抗原誘発性Th1・Th2サイトカイン産生に対する性ホルモンの影響の性差

The incidence, severity and prognosis of asthma can be affected by a number of factors, including the patient\u27s age and sex. Clinical observations and epidemiologic studies indicate that the prevalence and severity of asthma is higher among boys than girls, but that the ratio inverts after puberty. The reversal of the male/female prevalence of asthma at puberty strongly suggests a role of sex hormones. However, the mechanisms underlying the gender differences in the prevalence of asthma are not clear. Recently, we suggested that the sex differences were due to those in not only sex hormones but also lymphocyte functions based on findings in a murine model of allergic asthma. Therefore, we investigated the effect of sex hormones on antigen-induced cytokine production by lymphocytes to further investigate these gender differences. Splenocytes from ovalbumin (OVA)-sensitized female mice produced more IL-5, Th2 cytokine, than those from OVA-sensitized male mice, upon simulation with OVA. Progesterone decreased the production of IFN-g, Th1 cytokine, by splenocytes from both sensitized male and female mice. 17β-estradiol had no effect on Th1 and Th2 cytokine production by splenocytes from both mice. However, 5a-dihydrotestosterone decreased the production of Th2 cytokines by splenoytes from sensitized female mice but not these from male mice. Our findings suggest that lymphocytes from males and females have different sensitivities to sex hormones in antigen-induced cytokine production