Cytokine Pattern of the Peripheral Blood Mononuclear Cells ( PBMC's ) and Synovial Membrane in the Rheumatoid Arthritis Patients

Park, Won

Abstract

OBJECTIVE
To investigate the specific cytokine pattern and its profiles in rheumatoid arthritis (RA), we measured the mRNA expression of the IL-4, IL- 2, IFN-r7 and IL-10 in the PBMC s and synovial tissue samples. METHOD: We analyzed the cytokine mRNA copy number semiquantitatively in the fresh PBMC s from 13 rheumatoid patients who were not treated with corticosteroid or DMARDs(disease modifying antirheumatic drugs) which may affect the expression of cytokine and 16 healthy normal controls. Mononuclear cells were separated into three compartment(total PBMC, CD4+ cells, and CD4 cells) by the magnetic bead method. Synovial tissues were obtained from surgical procedure freshly. RNA was extracted from 1x10 cells of each PBMC compartment and synovial tissue. To determine the copy number of cytokine mRNA expression, RT-PCR and dot blot hybridization was performed with the RNA extracted from the samples. RESULT: In CD4+ compartment IFN(interferon)-r mRNA was marginally lower in RA patients(143+114) than in normal control(742+1052, p=0.0517) but IL(interleukin)-4 mRNA expression was higher in RA group(73+50 vs. 32+23 in normal control, p=0.0066). Also in CD4- compartment IFN-r mRNA expression was lower in RA(479+850 vs. 6154+15,059 in normal control, p=0.1875) although it was not significant statistically and IL-4 expression was higher in RA group(308+277 vs. 150+100 in normal group, p=0.0428). In PBMC compartment IFN-1 mRNA expression was also decreased in RA group (148+145 vs. 712 +768, p=0.0148), but IL-4 mRNA expression was marginally increased(186+145 vs. 109+62, p=0.0652). In synovium, interestingly, there was virtually no de novo synthesis of IL-4.
CONCLUSION
There is significant difference in cytokine pattern of peripheral PBMC between RA and control group. The main cellular IL-4 source in periph- eral blood is not the CD4+ cells. Also there is significant difference of cytokine pattern between the peripheral blood and eynovium in rheumatoid arthritis.