Invetigators set up at the University Hospital of Rennes, a database of more than 300 patients with LGL leukemia from major French services that support this disease, and published in 2010 the largest series of patients in the world (n = 229). However, the limited heterogeneity and retrospective data collected, as all previously released, makes it difficult the proposal of consensual treatment options. Combining the results of our series with those of the literature, invetigators estimate that overall response rate and complete response rate are 55% and 30% with methotrexate, 60% and 50% with cyclophosphamide, and 55% and less than 20% with ciclosporine A, respectively.