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Anti-CCP Elevated in Sputum of RA Patients’ FDRs
Arthritis Rheumatol; ePub 2017 Feb 9; Demoruelle, et al
Anti-cyclic citrullinated peptide (anti-CCP) is elevated in the sputum of first degree relatives (FDRs) of rheumatoid arthritis (RA) patients, including seronegative FDRs, suggesting the lung may be one site of anti-CCP generation in this population, a recent study found. The association of anti-CCP with elevated cell counts and neutrophil extracellular trap (NET) levels in FDRs supports a hypothesis that local airway inflammation and NET formation may drive anti-CCP production in the lung and may promote the early stages of RA development. Researchers evaluated induced sputum and serum from 67 FDRs and 20 RA subjects for anti-CCP-IgA and anti-CCP-IgG, with cut-off levels for positivity determined in a control population. They found:
- Sputum anti-CCP-IgA and/or anti-CCP-IgG was positive in 17/67 (25%) FDRs and 14/20 (70%) RA subjects, including a portion of FDRs who were serum anti-CCP negative.
- In FDRs, elevations of sputum anti-CCP-IgA and anti-CCP-IgG were associated with elevated sputum cell counts and levels of NET complexes.
Demoruelle MK, Harrall KK, Ho L, et al. Anti-citrullinated protein antibodies are associated with neutrophil extracellular traps in the sputum in relatives of rheumatoid arthritis patients. [Published online ahead of print February 9, 2017]. Arthritis Rheumatol. doi:10.1002/art.40066.