title: B cell subsets in postmenopausal women and the effect of hormone replacement therapy.
abstract: OBJECTIVE
  In elderly subjects the capacity for antibody production is depressed. This immunosenescence state of humoral immunity is associated with the occurrence of autoimmune disorders involving CD5+ B (B-1) cells. Since estrogen is capable of stimulating the production of autoantibodies, this sex steroid hormone may be a contributing cause of the higher incidence of autoimmune diseases in women. In the present study, B cell subsets in women during the postmenopausal period was determined. The effect of hormone replacement therapy (HRT) on B cell subsets was examined to establish whether the administration of gonadal hormones influence humoral immunity in postmenopausal women.
  
  
  METHODS
  Forty six untreated pre- and postmenopausal women and 39 women on HRT were studied. The proportion of B-1 (CD5+) and conventional CD5- B (B-2) lymphocytes was determined by two-color flow cytometry. Serum autoantibodies to a nuclear antigen and to interleukin (IL)-1alpha were measured by immunofluorescence and by radioimmunoassay, respectively. Thirteen women were examined prospectively before and during HRT.
  
  
  RESULTS
  In late postmenopausal women (> or = 30 years postmenopausal period), the proportion of B-2 cells was significantly reduced (p<0.01) compared to those of premenopausal and perimenopausal women. HRT induced a significant (p<0.01) increase in the percentage of B-2 cells, while that of B-1 cells remained unchanged. HRT did not affect autoantibody production.
  
  
  CONCLUSIONS
  HRT may retard the progress of immunosenescence by increasing the production of B-2 cells. Moreover, HRT appears not to increase the risk of autoimmune diseases developing in postmenopausal women.
authors.affiliation: Department of Obstetrics and Gynecology, School of Medicine, The University of Tokushima, 3-18-15 Kuramoto-cho, 770-8503, Tokushima, Japan. kamada@clin.med.tokushima-u.ac.uk
authors.forename: M
authors.initials: M
authors.lastname: Kamada
authors.forename: M
authors.initials: M
authors.lastname: Irahara
authors.forename: M
authors.initials: M
authors.lastname: Maegawa
authors.forename: T
authors.initials: T
authors.lastname: Yasui
authors.forename: S
authors.initials: S
authors.lastname: Yamano
authors.forename: M
authors.initials: M
authors.lastname: Yamada
authors.forename: M
authors.initials: M
authors.lastname: Tezuka
authors.forename: Y
authors.initials: Y
authors.lastname: Kasai
authors.forename: K
authors.initials: K
authors.lastname: Deguchi
authors.forename: Y
authors.initials: Y
authors.lastname: Ohmoto
authors.forename: T
authors.initials: T
authors.lastname: Aono
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016175:B-Lymphocyte Subsets / Q000187:drug effects*; D016022:Case-Control Studies; D004966:Estrogens, Conjugated (USP) / Q000494:pharmacology; D005260:Female; D020249:Hormone Replacement Therapy; D006801:Humans; D017258:Medroxyprogesterone Acetate / Q000494:pharmacology; D008875:Middle Aged; D017698:Postmenopause
chemical_list: D004966:Estrogens, Conjugated (USP); D017258:Medroxyprogesterone Acetate