title: B lymphocyte-typing for prediction of clinical response to rituximab.
abstract: BACKGROUND
  The prediction of therapeutic response to rituximab in rheumatoid arthritis is desirable. We evaluated whether analysis of B lymphocyte subsets by flow cytometry would be useful to identify non-responders to rituximab ahead of time.
  
  
  METHODS
  Fifty-two patients with active rheumatoid arthritis despite therapy with TNF-inhibitors were included in the national rituximab registry. DAS28 was determined before and 24 weeks after rituximab application. B cell subsets were analyzed by high-sensitive flow cytometry before and 2 weeks after rituximab administration. Complete depletion of B cells was defined as CD19-values below 0.0001 x10⁹ cells/liter.
  
  
  RESULTS
  At 6 months 19 patients had a good (37%), 23 a moderate (44%) and 10 (19%) had no EULAR-response. The extent of B lymphocyte depletion in peripheral blood did not predict the success of rituximab therapy. Incomplete depletion was found at almost the same frequency in EULAR responders and non-responders. In comparison to healthy controls, non-responders had elevated baseline CD95⁺ pre-switch B cells, whereas responders had a lower frequency of plasmablasts.
  
  
  CONCLUSIONS
  The baseline enumeration of B lymphocyte subsets is still of limited clinical value for the prediction of response to anti-CD20 therapy. However, differences at the level of CD95⁺ pre switch B cells or plasmablasts were noticed with regard to treatment response. The criterion of complete depletion of peripheral B cells after rituximab administration did not predict the success of this therapy in rheumatoid arthritis.
authors: Hans-Peter
authors: HP
authors: Brezinschek
authors: Franz
authors: F
authors: Rainer
authors: Kerstin
authors: K
authors: Brickmann
authors: Winfried B
authors: WB
authors: Graninger
mesh_terms: D058846:Antibodies, Monoclonal, Murine-Derived / Q000494:pharmacology / Q000627:therapeutic use*; D018501:Antirheumatic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000175:diagnosis / Q000188:drug therapy*; D001402:B-Lymphocytes / Q000187:drug effects* / Q000378:metabolism*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012042:Registries; D000069283:Rituximab; D016896:Treatment Outcome
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D018501:Antirheumatic Agents; D000069283:Rituximab