New autoantigens significantly associated with early RA

New autoantigens were significantly associated with the sera of patients with early rheumatoid arthritis and could be used for early disease diagnosis, according to recent study results.

French researchers tested sera from 20 patients with rheumatoid arthritis (RA) disease duration of less than 1 year, 19 patients with RA duration of more than 5 years and 23 controls (seven patients with ankylosing spondylitis, two with systemic lupus erythematosus, four with systemic sclerosis and 10 healthy patients). All were screened for 8,268 human protein arrays that were detected and validated by ELISA assays using 25 purified proteins. RA sera activity was analyzed through epitope mapping with overlapping 15-mer peptides.

The autoantibodies of RA patients with disease duration of less than 1 year preferentially recognized three proteins: WIBG within BGCN homolog (Drosophila), GABA(A) receptor associated protein like 2 (GABARAPL2) and zinc finger protein 706 (ZNF706).

“Of interest, autoantibodies to WIBG are very specific for early RA,” the researchers reported.

Thirty-three percent of the sera of the patients with RA of less than 1 year recognized WIBG, compared with 5% of sera of the other RA cohort and 2% of controls. Early RA patients’ sera preferentially recognized three linear peptides of WIBG, GABARAPL2 and ZNF706.

“There is a great need for new biological markers of RA to permit early intervention to potentially prevent inflammation and joint destruction,” the researchers concluded. “We found and validated three new autoantigens significantly associated with early RA patients. These autoantigens (ZNF706, GABARAPL2 and WIBG) and peptides derived from these autoantigens can be used to identify RA at the early stage of the disease.”

Disclosure: A patent was submitted by Inserm Transfert in May 2011, and the study was partially funded by Inserm.

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Source: Charpin C. Arthritis Res Ther. 2013;doi:10.1186/ar4255.