Source: Nervenarzt  |  Posted 9 years ago

Autoantibodies may play a pathological role in systemic autoimmune diseases, suggests recent research from Japan.

Previously, researchers at St Marianna University School of Medicine and the National Sagamihara Hospital in Kanagawa had reported that autoantibodies to the main epitope on CD69 had reacted to its homologous amino-acid sequence in low-density-lipoprotein-receptor-related protein 2 (LPR2). This is normally responsible for the reabsorption of protein.

Consequently, they furthered their research to investigate the prevalence of autoepitope distribution and the clinical significance of the autotabs to LRP2 in an unspecified number of patients with systemic autoimmune diseases. These were detected in the sera of patients with diverse rheumatologically defined diseases including rheumatoid arthritis (RA), systemic lupus erythematosus, Behcets disease, systemic sclerosis and osteoarthritis before being mapped autoepitopes.

A total of 87% of patients with rheumatoid arthritis were found to have these autoAbs as were 40% with SLE and 35% with systemic sclerosis. In addition, the autoantibodies were detected in 15% of patients with osteoarthritis and 3% with Behcet's disease.

The researchers further noted that most of the anti-LRP2 + serum samples recognised the presence of multiple epitopes on LRP2. While most of the tested anti-CD69 autoAb + samples reacted to LRP2-F3 which contained the homologous sequence to the main CD69 epitope, only 38% of the anti-LRP2-F3+ reacted to CD69.

Clinically, the presence of proteinuria in rheumatoid arthritis was seen to correlate with autoantibodies to LRP2-F4, -F5 and -F6 and the study noted that LRP2 is a major autoantigen in this specific rheumatologic disease.