Increased CD4+ expression and decreased IL-10 in the anterior chamber in idiopathic uveitis.

PURPOSE: To compare cell types and cytokines in aqueous humor from patients with uveitis either occurring in association with a systemic disease or apparently isolated and not associated with a systemic disease. METHODS: Cells were collected by centrifugation of fresh aqueous humor from uveitis and controls, and immunofluorescence techniques were performed with markers for T cells, B cells, and monocytes. Cytokines were measured in the aqueous supernatants, and serum samples were assayed for soluble interleukin-2 receptors. RESULTS: When aqueous samples from idiopathic uveitis were compared with those from uveitis associated with a systemic disease, there were increases in CD3+, CD4+ (p = 0.001), and activated CD4+ T cells (p = 0.02) and a decrease in B cells (p = 0.0013). This was not reflected in the peripheral blood where there were no differences in the cell types or in soluble interleukin-2 receptor levels. No cells were obtainable from control aqueous. Interleukins-10 and -12, interferon-gamma, and transforming growth factor-beta2 were detected in aqueous supernatants. Interleukin-10 was reduced (p = 0.024) in uveitis in comparison with controls. CONCLUSIONS: The results suggest a selective recruitment of CD4+ T cells within aqueous humor but only in idiopathic uveitis. In both disease groups there was a decrease in the immunoregulatory cytokine interleukin-10, which might enable an immune response to occur in an otherwise highly immunosuppressive microenvironment. Increases in activated CD4+ T cells combined with depressed interleukin-10 levels could partially explain why, for example, in acute anterior uveitis, the inflammatory disease is often more severe.

Characterization of phenotype and cytokine profiles of T cell lines derived from vitreous humour in ocular inflammation in man.

Intermediate uveitis (IU) and Fuchs' heterochromic cyclitis (FHC) are two chronic ocular inflammatory disorders. They differ considerably in ocular morbidity, which is higher in IU. T cell lines were derived from the vitreous humour (VH) and peripheral blood (PB) of 10 patients with IU and four patients with FHC. There was a predominance of CD8+ in all the lines. However, there was a significantly higher percentage of CD4+ T cells in the T cell lines derived from VH of IU (32.0 +/- 8.6%) compared with FHC patients (19. 2 +/- 8.9%) (P = 0.04). The VH-derived T cell lines (VDTC) produced significantly higher levels of IL-2, interferon-gamma (IFN-gamma) and IL-10, but not IL-4, compared with PB-derived T cell lines (PBDTC) in both entities. There was significantly higher IL-2 production by VDTC from IU when compared with FHC patients (1810 +/- 220 pg/ml versus 518 +/- 94 pg/ml; P = 0.009), which could account for the more aggressive clinical features of this condition. In contrast IL-10 production was significantly higher by the VDTC from FHC compared with IU patients. The high IL-10 production by T cells infiltrating VH of FHC patients could down-regulate the inflammatory responses, thereby contributing to the benign clinical course seen in these patients. The accumulation of T cells with differing cytokine profiles in the VH suggests an important role for these cytokines in the pathogenesis of these chronic uveitides.

Characterization of T cells and cytokines in the aqueous humour (AH) in patients with Fuchs' heterochromic cyclitis (FHC) and idiopathic anterior uveitis (IAU).

FHC and IAU are two forms of anterior uveitis which are localized to the eyes with no evidence of systemic involvement. However, FHC has distinct clinical features and differs from IAU in that the inflammation is low grade, steroid non-responsive, and has a less aggressive clinical course. To try to dissect the mechanism for this difference the phenotypes of the cells in the AH and blood (PB) and the cytokines present in the AH in patients with FHC and IAU were compared. Three-colour flow cytometry was performed on the cells isolated from the AH and PB. Percentage of cells bearing the following markers were determined: CD3, CD4, CD8, CD4/CD25, CD8/CD25, CD19 and CD14. The cytokines IL-4, IL-10, IL-12 and interferon-gamma (IFN-gamma) were assayed by ELISA. In both groups T cell numbers were higher in the AH than PB, although the distribution of T cell subsets in PB was similar. In the AH, CD8+ T cell numbers were higher in FHC than in IAU (P = 0.003), whilst CD4+ numbers were higher in IAU than FHC (P = 0.01). AH cytokine profiles were different in the two groups: IFN-gamma levels were higher and IL-12 levels lower in the FHC group than IAU (P = 0.02), whilst IL-10 levels tended to be higher in the FHC group (P = 0.5). We suggest that different local mechanisms governing the balance of T cell/cytokine-mediated inflammation in the anterior segment may underlie clinical differences such as chronicity and response to steroids in these disorders.

The kinetics of cytokine mRNA expression in the retina during experimental autoimmune uveoretinitis.

Experimental autoimmune uveoretinitis (EAU) was induced in Lewis rats and the inflamed retinas were examined for IFN-gamma, IL-2, IL-4, and IL-10 mRNA production at serial time points using the reverse transcriptase-polymerase chain reaction. IFN-gamma, IL-2, IL-4, and IL-10 mRNAs were all detected 24 hr before the earliest time point at which histological changes have previously been detected. IFN-gamma, IL-2, and IL-4 mRNA expression peaked during the active phase of the disease and declined in parallel with lymphocyte numbers as the inflammation resolved. IL-10 mRNA levels increased more slowly, reaching a maximum at later stages of disease. The observed pattern of cytokine mRNA expression in the retina in EAU is similar to that reported in experimental autoimmune encephalomyelitis (EAE). The increase in IL-10 mRNA expression in late disease may reflect a role in disease resolution as previously proposed in EAE.

Differential lymphokine expression by rat antigen-specific CD4+ T cell lines with antigen and mitogen.

Retinal soluble antigen (S-Ag) and purified protein derivative (PPD)-specific T cell lines established from Lewis rats were used to study the pattern of lymphokine expression to see if it varied with the inducing stimulus. Lymphokine mRNA expression was detected by PCR combined with Southern analysis after 6-hr stimulation and protein secretion assessed by bioassays at 24 hr poststimulation. S-Ag-specific T cell lines when stimulated with antigen expressed IL-2, IFN-gamma, and IL-4 mRNA, whereas only IL-2 and IFN-gamma could be detected in the supernatants. This is in contrast to the findings after stimulation of the PPD cell lines with PPD where IL-4 could be detected in the supernatants. The time course studies (3, 6, 24, 48, and 72 hr) with one of the S-Ag-specific T cell lines showed that S-Ag activation did not induce any detectable IL-4 bioactivity. However, when the S-Ag T cell line was stimulated by Con A or PMA, IL-4 was detected in the supernatants following Con A activation, suggesting that the way in which the T cell is activated has an effect on its resultant lymphokine secretion.

Systemic release of mucosal mast cell protease during infection with the intestinal protozoal parasite, Eimeria nieschulzi. Studies in normal and nude rats.

The systemic secretion of rat mucosal mast cell protease (RMCPII), a major product of rat mucosal mast cells (MMC), was examined during primary infections with the protozoan parasite, Eimeria nieschulzi in CFH/B, athymic (rnu/rnu) and euthymic (rnu/+) rats. Release of RMCPII into the blood stream (2.9 micrograms/ml of serum) of normal rats occurred within 1 day after infection. This response developed 3-6 hours after inoculation with oocysts, was dose-dependent, and was found in both naive and immune rats. Maximal release of RMCPII (4.5 micrograms/ml of serum) in naive rats occurs 9 days after primary infection, whereas the numbers of MMC and concentrations of mucosal RMCPII were maximal 14 days after infection, by which time the systemic RMCPII response had begun to decline. The numbers of MMC and concentrations of mucosal RMCPII in uninfected nude rats were similar to those in the heterozygous (rnu/+) litter-mates. After infection, the numbers of MMC and concentrations of mucosal RMCPII increased in the heterozygotes but not in nude rats. Similarly, RMCPII was detected systemically only in the heterozygotes.

Effects of experimental chronic pneumonia on bodyweight, feed intake and carcase composition of lambs.

The growth rate, feed consumption and carcase composition of nine untreated wether lambs (controls) were compared with those of lambs in which a chronic pneumonia had been experimentally induced. Six pneumonic lambs (group 1) were killed with the controls on day 109 and eight (group 2) lambs were killed when they had a similar mean liveweight to the controls (42 kg) on day 172. The mean liveweight gain of infected animals to day 108 was 59 per cent, the mean feed intake 69 per cent and the mean carcase weight of group 1 was 73.5 per cent that of the controls. Group 2 lambs required 25 per cent more feed and nine weeks longer than the controls to reach similar live and carcase weights. This depression of appetite and growth rate was most marked in the first 35 days after inoculation, but growth rates of infected lambs continued to be lower than those of the controls throughout the experiment. At slaughter, all infected lambs had consolidated lesions of pneumonia and a significant correlation was noted between the extent of lung lesions and total liveweight gain in individual lambs. Carcases of group 1 lambs had a proportionately low fat, high lean meat and bone content, indicative of immature development and consistent with a lowered feed intake. Carcases of group 2 lambs showed a similar trend but differences from the controls were not significant.