Background/Purpose:

Tobacco smoke has been associated to anti-cyclic citrullinated peptide (anti-CCP) antibodies positivity. Recently, in wood-smoke-induced chronic obstructive pulmonary disease (COPD) patients without rheumatoid arthritis (RA), anti-CCP antibody higher titers have been reported than in healthy individuals and tobacco-induced COPD. The anti-CCP and rheumatoid factor (RF) titers have not been examined in rheumatoid arthritis patients with biomass smoke exposure. The objective of the present study is to report the correlation between anti-CCP, IgG, IgM and IgA RF to biomass exposure index (BEI).

Methods:

A cross-sectional study was designed based on a cohort of Hispanic RA patients recruited from September 2014 to April 2015. All fulfilled the 1987 ACR and the 2010 ACR/EULAR classification criteria for RA. Biomass smoke exposure was expressed with the BEI calculated as the average hours of exposure per day multiplied by the number of years. Patients with a minimum exposure of 1 BEI were included. RF and Anti-CCP were measured by ELISA with cutoff points of <5U/mL and <20U/mL respectively. Sample calculation expecting a 0.5 correlation determined the need of at least 30 subjects.

Results:

Out of the 102 patients in the cohort, 46 (44.6%) had a BEI equal to or higher than 1 and were included in the analysis. A total of 41 (89.1%) were women with a mean age of 61.06 ±8.82 years and mean disease duration of 12.47 years ±8.81. None had renal or pulmonary disease at baseline. Activity by DAS28 ESR was 3.69 ±1.50 (moderate activity). The median BEI was 42 (p25=30, p75=80.25). All of the exposure was due to in-house cooking with wood. Anti-CCP positivity was present in 33 (71.7%) with a median titer of 150.10 U/mL (p25=2.74, p75=200). IgG RF was present in 11 (23.9%) at a median titer of 8.88 U/mL (p25=4.31, p75=19.98), IgA in 28 (60.9%) with a mean titer of 79.75 U/mL ±77.93, and IgM in 41 (89.1%) with a median of 112.91 U/mL (p25=67.77, p75=200). Spearman’s rho correlation showed no significant correlation between BEI and anti-CCP (p=0.386, rho= -0.131), IgG RF (p=0.147, rho= -0.217), IgA RF (p=0.501, rho= -0.102) and IgM RF (p=0.874, rho=-0.024). Additionally, no difference was found between exposed and not exposed patients regarding anti-CPP (p=0.715), IgG (p=0.335), IgA (p=0.954) and IgM (p=0.433) RF within the cohort. 

Conclusion:

In this Hispanic cohort of established rheumatoid arthritis patients with moderate disease activity exposed to biomass smoke, no correlation was found between BEI and anti-CCP, IgG RF, IgA RF, or IgM RF.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/anti-cyclic-citrullinated-peptide-antibodies-and-rheumatoid-factor-in-rheumatoid-arthritis-hispanics-exposed-to-biomass-smoke/