Gone Rogue

The body’s immune system is a complex organization of cells and chemical “signaling” compounds that was largely unknown until the last 100 years.  We are discovering more of the intricacies of how it works every day.  It evolved to help protect us from numerous pathogens in our environment.  Those pathogens include bacteria, viruses, fungi and a host of parasites.  I like to think of our immune system as our body’s police force.  A macrophage is a type of white blood cell (WBC) that represents the “cop on the corner” while macrophages circulating in the blood are the cops on patrol.  Fixed macrophages are the immune system’s “first responders,” and their “backup” are macrophages circulating in the bloodstream.  Depending on the type of emergency, there are additional aspects of the immune system that could come into play.  Once activated the immune system releases a number of inflammatory compounds that attract additional types and numbers of white blood cells.  Once the crisis has been dealt with, there is a mechanism by which that immune cascade can then be “shut down.”  Autoimmune disorders are an example of an inability to deactivate the inflammatory process once it has been set in motion.  Most macrophages are the “killer” type that seeks and destroys invaders.  A smaller force of “suppressor” type macrophages de-escalate the situation and restore the immune system to normalcy.  Researchers speculate that surviving infection with the COVID-19 may depend on the patient’s ability to suppress the inflammatory response triggered by the virus.  Studies from Wuhan, China found that an inflammatory marker, interleukin 6 (IL-6) was elevated in patients who died from COVID-19 infection when compared to survivors.  Infected patients with elevated IL-6 levels were found to progress to ARDS more frequently than those with more normal IL-6 levels.  Those patients who developed ARDS were more likely to require ventilator support and ultimately die.  These findings suggest that future therapies may include immune system modulators in addition to or in combination with antiviral drugs.

Researchers at New York University have found three early indicators in COVID-19 patients that have a high predictive value for progression to acute respiratory distress syndrome (ARDS).  Those indicators are:  a rise in the liver enzyme (ALT) alanine aminotransferase, deep muscle aches, and an elevated hemoglobin.  They reached this conclusion after examining records from Chinese patients previously treated for COVID-19.  The primary symptoms that suggest severe infection remain a high fever, dry cough and difficulty breathing.  This new information suggests that other factors may wish to be considered in patients who do not present with the most serious symptoms associated with COVID-19.  The addition of rapid, point of care (POC) testing will help identify individuals infected who should self-quarantine.  Since this particular version of the coronavirus, COVID-19, is a new entity we are still learning new information about the virus itself and how to combat it.  The advice of medical experts continues to be social distancing, frequent handwashing and avoid touching your face.

 

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