Fw: Self-Antigen May Perpetuate Lyme Disease Arthritis

[Guest guest]

Thought some of you might be interested in this. Theres a lot more lyme out there than we know and it is a lot more contagious than previously thought. kathy

http://rheumatology.medscape.com/reuters/prof/2001/05/05.07/20010504scie004.html

Self-Antigen May Perpetuate Lyme Disease Arthritis

WESTPORT, CT (Reuters Health) May 04 - A self-antigen, LFA-1aL, present on many immune cells, may perpetuate Lyme disease arthritis by stimulating the proliferation and activity of T cells primed against a Borrelia burgdorferi (Bb) surface protein.

Treatment-resistant Lyme arthritis is a chronic disease in which joint inflammation persists after the bacterium has apparently been eliminated, the authors explain. Prior studies demonstrating cross-reactivity between self and Bb antigens implicate a possible autoimmune mechanism, they add.

In a study reported in the April 15th issue of the Journal of Immunology, Dr. Brigitte T. Huber, from the Department of Pathology at Tufts University School of Medicine in Boston, and colleagues used T cells from transgenic mice and cloned human cells to assess a possible role for molecular mimicry in Lyme disease arthritis.

The T cells from the mice were hybrids against the outer surface protein A (OspA) of Bb. The cloned human T cells, which came from five patients with Lyme disease, were specific for the immunodominant epitope of OspA, the researchers state.

The immunodominant epitope stimulated almost all of the cloned human cells to proliferate and secrete interferon-gamma and interleukin (IL)-13, the investigators note. The self-antigen LFA-1aL only stimulated 10% of the clones to proliferate, but it caused a much greater percentage to secrete IL-13.

Assays with the murine cells revealed that much higher concentrations of LFA than OspA-monomers were needed to stimulate dual-reactive T cell hybrids, the investigators point out.

" The present data support a role for molecular mimicry in treatment-resistant Lyme arthritis, because cells derived from a single OspA-specific T cell are able to proliferate and secrete cytokines in response to a self antigen, LFA-1aL, " the researchers conclude.

J Immunol 2001;166:5286-5291.

Copyright © 2001 Reuters Ltd-------------------------------------------------