Serum levels of anti-cyclic citrullinated peptide antibodies are associated with a beneficial response to traditional herbal medicine (Kampo) in rheumatoid arthritis

This study investigated the usefulness of biomarkers indicating beneficial response to traditional herbal medicine (THM) among patients with rheumatoid arthritis (RA). We assessed 34 RA patients who received keishinieppiittokaryojutsubu (KER), one of the representative THM. The observational term was 12 months, and we calculated the disease activity score of 28 joints every 3 months and evaluated the response to KER using European League Against Rheumatism (EULAR) response criteria. Additionally, serum levels of anti-cyclic citrullinated peptide antibody (ACPA) were measured by enzyme-linked immunosorbent assay at the baseline and after 6 and 12 months of the treatment with KER. As a result, 14 (41.2%) of the 34 patients were defined as responders, 13 as non-responders and 7 as out of assessment after 6 months, respectively. Pretreatment levels of serum ACPA were lower in KER responders than in non-responders (P = 0.042), although other univariate analysis did not show any significant differences in baseline clinical measures between the two groups. Furthermore, responders to KER showed a significant decrease in the serum levels of ACPA. These findings suggest that pretreatment serum levels of ACPA are a useful predictor of a good response to treatment with KER. Furthermore, a decrease in serum levels of ACPA may be an adjunctive indicator in predicting the efficacy of this kind of treatment.