Methodology A: CLL specific peptides: (Specific aim 1) Whole blood samples are received from healthy volunteers and newly diagnosed and untreated CLL patients according to our Helsinki permit no. 0432-13-RMC. (Rabin Medical Center) Acquisition of samples at follow up and from an additional 80 patients will be covered by additional Helsinki submissions now underway. Lymphocytes are separated using Ficoll and the B cells isolated using a B-cell isolation kit. The B-cells from the healthy volunteers and an aliquot of those isolated cells from each patient are frozen for later use (see D: below). The remaining patient cells are divided into two fractions. One is used for RNA extraction. The other is exposed to an "Absorbed" phage library pre-absorbed on normal cells. After incubation, cells are washed and phage bound to the cell membrane are eluted and recovered. Cells are then lysed and the lysate retained. Phage in the eluate and lysate (membrane-bound and internalized respectively) are amplified separately in E.coli. The amplified phage are isolated and DNA prepared for NGS. Sequencing is carried out in an external core facility (The Technion Genome Center).