Cytokine-regulated expression of activated leukocyte cell adhesion molecule (CD166) on monocyte-lineage cells and in rheumatoid arthritis synovium.
OBJECTIVE
To determine whether monocyte/macrophage expression of the CD6 ligand, activated leukocyte cell adhesion molecule (ALCAM) (CD166), is regulated by cytokines during inflammation in rheumatoid arthritis (RA).


METHODS
We used flow cytometry to test whether cytokines present in rheumatoid synovium could regulate ALCAM cell surface expression on peripheral blood (PB) monocytes and RA synovial fluid (SF) macrophages, and we examined ALCAM expression in situ in RA synovium by immunofluorescence.


RESULTS
The monocyte differentiation factors interleukin-3, macrophage colony-stimulating factor (M-CSF), and granulocyte-macrophage colony-stimulating factor augmented ALCAM expression on PB monocytes. ALCAM was expressed on monocyte-lineage cells in situ in inflamed synovium from patients with RA (9 of 9), but not in uninflamed synovium from patients with joint trauma (0 of 3). Furthermore, in vitro culture-induced ALCAM expression on PB monocytes and CD14+ RA SF cells was inhibited by an M-CSF neutralizing antibody.


CONCLUSIONS
ALCAM expression on PB and SF monocytes/macrophages is enhanced by M-CSF.
Levesque
M C
MC
Duke University Medical Center, Durham, North Carolina 27710, USA.
Heinly
C S
CS
Whichard
L P
LP
Patel
D D
DD
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000473:pathology*; D019070:Cell Lineage / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000494:pharmacology*; D005455:Fluorescent Antibody Technique; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D007377:Interleukin-3 / Q000494:pharmacology; D018950:Lipopolysaccharide Receptors / Q000096:biosynthesis; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D008875:Middle Aged; D009000:Monocytes / Q000166:cytology* / Q000276:immunology*; D009500:Neutralization Tests; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis*; D013582:Synovial Fluid / Q000166:cytology
D016207:Cytokines; D007376:Interleukin-2; D007377:Interleukin-3; D018950:Lipopolysaccharide Receptors; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; D016173:Macrophage Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor