AI Summary
This article discusses how females, due to having two X chromosomes, have an immune system that is more effective at clearing infections and responding to vaccinations compared to males. However, females also face a higher risk of developing autoimmune diseases. Research shows that females have more CD4+ T cells, plasma cells, Treg cells, B cells, mucosa-associated invariant T cells, and naïve CD8+ T cells, while males have more monocytes, NK cells, and myeloid cells. The differences in immune responses between males and females may be linked to sex hormones, X and Y chromosomes, and immune cell composition.
In a recent review article published in the journal Nature Reviews Immunology, researchers synthesize the current knowledge on how having two X chromosomes affects the composition and function of the immune system.
Scientists have observed that female individuals can clear infection more quickly than males and have lower mortality after infection across all age groups, including infants and even before birth. They also respond more strongly to vaccination, as seen in female mice, whose immune responses persisted longer and were more resistant to viral and bacterial infections.
Review: The conneXion between sex and immune responses. Image Credit: Ustyna Shevchuk / Shutterstock
However, these advantages also come with an increased risk of developing autoimmune diseases such as systemic sclerosis (SSc), systemic lupus erythematosus (SLE), and Sjögren syndrome. Females account for 80% of autoimmune disease cases, and this proportion has increased over time. These differences could arise from sex hormone level variations, gonadal sex hormones, and the X and Y chromosomes.
Immune cell composition shows sex-based differences
Scientists used flow cytometric immunotyping to observe sex-based differences in humoral, cellular, and innate immune responses, including increases in clusters of differentiation (CD)4+ T cells in females, indicating higher thymic function.
Females also have more plasma cells, regulatory T (Treg) cells, CD19+ B cells, mucosa-associated invariant T cells, and naïve CD8+ T cells than males. However, males tend to have more CD16+ and CD14+ monocytes, natural killer (NK) cells, and myeloid cells. Differences between males and females in terms of humoral immunity include high immunoglobulin M (IgM)