Important control mechanism behind autoimmune diseases discovered

ScienceDaily (May 4, 2010) —Researchers at Karolinska Institutet have discovered a new controlmechanism in our immune system. The discovery is of potentialsignificance to the treatment of serious diseases such as MS (multiplesclerosis), rheumatoid arthritis, and SLE (systemic lupuserythematosus).
"Now that we've started to understand the regulatory mechanismsinvolved in these autoimmune diseases, we are hopeful that newtreatments can be found," says Mikael Karlsson, associate professor atthe Department of Medicine at Karolinska Institutet in Solna, and one ofthe team behind the study now published in the highly reputedperiodical, The Journal of Experimental Medicine.
An important component of our immune defence is a type of cell calleda B cell. Normally, the job of these cells is to produce antibodies,which in turn bind to and neutralise invasive microorganisms, such asbacteria and viruses. In people with an autoimmune disease, explains DrKarlsson, these B cells actually have an injurious effect and instead ofserving the body, are activated against its own tissues, which theystart to break down.
Patients with SLE and other autoimmune diseases have lower levels ofso-called NKT cells. Previously, it was not known what part these cellsplay in the origin and development of the disease; now, however, theresearch group at KI has shown that this deficiency is a contributorypathogenic factor.
"We've demonstrated that NKT cells can regulate how B cells becomeactivated against healthy tissue, and that a lack of NKT cells resultsin greater misguided B cell activation," says Dr Karlsson. "So now wecan mechanically link the NKT cell defect in patients to the disease."
The study also shows that the NKT cells directly impede faulty B cellactivation, and that they do so early in the misdirected process. Theteam managed to inhibit the activity of pathogenic B cells by adding NKTcells -- a result that may one day lead to new types of treatment.
"This means that new treatments specifically targeting the protectiveNKT cells can help this patient group," concludes Dr Karlsson.
Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.