GM-CSF does not increase CD20 antigen expression on chronic lymphocytic leukemia lymphocytes

Yagci M., Akar I., Sucak G., Haznedar R.

LEUKEMIA RESEARCH, vol.29, no.7, pp.735-738, 2005 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 29 Issue: 7
  • Publication Date: 2005
  • Doi Number: 10.1016/j.leukres.2004.11.021
  • Title of Journal : LEUKEMIA RESEARCH
  • Page Numbers: pp.735-738


CD20 antigen expression in B-chronic lymphocytic leukemia (B-CLL) is at significantly lower levels than in non-Hodgkins lymphoma, which may affect the degree of anti-CD20 antibody binding. Low density of CD20 expression on malignant cells may explain the lower response rates to anti-CD20 monoclonal antibody, observed in B-CLL. Upregulating the antigen receptor intensity on tumor cells may enhance the response rates. In this study, we examined the influence of granulocyte macrophage-colony stimulating factor (GM-CSF) on the expression level of CD20 antigen and percent of cells expressing CD20 antigen on B-CLL lymphocytes, in vivo. CD20 antigen expression was studied by flow cytometry at baseline, 12 and 24 h after GM-CSF injection. However neither upregulation of CD20 antigen nor a change of the proportion of CD20 positive cells was observed after a dose of 5 mu g/kg GM-CSF. Strategies other than GM-CSF priming needs to be evaluated in order to increase the efficacy of anti-CD20 monoclonal antibodies in B-CLL. (c) 2005 Published by Elsevier Ltd.