Background The anti-cyclic citrullinated peptide antibody (ACPA) is an important factor for diagnosis and treatment effect prediction of rheumatoid arthritis (RA). Measurement of hepatitis B (HB) antibody level for determination of previous HB infection is recommended when using anti-rheumatic drugs or biological products because of the possible reactivation of the HB virus.
Objectives We analyzed whether ACPA level and various background factors of RA patients, including the HB antibody positivity rate, are correlated.
Methods As of March 2014, we successfully analyzed the ACPA positivity rate and the correlation between HB antibodies (HBs and HBc) and various background factors of RA patients (age, onset time, disease duration, and drugs used) in 613 patients with ongoing RA treatment.
Results The RA cases consisted of 138 male and 475 female patients (77.5%) aged 23–91 years (mean ± SD, 63.1±13.3 years). The number of patients with RA stage I/II/III/IV was 10/207/228/166, and that with RA class 1/2/3/4 was 9/323/270/11. Among the 613 cases, 398 (64.9%) were positive for ACPA. A sex-related difference was not observed in the ACPA positivity rate. No significant differences according to the season or month of birth of the patients were observed in the ACPA positivity rates. The age at onset was 49.8±13.8 years overall, 46.6±12.5 years in the patients with positive ACPA results, and 55.6±14.3 years in the patients with negative ACPA results, suggesting that the age at onset was significantly younger in the patients with positive ACPA results (p<0.0001). The disease duration was 13.4±9.9, 16.4±9.4, and 7.8±7.2 years, respectively, suggesting that disease duration was also longer in the ACPA positive case. The biological product introduction rate was 84.0% in the positive cases and 50.9% in the negative cases, which was apparently higher in the positive cases (p<0.0001). The HBs antibody positive rates were 17.8% and 10.7% in the patients with positive and negative ACPA results, respectively, indicating a significantly higher rate in the positive cases (p<0.02). The HBc antibody positive rates were 16.8% and 13.5%, respectively. No statistically significant difference but a higher trend was observed (p=0.27). The hepatitis C virus antibody positivity rates were 3.3% and 2.8% in the patients with positive and negative ACPA results, respectively.
Conclusions There was a tendency for longer disease duration, and stage and class progressions in ACPA positive patients. The number of cases being introduced to biological products also increased. Furthermore, it is also important to pay attention to the possible reactivation of HB when administering a strong immunosuppressive therapy to those with high HBs antibody positivity rates and positive ACPA results.
Disclosure of Interest None declared