title: Repopulation of blood lymphocyte sub-populations in rheumatoid arthritis patients treated with the depleting humanized monoclonal antibody, CAMPATH-1H.
abstract: Patients with severe rheumatoid arthritis who had failed treatment with conventional therapies were treated with a course of five or 10 daily intravenous infusions of CAMPATH-1H, a humanized antibody against the CD52 antigen, resulting in profound depletion of peripheral blood mononuclear cells. During the subsequent 18 months, lymphocytes were analysed for sub-populations by fluorescence-activated cell sorter (FACS) and for proliferation in response to polyclonal T-cell stimulation with anti-CD3 or staphylococcal enterotoxin B (SEB). Treatment resulted in almost complete depletion of lymphocytes from the blood followed by gradual repopulation. CD16+ natural killer (NK) cells and CD14+ monocytes returned to pretreatment levels within 1-2 months. CD19+ B cells returned to within 50% of pre-treatment levels by day 66 and to within normal range by day 150, whereas CD8+ T cells recovered to 50% of pretreatment levels by day 66, but did not show any further increase during the rest of the study period. The most profound effects were on the CD4+ T lymphocyte sub-population, as the mean CD4+ count did not increase above 20% of pre-treatment level at any time during the study period (550 days), at all the doses tested. The T cells which initially repopulated the blood 1-2 months after treatment, nearly all expressed the activation markers human leucocyte antigen (HLA)-DR and CD45RO, although the percentage of T cells expressing these molecules gradually declined to normal levels over time. Proliferative responses to polyclonal T-cell stimulation (anti-CD3 and SEB) were also significantly reduced in the first few months after treatment, but recovered to pre-treatment levels by day 250. The relationship between these observations and the clinical response is discussed.
authors.affiliation: Biology Division, Wellcome Research Laboratories, Beckenham, Kent, UK.
authors.forename: S
authors.initials: S
authors.lastname: Brett
authors.forename: G
authors.initials: G
authors.lastname: Baxter
authors.forename: H
authors.initials: H
authors.lastname: Cooper
authors.forename: J M
authors.initials: JM
authors.lastname: Johnston
authors.forename: J
authors.initials: J
authors.lastname: Tite
authors.forename: N
authors.initials: N
authors.lastname: Rapson
mesh_terms: D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D015703:Antigens, CD / Q000276:immunology / Q000494:pharmacology*; D000951:Antigens, Neoplasm; D001172:Arthritis, Rheumatoid / Q000276:immunology / Q000628:therapy*; D001402:B-Lymphocytes / Q000276:immunology; D000074301:CD52 Antigen; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D006023:Glycoproteins; D006684:HLA-DR Antigens / Q000276:immunology; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology; D017493:Leukocyte Common Antigens / Q000276:immunology; D007958:Leukocyte Count; D008213:Lymphocyte Activation; D016131:Lymphocyte Subsets / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology; D013997:Time Factors
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000951:Antigens, Neoplasm; D000074301:CD52 Antigen; C000613862:CD52 protein, human; D006023:Glycoproteins; D006684:HLA-DR Antigens; D017493:Leukocyte Common Antigens