Previous studies found that the p35 subunit is constitutively expressed at low levels in a broad spectrum of cells (8), whereas EBI3 is selectively produced and highly inducible, and expressed in placental trophoblasts, dendritic and plasma cells, macrophages, endothelial cells, Hodgkin, and Reed-Sternberg lymphoma cells and B cell lymphomas (26, 33–37). Here, EBI3 is linked to B-cell non-Hodgkin lymphoma.