title: A pilot study of anti-CD5 ricin A chain immunoconjugate in systemic lupus erythematosus.
abstract: OBJECTIVE
  To determine the safety and clinical and biological effects of a murine monoclonal anti-CD5 ricin A chain immunoconjugate (CD5 Plus) in patients with systemic lupus erythematosus (SLE).
  
  
  METHODS
  An open label phase I study of CD5 Plus. A dose of 0.1 mg/kg was administered intravenously on 5 consecutive days. A second course of immunoconjugate was given to patients who failed to show any clinical response one to 2 months later.
  
  
  RESULTS
  Six patients (4 with glomerulonephritis and 2 with thrombocytopenia) were studied. Improvement was documented in 2 patients with nephritis; no effect on thrombocytopenia was observed. Adverse effects were mild and transient. Relative to pretreatment lymphocyte counts, the mean reduction in CD3+ T cell count was 69% at 2 weeks, 32% at one month, and 34% at 6 months following initial treatment. A comparable decrease in all subpopulations of mature T cells was noted, using a variety of surface markers, including CD4 and CD8. The mean percentage of T cells expressing the activation markers HLA-DR and interleukin 2R (IL-2R) was high before treatment, and remained so. There was a transient decrease in CD5+ B cells, but no persistent depletion of total B cell numbers. There was no consistent change in natural killer cell populations.
  
  
  CONCLUSIONS
  Anti-CD5 ricin A chain immunoconjugate is well tolerated in patients with SLE, causes modest T cell depletion which may persist for months, and may have some clinical efficacy in lupus nephritis.
authors.affiliation: Arthritis and Rheumatism Branch (ARB), National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health, Bethesda, MD 20892.
authors.forename: F J
authors.initials: FJ
authors.lastname: Stafford
authors.forename: T A
authors.initials: TA
authors.lastname: Fleisher
authors.forename: G
authors.initials: G
authors.lastname: Lee
authors.forename: M
authors.initials: M
authors.lastname: Brown
authors.forename: V
authors.initials: V
authors.lastname: Strand
authors.forename: H A
authors.initials: HA
authors.lastname: Austin
authors.forename: J E
authors.initials: JE
authors.lastname: Balow
authors.forename: J H
authors.initials: JH
authors.lastname: Klippel
mesh_terms: D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D015703:Antigens, CD / Q000276:immunology; D001402:B-Lymphocytes; D018956:CD5 Antigens; D005260:Female; D005434:Flow Cytometry; D005500:Follow-Up Studies; D006801:Humans; D018796:Immunoconjugates / Q000627:therapeutic use*; D000922:Immunotoxins / Q000627:therapeutic use*; D007275:Injections, Intravenous; D008181:Lupus Nephritis / Q000628:therapy*; D018655:Lymphocyte Count; D008297:Male; D010865:Pilot Projects; D010976:Platelet Count; D012276:Ricin / Q000627:therapeutic use*; D016176:T-Lymphocyte Subsets
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D018956:CD5 Antigens; D018796:Immunoconjugates; D000922:Immunotoxins; C068230:zolimomab aritox; D012276:Ricin