Immunity & Ageing：免疫系统衰老慢令女性更长寿

女性为何普遍比男性更长寿？一项最新研究成果显示，女性的免疫系统衰老速度较慢，这可能是令女性寿命更长的一大优势。

日本研究人员5月15日在英国《免疫与衰老》杂志上报告说，他们追踪了356名20岁至90岁健康男女的血液情况，特别是随着年龄增长，这些人血液中与免疫有关的白细胞和细胞因子水平的变化情况。

结果发现，虽然在衰老过程中白细胞总数都会下降，但男性白细胞中的Ｔ细胞和Ｂ细胞等淋巴细胞减少速度明显快于女性，而这两种细胞均与抵抗细菌感染有关。女性在衰老过程中，与免疫有关的细胞因子等其他几项免疫参数的表现也优于男性。

领导这项研究的日本东京医科齿科大学教授广川胜郁说，雌性激素有助于淋巴细胞的产生和调控，从而影响到免疫力，这可能是女性免疫系统衰老速度比男性更慢的原因之一。

研究人员说，女性比男性更长寿是普遍现象，曾有研究从线粒体基因差异等方面作出解释，而此次研究是首次从免疫系统角度解释这一现象。据介绍，日本女性比男性平均寿命要长将近6岁，英国两性间的平均寿命差为3岁。

Slower immune system ageing in women versus men in the Japanese population

Background Gender-related differences in humans are commonly observed in behaviour, physical activity, disease, and lifespan. However, the notion that age-related changes in the immune system differ between men and women remains controversial. To elucidate the relationship between immunological changes and lifespan, peripheral blood mononuclear cells from healthy Japanese subjects (age range: 20--90 years; N = 356) were analysed by using three-colour flow cytometry. The proliferative activities and cytokine-producing capacities of T cells in response to anti-CD3 monoclonal antibody stimulation were also assessed. Results An age-related decline in the number of T cells, certain subpopulations of T cells (including CD8+ T cells, CD4+CDRA+ T cells, and CD8+CD28+ T cells), and B cells, and in the proliferative capacity of T cells was noted. The rate of decline in these immunological parameters, except for the number of CD8+ T cells, was greater in men than in women (p < 0.05). We observed an age-related increase or increasing trend in the number of CD4+ T cells, CD4+CDRO+ T cells, and natural killer (CD56+CD16+) cells, as well as in the CD4+ T cell/CD8+ T cell ratio. The rate of increase of these immunological parameters was greater in women than in men (p < 0.05). T cell proliferation index (TCPI) was calculated from the T cell proliferative activity and the number of T cells; it showed an age-related decline that was greater in men than in women (p < 0.05). T cell immune score, which was calculated using 5 T cell parameters, also showed an age-related decline that was greater in men than in women (p < 0.05). Moreover, a trend of age-related decreases was observed in IFNgamma, IL-2, IL-6, and IL-10 production, when lymphocytes were cultured with anti-CD3 monoclonal antibody stimulation. The rate of decline in IL-6 and IL-10 production was greater in men than in women (p < 0.05). Conclusion Age-related changes in various immunological parameters differ between men and women. Our findings indicate that the slower rate of decline in these immunological parameters in women than that in men is consistent with the fact that women live longer than do men.