iThei mdcdaelcinfd o c elllllrllll mmthsl mbThkThhps“Your present circumstances don’t determine where you
can go; they merely determine where you start.”
—Nido Qubein10: Immune Imbalance
The Chicken or the Egg?
An alternative theory to pathogens causing autoimmunity is that autoim-
munity impairs our ability to keep the pathogens under control, and thus
people with autoimmune conditions may test positive for more patho-
gens than those without autoimmune conditions.
When considering targets for therapy, we always look at systems that are
malfunctioning. Scientists examine immune system imbalance to iden-
tify potential opportunities to impact autoimmune conditions.
Immune System Overview
White blood cells (also known as leukocytes) are immune cells that help
us defend against foreign invaders and infections. They are produced in
the bone marrow and can develop into a few different types of cells, in-
cluding lymphocytes (lymph cells).
Lymphocytes are further differentiated into B cells (these make antibod-
ies that mark pathogens by binding to them to aid in their destruction);
natural killer (NK) cells (these target infected or cancerous cells), and T
cells. T cells are the main cell types implicated in host defense (fighting
pathogenic invasions like our friends the CD8+ T cells) and autoimmu-
nity, specifically the T helper (Th) cells.
When responding to threats, the immune system decides which types of
cells should be produced. All Th cells start as naïve T-helper cells (Thp)
and are produced in the bone marrow. They are further differentiated
into three different cell types: 1) Th1 cells are produced in response to
bacteria and viruses, 2) Th2 cells are summoned in response to parasites,
and 3) Th17 cells are called in response to fungi. Additionally, the thy-
mus produces T regulatory cells, which are responsible for suppressing
the immune response and for self-tolerance.
Each T-cell type produces different interleukins (IL) that act as signaling