Boys and girls are different. Who knew? OK, we’ve all known that since preschool — so why is it taking the medical community so long to catch onto that basic fact, especially when it comes to disease and the different ways our bodies respond to them?
Now a set of new studies is examining exactly how our immune systems are different and why it’s so important we know this. To start, there three major ways we’re different than the dudes.
We got the power!
Chalk one up for the ladies: Our immune systems are both stronger and faster than men’s. (Who’s the weaker sex now, huh?) Researchers from the University of Tasmania in Australia reported at a recent meetup of microbiologists in Boston that female infants responded better to a new tuberculosis vaccine than male infants did — a finding that isn’t unique to that vaccine. The researchers speculate that women have had to develop tougher, more agile immune systems in order to protect fetuses when we’re pregnant.
Unfortunately, this can also work against us: A too-strong immune response can be just as deadly as a too-weak one, causing the body to attack itself over benign stimuli. This may be one reason why women are more likely to get autoimmune disorders, such as lupus and multiple sclerosis, and why we are affected by so many more strains of HIV than men are.
Hormones — they mess with everything, amiright, ladies? Well, in this case our monthly fluctuations may be a good thing. Although we may not like the zits and bloating that come with it, the researchers reported that when estrogen soars, it can activate cells that kill viruses. And testosterone — yes, women have it, too — suppresses inflammation.
Then there’s pregnancy, which means hormone fluctuation times 100. They noted that previous research has shown that a woman’s immune system is temporarily lowered during gestation but that having a baby can strengthen your immune system over your lifetime.
That double X
It’s not just physiological differences that matter. Our immune system goes right down to our genetics, the researchers reported. They found that the X chromosome carries a special protein called TLR7 that detects viruses and then sends out the cellular troops to kill them. Our double X means we have twice the protein and, therefore, twice the firepower for fighting infection. (The scientists noted that TLR7 seems to be unaffected by the process that suppresses other doubled-up X proteins.)
The “woman problem”
Unfortunately, many scientists ignore these basic biological realities, doing drug and vaccine testing only on men or doing it on both genders but not separating the results. This means that women often get too-high doses of medications and vaccines, which can have unintended, and sometimes very serious, health consequences. (Even worse: Women are more likely to be ignored, misdiagnosed or written off when they report pain or other adverse symptoms.)
“It’s sort of an inconvenient truth,” said Linde Meyaard, an immunologist at University Medical Center Utrecht in the Netherlands and one of the presenters at the Boston meeting. “People really don’t want to know that what they study in one sex is different from the other.”
So at least the medical community is starting to catch on, but we still have a long way to trek.