X0202 4 2006-01-30 0 0001130166 XCYTE THERAPIES INC XCYT 0001044321 MARXE AUSTIN W & GREENHOUSE DAVID M C/O SPECIAL SITUATIONS FUNDS 527 MADISON AVENUE, SUITE 2600 NEW YORK NY 10022 0 0 1 0 Common Stock 2006-01-30 4 P 0 10000 0.7485 A 4288088 I By Limited Partnerships This is a joint filing by Austin W. Marxe (Marxe) and David M. Greenhouse (Greenhouse). They share voting and investment control over all securities owned by Special Situations Fund III QP, L.P. (QP), Special Situations Cayman Fund, L.P. (Cayman) and Special Situations Life Sciences Fund, L.P. (LS), respectively. 2,952,923 shares of Common Stock are held by QP, 857,036 shares of Common Stock are held by Cayman and 478,129 shares of Common Stock are held by LS. The interest of Marxe and Greenhouse in the shares of Common Stock owned by QP, Cayman and LS is limited to the extent of his pecuniary interest. Austin W. Marxe 2006-02-01 David M. Greenhouse 2006-02-01