This study explored whether testing for anti-CCP3 antibodies in people who have musculoskeletal (MSK) symptoms but tested negative for anti-CCP2 antibodies could help predict the development of inflammatory arthritis (IA) or rheumatoid arthritis (RA). A total of 469 anti-CCP2 negative individuals with new MSK symptoms were studied. They were given anti-CCP3 tests, and their health was checked a year later to see if any developed IA or RA.
Results showed that very few (13%) progressed to IA or RA. Anti-CCP3 antibodies were found in only 3.4% of these individuals, but those with positive anti-CCP3 tests were more likely to report a worsening condition and be diagnosed with IA, though not necessarily RA. The results also indicated that lowering the threshold for anti-CCP3 positivity might improve its ability to predict disease progression.
Overall, while anti-CCP3 antibody testing had low sensitivity (ability to detect those who will develop the disease), it had high specificity (ability to correctly identify those who will not progress to IA/RA). The study suggests that anti-CCP3 antibodies could help predict the progression of IA or RA in patients who are anti-CCP2 negative, but further research is needed to fine-tune the testing criteria.