I saw this yesterday on the Yahoo Groups / PBC Organization (US) and thought I'd pass along to those of you who like to stay current on research.
Dr. Gershwin's PBC Research Update
Despite major advances in the treatment of rheumatoid arthritis and other
autoimmune diseases through the use of biologic agents, there has been a
relative lack of effort and success in primary biliary cirrhosis (PBC). There
are several reasons for this. One reason is that there are a relatively
small number of affected people and thus industry is not as interested in
major investments of their time and money. In addition, there is also only a
handful of researchers who study mouse models of primary biliary cirrhosis.
Mouse models are a major tool and resource to apply new therapeutic
efforts that can ideally be applicable to humans. Our own group, and particularly
through the help of the PBCers, has been studying a mouse model in which
experimental animals are injected with a chemical that is very similar to
something found in cosmetics and some foods.
This compound is called 2-octynoic acid and we identified this putative
chemical as a possible risk factor for PBC following intensive studies with a
technique called quantitative structure activity relationships (QSAR) with
human PBC sera. In fact, the sera we used to identify this chemical was
given by many dozens of PBCers at the many local and regional meetings that
we held in Davis and throughout the West Coast, and even including the
meeting we had in Las Vegas several years ago. In any case, our laboratory
believes that there is a critical involvement of something called autoreactive
T cells. These cells lead to the destruction of bile duct cells, and we
have demonstrated that one such population of T cells, called CD8 T cells,
play an exceedingly important role.
Based on this information, we have been attempting to control the
activation of these T cells and prevent their movement into the liver of our mice
with PBC. We believe that by reducing the ability of these cells to become
abnormal, we will reduce liver inflammation. The following is a little bit
complicated but essentially the activation of these T cells requires two
critical signals. There is also, and very importantly, a receptor found on T
cells which is called cytotoxic T lymphocyte antigen 4 (CTLA4). The
ability to interrupt the function of CTLA4 has already been successfully used to
treat rheumatoid arthritis. We treated our mice to reduce the activation
of T cells by blocking this receptor. Importantly we have shown that
treatment with this compound called CTLA4-Ig, led to a significant reduction in
liver disease, including reducing the inflammation and the severity of the
bile duct injury.
Our data suggest that an experimental clinical trial with this drug is
warranted in humans and we hope it will become an impetus for other efforts at
newer biologic therapy. We are very excited about this result, not only
because of its potential for a clinical trial, but also it helps us
understand the mechanisms by which bile duct injury occurs in sufferers of PBC.
Our mouse work continues and we hope will continue to lead to advances in the
treatment of PBC.
M. Eric Gershwin M.D., M.A.C.P., M.A.C.R.
Distinguished Professor of Medicine
The Jack and Donald Chia Professor of Medicine
Chief, Division of Rheumatology, Allergy and Clinical Immunology
451 Health Sciences Dr. Suite 6510
University of California at Davis
Davis Calif 95616