The effects of an anti-CD4 monoclonal antibody, keliximab, on peripheral blood CD4+ T-cells in asthma.

Abstract

CD4+ T-cells are likely to be involved as a source of pro-inflammatory cytokines in asthma. This study assessed the effects of an infusion of keliximab (IDEC CE9.1), an anti-CD4+ monoclonal antibody, on peripheral blood CD4+ T-cells in corticosteroid-dependent asthmatics. Three cohorts of patients (termed C0.5: n=6, C1.5: n=5, and C3.0: n=5) received a single infusion of 0.5, 1.5 or 3.0 mg x kg(-1), respectively, with a fourth receiving placebo (Cpl: n=6), and were followed-up for 4 weeks. By flow cytometry in peripheral blood, pre- and postinfusion assessment was made of: a) CD4 and CD8 counts and mean fluorescence; b) CD25, human leukocyte antigen-DR (HLA-DR), CD45RO and CD45RA expression on CD4+ T-cells; and c) interferon (IFN)-gamma, interleukin (IL)-4 and IL-5 expression in CD4+ T-cells. Keliximab's in vitro effects on allergen-specific peripheral blood mononuclear cells (PBMC) proliferation in atopic asthmatics were also evaluated. There was a significant increase in lung function (peak expiratory flow rate) in the C3.0 group. Following infusion in C0.5, C1.5 and C3.0 but not Cpl: 1) the CD4, but not CD8 count was significantly decreased; 2) there was total loss of Leu3a staining; 3) there were significant reductions in the mean fluorescence of OKT4 binding; and 4) there were significant reductions in the numbers of CD25, HLA-DR, CD45RO and CD45RA/CD4+ cells. There were no changes in CD4+ cell expression of IFN-gamma, IL-4 or IL-5. Keliximab caused a significant reduction in T-cell proliferation as compared to a control monoclonal antibody. Keliximab, as an anti-CD4 monoclonal antibody, leads to a transient reduction in the number of CD4+ T-cells and modulation of CD4+ receptor expression in severe asthmatics. The effects of keliximab may be mediated through a decrease in CD4+ surface expression and T-lymphocyte numbers, in addition to a reduction in allergen-induced proliferation.

• Authors: O M Kon, B S Sihra, L C Loh, J Barkans, C H Compton, N C Barnes, M Larché, A B Kay
• Journal: The European respiratory journal (Eur Respir J) Vol. 18 Issue 1 Pg. 45-52 (Jul 2001) ISSN: 0903-1936 [Print] England
• PMID: 11510804 (Publication Type: Clinical Trial, Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Antibodies, Monoclonal
• CD4 Antigens
• keliximab

Topics

• Adult
• Antibodies, Monoclonal (adverse effects, therapeutic use)
• Asthma (drug therapy, immunology)
• CD4 Antigens (immunology)
• CD4 Lymphocyte Count
• Cohort Studies
• Dose-Response Relationship, Drug
• Female
• Humans
• Infusions, Intravenous
• Lymphocyte Activation (drug effects, immunology)
• Male
• Respiratory Hypersensitivity (drug therapy, immunology)