New clues on menopause and the immune system
Menopause is more than hot flashes and sleep disruption. A groundbreaking study from Queen Mary University of London suggests that menopause can fundamentally alter the immune system, increasing vulnerability to infections. The research, published in Aging Cell, focuses on how ageing and sex differences shape a key group of immune cells called monocytes, which act as first responders to invading microbes.
Monocytes and the ageing immune system
Monocytes are white blood cells that help the body detect and clear bacteria. In the study, researchers compared blood samples from younger adults (under 40) with older adults (65 and above). They observed that after menopause, women tend to develop more inflammatory monocytes. These cells, while important in fighting pathogens, can become less effective at clearing bacteria when driven by chronic inflammation.
The team found a striking link between these changes and lower levels of complement C3, a protein that supports monocytes in engulfing and destroying harmful microbes. Notably, men of the same age did not show the same immune shifts, indicating that menopause exerts a uniquely disruptive effect on female immunity.
Could hormone therapy restore immune health?
To explore whether hormone replacement therapy (HRT) might influence this immune decline, the researchers examined peri- and post-menopausal women using HRT. The results were encouraging: women taking HRT exhibited healthier immune profiles, characterized by fewer inflammatory monocytes and a stronger capacity to fight infections. Their complement C3 levels were higher than those of age-matched controls, bringing their immune status closer to that of younger women.
Dr. Emma Chambers, the senior author and immunology expert at Queen Mary University, commented that menopause represents a crucial turning point for women’s immune health. “Our findings suggest that losing female hormones accelerates immune decline, but hormone therapy may help restore key aspects of immune function,” she said.
Implications for women and healthcare
The potential immune benefits of HRT add to its established role in managing menopausal symptoms. With millions of women in the UK entering or already in menopause, the study’s implications extend beyond personal health to workplace and community well-being. Fiona Miller Smith of Barts Charity highlighted the broader impact, noting that funding innovative health research can illuminate how menopause affects women in daily life and society at large.
What remains unknown and next steps
Despite the promising findings, experts caution that more work is needed before HRT can be routinely prescribed for immune health alone. Key questions remain about whether HRT reduces real-world infection rates and how different formulations, routes of administration, and treatment durations influence immune outcomes. The researchers emphasize the need for larger, long-term studies to confirm these associations and to determine which patients might benefit most from HRT as an immune-support strategy.
Context and takeaways for readers
Menopause can trigger meaningful changes in immunity, and HRT offers a potential path to mitigating infection risk in later life. While the study opens exciting possibilities, decisions about HRT should be made in consultation with healthcare providers, considering individual risk factors and treatment goals.
Study details and funding
The Aging Cell study was led by researchers at Queen Mary University of London and funded by Barts Charity and the Vivensa Foundation. The findings reinforce the importance of exploring sex-specific aging processes and how therapies like HRT might support immune health beyond symptom management.
