Megakaryocyte/platelet CLEC-2 expression is required for a fully functional lymphatic system, according to a new study by Bénézech and colleagues.¹  The thumbs-up symbol indicates like wild-type (WT); thumbs down indicates abnormal lymph node development and blood-lymph mixing and/or immune impairment. (A more detailed model is depicted in supplemental Figure 5 of the article by Bénézech et al,¹  available on the Blood Web site.)