Synovial effusion and synovial fluid biomarkers in psoriatic arthritis to assess intraarticular tumor necrosis factor-α blockade in the knee joint.
BACKGROUND
The purpose of this study was the evaluation of synovial effusion (SE), synovial fluid (SF) and synovial tissue (ST) biomarkers in relation to disease activity indexes to assess the response to intraarticular (IA) tumor necrosis factor (TNF)-α blockers in psoriatic arthritis (PsA).


METHODS
Systemic and local disease activity indexes (disease activity score (DAS); the Ritchie articular index (mRAI), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP); Thompson articular (THOMP) and joint articular (KJAI)-Index ) and ST samples were assessed at baseline, throughout treatment, and during the follow-up in 14 patients affected with PsA who underwent IA injections (0.5 ml to 12.5 mg) in the knee joint of etanercept (E) or placebo (P) once every two weeks for a 10-week period. Total SF white blood cell (WBC) counts (WBC/μl) and SF cytokine/chemokine (CK/CCK) levels were measured before IA-E at baseline, after IA-E, and as long as there were adequate amounts of SF for knee aspiration (post). Characterization of synovial mononuclear cell infiltration and synovial vessels was carried out in 8 out of 14 knees by staining serial sections of synovial tissue biopsies for CD45, CD3, CD68, CD31 and CD105.


RESULTS
At baseline, CRP and/or ESR were significantly correlated with SF-CK (interleukin- (IL-)1β, IL-1Ra, IL-6, IL-8) and CCK (CCL3). Post-IA injections, there was a decrease in SE in the knees in which aspiration following IA-E injection was possible as well as a significant reduction in SF WBC/μl and in SF-CK (IL-1β, IL-1Ra, IL-6 and IL-22). Pre- and post-IA-E injections, there were significant correlations between ST markers and SF-CK (IL-1β with CD45; IL-1β and IL-6 with CD31) and between SF-CCK (CCL4 and CCL3 with CD3). At the end of the study, there was a significant reduction in disease activity indexes (CRP, DAS, RAI, THOMP, KJAI) as well as in the ST markers (CD45; CD3).


CONCLUSIONS
Synovial effusion regression is a reliable indicator of the response to IA TNF-α blockers in PsA patients as it is confirmed by the correlation between SF biomarkers to disease activity and synovial tissue inflammation.
Fiocco
Ugo
U
Department of Clinical and Experimental Medicine, University of Padova, Padova, Italy. ugo.fiocco@unipd.it
Sfriso
Paolo
P
Oliviero
Francesca
F
Roux-Lombard
Pascale
P
Scagliori
Elena
E
Cozzi
Luisella
L
Lunardi
Francesca
F
Calabrese
Fiorella
F
Vezzù
Maristella
M
Dainese
Serena
S
Molena
Beatrice
B
Scanu
Anna
A
Nardacchione
Roberto
R
Rubaltelli
Leopoldo
L
Dayer
Jean Michel
JM
Punzi
Leonardo
L
D015535:Arthritis, Psoriatic / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D015415:Biomarkers / Q000378:metabolism*; D016903:Drug Monitoring / Q000379:methods* / Q000592:standards; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage*; D007270:Injections, Intra-Articular; D053590:Interleukin 1 Receptor Antagonist Protein / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D007378:Interleukins / Q000378:metabolism; D007719:Knee Joint / Q000378:metabolism / Q000473:pathology; D007958:Leukocyte Count; D015203:Reproducibility of Results; D013582:Synovial Fluid / Q000378:metabolism*; D013583:Synovial Membrane / Q000378:metabolism / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*; D000097043:Interleukin-22
D015415:Biomarkers; D007166:Immunosuppressive Agents; D053590:Interleukin 1 Receptor Antagonist Protein; D053583:Interleukin-1beta; D015850:Interleukin-6; D007378:Interleukins; D014409:Tumor Necrosis Factor-alpha; D000097043:Interleukin-22; C508600:IL6 protein, human