Article Text

AB0312 Effect of tocilizumab on anti-cyclic citrullinated peptide antibodies and rheumatoid factor in patients with rheumatoid arthritis
  1. M. Sato1,
  2. M. Takemura2,
  3. K. Shimizu1
  1. 1Orthopaedic Surgery
  2. 2Informative Laboratory Medicine, Gifu University School of Medicine, Gifu, Japan


Background Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by synovial inflammation that eventually results in joint destruction and functional damages. Rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibodies (anti-CCP) are useful diagnostic tools for subclinical and early RA. RF titers decrease with successful drug therapy. Some reports have shown that tumor necrosis factor (TNF)-alpha blockers reduce anti-CCP.

Objectives To analyze the effect of tocilizumab (TCZ) therapy on anti-CCP and IgM RF in patients with RA.

Methods Forty-six patients (38 women and 8 men; mean age 58.3 years, range 25 – 76 years) treated with TCZ were enrolled. All patients met the American College of Rheumatology classification criteria for RA. Patients received 8 mg/kg TCZ intravenously every 4 weeks. Serum samples were collected at baseline, 12 weeks, and 52 weeks. Sera were stored at -80 degree until they were assayed. Anti-CCP was measured by enzyme-linked immunosorbent assay (ELISA), and RF was detected by immune nephelometry. Anti-CCP was considered positive when the titer was greater than 5 U/mL. RF was considered positive when the titer was greater than 15 IU/mL.

Results At baseline, 37 patients were positive for anti-CCP (80%) and 35 were positive for RF (76%). Thirty-two patients (70%) were positive for both anti-CCP and RF. There was a weak correlation between anti-CCP and RF at baseline (r =0.186). No differences were noted in disease activity relative to the patient’s anti-CCP and RF positivity. Three patients who were positive for anti-CCP at baseline became anti-CCP negative after TCZ therapy, with titers below 10 U/mL. RF titers in 8 patients changed from positive to negative during the course of treatment. These RF titers ranged from 22 to 102 IU/mL. Anti-CCP levels decreased at 12 weeks (p=0.06), and then increased at 52 weeks (p<0.005). The concentrations of anti-CCP at baseline, 12 weeks, and 52 weeks were 201±40, 188±39, and 248±52 U/mL, respectively. These changes in anti-CCP levels were greater than in biologics- naïve patient group. RF titers decreased in association with the improvement in RA disease activity (p<0.0001). RF titers at baseline, 12 weeks, and 52 weeks were 157±37, 107±26, and 98±26 IU/mL, respectively.

Conclusions RF titers may be useful for RA treatment not only as a diagnostic tool but also for monitoring the efficacy of TCZ therapy. However, although TCZ treatment directly influenced anti-CCP titers, these changes were not associated with clinical response to TCZ therapy. These results suggested that TCZ treatment had different effects on anti-CCP and RF production in RA patient sera. We conclude that anti-CCP and RF might be independent antibodies in the immune network of RA.

Disclosure of Interest None Declared

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