An exploratory study to determine whether infliximab modifies levels of rheumatoid factor and antibodies to cyclic citrullinated peptides in rheumatoid arthritis patients.

OBJECTIVES: The aim of this study was to investigate the relationship between serum infliximab (IFX) levels and changes of RF and ACPA levels in patients with rheumatoid arthritis (RA). METHODS: Enzyme-linked immunosorbent assays (ELISA) [Promonitor® IFX R1 (version 2) (Progenika Biopharma, Spain)] were used to measure drug levels and antidrug-antibodies (ADAb) in IFX RA-treated patients (n=19). Disease activity was assessed using DAS28. IgM rheumatoid factor (RF) and IgM, IgA and IgG anti-cyclic citrullinated peptide (ACPA) were determined through ELISA. RESULTS: A significant decrease in RF (p=0.01), ACPA IgG (p=0.007), IgM (p=0.01) and IgA (p=0.03) was observed in patients presenting adequate levels of serum IFX. No significant changes to RF or ACPA were observed in patients with undetectable IFX. CONCLUSIONS: Data from this study support the hypothesis that the anti-TNF antagonist IFX downregulates autoantibody levels in RA patients when IFX levels are detectable. Larger-scale studies need to be performed to establish RF and ACPA presence as therapeutic response predictive factors.

Ultrasound-detected joint inflammation and B cell count: related variables for rituximab-treated RA patients?

This cross-sectional observational study aimed to explore the relationship between B cell count and ultrasound (US)-detected synovitis, in patients with rheumatoid arthritis treated with rituximab. Thirty-seven consecutive RA patients treated with RTX were recruited for the study. The patients underwent clinical [i.e., Disease Activity Score 28 joints (DAS28)], laboratory, and US assessment of 12 joints. Each joint was semiquantitatively (0-3) scored on B-mode and power Doppler mode. The scores were summed, and a global index was created for BM (BMS) and PD scores (PDI) synovitis. BM subclinical synovitis was evident in all patients, with PD synovial signal detected in 16 patients (43.2 %). No correlation was found between DAS28 and US scores. B cells were detected in 27 (72.9 %) patients, but there was no association in the mean B cell count and disease activity as measured by DAS28 (DAS28 < 2.6 = 34.53, DAS28 > 2.6 = 49.45, p = 0.52) and PDI score (PDI < 1 = 49.48, PDI > 1 = 35.44, p = 0.54). There was no correlation between the B cell count and DAS28, BMS, and PDI (r = 0.020, p = 0.907; r = -0.151, p = 0.371; r = -0.099, p = 0.558, respectively). In RTX-treated RA patients, no relationship could be established between US-detected synovitis and peripheral blood B cell count.

Does ultrasound-scored synovitis depend on the pharmacokinetics of subcutaneous anti-TNF agents in patients with rheumatoid arthritis?

OBJECTIVE: The aim of this study was to investigate the influence of the pharmacokinetics of s.c. anti-TNF agents on the grade of US-detected synovitis in RA patients. METHODS: Fifty RA patients were prospectively recruited from the Biologic Therapy Unit of our hospital. Inclusion criteria were being in treatment with s.c. anti-TNF agents and having had neither changes in therapy nor local corticosteroid injections in the previous 3 months. Patients underwent clinical, laboratory [28-joint DAS (DAS28) and Simplified Disease Activity Index (SDAI)] and US assessment at two time points, i.e. at peak plasma drug concentration and at trough plasma drug concentration. US assessments were performed blindly to the anti-TNF agent, the administration time and the clinical and laboratory data. Twenty-eight joints were investigated for the presence and grade (0-3) of B-mode synovitis and synovial power Doppler signal. Global indices for B-mode synovitis (BSI) and Doppler synovitis (DSI) were calculated for 12 joints and for wrist-hand-ankle-foot joints. B-mode US remission was defined as a BSI <1 and Doppler US remission as a DSI <1. RESULTS: There were no significant differences between the clinical, laboratory and B-mode and Doppler US parameters at peak time and trough time (P = 0.132-0.986). There were no significant differences between the proportion of patients with active disease and those in remission according to DAS28, SDAI, B-mode US and Doppler US at peak time and trough time assessments (P = 0.070-1). CONCLUSION: Our results suggested that s.c. anti-TNF pharmacokinetics do not significantly influence US-scored synovitis in RA patients.