Quantification and Molecular Characterization of Anti-citrulline Antibodies in Rheumatoid Arthritis

Autoimmune diseases are believed to result from the inability of the immune system to distinguish self and non-self. Rheumatoid Arthritis (RA) is a systemic autoimmune disease that leads to joint destruction and affects more than 1.5 million adults (Centre for Disease Control). Auto-antibodies against citrullinated proteins (ACPA) are present in approximately 60-75% of RA patients with 96% specificity. Although the importance of ACPA, both as a causative agent and diagnostic marker, has been established, the reactivities of single ACPA and the eptiopes are unknown. Isolation and characterization of protein targets of ACPA would shed light on the underlying mechanism of RA and would offer (i) earlier diagnosis and (ii) routes for therapeutic intervention. Here, we employ a novel high-throughput methodology, microengraving, based on fabricated nanowells arrays, to isolate antibodies from stimulated memory B cells of RA patients. In conjunction with single-cell RT-PCR amplification this technique is employed to perform molecular characterization of ACPA antibodies.