TeachableMedicalNews article 04242020
Teachable moment in classrooms:
- blood chapter – white blood cell types and their functions
- blood chapter – malfunctioning mechanisms in leukemia
- respiratory system chapter – alveoli as the sites of gas exchange
- respiratory system chapter – immune defense cells of alveoli
- lymphatic and immune system chapter – events of inflammation
How could the leukemia fighter drug Calquence help us defeat the SARS-CoV-2 coronavirus?
The news item: Recent articles reported that the anti-cancer drug will be evaluated as potential treatment of SARS-CoV-2 infected patients:
AstraZeneca to test impact of cancer drug Calquence on coronavirus patients
Calquence (acalabrutinib) belongs to a class of drugs called Bruton’s tyrosine kinase (BTK) inhibitors which can suppress autoimmune diseases. The drug, which is currently used to treat certain types of blood cancers, has already been approved for the treatment of adult patients with chronic lymphocytic leukaemia in the U.S.
The news item mentions cytokine storm in coronavirus infected patients, and that the drug is a BTK inhibitor.
So, Why Do I Care?? Have you been living under a rock in the last few months??? The coronavirus, SARS-CoV-2, responsible for the COVID 19 disease has so far infected over 2.7 million people, and caused over 191,000 deaths worldwide (on the date of this article). The virus attacks the respiratory system, and may cause pneumonia and respiratory failure. The leukemia fighting drug Calquence holds promise as a possible treatment to lower the lethality of the virus.
Plain English, Please!!! First, let’s talk about what Calquence is. This drug is used to fight leukemia, the disorder where white blood cells multiply out of control. Those cancerous white blood cells are stimulated by cytokines, and Calquence can slow the action of cytokines. So, this leukemia fighter drug is not expected to kill the virus itself, but to prevent the lethal consequence of the SARS-CoV-2 infection, the cytokine storm.
Second, let’s talk about the cytokine storm. Our body reacts to viral infections with the process called inflammation. That defensive process includes immune system cells such as the white blood cells lymphocytes, neutrophils and monocytes that supposed to remove the virus from the site of infection, in our case the alveoli of the lungs. The white blood cells are called to the inflamed alveoli and stimulated to remove the virus. If we want to ask for help from friends, we send them a text, call them, or alert them on social media. For the immune system such a “call and stimulation” is done by the chemicals called cytokines. In some virus infected people large amounts of cytokines are made, and a lot of white blood cells will come to the alveoli, and then they release even more cytokines. This cloud of cytokines is called the cytokine storm. The large number of highly stimulated white blood cells damage small blood vessels, and fluids leak out and pool in the air sacs. That’s why shortness of breath develops, and ventilator machines are needed for the patients. The large cloud of cytokines can damage blood vessels in the heart and kidneys as well.
Third, let’s talk about how Calquence may help SARS-CoV-2 patients. When a white blood cell is stimulated by cytokines, there are many chemical reactions needs to happen inside the cell. Those reactions follow each other just like when a line of dominos are toppled over once you push the first domino. If you remove one domino piece from the line, the toppling action stops, and never reaches the end. Calquence removes a domino piece from the line of chemical reactions. That particular domino piece is called BTK (Bruton’s Tyrosine Kinase). Inhibiting BTK disrupts the line of reactions, and the white blood cells are not called to the alveoli, and do not get stimulated. That lowers the overall amount of cytokines, snuffs out the cytokine storm, and prevents deadly damage to the patient.
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