Monday, March 17, 2014

NeuroImmunology

NeuroImmunology
T helper (Th) cells play an important role in mediating and maximizing the potential of the immune system. Th1 cells are the subset of T helper cells which are associated with ‘cell-mediated’ immunity, they activate pro-inflammatory cytokines and it is their role to co-ordinate other immune cells by surveying the body for potential intracellular infection and/or parasitic invasion. Th1 cells are associated with externalization of infection, in that they are designed to get symptoms out of the body, such as is seen with fever, cough, vomiting or diarrhea. They also inhibit Th2 cell activity, the subset of T helper cells whose function aids ‘humoral’ immune responses and that are also associated with the secretion of anti-inflammatory cytokines.
The Humoral immune system plays a strong role in allergic diseases, in asthma, eczema, atopic dermatitis and extracellular infections. Humoral immunity is more of a non-specific response, is associated with Th2 cell activity, and is immunity that tends to internalize infections, often leading to chronic ongoing infection and/or hypersensitivity. A newborn child is born with an immature cell-mediated immune system, has Th2 dominance and therefore relies more upon maternal antibodies. With maturation and age, this tendency of a Th2 dominant immunity (humoral) gradually shifts towards more of a Th1 dominant (cell mediated) immunity. The maturation of their (cell mediated) immune system is actually achieved through illness/inflammation. In the case of vaccinations, the vaccine antigens are intended to stimulate a Th2 response, thereby never resulting in actual immunity but instead, resulting in more of a chronic ongoing infection. Strong humoral responses will inhibit cell mediated responses to the same antigen and vice versa in that, it is the humoral or cell mediated system that responds, not both.
Although a healthy immune system (Immunostasis) requires a balance between both Th1 and Th2 cell responses , a high Th1/Th2 cell ratio is required for protecting the body against viruses, fungi, parasites, Protozoa, Cancer, from Allergies and from transplant rejection.
Immune-System
Psychoneuroimmunology, a term coined by Dr Robert Ader in 1981 is the study of the relationship between thought, mood, behavior and immune function. Love, happiness positive emotions, laughter and a good mental attitude have been shown to have an exceptionally powerful effect on immunity and a person’s ability to cope with disease. Through laughter and feeling positive emotions a person can psychologically increase their Th1/Th2 ratio.
A Th1/Th2 ratio can also be increased through nutritional supplementation. Th1 ‘up regulators’ include Probiotics, Fish Oils, Shiitake Mushrooms, Melatonin, Selenium, Zinc and Antioxidant supplements. , , .
Participating in low intensity exercise, particularly walking, Tai Chi, Qigong or Yoga, has been shown to have the ability to increase a person’s Th1/Th2 ratio. In one particular study, Tai Chi was shown to boost the participants cell mediated immunity whilst in another, Th1/Th2 ratios in type 2 diabetics were pushed more towards Th1 after participation in a 12-week program of Tai Chi. The positive effect of Qigong on the immune system was also indicated by a study in 1995 along with another study supporting the beneficial changes on immunity through yoga practice. It has been proposed that Tai Chi, Yoga and Qigong all have the ability to boost a person’s Th1/Th2 cell ratio in that all these forms of exercise similarly have slow controlled meditative type movements, a focus on the breath and the ability to reduce stress levels, in common.
Conversely, there are also many known factors that can contribute to a low Th1/Th2 ratio pushing the balance of Th1 to Th2 cells in the direction of Th2 dominance. Pregnancy, particularly the progesterone hormone of pregnancy, results in 9 months of Th2 dominance, due to progesterone’s ability to suppress Th1 cells. , Progesterone modulates the Th1/Th2 balance in pregnancy with evidence indicating “the maternal immune system may tolerate fetal antigens by suppressing cell-mediated immunity while retaining normal humoral immunity” . This occurs so that both the pregnant mother and fetus’s bodies, both demonstrating Th2 dominance, do not recognize each other as being foreign, thereby avoiding an unwanted immune attack.
Prenatal stress has also been shown to have an inducing effect on generating a low Th1/Th2 ratio in the fetus. Stress in the pregnant mother causes an elevation in levels of cortisol, and although the placenta will ‘inactivate’ the majority of this cortisol circulating within the maternal circulation, 10-20 % of this cortisol does pass onto the fetal circulation. Raised cortisol (stress hormone) levels result in a depressed immune system and a low TH1/TH2 ratio.
When a child is born vaginally, their first ‘meal’ is the cervical/vaginal flora (good flora) they receive when passing through the birth canal. This is their first contact (coming from the placental environment) with the ‘outside’ world and it is this exposure to the vaginal bacteria that stimulates the Th1 cells for the very first time. In the case of a baby born by C-section, they miss out then on this contact with the vaginal flora and as such, a child who is born via cesarean section is likely to have a lower Th1/Th2 ratio in the neonatal period than that of a child born naturally.
The nutrition that a baby receives after it is born also plays an extremely important role in the development of that child’s immune system. Colostrum has been shown to have an enhanced effect on the synthesis of Interleukin 2 (IL-2) (which is associated with cell-mediated immunity) and this then followed by feeding the child with breast milk also enhances the immunologic capabilities of the newborn. There are significant numbers of studies supporting the benefits of breast milk as opposed to formula milk in the development of a child’s cell mediated immunity thereby evidencing that formula fed infants are at risk of developing a low Th1/Th2 ratio. Formula-fed children do not receive the maternal antibodies found in breast milk and have been found to be more susceptible to (respiratory tract and urinary tract) infections and Otitis media.
Vaccinations given in early childhood stimulate a Th2-type immune response and in particular, delaying DPT vaccination in infants has been shown to reduce the risk of childhood asthma , a Th2 dominant condition. Another study also suggests that low-risk children in families that refuse vaccination are less likely to report asthma and other allergic symptoms thereby further supporting that vaccinations are Th2 ‘up regulators’ which contribute to a low Th1/Th2 ratio in children.
Antibiotic use us early infancy has also been shown to disrupt the Th1 /Th2 balance causing a shift towards Th2 dominance. This is thought to occur due to the disruption of intestinal micro-flora preventing Th1 cell maturation.
child sleepingSleep has also been shown to have an effect on the Th1/Th2 balance. Sleep induces a shift in the Th1/Th2 balance towards increased Th1 activity and conversely insomnia unrelated to medical disorders has been shown to cause a shift in the Th1/Th2 balance toward Th2 dominance. This exemplifies the importance of infants (and adults also for that matter) getting good quality sleep to prevent Th2 dominant immunity.
Where happiness, exercise and a positive mental attitude all contribute to a high Th1/Th2 ratio, depression, a sedentary lifestyle and negative attitudes can also disrupt the Th1/Th2 ratio leading to Th2 dominance.
A Th2 dominant child receiving chiropractic care would also benefit from taking pro-biotic and fish oil supplements as part of their care program, amongst other mineral supplementation mentioned previously. Parents should also be advised of the benefits of a diet rich in antioxidants in conjunction with their child receiving enough good quality sleep and participating in regular physical activity. In addition to chiropractic adjustments, these additional lifestyle changes would help to restore balance in their child’s (Th2 dominant) immune system more effectively. Freeing a child’s spine of nervous system interference not only restores function to that child’s body, but also allows them to better reap the benefits of these new integrated lifestyle changes. Dependant of the child’s birth and vaccination history, and whether or not a child was breast-fed or has ever received antibiotics, the chiropractor may choose to initially schedule adjustments more frequently until restoration of immune function (and nervous system function) is evident.
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Cited by 
Dr. Karen Jaffe, D.C., CACCP

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