Immunogenicity and Lupus-Like Autoantibody Production Can Be Linked to Each Other along With Type I Interferon Production in Patients with Rheumatoid Arthritis Treated With Infliximab: A Retrospective Study of a Single Center Cohort

Abstract

Besides anti-drug antibodies, anti-nuclear antibodies and anti-DNA antibodies are often induced in patients with rheumatoid arthritis treated with tumor necrosis factor inhibitors. We examined the association between immunogenicity, autoantibody production, and serum cytokine profiles in patients with rheumatoid arthritis treated with infliximab. Japanese patients with rheumatoid arthritis (n = 57) were retrospectively examined. Serum trough levels of infliximab, anti-drug antibody, anti-nuclear antibody, and anti-DNA (Farr), anti-single-stranded DNA and anti-double-stranded DNA antibodies were measured. Interleukin-6, interferon-γ, interferon-α, and B-cell activating factor levels were also measured in the same sera. Then, we validated the association between anti-drug antibody and these serum markers along with clinical response to infliximab. Anti-drug antibodies developed in twenty-one patients (36.8%), whose serum trough levels of infliximab were significantly lower than those in anti-drug antibody-negative patients (0.09 ± 0.03 vs. 2.48 ± 0.326 μg/mL, p < 0.0001). There were no significant differences in clinical backgrounds between the two groups. The anti-drug antibody-positive patients were more likely to develop anti-nuclear antibody titers of ≥ ×160 compared to the negative patients (14 to 57% vs. 17 to 33%). In addition, anti-DNA antibodies (Farr) (from 1.5 ± 0.4 to 35 ± 17 IU/mL, p = 0.0001), especially IgM-anti-double stranded DNA antibody (from 5.1 ± 0.7 to 41 ± 8.9 IU/mL, p < 0.0001), and IgG-anti-single stranded DNA antibody (from 13 ± 1.1 to 35 ± 13, p = 0.0145) were significantly increased in anti-drug antibody-positive but not in negative patients. Moreover, the anti-drug antibody-positive, but not the negative patients, showed significant increased levels of interferon-α (from 248.7 ± 102.3 to 466.8 ± 135.1 pg/mL, p = 0.0353) and B-cell activating factor (from 1073 ± 75.1 to 1387 ± 136.5 pg/mL, p = 0.0208) following infliximab treatment. The development of anti-drug antibody against infliximab and lupus-like autoantibody production in patients with rheumatoid arthritis treated with infliximab can be linked each other along with increased lupus-associated cytokine levels including type I interferons.

Fig 1. Anti-drug antibody (ADA) is associated with reduced clinical response.

(A) Treatment efficacy defined as low disease activity (LDA) or remission at 6 months. Percentages and absolute numbers of each group of patients are indicated below the graphs. ADA positivity was based on the assessment of 6 months. Fisher’s exact test was used for comparison. (B) Cumulative drug retention rates. A log-rank test was used for comparison between the two groups.

Fig 2. The association between ADA and ANA.

(A) The proportion of ADA (n = 21) and ANA (≥ ×160, n = 15) positive patients at different time points after IFX treatment in the ADA-positive group. A log-rank test was used for comparison between ADA and ANA curves. (B) Changes in the ANA staining pattern before (pre) and after (post) IFX. Numbers in bar graphs indicate percentages of patients with Hom/Spe pattern of FANA. None, ANA titer was ≤ ×40; Hom/Spe, homogenous/speckled. The chi-square test was used for comparison. * p = 0.037 (ADA-negative group) and p = 0.032 (ADA-positive group), ns: not significant.

Fig 3. The association between ADA and anti-DNA Ab.

The baseline (pre) and the peak (post) values of anti-DNA Ab (Farr) (A), IgG-anti-dsDNA Ab (B), IgM-anti-dsDNA Ab (C), and IgG-anti-ssDNA Ab (D). The upper limit normal values are indicated by dashed lines. The post values are the highest titers observed during the follow-up periods. Each dot represents a single serum sample, and the data are presented as mean ± SEM. A paired t-test for intra-group comparison or the Mann-Whitney test for inter-group comparison was used. ns: not significant.

Fig 4. Serum cytokine levels before and 12 months after IFX treatment.

The pre- and post-treatment levels of IL-6, IFN-γ, IFN-α2 and BAFF were compared between ADA-positive (+) and ADA-negative (-) groups. Data are presented as mean + SEM. A paired t-test for intra-group comparison and the Mann-Whitney test for inter-group comparison were used.