M. Shingu et al., PRODUCTION OF SOLUBLE ICAM-1 BY MONONUCLEAR-CELLS FROM PATIENTS WITH RHEUMATOID-ARTHRITIS PATIENTS, Inflammation, 18(1), 1994, pp. 23-34
The present study was designed to quantify the level of the soluble fo
rm of ICAM-1 (sICAM-1) produced by mononuclear cells (MNC) of rheumato
id arthritis (RA) patients, and to correlate these levels with the dis
ease activity and with the amounts of cytokines or rheumatoid factors
(RF) produced by MNC. Unstimulated synovial fluid (SF) MNC produced hi
gher amounts of sICAM-1 than peripheral blood (PB) MNC in RA patients
(P < 0.01). sICAM-1 production by PHA-stimulated MNC was higher in RA
SF MNC than RA or normal PB MNC (P < 0.01). The amounts of SICAM-1 pro
duced correlated with the amounts of soluble IL-2 receptor produced (P
< 0.02) but not with IL-1B or the Lansbury activity index in RA PB MN
C. sICAM-1 correlated with the amounts of soluble CD23 and IL-4 produc
ed by normal PB MNC (P < 0.01). The amounts of sICAM-1 correlated with
IgG-RF (P < 0.02) and IgM-RF (P < 0.01) produced by unstimulated MNC
obtained from the bone marrow (BM) of RA patients. ICAM-1 expression o
f T-lymphocyte subsets, B lymphocytes, and monocytes obtained from RA
PB and RA BM assayed by two-color flow cytometry ranged from 0.1 to 6%
, which was not appreciably different from that of normal controls. Th
e monocyte fraction of RA PB MNC produced significantly higher amounts
of sICAM-1 than lymphocyte fraction. These results suggest that sICAM
-1 produced by MNC may be a marker of cell activation in T and B lymph
ocytes, in contrast to the transient increase of ICAM-1 expression.