Mutations with benefits – resisting epidemics.

The term “mutation” is a bit loaded, as it implies a defect or deficiency or aberration of some sort. But the value of a particular version of a gene is very much dependent on its context – what might be a defect in one context conveys an advantage in another. And that context means not Read More …

Does taking aspirin prevent the immune system from killing common cold viruses?

This is a great question. After all, if the purpose of fever is to fight infection, it stands to reason that suppressing fever weakens the body’s response to infection. And this reasoning has some experimental support – in both humans and animals, moderate fever seems to decrease the damage and mortality caused by infections [1] Read More …

Why is Staphylococcus aureus golden-colored?

Staph aureus excels at evading the human immune system, and its innocuous-seeming color is just one more of its tricks. The characteristic golden color was noted when it was first isolated from infected surgical wounds in 1881[1] From Microbiology in Pictures The pigment is a carotenoid, a cousin to the anti-oxidant vitamin A found in carrots Read More …

Will human immunity to Cas9 make CRISPR useless?

This paper shows that a large fraction of humans have antibodies agains Cas9. This is not a surprise. Why? Because Cas9 is a bacterial protein, and its common bacterial sources (Staph and Strep) colonize or infect most humans at some point in their lives. Even though Cas9 is an intracellular protein, lysis of bacterial cells or Read More …

How does smoking marijuana make the human immune system stronger?

I don’t believe there is any evidence that smoking marijuana makes the immune system stronger – that is, able to better fight off infections. Smoke of any kind will cause lung damage, and is likely to make you more susceptible to lung infections. There is some evidence that pot smokers suffer from increased rates of Read More …

Why are we getting all kinds of diseases nowadays? Are our immune systems becoming weaker? If so, why?

It does seem like we are being confronted with an onslaught of new diseases – Ebola, Zika, MRSA, CRE etc. But seeming and being are two different things. Our notions of probability and prevalence are strongly biased by their availability to our memory. Dying from these diseases is a horrible prospect that triggers a strong Read More …

Can we evolve to be immune to diseases?

We can and we do evolve immunities to specific diseases. Tuberculosis is a good example. In the 17th-19th centuries it was often the largest single cause of death among Europeans, particularly in cities[1] . What’s more, it was a disease of young adults, with most victims being in their 20s and early 30s. TB exerted Read More …

How should CAR-T therapy be priced?

As with all things, we should be concerned with value, not price. Novartis’ pricing scheme easily passes the value test. There is no objective value that can be put on saving a life, of course. But we can still make estimates. Britain’s National Institute on Cost Effectiveness (NICE) evaluates treatments with respect to their value. Read More …

Gastroenterology: Is there really a link between gut bacteria and depression or is this just fancy pop science?

The evidence for a link between gut bacteria and depression/anxiety disorders is compelling. The gut microbiome of clinically depressed patients is substantially altered [1], and gut disorders such as Inflammatory Bowel Disease show both an altered microbiome and an increased risk of depression [2] . We also know that recurrent antibiotic use, which inevitably disrupts the gut microbiota[3] , Read More …

Is it beneficial for our immune system to expose ourselves to bacteria?

“Beneficial” is not quite the word I would use. “Co-dependent” is a bit more accurate. Imagine a tug of war, our immune system on one side and bacteria on the other. Our bodies put just enough energy into our immune systems to ensure that there is an even match – that there is a stable Read More …