title: Changes in peripheral blood mononuclear cell subpopulations during antithymocyte globulin therapy for severe aplastic anemia.
abstract: The short-term effect of a domestically produced equine antithymocyte globulin (ATG) was analyzed in 6 patients with acquired severe aplastic anemia (AA). All patients received 5 doses of ATG every other day in a 60-min intravenous infusion. Five peripheral blood immunoregulatory mononuclear cell (MNC) subsets, defined by monoclonal antibodies, were enumerated before and 24 h after each application of ATG. Following the first dose of ATG there was a significant and transient reduction in the absolute number of helper T lymphocytes. There was no statistically significant difference pre-ATG to post-ATG in the absolute number of MNC expressing activation antigen Tac (interleukin-2 receptor). However, Tac+ cells, which were significantly increased before ATG therapy, decreased to nearly normal levels after the fourth dose of ATG. A significant and sustained increment in the absolute number of monocytes (CD14+ cells) occurred following the third dose of ATG. The absolute numbers of MNC, suppressor T lymphocytes and cells bearing HLA-DR antigen remain without significant change along ATG treatment. These results suggest that: (a) Tac+ cells are probably involved in the pathogenesis of AA; (b) the target of ATG may be a Tac+ cell, and (c) ATG may stimulate monopoiesis.
authors.affiliation: Departamento de Hematologia, Instituto Nacional de la Nutrición Salvador Zubirán, México.
authors.forename: X
authors.initials: X
authors.lastname: López-Karpovitch
authors.forename: M E
authors.initials: ME
authors.lastname: Zarzosa
authors.forename: M R
authors.initials: MR
authors.lastname: Cárdenas
authors.forename: J
authors.initials: J
authors.lastname: Piedras
mesh_terms: D000208:Acute Disease; D000741:Anemia, Aplastic / Q000097:blood* / Q000628:therapy; D000911:Antibodies, Monoclonal; D000961:Antilymphocyte Serum / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D006801:Humans; D007958:Leukocyte Count / Q000187:drug effects; D007963:Leukocytes, Mononuclear / Q000145:classification* / Q000187:drug effects / Q000276:immunology; D010641:Phenotype; D013601:T-Lymphocytes / Q000276:immunology*; D013997:Time Factors
chemical_list: D000911:Antibodies, Monoclonal; D000961:Antilymphocyte Serum