Th1 and Th2 Immunity

The dog days of summer are fully upon us and for some, unfortunately, this season also brings the plague of seasonal allergies. If this includes you, please read on for some tips for circumventing the runny nose and eyes. This is also applicable if you have asthma, food allergies and eczema. As these conditions are all interrelated. Many people who experience one of these conditions can experience all of them simultaneously. These conditions are a response to an immune system balancing issue.

What is Th1 and Th2 immunity?

The immune system is a complex, integrated system that protects us against illness. The primary function of the immune system is to recognize the difference between normal cells (self) and invaders (non-self). The immune system must protect self and eliminate the “non-self” which includes viruses, bacteria, parasites and cancer cells.

One of the mechanisms that the immune system uses is called adaptive immunity. The adaptive immune system consists of special types of white blood cells (WBC) called B cells and T cells – these cells are also called lymphocytes. B cells make antibodies against foreign invaders so that the immune system can remember the pathogen and quickly eliminate it in any future encounters. T cells are responsible for either actively killing (called killer T cells) or helping to kill (called helper T cells) the pathogen.

Of all the types of the the cells we have in our bodies, helper T cells are considered the biggest producers of cytokines, a chemical signal that tell other cells in the immune system what to do. There are two main types of helper T cells these are: Th1 cells and Th2 cells.

Th1 cells eliminate the invaders that occur inside our cells (viruses and intracellular bacteria). Th2 cells destroy pathogens that occur outside our cells (bacteria and parasites).

Why is this important?

A healthy immune system chooses which type of cell to produce and can easily switch back and forth between Th1 and Th2 type responses.  An unhealthy immune system gets “stuck” in one of these responses – leading to excessive production of only one type of cytokines.

When people get stuck in a Th2 response, this activates eosinophils – a reaction which leads to the symptoms we recognize as “allergies”.  For some people this can become severe, leading to asthma, eczema, and anaphylactic reactions.

Factors believed to increase Th2 cell expression and suppress Th1 cell immunity

Diet factors: Processed foods, heated vegetable oils (safflower, soy, canola and sunflower), high sugar and/or alcohol intake.

Environmental factors: tobacco use, heavy metal burden, pesticides, air and water pollutants.

Gut dysbiosis: Candida overgrowth, overpopulation of e-coli.

Stress: Prolonged circulation of high levels of the stress hormones such as cortisol.

Pharmaceutical Medications: prolonged use of steroid medications, excessive use of antibiotics in childhood, growing use of combination vaccines and use of certain adjuvants.

How can we balance our immune systems?

Naturopathic doctors have several strategies to balance Th1 and Th2 immunity. These include:

Probiotics: Probiotics refer to beneficial bacteria that reside in healthy human intestines.  This good bacteria alters Th2 cytokine production in both healthy and “allergic” people.  Probiotics appear to stimulate the immune system in the gut called GALT (Gut-associated lymphatic tissue) which promotes healthy immune activity.

Fish oil: Fish oil blocks inflammatory cytokines by irreversibly binding to immune system enzymes.  Irreversible is good!  This means that when the body needs an appropriate immune response it can still have one.  For fish oil it is absolutely essential that you buy a high quality product – they are frequently contaminated with mercury (since some types of fish are high in mercury) seek out cold pressed cold water fish. We like Super EFA liquid or Nordic Naturals (available at Head to Heal dispensary) and NutraSea (available at local health food stores).

Vitamin A and vitamin D: Vitamin A, in combination with appropriate amounts of vitamin D, turn off inflammatory immune responses.  These two nutrients take immature T-helper cells and switch them to an anti-inflammatory version called T-regulatory (T-reg) cells.  This can be helpful for patients who have either excess Th2 OR Th1 responses.  BUT vitamin A and vitamin D, can be toxic in high levels.

Herbs and homeopathics: Naturopath doctors have many anti-inflammatory or immune modulating herbs to alter your Th1/Th2 ratio.  It is best to treat the individual by consulting with a Naturopathic doctor.

Naturopathic doctors treat the individual and their own particular biochemistry.  There are many different types of biochemistry – and ND will help the individual determine what is a good protocol to help balance their immunity.