Production of T-cell cytokines at the single-cell level in patients with inflammatory arthritides: enhanced activity in synovial fluid compared to blood

Abstract

We used a newly developed, sensitive ELISPOT technique in order to estimate the number of cells producing interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) in synovial fluid mononuclear cells (SFMC) and peripheral blood mononuclear cells (PBMC) in patients with rheumatoid arthritis (RA) and other inflammatory arthritides, and to correlate the results with clinical and laboratory parameters of disease activity. SFMC and PBMC were cultured either without stimuli or with a standardized dose of phytohaemagglutinin (PHA) for 6 h. Twenty-nine patients, 16 with RA and 13 with other inflammatory joint diseases, were investigated and compared to PBMC from 25 healthy controls. The mean number of IFN-gamma-producing cells was 37.1/10(5) plated SFMC (range 0-121.5). The corresponding value for PBMC was 5.1 (0-39). The difference was highly significant (P = 0.0033 for RA patients, P = 0.0050 for non-RA patients and P < 0.0001 for all patients). Forty-five per cent of SFMC samples (range for all samples 0-38.5 SFC/10(5) MNC) and 25% of PBMC samples (0-20.5) exhibited spontaneous IL-4 production, yielding a significant difference for all patients treated collectively (P = 0.021). Although the cells that spontaneously secrete these cytokines are relatively few, quantification of these cells thus shows increased functional T-cell activation and decreased ratio of cells spontaneously producing IL-4 vs IFN-gamma in the joint fluid as compared to blood of arthritis patients.

A proinflammatory role for IL-18 in rheumatoid arthritis

“…T-cell clones grown out of synovial tissues are similarly usually of Th1 phenotype (6). Up to 80% of synovial T cells are CCR5 + (33), and when stimulated and analyzed by immunofluorescence or ELISPOT (7,8) are found to express predominantly IFN-γ, but not IL-4. Moreover, recent preliminary data suggest that initial peripheral blood Th1/Th2 ratios determined by intracellular FACS may predict responsiveness to disease-modifying antirheumatic drug therapy 9 months later (34).…”

“…Moreover, in all synovial tissues tested (n = 10), the combination of IL-12, IL-15, and IL-18 proved optimal in inducing IFN-γ production. The absolute levels of IFN-γ detected ex vivo in synovial tissues, however, are usually low (30), although intracellular FACS and ELISPOT analyses indicate that a majority of synovial T cells exhibit the potential for IFN-γ expression (7,8). Thus, we investigated the effect of coincident IL-10 and TGF-β addition on IFN-γ production in vitro.…”

“…Several data suggest that rheumatoid arthritis (RA) is a "Th1-associated" disease (5)(6)(7)(8). However, the factors that initiate and sustain Th1 responses in RA synovium are unclear.…”

Dendritic Cells (DCs) in Rheumatoid Arthritis (RA): Progenitor Cells and Soluble Factors Contained in RA Synovial Fluid Yield a Subset of Myeloid DCs That Preferentially Activate Th1 Inflammatory-Type Responses

“…Mature DCs derived from progenitor cells in vitro with myeloid DC growth factors and IFN-␥ exhibit a greater capacity to activate IFN-␥-producing T cells (Th1-type cells) than cells cultured with myeloid DC growth factors alone (57). Thus, IFN-␥ existing in RA SF (58,59) may also skew DC development and function toward a Th1 response. Other factors known to promote CD14-DC growth and that are prevalent in RA SF, such as hyaluronan and fibronectin (1, 2, 60, 61), may contribute to the formation of a Th1 response as well.…”

A Novel Therapeutic Approach Targeting Articular Inflammation Using the Filarial Nematode-Derived Phosphorylcholine-Containing Glycoprotein ES-62

“…T cell effector function may be via cytokine secretion, e.g., IFN-␥ or IL-17, or through cell contactdependent cognate interactions with macrophages via ligand pairs such as LFA-1/ICAM-1 and CD40/CD154 (17)(18)(19)(20)(21)(22). Most data therefore suggest that RA is mediated via a type 1 T cell (Th1) response associated with excess monokine production (23)(24)(25)(26)(27). Given that it is anti-inflammatory/Th2 inducing, we hypothesized that ES-62 should possess powerful immune modulatory, antiarthritic properties.…”