What is the origin of 'sleep tight'?
Read moreOne of the mysteries of the English language finally explained.
A syndrome observed in laboratory animals injected as newborns with lymphoid cells from an adult individual, characterized by growth retardation and abnormalities of the liver, spleen, and lymph nodes (later recognized as a form of graft-versus-host disease).
1950s; earliest use found in Journal Cellular & Comparative Physiology.