19 Oct 2017 | 05:16am IST
Understanding the difference between defence or disease
When your child is fit as a fiddle, you tend not to think too much about his/her immune system. But given the fact that we have just come out of the rainy season and are moving towards the cooler months, chances are, many of us are wondering how our bodies ward off diseases
Dr Dorland Martins/ Dr Silroy Martins
All around us are bacteria, viruses, parasites, dust,
pollen and a whole host of other
substances that have the potential to make us very sick. Yet amazingly, most of
us don’t get sick that often. This is because your body is able to fend off
these potential invaders with several layers of defence, otherwise known as
your immune system. Not only is your immune system designed to seek out and
destroy these disease causing substances, it also remembers these substances it
encounters so that they are dealt with when they return in future.
LAYERS
OF DEFENCE
When you come into contact with a foreign
substance, your first layer of defence aims to stop the invader from entering
your body in the first place. It might help to think of this as a wall around a
castle. Your outer layer of defence includes a physical barrier – your skin –
and bodily fluids designed to wash away infections (your tears, mucus found in
parts of the body lined with mucus glands.
These mucus secretions in the form of
trivial runny nose and sneezing are a very effective way of protecting us from
infections. Many a time, we misunderstand this very protective reaction of the
body as DISEASE and we hurry to suppress these very symptoms that were aimed at
protecting us. Nasal sprays intended to give quick fix relief by suppressing
these fighting responses of the body, unintentionally give the invaders easy
excess to the interiors of the body. Bypassing your first defence line is like
putting down a ladder across the boundary wall, giving the enemy excess to the
castle. The next line of defence comes in the form of tonsils. Tonsils are the
two lymph nodes located on each side of the back of your throat.
They produce white blood cells to help
your body fight infection. The tonsils combat bacteria and viruses that enter
your body. As the body is trying to fight against the harmful stimulus or a
viral infection, it gets inflamed, leading to pain, redness, fever, discomfort
in swelling. We may think we have outsmarted this God given defence by removing
these gatekeepers that guard our lower respiratory tract but after suppressing
the initial defences of the body, the organisms get easy excess to the lower
respiratory tract and the child begins to suffer from repeated lower respiratory
tract infections leading to coughs.
Wikipedia defies cough as “a sudden and often repetitively
occurring, ‘protective’ reflex, which helps to clear the large breathing
passages from fluids, irritants, foreign particles and microbes’. Unmonitored
over use of cough suppressants are only bound to suppress the cough and could
lead to more serious life threatening illnesses. Many of our young patients
suffering with asthma come to us with a history of such suppressions. The
journey usually starts with a skin rash that has been suppressed with
ointments, followed with repeated runny nose and sneezing. This in turn is
repeatedly treated with nasal sprays followed with more frequent attacks of
coughs. Only to be diagnosed with Asthma.
When you get an infection, besides these protective responses,
your body activates a complex system designed to seek out and rid your body of
the infection. This adaptive immune system, which helps your body adapt to the
infection and create immunity, is somewhat like the castle guards who run from
room to room seeking out the dangerous invaders.
FIGHTING
AN INFECTION
When the body senses there is a virus or other infections,
foreign substance, the body reacts to try and destroy the foreign invaders. One
of the first things that happen is a type of white cell called macrophage is
activated. Macrophages recognise a foreign substance and swallow them up to
destroy them. However, the macrophages can be overwhelmed if they get a large
dose of infection.
At this point the body needs to ramp up the way it fights the
infection and activates other parts of the complex immune system. This includes
activating other types of white cells (B-cells and T-cells). B-cells make
protein antibodies that attach to the virus and label it as foreign for T cells
to destroy. After an infection has cleared, a small number of B and T cells
persist in the blood with memory of the virus, allowing them to activate and
destroy viruses more quickly next time.
WHAT’S
MAKING YOU FEEL LOUSY?
The symptoms you experience when you come down with a cold or
flu are not only the result of the infection; they are also the result of your
body’s immune response to the infection. When you get an infection, your body
also activates other systems, including cytokines (chemical messengers) and the
complement system. These trigger inflammation and can cause symptoms like
redness, warmth, swelling, pain. So your runny nose is actually caused by a
local inflammatory response to the virus.
But you can have an infection and not actually have any
symptoms. This is known as a subclinical infection. You may have got a
subclinical dose of the infection where you feel a bit irritable and grumpy as
you fight off the virus but don’t even realise you have an infection. There are
a number of factors that will determine whether you will get sick after you’ve
been exposed to a cold or flu virus, including whether you have had it before,
what size dose of the virus you got, how infectious and virulent the bug is and
your general health and how well your immune system is functioning. Most
healthy people have a healthy immune system and the body is always striving to
protect you or get rid of the infection. The only problem lies in our
understanding of these reactions of the body as defence or disease.
The
writers are consultants at VitaNova Clinics
