With the SARS-CoV-2 virus infecting people with COVID-19 globally, the body’s immune system plays a key role in determining how mildly or seriously the disease affects us. Dr Victor Ti who has vast experience as a specialist and generalist explains this defence mechanism.
At the time of writing, COVID-19 has infected nearly 1,350,000 people worldwide, with virus transmission showing no signs of slowing down. The staggering number of cases has naturally led to escalating fear and anxiety among the public.
When our life is subjected to danger, we should certainly do all we can to protect ourselves. Any effort, however small it may be, to strengthen our internal body defence may determine the difference in the final outcome of our wellbeing. Apart from all the public health measures that were already put in place, we should not forget that we have our own immune system within us that has been successfully combating a great number of harmful viruses, bacteria and fungi, to ensure our survival.
Thus, we should try to understand how this innate system works and explore whatever possible ways that could enhance its capacity. Let me share with you how our immune function can be optimised to hopefully help us counter the coronavirus.
The immune system, or as you may call it the ‘defence ministry,’ is certainly very sophisticated and dynamic, having evolved over thousands of years to meet the ever-changing challenges in nature that emerge from time to time. Our varying immune response may be one of the main factors that explains why different people responded so uniquely to coronavirus infection.
Why were some of those infected able to function normally without exhibiting any clinical symptoms whereas some suffered severe pneumonia and others succumbed to death? To answer these, we ought to understand first, relevant aspects in human immunology. By doing so, we may also learn how certain micronutrients such as vitamin D and Zinc play a pivotal role in enhancing our immune system to destroy the invading viruses or bacteria.
Within our body, there are innate ‘ammunitions of defense’ called antimicrobial peptides (AMPs), such as the cathelicidins and defensins, which are wide-spectrum antimicrobes with powerful antiviral, antibacterial and antifungal properties. While antibiotics are known to most of us, the AMPs that are present naturally within our body are almost unheard of by many.
These AMPs act very differently from most conventional antibiotics in ways that are most intuitive and effective. The AMPs may destabilise microbial cell walls or viral envelopes, or puncture holes through them and damage them. Alternatively, they may create channels where water penetrates excessively into the cells, over-distending and rupturing them, causing the death of the harmful viruses or microorganisms. These AMPs may also enhance our immune system by modulating it to fight the invading foreign agents more effectively.
They are found in the cellular organelles called lysosomes, which are found in many human cells especially in our macrophages. Macrophages are specialised cells differentiated from a group of our frontline white blood cells called monocytes. These macrophages are capable of gobbling up viruses, bacteria or fungi which are then destroyed by the AMPs released from the many lysosomes lying within.
Apart from the macrophages, the AMPs are also found in another group of white blood cells called polymorphonucleocytes (PMNs). More importantly, they are also present naturally in the surface cells lining our skin and the internal tubular passages of our body such as our airway, intestines and urinary tract. These outer layers of cells called epithelial cells are the top layers of cells that the invading microorganisms need to penetrate to get into our body tissues.
Upon entering our body, they will be surrounded by the macrophages and PMNs, the frontline ‘soldiers’ in our blood, which circulate throughout our whole body. Both the macrophages and PMNs patrol and carry out round-the-clock surveillance of all the systems in our body, gobbling up whatever harmful microorganisms they encounter. As mentioned, these enemies are then destroyed with the AMPs released from the lysosomes lying within the macrophages and PMNs. Using a simple analogy, the lysosomes can be viewed as the artillery and the AMPs as the ammunition that kills the invading enemies.
It is interesting to note that the functions of the AMPs are strongly linked to certain micronutrients. Among them, vitamin D stands out to be the most important micronutrient that enhances our immune system against various infections. From as many as 11,000 studies, there is enough evidence to show that vitamin D reduces the probability of individuals contracting respiratory infection. For those who have already contracted the infection, vitamin D modulates the infection rendering it less serious.
Vitamin D is a super-promoter of some 2,000 genes, that make up approximately 10 percent of the human genome, many of which are involved in a broad spectrum of defensive immunological function. Vitamin D is known to regulate expression of the two most well-known AMPs – cathelicidin and defensins – that act against viruses, bacteria and fungi.
Zinc is another micronutrient that has a broad-spectrum antiviral activity against a variety of viruses. Increased Zinc concentration in the cells is noted to inhibit polymerases that are essential for the completion of different phases of the viral life cycle. It also helps in the production of immunological cytokines necessary for the maintenance of a robust immune response to the invasion of the viruses.
Studies in the US, India, South Africa and Peru have shown that oral zinc supplementation reduces the incidence rate of acute respiratory infections by 35 percent and shortens the duration of flu-like symptoms by approximately two days.
In this challenging time, it is wise to take whatever supplements that have been proven to be beneficial in enhancing our immune system. Nonetheless, we must continue to practise social distancing, wearing of mask, use of hand sanitiser, frequent handwashing and the avoidance of touching our face with our hands, which are all good public health measures to mitigate the spread of COVID-19 virus.￼
Dr Victor Ti, MD, MFAM (Malaysia), FRACGP (Australia), Dip P Dermatology (UK), Dip STDs/AIDS (Thailand), Dip. AARAM (USA), LCP of Aesthetic Med (Malaysia) is an experienced specialist and generalist (Family Physician) at the capital’s BH Clinic. As a specialist and generalist, he is skilled at diagnosing all general diseases and excluding the sinister ones. Apart from the general diseases, Dr Ti is also proficient in handling skin diseases, sexually transmitted diseases, minor surgery and aesthetic medicine. He can be reached via email at [email protected], WhatsApp at +60164122977 or mobile number 023900446.