Vargas-Hernandez A, et al. - In a study sample of patients with Signal Transducer and Activator of Transcription (STAT)1 gain of function (GOF) mutations, researchers assessed the function of natural Killer (NK) cell. They concluded that properly regulated STAT1 signaling is critical for NK cell maturation and function. In this patient population, modulation of elevated STAT1 phosphorylation with ruxolitinib is an important option for therapeutic intervention.