This article is from the WeChat public account: Nutshell (ID: Guokr42) , author: famfamfam, Barley, FIG question: IC Photo
In the statistics of cases of new coronary pneumonia, there are often more male patients than female patients. On March 3, a team from the People’s Hospital of Wuhan University published a study on the preprinted platform SSRN to sort out the gender differences among infected people.
So, does the virus really favor men?
What the research says
Researchers analyzed data from 6013 cases from January 1st to 29th, and found that 55.9% of patients were male; Of the patients entering the intensive care unit, 58.8% were male. In other words, men are not only more susceptible to the new crown virus, they also seem to have more severe symptoms. This conclusion is also consistent with previous research.
Among them, 425 data were divided into three groups according to time. Researchers found that before January 1, January 1 to January 11, and January 12 to January 22, men The proportion of patients was 66.0%, 59.3%, and 47.7%, showing a downward trend.
Then they analyzed their hospital (Wuhan University People’s Hospital) . They divided male and female patients into three groups according to the degree of symptoms. It was found that 11.8% of male patients were critically ill, while 7% of female patients were critically severe. In other words, it appears that men’s illnesses are generally more severe.
In addition, of the 67 asymptomatic infections confirmed in their hospital, 47 were women.
Investigators speculate that the gender difference in infected people may not be because the virus prefers to infect men, but because men and women have different resistances to the virus. In other words, the number of men and women infected with the new crown virus may be flat; however, women are more resistant, their immune systems are better able to kill the virus, or patients are less likely to show symptoms. Therefore, women infected with the virus may have a longer incubation period, may have relatively mild symptoms, and may be relatively undetected because of mild or no symptoms.
Note that this article has not been peer reviewed and has not been formally published. The statement that women have a longer incubation period is only inferred from the change in the infection rate between men and women. To really make a conclusion, more data is needed.
The researchers concluded that “women play an important role in the spread of new coronary pneumonia.” They called for different control measures for women on a global scale, such as nucleic acid testing of women with a clear history of exposure, and medical observation of women whose isolation period should exceed 14 days.
However, if men and women have different resistances to the new crown virus, it is not unique to this virus.
New crown virus under electron microscope | NIAID RML / NIH
Men and women are inherently different in the face of viruses
Actually, men and women are inherently different when it comes to viruses.
Usually, under the premise of similar exposure to the virus, men are more likely to develop infections and the degree of infection is higher. High) ; and if the virus infections are similar, women’s symptoms may be worse and their prognosis worse.
Women have a higher level of immune response than men, both non-specific and specific immunity. High levels of immune response allow women to clear the virus faster, but they are also more prone to excessive immune responses. After vaccinating against viral infections, women often produce higher levels of antibodies and more serious adverse reactions. Decreased viral load, pharmacokinetics, and adverse reactions during treatment with antiviral drugs are also gender-related.
Specifically, the gender differences in immune response include the following aspects:
1. Non-specific immune aspects
Non-specific immunity, also known as “native immunity”, is the body’s own immune capabilities. This immune response is rapid, but it does not provide lasting protection. Non-specific immune response levels are higher in women than in men.
Many natural immune-related cells in women Sexual immune response levels are generally better than menSex is higher.
Women’s pathogen recognition and immune mechanism are stronger than men’s, and pattern recognition receptors (PRR) The process of detecting pathogenic microorganisms has gender difference.
Advanced knowledge: what is PRR?
Pattern recognition receptors (PRR) is a class of immune receptors, which are mainly expressed on the surface of the body’s natural immune cells, and can recognize pathogens. Related pattern molecules (PAMP) .
Pattern recognition receptors play an important role in the viral infection itself and its inflammatory response. Its functions include (but not limited to) identify various pathogens, cause rapid immune response, start cell activation and inflammatory signal transduction, and so on.
Pathogen-associated model molecules (PMAP) are a class of molecules not found in the human body. They exist on the surface of pathogenic microorganisms, have a constant structure, and are evolutionarily conservative. Includes products of viruses, components of bacterial cell walls, and more. Many different microorganisms share the same PAMP, so the human immune system learns to recognize PAMP as a signal of pathogen invasion.
The mutual recognition and role of PRR and PAMP is the key to start the natural immune response.
Type I interferon (IFN-α and IFN-β) is the first line of defense against viruses “Line of defense” plays an important role in mucosal immunity. One type of IFN-α is produced more in women, those induced by the Toll-like receptor TLR7.
Advanced knowledge: What is a Toll-like receptor?
Toll-like receptors are an important class of protein molecules involved in non-specific immunity, and they are also the bridge connecting non-specific and specific immunity. ZhToll-like receptors can also recognize PAMP, and can also recognize the signal released when (including destruction by viruses) .
2. Specific immune aspects
Different from natural immunity, specific immunity is the immune response produced by the body after contacting a specific pathogen, and it specifically targets a certain pathogen. Similarly, women have higher levels of specific immune responses than men.
Influencing factors of specific immune response levels, such as CD3 + and CD4 + cell counts, CD4 +: CD8 + cell ratio, helper T cells 1 span> Inflammatory response and cytotoxic T cell activity are higher in women. There is a gender difference in the response of CD4 + T cells to some cytokines.
3. Expression of immune-related genes
Many immune-related genes are more highly expressed in women.
1) Many genes corresponding to antiviral and proinflammatory molecules have estrogen response elements in their promoters, so women have higher expression levels of these genes.
2) Several immune-related genes are encoded on the X chromosome. Although males also have an X chromosome, X-chromosome-related genes in female immune cells are more activated than males.
3) Many genes involved in the immune mechanism of Toll-like receptors (TLR) and type I interferon also have gender The difference, even the expression level of women can reach ten times that of men.
4. Regulating hormones
Some sex hormones (such as testosterone, estradiol, progestin) can affect the function of immune cells by binding to specific receptors. Many immune cells (such as lymphocytes, macrophages, dendritic cells) The relevant receptors are expressed on the surface.
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Lymphocytes under electron microscope | Dr. Triche / National Cancer Institute
This means that men and women are inherently different in the face of a virus.
At present, the differences between the new crown viruses in different genders do not leave anything out of the normal virus category. To say that it is different from other viruses, it is probably that there are more news reports about it.
References
[1] Qiutang Xiong, Ming Xu et al. Women May Play a More Important Role in the Transmission of the Corona Virus Disease (COVID-19) than Men.https: / /papers.ssrn.com/sol3/papers.cfm?abstract_id=3546061&download=yes
This article is from WeChat public account: 果壳 （ID : Guokr42) , author: famfamfam, Barley