The purpose of this study is to determine the activity of anti-Tac(Fv)-PE38 (LMB- 2) in patients with Tac-expressing Chronic Lymphocytic Leukemia (CLL). The primary endpoint of this trial is response rate. We will also evaluate response duration, LMB-2 immunogenicity, pharmacokinetics, toxicity, and monitor soluble Tac levels in the serum.