The results of a recent study have shown that the specific location of the TRAF1 (Tumor Necrosis Factor-Receptor Associated Factor 1) and C5 (complement component 5) may have an important role in multiple autoimmune diseases, including type 1 diabetes and systemic lupus erythematosus (SLE). This is information reported by lead researcher Ms. Fina Kurreeman, of Leiden University Medical Center in The Netherlands, at the 2008 Annual Congress of the European League Against Rheumatism (EULAR), in Paris, France.

Both TRAF1 and C5, immune-related genes which sit adjacent to one another on chromosome 9 at location q33-34, are thought to be closely involved in the onset and/or perpetuation of the inflammatory process. The TRAF1/C5 gene has previously been established as a genetic risk factor for rheumatoid arthritis. In the study reported by Ms. Kurreeman, a further link was found between the gene location and the presence of autoantibodies (antibodies against antigens naturally occurring in the human body commonly found in patients with immune disorders). Because many autoimmune disorders tend to coexist within a given family as well as in an individual, the indication is that there may be a common genetic pathway. This was something that the researchers were eager to investigate.

In this study, genotyping of 735 type 1 diabetes patients and 746 SLE patients from Spain and The Netherlands identified a significant association of one part of the TRAF1/C5 gene with type 1 diabetes (odds ratio 1:14,p=0.027) and SLE (odds ratio 1.16,p=0.016). In order to test the reliability of this finding, researchers replicated the test in a homogeneous patient population originating from Crete, where an increase in the same part of the TRAF1/C5 gene also was observed when compared to respectively matched controls (odds ratio 1.64,p=0.002); odds ratio 1.43,p=0.002).

A further joint analysis of all type 1 diabetes patients (n=834) and SLE patients (n=1018) yielded a common odds ratio of 1.19,p=0.002) and 1.22,p<0.001, respectively) indicating that this genetic risk factor has modest effect sizes in these diseases.

Ms. Kurreeman commented, "We hope that further study will give an insight into potential shared genetic pathways across autoimmune disorders and may even stimulate innovation into novel therapeutic targets in the future."
_________
Adapted from "Specific Location Of The TRAF1/C5 Gene Associated With Multiple Autoimmune Diseases," SCIENCE DAILY, June 13, 2008