Steady-state egress of hematopoietic progenitor cells can be rapidly amplified by mobilizing agents such as AMD3100, the mechanism, however, is poorly understood. We report that AMD3100 increased the homeostatic release of the chemokine SDF-1 to the circulation in mice and non-human primates. Neutralizing antibodies against CXCR4 or SDF-1 inhibited both steady-state and AMD3100-induced SDF-1 release and reduced egress of murine progenitor cells over mature leukocytes. Intra-bone injection of biotinylated SDF-1 also enhanced release of this chemokine and murine progenitor cell mobilization. AMD3100 directly induced SDF-1 release from CXCR4+ human bone marrow osteoblasts and endothelial cells and activated uPA in a CXCR4/JNK-dependent manner. Additionally, ROS inhibition reduced AMD3100-induced SDF-1 release, activation of circulating uPA and mobilization of progenitor cells. Norepinephrine treatment, mimicking acute stress, rapidly increased SDF-1 release and progenitor cell mobilization, while β2-adrenergic antagonist inhibited both steady-state and AMD3100-induced SDF-1 release and progenitor cell mobilization in mice. In conclusion, this study reveals that SDF-1 release from bone marrow stromal cells to the circulation emerges as a pivotal mechanism essential for steady state egress and rapid mobilization of hematopoietic progenitor cells, but not mature leukocytes.

Despite heterogeneous eligibility criteria and study designs across the five studies and different modified JIA ACR30 criteria, this meta-analysis of short-term RCTs presents empirical evidence that canakinumab and tocilizumab are more effective than rilonacept. Biologic agents in sJIA seem safe and comparable with respect to SAE risk in the short term.

Introduction: On April 13, 2017, a bill to legalize cannabis was introduced to the Canadian Parliament and presented to the public. On October 17, 2018, Canada legalized recreational cannabis use. We assessed intoxication severity, reflected by ICU admission rates, risk factors and other characteristics in children who presented to the emergency department (ED) with cannabis intoxication, before and after legalization. Methods: A retrospective cohort study of children 0-18 years who presented to a pediatric ED