Anti-carbamylated protein antibodies as a clinical response predictor in rheumatoid arthritis patients treated with abatacept.

Abstract

OBJECTIVES:

Carbamylation is an irreversible post-translational modification of proteins. The presence of anti-carbamylated protein antibodies (anti-CarP) has been observed in rheumatoid arthritis (RA). This study was focused to verify whether anti-CarP antibodies can be used as a predictive factor of clinical response to abatacept (CTLA4-Ig) in RA patients.

METHODS:

Sixty RA patients treated with abatacept were enrolled. A home-made ELISA for anti-CarP and a commercial anti-CCP3.1 kit for anti-citrullinated proteins antibodies (anti-CCP) were applied to determine serum levels every six months of therapy. Rheumatoid factor (RF) was also tested.

RESULTS:

Anti-CarP positive patients (n=18) were younger (p=0.01) and with a longer disease duration (p=0.05) when compared to anti-CarP negative patients (n=42) at baseline. Considering the entire cohort, a significant reduction of anti-CarP titre after twelve-months of treatment was shown (p<0.01). A significant reduction of Disease Activity Score (DAS) 28-C-reactive protein (CRP) in the first six months of therapy was found in the subgroup of anti-CarP positive patients in comparison with the negative ones (p=0.003). No significant results were found by dividing the cohort using the positivity to anti-CCP and/or RF.

CONCLUSIONS:

Earlier onset and a longer disease duration in anti-CarP positive patients might suggest they are specific risk factors for RA in this subgroup of patients. The correlation between the anti-CarP positivity at baseline and the reduction of disease activity during the first six months of treatment with abatacept allowed us to hypothesise that anti-CarP antibodies, but not anti-CCP and/or RF, could be used as a good clinical response predictor.

• Authors: Rajesh Kumar, Silvia Piantoni, Michele Boldini, Emirena Garrafa, Chiara Bazzani, Micaela Fredi, Roberta Ottaviani, Ilaria Cavazzana, Angela Tincani, Franco Franceschini
• Journal: Clinical and experimental rheumatology (Clin Exp Rheumatol) 2021 Jan-Feb Vol. 39 Issue 1 Pg. 91-97 ISSN: 0392-856X [Print] Italy
• PMID: 32359037 (Publication Type: Journal Article)

Chemical References

• Autoantibodies
• Peptides, Cyclic
• Abatacept
• Rheumatoid Factor

Topics

• Abatacept (therapeutic use)
• Arthritis, Rheumatoid (diagnosis, drug therapy)
• Autoantibodies
• Humans
• Peptides, Cyclic
• Rheumatoid Factor