Macrophage inflammatory protein 1 alpha expression by synovial fluid neutrophils in rheumatoid arthritis.
OBJECTIVE
To determine the contribution made by synovial fluid (SF) neutrophils to the augmented expression of macrophage inflammatory protein 1 alpha (MIP-1alpha) in rheumatoid arthritis (RA).


METHODS
Neutrophils were isolated from samples of SF from RA patients and peripheral blood (PB) samples from RA patients and healthy controls. Cell associated MIP-1alpha was visualised immunohistochemically, and cell associated MIP-1alpha as well as MIP-1alpha secreted into the SF was assayed by ELISA. Steady state expression of MIP-1alpha mRNA was assessed by reverse transcription polymerase chain reaction (RT-PCR).


RESULTS
Freshly isolated SF neutrophils contained significantly higher concentrations of both MIP-1alpha protein and its transcript than PB neutrophils from either RA patients or healthy controls; incubation in the absence or presence of tumour necrosis factor alpha for 24 hours resulted in a significant increase in MIP-1alpha secretion by RA SF neutrophils compared with neutrophils obtained from either normal PB or RA PB; and expression of MIP-1alpha by SF neutrophils was well correlated with both RA disease activity and SF mononuclear cell (MNC) counts.


CONCLUSIONS
Expression and secretion of MIP-1alpha by SF neutrophils may be indicative of local and systemic inflammation in RA. Moreover, this C-C chemokine may contribute to the recruitment of MNCs from the bloodstream into synovial joints and tissues.
Hatano
Y
Y
The First Department of Internal Medicine, Showa University School of Medicine, Tokyo, Japan.
Kasama
T
T
Iwabuchi
H
H
Hanaoka
R
R
Takeuchi
H T
HT
Jing
L
L
Mori
Y
Y
Kobayashi
K
K
Negishi
M
M
Ide
H
H
Adachi
M
M
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D015415:Biomarkers / Q000032:analysis; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019402:Macrophage Inflammatory Proteins / Q000032:analysis* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000737:chemistry*; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018709:Statistics, Nonparametric; D013582:Synovial Fluid / Q000276:immunology*
D015415:Biomarkers; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D019402:Macrophage Inflammatory Proteins; D012333:RNA, Messenger