Extravasation into synovial tissue induces CCL20 mRNA expression in polymorphonuclear neutrophils of patients with rheumatoid arthritis.
OBJECTIVE
Examination of expression of the chemokine macrophage inflammatory protein-3a (CCL20/Mip-3alpha) in blood polymorphonuclear neutrophils (PMN) and synovial fluid (SF) PMN of patients with rheumatoid arthritis (RA).


METHODS
Paired samples of blood PMN and SF PMN were obtained from 11 patients with RA. In addition, SF was prepared from 9 patients with osteoarthritis (OA) and 10 patients with juvenile idiopathic arthritis (JIA). PMN were isolated via density centrifugation to a purity of 98%. Total RNA was isolated and the expression of CCL20 was determined by reverse transcription-polymerase chain reaction (RT-PCR) and quantitative real-time PCR. In some experiments blood PMN obtained from healthy donors were stimulated with individual SF of patients with RA. For quantitative considerations, CXCL8, CCL20, interleukin 1, and tumor necrosis factor-alpha (TNF-alpha) levels were determined in SF by ELISA.


RESULTS
In SF of RA patients CCL20 and CXCL8 levels were elevated, up to 7.5 ng/ml and 23.6 ng/ml, respectively. No significant level of either chemokine was found in SF of patients with JIA and OA. CCL20 mRNA was undetectable in blood PMN of all patients with RA. In SF PMN, CCL20 mRNA was found in 6/11 RA patients. Expression of CCL20 mRNA in 5/6 SF PMN samples was observed in the absence of detectable TNF-alpha levels in SF. Cell culture experiments, however, confirmed the ability of TNF-alpha in SF to induce CCL20 mRNA expression in blood PMN. Notably, expression of CCL20 was also found in PMN after stimulation with SF lacking TNF-alpha.


CONCLUSIONS
Recruitment of PMN to the synovial microenvironment induces expression of CCL20 mRNA independent of the concentrations of TNF-alpha accumulating in SF of patients with RA.
Schlenk
Judith
J
Institute for Clinical Microbiology, Immunology and Hygiene, University of Erlangen-Nuremberg, Erlangen, Germany.
Lorenz
Hanns-Martin
HM
Haas
Johannes-Peter
JP
Herrmann
Martin
M
Hohenberger
Gerd
G
Kalden
Joachim R
JR
Röllinghoff
Martin
M
Beuscher
Horst Ulrich
HU
D000328:Adult; D000368:Aged; D001171:Arthritis, Juvenile / Q000378:metabolism / Q000473:pathology; D001172:Arthritis, Rheumatoid / Q000378:metabolism* / Q000473:pathology; D016022:Case-Control Studies; D002478:Cells, Cultured; D054418:Chemokine CCL20; D019742:Chemokines, CC / Q000235:genetics* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism; D019402:Macrophage Inflammatory Proteins / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000378:metabolism*; D010003:Osteoarthritis / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013582:Synovial Fluid / Q000378:metabolism; D013583:Synovial Membrane / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
C108355:CCL20 protein, human; D054418:Chemokine CCL20; D019742:Chemokines, CC; D016209:Interleukin-8; D019402:Macrophage Inflammatory Proteins; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha