title: New insights in the management of patients with hairy cell leukemia.
abstract: OBJECTIVE
  Although hairy cell leukemia (HCL) was identified in 1958 by Bouroncle and colleagues, HCL remains in 2015 a mysterious disease. Accurate diagnosis of HCL relies on the recognition of hairy cells by morphology and flow cytometry in blood and/or bone marrow. However, there are cases difficult to diagnose, particularly in variants of HCL. Furthermore, some diseases such as splenic diffuse red pulp small B-cell lymphoma are very close to HCL and may be misdiagnosed. Major advances in the management of patients who have HCL have been made following the use of purine nucleoside analogs. However, new treatment options can be available in relapsed/refractory HCL: monoclonal antibody therapy, BRAF inhibitors, or immunotoxins.
  
  
  RESULTS
  The presence of the BRAFV600E mutation was recently identified in most cases of HCL and its absence in variants of HCL and in other B-cell chronic lymphoproliferative disorders. The precise cellular origin of HCL remains elusive but BRAF mutations were detected in hematopoietic stem cells of patients with HCL. Assessment for minimal residual disease is important in clinical trials. Minimal residual disease detection can clearly predict inferior long-term outcomes or early relapses in patients with HCL. Recent reports have shown that inhibition of BRAF kinase by drugs such as vemurafenib is effective in relapsed/refractory HCL. Immunotoxins offer new opportunities even in patients without BRAF mutations.
  
  
  CONCLUSIONS
  All these findings have major implications for diagnosis, monitoring, and treatment of HCL and variant forms of HCL.
authors.affiliation: aLaboratoire Hématologie bService Hématologie Clinique, CHU Côte de Nacre, Caen, France.
authors.forename: Edouard
authors.initials: E
authors.lastname: Cornet
authors.forename: Gandhi
authors.initials: G
authors.lastname: Damaj
authors.forename: Xavier
authors.initials: X
authors.lastname: Troussard
mesh_terms: D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001402:B-Lymphocytes; D018572:Disease-Free Survival; D006801:Humans; D000922:Immunotoxins / Q000627:therapeutic use*; D007211:Indoles / Q000627:therapeutic use*; D007943:Leukemia, Hairy Cell / Q000175:diagnosis / Q000188:drug therapy* / Q000235:genetics; D009154:Mutation; D048493:Proto-Oncogene Proteins B-raf / Q000037:antagonists & inhibitors*; D011687:Purines / Q000627:therapeutic use*; D012008:Recurrence; D013156:Splenectomy; D013160:Splenic Neoplasms / Q000175:diagnosis / Q000188:drug therapy* / Q000235:genetics; D013449:Sulfonamides / Q000627:therapeutic use*; D000077484:Vemurafenib
chemical_list: D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D000922:Immunotoxins; D007211:Indoles; D011687:Purines; D013449:Sulfonamides; D000077484:Vemurafenib; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; C030985:purine