In the future, patients may be faced with a very curious question at the doctor’s office: What time are you?
This puzzling question is becoming increasingly crucial in the study of vaccines. More specifically, medical professionals are looking for a link between people’s ‘biological clock’ and their immunity response. Researchers Dr. Nicolas Cermakian of McGill’s Douglas Research Centre and Dr. Nathalie Labrecque of the Maisonneuve-Rosemont Hospital Research Centre recently carried out a study to discover whether immune systems respond more effectively to threats at certain times of the day.
According to Cermakian, there are ‘clocks’ all over our bodies. This clock gene regulates all bodily functions, including digestion, body temperature, and hormonal cycles.
T cells are responsible for attacking and ridding the body of abnormal cells, such as viruses, bacteria, and cancer cells. Using mice as their test subjects, Cermakian and Labrecque delivered abnormal cells to T cells at different times of the day. They found that the T cells functioned very differently depending on the time.
“We realized that T cells were responding much faster [and] much more strongly when [the test] was done in the middle of the day,” Cermakian said in an interview with The McGill Tribune.
The T cells’ performance during the day were more than twice as efficient as their performance during the night. While Cermakian explained that these results may not translate identically to humans, these results should be significant enough to influence the time at which vaccines are administered to patients.
More generally, Cermakian emphasized that the time of day must be considered when designing treatments for patients, including cancer therapies.
“For some cancer treatments, […] it has been found that some times during the day are more efficient than others, and there are [fewer] secondary effects when you do it at the right time [of day],” Cermakian said.
However, this does not necessarily mean that doctors should always administer vaccines within a certain time period. Cermakian pointed out that circadian rhythms, like many other aspects of the human body, differ between individuals. This biological clock regulates our sleep-wake cycle that varies from person to person.
“We have to realize that […] our clocks don’t all run the same way,” Cermakian said. “Some of us are morning people, some of us are late people.”
Even if researchers come up with a time period that, on average, produces the most efficient T cell response, Cermakian suggested that this average time period may not be helpful in practice. For many people, the ideal time may be a few hours earlier or later, and it will be the responsibility of researchers and physicians to take these differences into account.
“We are not all the same, […] and we have to design the treatment according to that,” Cermakian said. “As with many other parts of medicine, it’s important to tailor the treatment to the particular person.”
Cermakian noted that greater personalization in medicine is filled with possibility. Currently, there is no reliable way to efficiently determine a person’s circadian rhythm. However, ongoing research from the Douglas Research Centre points toward a future where doctors can evaluate patients’ circadian rhythms by taking a quick blood or inner-cheek sample. By analyzing patients’ metabolic rates with information from these cell samples, doctors can attempt to devise treatments that are specifically tailored to their patients’ unique time, creating personalized and effective health care.