Think of your immune response as a giant machine-learning problem, with your body as the computer.
Immune cells travel around your body, sampling all sorts of matter they come into contact with, from your own cells to the cells of organisms that definitely shouldn’t be there. If immune cells encounter something they know shouldn’t part of your body—bacteria or a virus, say—the body scales up the cells that know how to deal with that interloper.
If there’s a cell that’s seen the intruder before and knows how to tackle it, your body rapidly reproduces it thousands of times—enough that it can overwhelm the bacteria or virus before it has time to make its home in your body. And once the invader is routed, the immune system reduces the number of those cells again, keeping just enough in reserve that — should the bacteria try a repeat assault—there are enough immune foot soldiers to rout them once again.
This process can help keep you healthy, but could also be the key—with a little bit of help from cloud computing-powered artificial intelligence—to helping identify diseases much earlier than doctors are able to do right now.
Earlier this year, Microsoft announced a deal with Adaptive Biotechnologies, a health-tech and gene-sequencing company based out of Seattle. Adaptive Biotechnologies’ gene sequencers are currently used to detect residual myeloma—that is, cells that show a person who’s been treated for blood cancer isn’t entirely free of the disease.
Now, the company is thinking beyond just tracking down a single disease; it’s aiming to identify anything that could throw your immune system out of whack, from infections to cancer—and it’s relying on Microsoft’s machine-learning capabilities to help it get there.
The human immune system works on multiples large enough to make your head spin. There are two billion lymphocytes in the body, among them what’s known as ‘helper’ T cells, others as ‘cytotoxic’ or ‘killer’ T cells.
Each T cell can recognise the antigens—the triggers that will set off the immune system—that are the signatures of bacteria, viruses, fungi or other invaders that have entered the body. Each T cell can bind to hundreds of different antigens, each potentially unique to a different bacteria or virus.
Once a T cell has got a hit, depending on what type of T cell it is, it may kill the invader, or signal the millions of other immune cells to come and take on the wrongdoer too. Anyone taking a snapshot of the immune system when the T cells are activated, by noting which T cell receptors are activated and which antigens they bind to, could work out which disease has taken over the body. And, once the disease is known, doctors can see more clearly how it can be treated.
Adaptive Biotechnologies started in 2009, set up to read and scan the immune system and the receptors on immune cells. Over time, the company began not only tracking immune receptors, but working out the link between the receptors and the antigens they bind to. By working out the binding relationships, the company started making steps toward being able to diagnose particular diseases from the immune receptors.
A single blood sample will typically extract about a million T cells. Each of those T cells has a receptor that is genetically programmed to bind to specific antigens. “Being able to translate the readout of those T cell receptors’ DNA sequences to a set of antigens, and then do the perfect translation of those antigens, to disease states is also a very, very large machine-learning problem,” Peter Lee, Microsoft’s corporate VP of artificial intelligence and research said.
And that’s where Microsoft’s machine learning comes in. Microsoft is using algorithms that have been adapted from the ones the company currently uses for natural-language translation. “There’s some similarity to what we do with the Bing search engine that’s called topic identification,” Lee said. Microsoft uses Adaptive Biotechnologies’ MIRA system to generate training data—training data that’s used to create a ‘translation map’ from T cell receptors to antigen, and then map those antigens back to diseases as accurately as possible.
If this all sounds a bit abstract, the practice could have concrete benefit: if the mapping works as Adaptive and Microsoft hope it should, it could mean that patients could be diagnosed with diseases before they even know they’re sick. For example, the symptoms of ovarian cancer are so insidious, it’s often not detected until it’s at a late stage, when it carries a poor prognosis. By pre-emptively testing people with genetic mutations, such as BRCA1, that put them at greater risk of ovarian cancer, the test could pick up the tell-tale immune signals that indicate early cancer. The earlier you catch the disease, the better chance there is of treating it successfully.
