The Impact of Sex on Immune Defense and Disease Risk: Unveiling the Unseen Battle.
When a disease affects individuals, from the most common childhood asthma in children to the prevalence of lupus in women, biology has a lot to say. Scientists have gathered compelling evidence explaining why our defenses act – and fail – differently depending on whether we are XX or XY.
Genes and chromosomes: the origin of the difference
In each cell, genes and chromosomes mark the starting point. Women, with two X chromosomes, have a broader immune repertoire: the X chromosome harbors numerous genes related to the defensive response, and having two copies can intensify certain reactions. However, hormonal changes can also play a role, favoring the development of autoimmune diseases such as multiple sclerosis or Sjögren’s syndrome.
Furthermore, cells do not always activate the same X chromosome. This phenomenon creates a mosaic of cells with different immune behaviors in the same organ, increasing versatility against infections like COVID-19.
Hormones and tissues: signals that change the strategy
Beyond their reproductive role, hormones modify the gene expression of immune cells. This means that two cells of the same type can behave differently.
Tissues also show different vulnerabilities: the lungs and the brain, for example, seem to be particularly affected. This partly explains why Parkinson’s is more common in men and Alzheimer’s in women.
Personalized medicine: the future ahead
Understanding how sex influences immunity paves the way for more precise treatments, especially in cancer and immunotherapy. According to researcher Sonia Sharma, “a one-size-fits-all medical strategy does not work for everyone,” and tailoring treatments based on sex differences could significantly improve outcomes.
Environmental factors such as nutrition, chemical exposure, and differences in the skin and gut microbiome add another layer of complexity. The challenge, scientists say, is to integrate all these aspects to design therapies that work better for each case.
