title: Serum anticyclic citrullinated protein antibody titers are correlated with the response to biological agents in patients with rheumatoid arthritis.
abstract: Anticyclic citrullinated protein antibody (ACPA) is known as an important indicator for diagnosis of rheumatoid arthritis (RA). Our aim was to examine the relationship between the serum ACPA titer at baseline and responsiveness to biological agents (antagonists of either tumor necrosis factor or interleukin 6) in patients with RA. ACPA was measured using second-generation chemiluminescent enzyme immunoassay. Disease activity was assessed using disease activity scores 28. Fifty-seven RA patients with biological agents were enrolled, and the median ACPA titer at baseline was 110.0 U/mL. The median ACPA titer was 23.3 U/mL and 183.0 U/mL in the good and moderate response groups, respectively, which were significantly lower than in the no response group (404.0 U/mL). In addition, 69.2% and 26.9% of patients with low (<100 U/mL) and moderate (100-499 U/mL) basal ACPA titers showed a moderate to good response. Of the patients with higher (≥500 U/mL) basal ACPA titers, only 14.0% and 42.5% showed a good or moderate response, respectively. The remission rate was 77.8% in the ACPA-negative, which was significantly higher than the rate of 25% in the ACPA-positive patients. The results suggest that the ACPA titers are correlated with the efficacy of the biological agents used in patients with RA.
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Ryo
authors: R
authors: Takahashi
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Sakiko
authors: S
authors: Isojima
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Masayu
authors: M
authors: Umemura
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Yoko
authors: Y
authors: Miura
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Nao
authors: N
authors: Oguro
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Syo
authors: S
authors: Ishii
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Shinya
authors: S
authors: Seki
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Takahiro
authors: T
authors: Tokunaga
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Hiroyuki
authors: H
authors: Tsukamoto
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Hidekazu
authors: H
authors: Furuya
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Ryo
authors: R
authors: Yanai
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Tsuyoshi
authors: T
authors: Kasama
keywords: biological agents; remission