, alternative considerations include monogenic autoinflammatory disease (e.g., NLRP3/NOMID, NLRC4), primary immunodeficiency, inborn errors of metabolism (Poretti et al., 2013; Schrier Vergano, 2022), and congenital leukemia (Brown et al., 2019; Brown, 2021).