Interleukin-21 enhances rituximab activity in a cynomolgus monkey model of B cell depletion and in mouse B cell lymphoma models. oleh Cecile M Krejsa, Rick D Holly, Mark Heipel, Ken M Bannink, Rebecca Johnson, Richard Roque, Jane Heffernan, Julie Hill, Lay Chin, Felecia Wagener, Faith Shiota, Katherine Henderson, Pallavur V Sivakumar, Hong-Ping Ren, Fariba Barahmand-Pour, Don Foster, Chris Clegg, Wayne Kindsvogel, Rafael Ponce, Steven D Hughes, Kim Waggie