Angiogenic responses of CAM to CM derived from CLL cells.

(A) Representative angiogenic response and its inhibition by a blocking anti-hVEGF mAb. The white area represents the site of application of filters containing either CM (collected from the PMA-stimulated cells) alone (i) or the same CM preincubated with anti-hVEGF MoAb for 2 hours at RT (ii). Microvessels radiating from the site of sample application in (i) are not formed in the presence of the blocking mAb (ii). (Original magnification, × 8.) (B) The semiquantitative data obtained by using rhVEGF and CM collected from PMA-stimulated cells from 2 patients. The grading of the angiogenic response is described in “Materials and methods.” *P < .05 vs control andP < .05 vs sample without the neutralizing antibody (Mann-Whitney U test). Each bar represents the score of 10 CAM used in 2 separate assays with similar results.