SELECTED TH1 AND TH2 CYTOKINE MESSENGER-RNA EXPRESSION BY CD4(-CELLS ISOLATED FROM INFLAMED HUMAN GINGIVAL TISSUES() T)

Elevated numbers of plasma cells are associated with localized and chr onically inflamed gingiva of patients with adult periodontitis. Howeve r, only limited information is currently available as to how cytokines produced by CD4(+) T cells are involved in these increased B cell res ponses in affected gingival tissues. When gingival mononuclear cells ( GMC) were isolated from inflamed tissues and examined by flow cytometr y, similar to 20-30% of lymphocytes were CD4(+) T cells. For the analy sis of Th1 and Th2 cytokine expression by these CD4(+) T cells, RNA wa s extracted and reverse transcriptase-polymerase chain reaction (RT-PC R) was performed by using specific 5' and 3' primers for interferon-ga mma (IFN-gamma) and IL-2 (Th1), IL-4, IL-5, IL-6, IL-IO and IL-13 (Th2 ) and beta-actin (internal control). Two distinct cytokine profiles we re noted based on the expression of selected Th1 and Th2 cytokines, wh ere one pattern was represented by expression of mRNA for IFN-gamma, I L-6, IL-10 and IL-13, while the second consisted of mRNA for IFN-gamma , IL-6 and IL-13. In most samples, mRNA for IL-2, IL-4 and IL-5 were n ot detected by cytokine-specific RT-PCR. When RNA was isolated from CD 4(+) T cells of concanavalin A-stimulated peripheral blood mononuclear cells (PBMC) of the same patients and examined by RT-PCR, mRNA for al l Th1 and Th2 cytokines were detected. These findings suggest that alt hough human CD4(+) T cells are capable of producing an array of Th1- a nd Th2-type cytokines, the CD4(+) T cells associated with periodontiti s are limited to production of IFN-gamma, IL-6, IL-13 and in some inst ances IL-10. CD4(+) T cells from diseased periodontal tissues are divi sible into two groups based upon whether or not IL-10 is produced, tog ether with IFN-gamma, IL-6 and IL-13.