Newresearch on mice has found a possible explanation for why autoimmune diseases are more common in females, and it has to do with their extra X chromosome.

　　对老鼠进行的一项新研究或许解释了自身免疫性疾病在女性中更常见的原因，而这可能与她们的另一条X染色体有关。

　　Amongst animals, females generally tend to have stronger and morerobustimmune systems. While this can help them to cope better with vaccines and infections, it can also cause an overactive immune response.

　　在动物中，雌性往往有更强大的免疫系统。虽然这可以帮助她们更好地应对疫苗和感染，但也可能会导致过度的免疫反应。

　　This means females are much more vulnerable to autoimmune diseases. In fact, women are two to three times more likely than males to develop multiple sclerosis (MS), and nine times more likely to develop lupus.

　　这意味着女性更容易患上自身免疫性疾病。事实上，女性患多发性硬化症的概率是男性的两到三倍，而患狼疮的概率是男性的九倍。

　　Exactly why this discrepancy exists remains a mystery. Clear biological differences between the sexes usually boil down to hormones, chromosomes, or some combination of both. But while the role of testosterone, estrogen and progesterone in autoimmunity have been reasonably well explored, the part that X and Y chromosomes play remains far more murky.

　　存在这种差异的确切原因仍然是个谜。两性之间明显的生物学差异通常可归结为荷尔蒙、染色体或两者的某种结合。虽然人们已经对睾酮、雌激素和黄体酮在自身免疫中的作用进行了适度的探索，但X染色体和Y染色体的作用依然不明。

　　This is quite the oversight, considering that X chromosomes carry several immune-related genes, and females have two of them, one from the mother and one from the father. In comparison, males just have one X chromosome, from their mother.

　　考虑到X染色体携带有与免疫相关的基因，而女性有两条分别来自母亲和父亲的X染色体，而男性只有一条来自母亲的X染色体，这是一个相当大的疏忽。

　　Based on their work in mouse models, researchers from the University of California Los Angeles (UCLA) now think this extra X chromosome females get from the father brings a significant contribution to autoimmune issues.

　　如今加州大学洛杉矶分校的研究人员基于对小鼠的研究，认为女性从父亲那里获得的另外一条X染色体会对其自身免疫问题产生重要影响。