Postmenopausal changes in production of type 1 and type 2 cytokines and the effects of hormone replacement therapy

OBJECTIVEAn appropriate defense against infective agents or malignant cells is attributed to the exquisitely balanced T helper 1 type (cellular) and T helper 2 type (humoral) immune reactions. We investigated the effect of hormone replacement therapy (HRT) on postmenopausal changes in the production of interferon (IFN)-γ and interleukin (IL)-10, a type 1 and a type 2 cytokine, respectively. DESIGNBoth cytokines were measured by ELISA in the supernatant of lipopolysaccharide-stimulated whole blood cells from 72 untreated and 44 HRT-treated women. Thirteen women were examined before and during HRT. RESULTSThe production of IFN-γ in women in their 40s and in postmenopausal women was significantly higher compared with that of younger women. However, IFN-γ fell to the lowest level in the late postmenopausal stage, whereas the production of IL-10 increased gradually with age and in parallel with the postmenopausal period. Thus, in women in the mid-and late postmenopausal period, excessive production of type 2 cytokine (IL-10) compared with type 1 cytokine (IFN-γ) occurred. The IFN-γ levels of women on HRT were significantly lower than those of untreated women in the early and mid-postmenopausal stages, and IL-10 levels of women on HRT were significantly lower than those of untreated women in the mid-and late postmenopausal stages. HRT induced a significant decrease in the production of IL-10 and tended to lower the level of IFN-γ. CONCLUSIONSProduction of IL-10 is augmented in postmenopausal women. HRT probably prevents postmenopausal women from an aberration of the immune system by improving the balance of type 1 and type 2 immune reactions.