HPX and B-cell chronic lymphocytic leukemia: Moreover, based on four-color confocal microscopy real-time movies, we found that upon binding of the CD37-Hx mAb to CLL cells in the presence of NHS, C3b is rapidly colocalized with cell-bound CD37-Hx mAb, and the same pattern of rapid cell killing mediated by Ca2+ influx is evident [80].