Restricted cytokine expression in rheumatoid arthritis.
OBJECTIVE
To determine the cytokine profile of the phenotypically activated T cell in rheumatoid arthritis (RA) synovium.


METHODS
Interleukin-2 (IL-2), IL-2 receptor (IL-2R), IL-6, IL-4, and interferon-gamma (IFN gamma) gene expression was examined in T cells from freshly isolated synovial fluids (SF) and synovial tissues (ST) from patients with RA. Estimates of baseline expression were determined using unstimulated peripheral blood (PB) T cells from healthy individuals. The corresponding positive controls were phytohemagglutinin-activated tonsil T cells.


RESULTS
In studies of paired PB and SF T cell samples from 17 RA patients, IL-2 messenger RNA (mRNA) levels in only 1 PB and 3 SF samples were more than 2 standard deviations above the mean of levels in unstimulated PB from healthy donors. Similarly, only 5 PB and 7 SF samples exhibited elevated IL-2R mRNA levels. IFN gamma gene expression was not detected in any of the paired RA PB or SF samples. Fractionated T cells from 12 RA ST were screened with similar results: Only 1 of 12 samples exhibited IL-2 mRNA levels more than 2 standard deviations above levels in baseline controls. IL-2R mRNA levels were low or not detected, and IFN gamma mRNA was absent. Subsequent studies showed that IL-4 and IL-6 gene expression levels were also low in RA tissues compared with tonsil T cell-positive controls.


CONCLUSIONS
These data provide evidence for restricted cytokine expression in the T cell population in RA tissues.
Chen
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Department of Microbiology, University of Toronto, Ontario, Canada.
Keystone
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EC
Fish
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EN
D000199:Actins / Q000235:genetics; D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000235:genetics / Q000378:metabolism*; D016207:Cytokines / Q000235:genetics / Q000502:physiology*; D005260:Female; D015870:Gene Expression; D006801:Humans; D007371:Interferon-gamma / Q000235:genetics / Q000502:physiology; D007376:Interleukin-2 / Q000235:genetics / Q000502:physiology; D015847:Interleukin-4 / Q000235:genetics / Q000502:physiology; D015850:Interleukin-6 / Q000235:genetics / Q000502:physiology; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis; D015375:Receptors, Interleukin-2 / Q000235:genetics; D013601:T-Lymphocytes / Q000276:immunology*
D000199:Actins; D016207:Cytokines; D007376:Interleukin-2; D015850:Interleukin-6; D012333:RNA, Messenger; D015375:Receptors, Interleukin-2; D015847:Interleukin-4; D007371:Interferon-gamma