Modulation of CD20 antigen expression after rituximab treatment: A retrospective study in patients with chronic lymphocytic leukemia

Fiorella D'Auria, Roberto Guariglia, Oreste Villani, Giovanna Mansueto, Vitina Grieco, Antonia Zonno, Gabriella Bianchino, Luigina Di Giovannantonio, Giulia Vita, Pellegrino Musto

Research output: Contribution to journalArticlepeer-review


Background: CD20 antigen down-modulation by anti-CD20 rituximab treatment is a well-recognized phenomenon in patients with non-Hodgkin's lymphoma. However, few data are currently available on this topic in other lymphoproliferative disorders, in particular in chronic lymphocytic leukemia (CLL).Objective: The aim of this study was to establish how many patients with CLL show a disappearance of CD20 antigen after salvage treatment with rituximab and its possible clinical significance.Methods: We sequentially analyzed CD20 expression by flow cytometry in patients treated with rituximab in combination with other agents for relapsed/resistant disease.Results: Eleven white patients with CLL (6 females, 5 males; median age, 71.6 years [range, 60-84 years]) were included in the study. Three of the 11 patients were not positive for CD20 due to complete response at baseline. Four of the remaining 8 patients (50%) lacked CD20 antigen on neoplastic cells after monoclonal antibody treatment. Two of them developed Richter's syndrome and died within 4 months. The phenomenon was transient in the other 2 patients, who were alive after a follow-up of 25 and 26 months, respectively, with CD20-positive recurrent disease.Conclusions: In this study, CD20 antigen disappearance in patients with CLL treated with rituximab-containing salvage regimens occurred in 4 of 8 (50%) tested patients, half of whom developed Richter's syndrome. [Note: Since the initial writing and submission, a third patient developed Richter's syndrome.] In 2 patients (50%), CD20 returned at progression.

Original languageEnglish
Pages (from-to)1911-1916
Number of pages6
JournalClinical Therapeutics
Issue number11
Publication statusPublished - Oct 2010


  • CD20 expression
  • Chronic lymphocytic leukemia
  • Non-Hodgkin's lymphoma
  • Rituximab

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)


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