Graphing the Covid-19 immune response

In the midst of a flood of press conferences with bright news, President Trump’s doctors implemented a series of treatments. Usually reserved for the most serious cases of Covid-19..External observers were left to solve the puzzle through contradictory messages to determine the seriousness of his condition and how it would notify him. Treatment plan..

Mr. Trump Leaving Walter Reed Medical Center The future of his health is uncertain on Monday night to continue his recovery at the White House.The doctor is the president Remains at an unstable point in the course of his illness.. Coronaviruses can be tricky enemies. For many who have serious cases of Covid-19, the greatest threat to survival is not the pathogen itself, but the deadly force that the body marshalls to fight it.

To quell the virus, the immune system unleashes a powerful weapon. Sometimes these turn inward and destroy healthy tissue. This fight against friendly fire has become as important a part of the Covid-19 treatment strategy as it is to quell the virus itself.

Mild and severe cases

From the moment the coronavirus enters the body, the immune system begins to defend and fires a battalion of cells and molecules at the invaders.

Most people infected with the coronavirus sometimes recover without experiencing symptoms and do not progress to severe Covid-19. In some cases, the virus may even be put under control before it settles in the body.

Once the virus has set its foothold, it quickly penetrates the cells and repeatedly copies to the level of the virus. Viral load, build up. Viral load can even peak before symptoms appear, even if symptoms appear.

Still, symptoms such as fever, cough, congestion, and malaise (all of which have been reported to Mr. Trump) indicate that an immune response is ongoing in the body and may reduce viral load. is showing. When the immune system finishes work, symptoms may relieve without medical intervention.

However, in severe cases, the conflict between the virus and the immune system is even longer. Other parts of the body, including those that are not directly affected by the virus, become collateral damage, causing serious and potentially life-threatening symptoms.

[For more details on the progression of a typical Covid-19 case, see Charting a Coronavirus Infection.]

Immune system trigger

A typical immune response is two Phase.. First, a fast-acting fighter cadre rushes to the site of infection and attempts to lock in the intruder.This so-called Congenital reaction Buy the rest of the immune system and launch a second, more coordinated attack. Adaptive response, About a week later, it starts when the first wave begins to weaken.

However, in people with severe illness, the immune system appears to be out of timing. Mobilization of the first wave is too late and you have to play a desperate game of catch-up that continues after reinforcements arrive. Unimpeded, the level of the virus rises dramatically, perhaps tricking the immune system into prolonging its siege.

Innate immune response

In response to the invading virus, the body rapidly develops molecules called cytokines. It acts like a microscopic alarm, mobilizing reinforcements from elsewhere in the body. Their arrival causes inflammation. Tissues swell with blood and cells, becoming warm, red, and painful.

Infection can be mild if the innate immune system progresses early against the virus. However, when the body’s defenses are flagged, the coronavirus can continue to replicate and increase viral load. In the face of growing threats, innate immune cells continue to seek help, fostering a vicious cycle of recruitment and destruction. Excessive inflammation over a long period of time can cause life-threatening damage to vital organs such as the heart, kidneys, and lungs.

Certain cytokines, such as interferon, can also strengthen cells against the coronavirus and suppress their spread in the body. However, scientists have discovered that the coronavirus may have the ability to slow the rise of interferon. This allows severe cases of Covid-19 to copy themselves without being checked for pathogens.

Adaptive immune response

Finally, Second wave of immunity Cells and molecules can arrive and be targeted more than their early counterparts, resulting in the coronavirus and the cells it infects.

The main condition of the wave after this is an antibody, a molecule that can flag the coronavirus for destruction or prevent the coronavirus from invading cells.In severe cases of illness, antibodies Accumulate faster and to higher levels Than in mild cases. Experts are still uncertain how this strong antibody response can affect the disease.

The second wave also includes T cells, called B cells, that can help immune cells mature into antibody makers and self-destruct coronavirus-infected cells.Some people may have T cells Already aware of the coronavirus, Even before these individuals are infected. Experts still do not know if these existing T cells will play a beneficial role.

Antivirus treatment

One way doctors can fight the coronavirus is through treatment that may reduce the amount of virus in the body.

On friday, the president Experimental antibody cocktail Developed by the pharmaceutical company Regeneron.The next day he started Antiviral course remdesivir.. According to experts, such treatments may be best given early in the infection to control the virus before it runs out of control.

Regeneron products include two types Monoclonal antibody — Synthesis of natural antibodies that isolate and neutralize coronavirus in the laboratory, mass-produced mimics. Monoclonal antibodies have not yet been given an urgent green light by the Food and Drug Administration to treat people infected with the coronavirus.But preliminary results suggest that they may be able to Reduce viral load and speed recovery..

RemdesivirOn the other hand, it acts on viruses that have already invaded cells. It blocks the process by which the coronavirus replicates by interfering with new viral genes. The FDA granted remdesivir urgent permission to treat critically ill Covid-19 patients in May after the data showed shorter hospital stays.

A few Other treatments It may work especially well in the early stages of the disease. Some experts say interferon Immediately after infection, other methods may help reset the confused immune response. However, if the molecules are administered after too long a delay, they can cause the extreme inflammation seen in patients with serious illness.

Anti-immunotherapy

In patients with severe illness, doctors may also give treatment to control the excessive immune response.

On Sunday, President Trump’s doctor reported that he had taken the course again. Dexamethasone, A steroid that broadly blunts the immune response by suppressing the activity of some cytokines. Dexamethasone has been shown to reduce the mortality rate of hospitalized Covid-19 patients with illness enough to require ventilation or oxygenation. However, it is much less likely to help and even harm patients in the early stages of infection or with mild illness. Experts say that improper or premature administration of dexamethasone can impair a useful immune response and cause the virus to destroy the body.

Dexamethasone belongs to a class of drugs called Corticosteroid, Contains hydrocortisone and methylprednisolone — Also benefits Covid-19 patients with severe illness..

Risks and unknowns

It remains unknown when Mr. Trump will be Infected with a virus And when his symptoms first appeared. But the acceleration of his treatment strategy His condition may have been worse More than officials and doctors allow.

At the age of 74, about £ 240, Trump is in a high-risk age group and is on the verge of obesity. It can get worse Severity of Covid-19. Men also tend to have a poor prognosis for their illness.

Still, many of the factors that cause serious Covid-19 remain a mystery. Some of Trump’s treatments are not available to most people except in clinical trials that study highly ill inpatients.To date, none has been fully approved by the FDA Treatment of Covid-19 Exists. And researchers are still puzzled by the dynamics of successful recovery — a series of studies complicated by the increasing number of Covid-19 survivors. Symptoms continue months after the infection disappears.. What happens next for Mr. Trump and many others like him is an open question.

Coronavirus tracking

Source: US Center for Disease Control and Control; Taison Bell, University of Virginia; Deepta Bhattacharya, University of Arizona; Akiko Iwasaki, Yale University; Marion Pepper, University of Washington; Iran Schwartz, University of Alberta.