B cell subsets in postmenopausal women and the effect of hormone replacement therapy.
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.
Kamada
M
M
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
Irahara
M
M
Maegawa
M
M
Yasui
T
T
Yamano
S
S
Yamada
M
M
Tezuka
M
M
Kasai
Y
Y
Deguchi
K
K
Ohmoto
Y
Y
Aono
T
T
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
D004966:Estrogens, Conjugated (USP); D017258:Medroxyprogesterone Acetate