Dödligt virus från Kina orsakar panik (SARS-CoV-2, COVID-19)

”The Coronavirus Patients Betrayed by Their Own Immune Systems

A “cytokine storm” becomes an all-too-frequent phenomenon, particularly among the young. But treatments are being tested.

The 42-year-old man arrived at a hospital in Paris on March 17 with a fever, cough and the “ground glass opacities” in both lungs that are a trademark of infection with the new coronavirus.

Two days later, his condition suddenly worsened and his oxygen levels dropped. His body, doctors suspected, was in the grip of a cytokine storm, a dangerous overreaction of the immune system. The phenomenon has become all too common in the coronavirus pandemic, but it is also pointing to potentially helpful drug treatments.

When the body first encounters a virus or a bacterium, the immune system ramps up and begins to fight the invader. The foot soldiers in this fight are molecules called cytokines that set off a cascade of signals to cells to marshal a response.

Usually, the stronger this immune response, the stronger the chance of vanquishing the infection, which is partly why children and younger people are less vulnerable over all to coronavirus. And once the enemy is defeated, the immune system is hard-wired to shut itself off.

“For most people and most infections, that’s what happens,” said Dr. Randy Cron, an expert on cytokine storms at the University of Alabama at Birmingham.

But in some cases — as much as 15 percent of people battling any serious infection, according to Dr. Cron’s team — the immune system keeps raging long after the virus is no longer a threat.

It continues to release cytokines that keep the body on an exhausting full alert. In their misguided bid to keep the body safe, these cytokines attack multiple organs including the lungs and liver, and may eventually lead to death.

In these people, it’s their body’s response, rather than the virus, that ultimately causes harm.

Cytokine storms can overtake people of any age, but some scientists believe that they may explain why healthy young people died during the 1918 pandemic and more recently during the SARS, MERS and H1N1 epidemics.

They are also a complication of various autoimmune diseases like lupus and Still’s disease, a form of arthritis. And they may offer clues as to why otherwise healthy young people with coronavirus infection are succumbing to acute respiratory distress syndrome, a common consequence of a cytokine storm.

Reports from China and Italy have described young patients with clinical outcomes that seem consistent with this phenomenon. It’s very likely that some of these patients developed a cytokine storm, Dr. Cron said.

In the case of the 42-year-old patient, the suspected cytokine storm led his doctors to eventually try tocilizumab, a drug they have sometimes used to soothe an immune system in distress.”

”Randy Cron, M.D., Ph.D., is an expert in a dangerous immune reaction to some infections, called cytokine storm syndrome:

“Cytokines are inflammatory immunologic proteins that are there to fight off infections and ward off cancers,” said Cron, a University of Alabama at Birmingham professor of pediatrics and medicine. ”But when they are out of control, they can make you very ill.”

A cytokine storm is the result of an immune system gone wild. The body’s own killer immune cells are often defective, resulting in increased production of inflammatory proteins that can lead to organ failure and death.”

”(...I vissa fall hos unga patienter kan ett starkt immunsystem ha motsatt effekt där levern är i riskzon”

”(...)When a pathogen enters the body of a strong immune system and explodes, it can cause the person’s immune system to overreact. And in this case the immune system attacks not only the pathogens, but also lymphocyte cells.”