Patients receive anti-CD19 monoclonal antibody MOR00208 intravenously (IV) over 2 hours on day 1 (days 1, 2, 8, 15, and 22 of course 1) and lenalidomide orally (PO) daily on days 1-28 (days 9-28 of course 1). Treatment repeats every 28 days for up to 12 courses in the absence of disease progression or unacceptable toxicity.