T-Lymphocytes - Chronic Obstructive Pulmonary Disease - page 236

Figure 8 Role of immune tolerance in the development of autoimmune disease and
possibly COPD. The left panel represents zero tolerance and the full-blown disease.
The right panel represents 100% tolerance and no disease. Since tolerance is not an
all or nothing phenomenon, different degrees of tolerance = immunity would produce
different disease severity (between left and right panels). The degree and persistence
of the innate immunity which conditions the costimuli, and thus the microenviron-
ment of the DCs could be the most important determinant of the immunity =
tolerance balance.
inhibit other immune cell functions, either directly through cell-cell contact
or indirectly through the secretion of anti-inflammatory mediators such as
IL-10, TGF-b, or IL-4 (213). The importance of these cells in the prevention
of Type I diabetes development in predisposed individuals has recently been
demonstrated (214).
A recent report by Barcel´ et al. (215) showed that smokers who
develop COPD have a deficient response of CD4 þ CD25 þ regulatory
T-cells in the BAL and the peripheral blood. This observation opens up
an important area of research in the immunology of COPD, and we await,
with interest, further developments in this field.
Genetic factors might ultimately be responsible for the disturbance in
the natural balance between immunogenic and tolerogenic stimuli that can
give rise to autoimmune disease. The predisposition to autoimmune disease
represents the net effect of enhancing and protective genes (216,217), and as