van Delft MAM, et al. – In this research work, the scientists explored the Anti–carbamylated protein (anti–CarP) antibody isotype and IgG–subclass usage in rheumatoid arthritis (RA) patients. They discovered that the anti–CarP antibody response uses a broad spectrum of isotypes and appeared to be an actively ongoing immune reaction, in RA. In addition, the anti–CarP and anti–citrullinated protein antibody (ACPA) autoantibody responses appeared to be differentially regulated.