The female immune system: How is it different?

The female immune system

How is it different?

Sex chromosomes and hormones are closely linked to the immune system and its activity. The female immune system is thus considerably more active during the fertile phase of life than its male counterpart - a fact that comes with both advantages and disadvantages. Why is this the case, and what happens when the stimulating hormones withdraw?

Incessantly and mostly unnoticed, our immune system constantly fends off external substances and organisms, which is what makes us viable in the first place. A range of different immune cells such as granulocytes, macrophages, killer cells, T and B lymphocytes, as well as antibodies, inflammatory messengers and antibiotic substances play a part in this defense.

A woman's immune system functions for two

Women and men react differently to many environmental stimuli, including microbiological germs. The female immune system is more active and reacts more strongly to antigens.

This gender-specific response is due to biological tasks. The female immune system is required to function for two: It produces more antibodies during pregnancy to protect the fetus in the womb from potential infections. This protection mechanism continues to work well beyond birth. This is known as maternal passive immunity.

The second X chromosome plays a key role

The lifestyle influences the immune response as well. It does indeed appear that the sexes are becoming increasingly similar in this respect. But women are still ahead in terms of health behaviour – including the consumption of tobacco and alcohol, preventive care, body weight, diet, and stress levels.

A further key aspect is that women have two X chromosomes. These encode vital parts of the immune system. In contrast, men have one X and one Y chromosome. The latter contains only little genetic information and plays no important role in the immune system.

Stimulating estrogens, inhibiting testosterone

Sex hormones have a stimulating or inhibitory effect on the immune system: For example, female estrogens encourage the production of antibodies and boost the production of T lymphocytes, especially T helper cells (CD4 lymphocytes). In turn, these activate macrophages and antibody-forming B lymphocytes, among other things.

In contrast, female progesterone has an inhibitory effect: among other things, it stimulates the formation of anti-inflammatory Th2 cells. This also plays an important role in a healthy pregnancy. Testosterone, predominant in men but also present in women, similarly curbs the immune response, particularly the proliferation of immune cells.

The advantages and disadvantages of a stronger immune system

Whilst women are significantly less prone to complicated infections, such as COVID-19 has also shown, they are more likely to suffer from allergies and autoimmune reactions.

Bronchial asthma affects 9.9% and allergic rhinitis even 14.8% of women (men: 5.5% and 9.4% respectively).

A survey by the Central Institute for Statutory Health Insurance Physicians also found that 80% of all autoimmune diseases occur in women, including lupus erythematosus, Hashimoto's thyroiditis, and rheumatoid arthritis.

The cardiovascular system, defense against infection, hair: hormonal decline during the menopause

As a result of declining hormone levels, particularly estrogen, the female body's immune system undergoes a major change during the menopause and reduces its activity. This means that females are more prone to problems that were previously associated with men, such as cardiovascular disease, infections, and hair loss: as estrogen declines, the balance shifts in favour of testosterone, especially DHT.
If there is a corresponding genetic predisposition (around a third of women), this leads to a shortened growth phase and increased degeneration of the hair follicles. The hair becomes partially thin, dull and the scalp can become increasingly shimmering.

This often occurs diffusely across the head, particularly around the hairline and centre parting. This is where a healthy lifestyle crucial. The application of Thymuskin to the scalp is also suitable for external stimulation of the hair follicles: According to studies, the thymus peptides contained can prolong the growth phase of the hair and stimulate the development of new hair cells.