Hormone Replacement Therapy May Be Key to Restoring Immunity in Menopausal Women

By Irene Yeh

Menopause typically occurs between the ages of 45 and 55, preceded by a 10-year-long peri-menopausal phase. Symptoms include hot flashes, joint pain, fatigue, and brain fog—all of which can have a significant impact on quality of life. To help manage symptoms, hormone replacement therapy (HRT) is often prescribed. Researchers at Queen Mary University of London have discovered another use for HRT for menopausal women: reverse changes in the immune system and potentially even boosting immunity.

Menopause can lead to increased occurrence of inflammatory diseases, including asthma, and increased risk of urinary tract infections (Aging Cell, DOI: 10.1111/acel.70249). This can lead to an increase of monocytes, immune cells that act as “first responders” to infection. The study analyzed how aging and sex difference influence monocytes, and it was found that, after menopause, women developed more monocytes.

While previous studies observed the effects monocytes have on older people’s immunity, there are limited data on the impact of age and sex on monocyte function. Additionally, there are no studies that assess how increasing age and biological sex affect monocyte phenotype and function.

Observing and Analyzing the Monocytes

The team recruited men and women 18 years and older and collected blood samples. Individuals with a recent history of neoplasia, inflammatory disorders that required immunosuppressive medications, were anemic, or had a current pregnancy were excluded. The researchers observed a significant downward shift in protein expression with age, especially when it involved metabolism, complement activation, and phagocytosis, which is when a cell engulfs and destroys another particle. These findings were validated by a significant reduction of C3, an immune protein that helps monocytes destroy harmful microbes.

When analyzing C3 in perimenopausal and menopausal women with and without HRT, it was found that there was significantly more C3 in females on HRT. With this increase in C3, this means that there were also enhanced levels of monocyte phagocytosis. This also indicates that the older perimenopausal and menopausal female participants on HRT immune systems were boosted compared to their counterparts not on HRT. Additionally, there was significant negative correlation between C3 and the age of females, but not in males, which suggests that menopause uniquely disrupts female immunity.

More Research Needed

The results do not mean that HRT should be prescribed to every woman undergoing perimenopause or menopause for immunity enhancement. There is little evidence that supports how HRT drugs could be crucial in improving the immune health of females during aging, and more research still needs to explore the full effects of HRT on the immune system. Further research also needs to be conducted on the potential for age reversing in inflammatory monocyte subsets. The team also could not determine that the individuals were at the same stage of ovarian aging. As such, in order to fully validate the effects of HRT, there needs to be a study conducted on individuals pre- and post-HRT.