Quantitation of IL-2Rp75 (CD122) expression on mononuclear cells in rheumatic disease.
OBJECTIVE
To compare expression of the p75 chain of the interleukin-2 receptor (IL-2Rp75, CD122) on peripheral and synovial mononuclear cells in rheumatoid and non-rheumatoid inflammatory arthritis.


METHODS
Peripheral blood (PBMC) and synovial (SFMC) mononuclear cells were isolated from subjects with rheumatoid arthritis (n = 16) and non-rheumatoid inflammatory arthritis (n = 12). PBMC were isolated from six healthy controls. Expression of CD122 was examined using indirect immunofluorescence and quantitative flow cytometry.


RESULTS
There was no difference in IL-2Rp75 expression on PBMC from rheumatoid arthritis patients, non-rheumatoid arthritis patients, and controls. In subjects with rheumatoid arthritis there was no difference in IL-2Rp75 expression on PBMC and SFMC. However, in the non-rheumatoid arthritis group there was an increase in IL-2Rp75 expression on SFMC compared with PBMC (P = 0.0032). On SFMC there was a greater expression of IL-2Rp75 in non-rheumatoid arthritis than in rheumatoid arthritis (P = 0.0007). Expression was greater on CD8 positive cells and in subjects with shorter duration of disease.


CONCLUSIONS
The p75 chain of the IL-2 receptor, an important T cell activation antigen, is not upregulated in synovial fluid. This appears to be a disease specific defect and provides further support for the concept of "frustrated" or incomplete T cell activation in this disease.
Creamer
P
P
Rheumatology Unit, Bristol Royal Infirmary, United Kingdom.
Hall
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ND
D001168:Arthritis / Q000276:immunology*; D001172:Arthritis, Rheumatoid / Q000276:immunology; D001773:Blood Cells / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008875:Middle Aged; D015375:Receptors, Interleukin-2 / Q000378:metabolism*; D013582:Synovial Fluid / Q000166:cytology
D015375:Receptors, Interleukin-2