Download Hygiene hypothesis and allergic pathologies

Hygiene hypothesis and allergic
pathologies.
“another problem with having
money”
Introduction- What is the Hygiene
Hypothesis
• Definition 1: The hygiene hypothesis, suggests an
inverse relation between the incidence of
infectious diseases in early life and the
subsequent development of allergies, asthma and
recent evidence suggests also autoimmune
disorders.
• Definition 2:The hygiene hypothesis states that a
lack of early childhood exposure to infectious
agents, symbiotic microorganisms (e.g., gut
flora or probiotics), and parasites increases
susceptibility to allergic diseases by suppressing
natural development of the immune system
Introduction- What is an allergy
• A common example is allergic rhinittis
caused by the body reaction to harmless
pollen as a forgein and dangerous
subtance .
• This leads to a immune response which
leads to antibodies being produced
against pollen.
• This leads to typical symptoms of
inflammation :rubor tumor calor dolor.
Introduction- What is an
autoimmune disorder.
• A common example is multiple sclerosis
caused by the body reaction to its own nerve
bodies which are detected are forgein.
• This leads to a immune response which leads
to destruction of the bodies own nerve
strutures.
• Other examples frequently encountered
include : SLE, Rheumatic fever, Hasimotos
throiditis.
IMMUNOREGULATORY SUBSETS OF T CELLS
- mature T cells (TH0) differentiate into functionally distinct
subsets after antigen stimulation
presentation
of microbial. Ag
(LPS, CpG, lipoteichoic a.)
presentation of
environmental. Ag
nonmicrobial origin
TH0
(allergens)
dendritic c., macrophage,
B-cells,
intensive, long term
IL-12
TH1
TH1
TH1
cytotoxic reactivity
immunopathological reaction
IVth type
weak, short term
IL-4
INHIBITION
TH2
TH2
TH2
antibodies production, isotypic switching
immunopathological reaction Ist
type
Pathogensis
• Allergic diseases are caused by harmless antigens such as
Pollen in allergic rhinittis (hayfever) via Th2
• Many bacteria and viruses elicit a Th1-mediated immune
response, which down-regulates Th2 responses.
• Insufficient stimulation of the Th1 arm, leads to an overactive
Th2 arm, stimulating the antibody-mediated immunity of the
immune systems, which leads to allergic reactions within the
body.
• The major proposed alternative mechanistic explanation of
the rise in autoimmune dieseases is that the developing
immune system must receive stimuli (from infectious agents,
symbiotic bacteria, or parasites) in order to adequately
develop regulatory T cells.
Expansion of theory.
• It can be put simple layman terms that the immune system
needs training i.e exposure to forgein bodies to work properly
, due to modern practises of elminating all bacteria where
possible (e.g pasteuration of milk) has meant that in devolped
countries both allergic and autoimmune dieseases have
increased signifcantly.
• H. pylori has been with humanity since before we left Africa.
In days of old, when humans routinely encountered H.
pylori early in childhood, the bug taught their immune cells
tolerance and protected against asthma. Now, since we grow
up in cleaner environments, we encounter it later. Not only
does its early absence predispose to asthma, its late
introduction induces ulcers.
• It is proven that H pylori protects against heartburn,
esophageal cancer, asthma, and eczema.*
Outcomes
Helminthic therapy, a type of immunotherapy, is
the
treatment of autoimmune diseases and
immune
disorders by means of deliberate infestation
with a
helminth or with the ova of a helminth.
Helminths are
parasitic worms such as hookworms and
whipworms.
Supporting
Evidence
“The Hygiene Hypothesis originated with earlier experiments with
animals, mainly mice and rats born and raised in "germ-free" or
sterile environments. When experimentally exposed to low doses of
an infectious agent that would not harm normally raised rodents,
these germ-free adolescent and young adult animals became
infected quickly and often died”
Medicine.net Charles P. Davis, MD, PhD
Supporting
Evidence
“Sardinians are an isolated, inbred group, and they have
experienced a twin epidemic of multiple sclerosis and type I
diabetes, both autoimmune diseases, in the past sixty years—ever
since they got rid of malaria. For the past few thousand years, those
Sardinians that were genetically resistant to the malaria parasite
survived; those that were not did not. The relentless presence of
malaria in their environment shaped their genomes.”
Velasquez-Manoff- An Epidemic of Absence: A New
Way of Understanding Allergies and Autoimmune Diseases
Bilbography
• Commentary. The coming-of-age of the hygiene hypothesis
Fernando D Martinez http://link.springer.com/article/10.1186/rr48
• http://en.wikipedia.org/wiki/Hygiene_hypothesis
• http://www.medicinenet.com/script/main/art.asp?articlekey=155757
• Velasquez-Manoff- An Epidemic of Absence: A New Way of
Understanding Allergies and Autoimmune Diseases
• http://www.helpmychronicpain.com/Portals/67234/images/Screen%2
0shot%202011-10-23%20at%2012.09.05%20PM-resized-600.png
• http://seekingalpha.com/article/329752-coronado-biosciencesphase-ii-trials-provide-multiple-shots-on-goal
• http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1782226/