TY  - JOUR
A1  - Gernert, Michael
A1  - Schmalzing, Marc
A1  - Tony, Hans-Peter
A1  - Strunz, Patrick-Pascal
A1  - Schwaneck, Eva Christina
A1  - Fröhlich, Matthias
T1  - Calprotectin (S100A8/S100A9) detects inflammatory activity in rheumatoid arthritis patients receiving tocilizumab therapy
JF  - Arthritis Research & Therapy
N2  - Background
Assessing serological inflammation is difficult in tocilizumab (TCZ)-treated rheumatoid arthritis (RA) patients, as standard inflammation parameters, like erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), are influenced by interleukin-6-receptor inhibition. Calprotectin in the serum, also named S100A8/S100A9, might be a more useful inflammation parameter in TCZ-treated patients.

Methods
Sixty-nine RA patients taking TCZ were included. Serum-calprotectin levels were assessed, as well as ESR, CRP, need for a change in disease-modifying anti-rheumatic drugs due to RA activity (= active RA), and the RA clinical disease activity score (CDAI). Forty-five RA patients taking tumor-necrosis factor-inhibitors (TNFi) were investigated for the same parameters.

Results
TCZ-treated patients with active RA had higher calprotectin values than not active RA patients (4155.5 [inter quartile range 1865.3–6068.3] vs 1040.0 [676.0–1638.0] ng/ml, P < 0.001). A calprotectin cut-off value of 1916.5 ng/ml resulted in a sensitivity and specificity of 80.0 %, respectively, for the detection of RA disease activity. Calprotectin values correlated with CDAI-scores (r = 0.228; P = 0.011). ESR and CRP were less suitable to detect RA activity in TCZ-treated patients. Also TNFi-treated patients with active RA had higher calprotectin values compared to not active RA (5422.0 [3749.0–8150.8] vs 1845.0 [832.0–2569.0] ng/ml, P < 0.001). The calprotectin value with the best sensitivity and specificity for detecting RA activity was 3690.5 ng/ml among TNFi-treated patients.

Conclusion
Calprotectin in the serum can be a useful inflammation parameter despite TCZ-treatment.
KW  - calprotectin
KW  - inflammation marker
KW  - c-reactive protein
KW  - tocilizumab
KW  - rheumatoid arthritis
KW  - S100A8/S100A9
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-300523
VL  - 24
IS  - 1
ER  -