How Covid Sends Some Bodies to War With Themselves - The New York Times | Virus World | Scoop.it
From www.nytimes.com - August 15, 2020 10:01 PM

Many Covid-19 patients may be dying from their immune response to the virus, not from the virus itself. Can science figure out how to save them? Back in April, as the pandemic was cresting over New York, Iris Navarro-Millán, a physician at Weill Cornell Medicine in Manhattan, treated a Covid-19 patient, a Hispanic woman in her 60s, who would prove to be a turning point in how she approached the disease. The woman was just a little short of breath when Navarro-Millán first saw her; a day later, she deteriorated so rapidly that she was rushed to intensive care, put on a ventilator and hooked up to a dialysis machine for her failing kidneys. Navarro-Millán feared that she would die. (She survived after spending two months sedated on the breathing machine.) When Navarro-Millán saw another Covid-19 patient soon after — a white man in his 60s already struggling to breathe — her first thought was, Not again. Believing that the prevailing standard of care — which, lacking drugs to directly fight the virus, consisted primarily of supportive measures like supplemental oxygen — was insufficient, she resolved to try something different, a treatment that was heretical in some circles but that she thought could save his life.

 

Navarro-Millán had unusual expertise for a hospitalist. Weill Cornell had asked her to move into that role when the pandemic hit, but she was a rheumatologist by training, a doctor whose specialty is autoimmune ailments in which the immune system, tasked with defending the self from invading pathogens, inexplicably turns on the body’s own tissues. Now she drew on her experience to try to help this Covid-19 patient. She suspected that the greatest danger here wasn’t the coronavirus itself but an immune overreaction so severe that it could cause lungs to fill up with fluid and prompt organs to shut down, possibly killing the patient. Rheumatologists often describe this type of immune reaction as a “cytokine storm” or “cytokine release syndrome.” Cytokines are proteins released by cells in order to send messages to other cells — signaling, for instance, that a viral invasion is underway. The number of different cytokines is large, perhaps exceeding 100, and each one calls for a specific response. To save her patient, Navarro-Millán decided that she would have to calm his immune system and prevent that storm from getting started. Early in her career, Navarro-Millán worked at the University of Alabama at Birmingham, where most of her patients had lupus, an autoimmune disease that can affect various parts of the body, including the kidneys, blood and even the brain. Its sufferers are especially prone to cytokine storms, which are often triggered by viral infections. What Navarro-Millán saw now in her Covid-19 patients wasn’t, she thought, all that different from what she encountered in Alabama.

 

A major lesson learned from her years there was that saving patients from cytokine storms often required doctors to intervene early, preferably long before the patients landed in the I.C.U., when it was frequently too late to bring the immune system to heel. So, the sooner she treated her Covid patient by tamping down his inflammatory response, she figured, the better. At the same time, she was leery of subduing his immune system for too long or too profoundly, because that might hobble his body’s ability to fight the virus that was making him sick in the first place. An array of drugs was available to her, ranging from antibodies that target specific pathways in the immune system to molecules that have a more widespread effect on the body. One, called tocilizumab, blocked the cytokine interleukin-6, but it remained in the body for up to a month — too long, in her view. Steroids, which dampen the entire immune system, might open the door to other infections. (Hydroxychloroquine, an antimalarial drug that has been promoted by President Trump for its supposed coronavirus-fighting potential, also happens to suppress the immune system. But because this effect, which is mild, comes only after months of daily use, it is unlikely to be suitable as a way to quell an immune firestorm started by an infection. The evidence so far suggests that it doesn’t work as an antiviral remedy, either, and that it can cause severe side effects.)..