• To evaluate whether CAMPATH-1H given to patients with CLL after maximum response to chemotherapy will: a) eliminate residual disease (documented by flow cytometry) or b) convert partial remission to complete remission [ Time Frame: Response evaluation at end of each course (4 weeks of therapy) (within 0-8 weeks). Patients followed until progressive disease is documented or death ] [ Designated as safety issue: No ]
  

• To evaluate the time-to-progression of patients according to pretreatment characteristics and response status at study entry. [ Time Frame: Response evaluation at end of each course (4 weeks of therapy) (within 0-8 weeks). Patients followed until progressive disease is documented or death. ] [ Designated as safety issue: No ]
  
• To evaluate whether CAMPATH-1H given to patients with CLL after maximum response to chemotherapy will eliminate minimal residual disease as determined by real-time quantitative PCR. [ Time Frame: Response evaluation at end of each course (4 weeks of therapy) (within 0-8 weeks). Patients followed until progressive disease is documented or death. ] [ Designated as safety issue: No ]
  

Approximately 95% of cases involve the clonal proliferation of B cells. Paraproteins, often of the IgM class, can be detected in the serum and/or urine of most patients with CLL. Unique cell surface markers are increasingly being used to diagnose the disease, and in approximately 40% of patients, cytogenetic abnormalities (for example, trisomy 12) can be found. Patients commonly present with lymphocytosis, lymphadenopathy, splenomegaly and symptoms of fatigue, weight loss, and malaise. In more advanced cases anemia and thrombocytopenia can also occur. The clinical course of CLL is unpredictable, with survival from initial diagnosis varying from 1 to 20 years (2). In addition, there is a subset of patients with indolent CLL whose absolute lymphocyte count is less than 30 x 109/L and who rarely die from the disease.

CLL is commonly staged according to the 5-point system proposed by Rai (Appendix B) and co-workers. While Rai staging is a relatively good predictor of overall survival, it cannot predict the prognosis in individual patients.