The specificity of monoclonal anti-citrulline protein antibodies.

I read with great interest the article by Steen et al demonstrating that human plasma cell-derived monoclonal antibodies to post-translationally modified proteins recognize amino acid motifs rather than specific proteins (1). However, I believe some potentially misleading conclusions are drawn. In their paper, they report the isolation of IgG-secreting synovial plasma cells from one presumably high ACPA responder RA patient, followed by generation of the corresponding recombinant antibodies for evaluating their specificities and functions. This article is protected by copyright. All rights reserved.