Aqueous cytokine changes associated with Posner-Schlossman syndrome with and without human cytomegalovirus

AIM

To study the differences in aqueous cytokines in Posner-Schlossman Syndrome (PSS) patients with and without human cytomegalovirus (CMV) DNA in the aqueous humor.

METHODS

This is a prospective study. Fifty-three uveitis patients with clinical signs of PSS were enrolled and aqueous humor samples were collected. Fourteen PSS patients were positive of CMV DNA in the aqueous by polymerase chain reaction (PCR) analysis. These eyes were negative of common ocular pathogens such as herpes simplex virus, varicella-zoster virus, rubella virus and toxoplasma. Twenty-five otherwise healthy cataract patients were enrolled as controls. Cytokine concentration was measured by a magnetic color-bead-based multiplex assay and analyzed using statistical and classification approaches.

RESULTS

The average age of 53 PSS patients was 48.74±13.43 years (yrs) (mean ± standard deviation) and 66.3±15.0 yrs for the controls. The median CMV viral DNA copy number was 26000/mL aqueous (range 1400 to 85000 copies/mL) in 14 CMV positive patients as determined by quantitative PCR. PSS aqueous had significantly higher Interleukin (IL)-8 (CXCL8), monocyte chemotactic protein-1 (CCL2), macrophage inhibitory protein 1-β (CCL4), granulocyte colony-stimulating factor (GCSF) and transforming growth factor-β (TGF-β) levels than controls after adjusted by age and gender. IL-2, IL-12, tumor necrosis factor-α (TNF-α) and interferon-α (IFN-α) levels were significantly lower in PSS aqueous than controls. No difference between CMV positive PSS and CMV negative PSS aqueous was observed. Over 97% of PSS samples were distinguished from controls by elevated CXCL10 (>500 ng/mL), CXCL8 (>30 ng/mL) and CCL2 (>60 ng/mL) levels.

CONCLUSION

PSS eyes were characterized by elevated aqueous chemokine concentration. The presence of CMV viral DNA was not associated with significant change of the type of cytokine expression in PSS patients.

Detection of endogenous 12-hydroxyeicosatrienoic acid in human tear film

PURPOSE

Increased production of 12-hydroxyeicosatetraenoic acid [12(R)-HETE] and 12-hydroxyeicosatrienoic acid [12(R)-HETrE] positively correlates with the in vivo progression of ocular surface inflammation in rabbits. Tear film was collected from human subjects with inflamed eyes to determine whether these eicosanoids could be detected from endogenous sources.

METHODS

Control and inflamed eyes were assessed and assigned a subjective inflammatory score. Tears were collected and extracted with an internal standard. Single-ion-monitoring gas chromatography-mass spectrometry (SIM-GC-MS) was performed to quantitate endogenous levels of 12-HETE and 12-HETrE.

RESULTS

12-HETrE was detected in the tear film of both control and inflamed eyes, with the mean level being seven times higher in inflamed tears. 12-HETE was not detected in control tears and was detected in only 6 of 38 inflamed-eye tear samples.

CONCLUSIONS

The current findings demonstrate that the human eye produces detectable amounts of 12-HETrE, which is released into the tear flow. The increased levels of 12-HETrE associated with ocular surface inflammation suggest that this eicosanoid may contribute to inflammation of the ocular surface in humans.

The effect of phenylephrine on pain and flare intensity in eyes with uveitis

PURPOSE

To investigate the influence of protein concentration in the anterior chamber, measured by laser flare meter, on pain sensation after phenylephrine instillation in patients with iridocyclitis.

METHODS

Twenty-five consecutive patients with iridocyclitis were included. Patients with cataract, exfoliation syndrome, diabetes mellitus, glaucoma or any other previous ocular diseases or ocular surgery were excluded. Patients were divided into two groups: Group 1--without fibrinoid reaction (FR) in the anterior chamber (18 patients), and Group 2--with FR (7 patients). Protein concentration in the anterior chamber was measured with laser flare meter (FC 500, Kowa Co., Japan). Pupil size was measured by Alcon Tilo Scale, and pain sensation was estimated by Visual Analogue Scale (VAS, Kabi Pharmacia). All measurements were done before and 1 hour after topical instillation of 10% phenylephrine hydrochloride into the subconjunctival sac of the inflamed eyes.

RESULTS

Eyes with iridocyclitis and fibrinoid reaction (FR) have a higher flare intensity compared to those without FR (p<0.05). Pupil size was significantly increased after phenylephrine instillation in both study groups (Wilcoxon test, p<0.05). The VAS pain and flare intensity were significantly decreased in group without FR after phenylephrine instillation (Group 1) compared to values before treatment (Wilcoxon test, p<0.05). In eyes with FR (Group 2), no significant influence of phenylephrine instillation was found on VAS pain and flare intensity.

CONCLUSIONS

After phenylephrine instillation, flare intensity and pain were significantly decreased only in eyes with iridocyclitis and without FR. The decreasing level of flare intensity, and paralysis of the pupil after phenylephrine instillation seem to alleviate pain in those eyes.

Iris crystals in chronic uveitis

AIMS

To analyse the unusual physical sign of iris crystals occurring in patients with uveitis.

METHODS

Demographic details and clinical features were documented in 24 patients with chronic uveitis and iris crystals. Plasma immunoglobulin subclasses were measured, and a histopathological review of iridectomy specimens from 33 patients with chronic uveitis was also undertaken.

RESULTS

The mean age of patients was 38 years, with a slight preponderance of females. 17 patients had Fuchs' heterochromic cyclitis although a number of other uveitis entities were represented. There was no correlation between severity of clinical signs and presence of iris crystals. Over a mean follow up period of 15 months no significant change in the number, size, or position of the crystals was seen except in four patients who underwent intraocular surgery. Only three patients had raised plasma IgG1. The review of the histology of iridectomy specimens failed to show evidence of Russell body formation in any patient.

CONCLUSIONS

Iris crystals appear to be rare but may be underreported as they are small and can easily be missed. They are likely to be associated with disease processes in which there is active immunoglobulin production within the anterior chamber, such as Fuchs' heterochromic cyclitis.

Aqueous flare in patients with monocular iris atrophy and uveitis. A laser flare and iris angiography study

PURPOSE

To study aqueous flare longitudinally in patients with Fuchs' heterochromic uveitis (FHU) and for comparison in another group with iris atrophy (non FHU).

METHODS

A new laser flare meter was used. Iris angiography was performed in most FHU patients.

RESULTS

The flare values in the affected eyes in the FHU group were always higher compared to the normal eyes and rather constant over time. Cataract surgery did not permanently change the flare values. Systemic - but not local steroid therapy caused normalization of the flare. Iris angiography displayed leakage in all FHU eyes. Leakage from original vessels dominated although some newly-formed leaking vessels were observed.

CONCLUSIONS

The results support the notion that FHU is a low grade, chronic, stable disease. Leaking iris vessels, original or newly-formed, are probably the source of the increased flare. Our hypothesis is that inflammation plays a major part. Atrophy per se does not enhance flare.

Ocular inflammation stimulated by the immunomodulator AS101 [ammonium trichloro(dioxyethelene-O-O') tellurate]

The purpose of this study was to investigate the effect of a novel immunomodulator, AS101 [ammonium trichloro(dioxyethelene-O-O') tellurate], in the eye. Lewis rats were injected intravitreally with AS101 at a concentration of 13 micrograms/ml in one eye and BSS in the contralateral eye. Control animals were injected with BSS into the central vitreous of both eyes. Ocular inflammation was evaluated at 20 hours by histology, immunopathology, and by cell count, protein and cytokine measurement in the aqueous humor. At 20 hours, eyes injected with AS101 developed iridocyclitis and mild vitritis versus minimal inflammation and/or protein in contralateral eyes or eyes of control animals (p = 0.0121). The inflammatory infiltrate was mixed in character. Major Histocompatibility Complex (MHC) class II antigens and intercellular adhesion molecules (ICAM-1) were expressed in the anterior segment of eyes injected with AS101. In the aqueous humor of these eyes there were significant quantities of inflammatory cells, protein (mean +/- SEM = 11.2 +/- 2.3 mg/ml) and the cytokine interleukin 6 (IL-6) (450 units/ml) compared with contralateral eyes (p = 0.0005 for inflammatory cells; protein, mean +/- SEM = 1.6 +/- 0.17 mg/ml; IL-6 = 12 units/ml) and both eyes of control animals injected with BSS (p = 0.8955 for inflammatory cells; protein, OD = 1.5 mg/ml, OS = 0.7 mg/ml; IL-6, OD = 8 units/ml, OS = 13 units/ml). AS101 has a local inflammatory effect in the eye. This compound may activate ocular inflammation by releasing cytokines such as IL-6.

Correlations between laser flare measurements and anterior chamber protein concentrations

The laser flare cell meter quantifies anterior chamber (AC) protein (flare) by measuring light scattering of a helium-neon laser beam in the AC. The relationship between photon count and protein concentration both in vitro and in vivo was assessed. The reproducibility of the in vitro photon count measurements was 7.3%. There was a significant linear relationship between photon count and the concentration of both albumin (r = 1.0, P = 0.0001) and immunoglobulin G (IgG, r = 0.99, P = 0.0001) in vitro, but the linear-regression formulas were different with greater light scattering by IgG than by albumin at the same concentration. Laser flare measurements were done on 22 patients (12 normal eyes, 5 eyes with Fuchs' heterochromic cyclitis, and 5 uveitic eyes) before cataract surgery. Aqueous humor obtained from these patients by paracentesis was analyzed for total protein, albumin, and IgG concentration. There was a significant linear relationship (r = 0.88, P = 0.0001) between the laser flare value (range, 5.8-107.8 photons/msec) and the total aqueous protein concentration (range, 14-388 mg/dl). Use of an in vitro albumin calibration curve to convert photon count into protein concentration was found to overestimate the actual protein concentration. This overestimation was slight in normal eyes and increased with increased blood-aqueous barrier breakdown. The use of such a calibration curve therefore is not appropriate in studies on diseased eyes. The authors recommended that laser flare results be expressed in either photons per milliseconds or converted into an equivalent protein concentration using a calibration curve based on actual AC protein measurements.

Analysis of aqueous humour in uveitis by high performance liquid chromatography and sodium dodecyl sulphate-polyacrylamide gel electrophoresis

Aqueous humour from patients with Fuchs' heterochromic cyclitis (FHC) and other types of uveitis was analysed by high performance liquid chromatography (HPLC) and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Using HPLC, the number of peaks and their respective elution times were similar for the FHC, uveitis and control groups. SDS-PAGE and silver staining showed immunoglobulin G migrating as two to four distinct bands in all non-reduced samples. In the reduced state, 1-5 unidentified low MW bands (10-19 kD) were seen. Two bands at 19 and 10 kD appeared to be specific for the uveitis group, and a band at 11 kD was present in 76% of uveitis and 19% of FHC patients. None of these three bands were detected in any of the control group. As yet the identity of these low MW proteins and their possible significance in the pathogenesis of intraocular inflammation are unknown.

Analysis of aqueous humor immunoglobulin G in uveitis by enzyme-linked immunosorbent assay, isoelectric focusing, and immunoblotting

Immunoglobulin G (IgG) in aqueous humor from patients with various uveitis syndromes was analyzed using a number of immunologic techniques. Sixty-five percent of patients with Fuchs' heterochromic cyclitis (FHC), 70% of patients with other forms of uveitis, and 44% of controls showed local synthesis of IgG, as demonstrated by an elevated IgG:albumin relative concentration ratio. Using an enzyme-linked immunosorbent assay to measure the concentration of IgG subclasses 1-4, a relative excess of IgG1 was found in the aqueous compared with the serum in FHC. Isoelectric focusing and immunoblotting studies revealed oligoclonal IgG bands in the aqueous of 13 of 23 (57%) patients with FHC, most being of the IgG1 subclass. Oligoclonal bands were not found in 18 patients with other types of uveitis or 13 patients undergoing surgery for senile cataract. These findings indicate intraocular production of IgG of restricted specificity in FHC, providing further evidence for local immune dysfunction in this condition. As yet the antigenic stimulus for this oligoclonal B-cell response has not been identified.

Aqueous humor interleukin-6 levels in uveitis

The level of Interleukin-6 (IL-6) in the aqueous humor of 24 patients with 2 types of uveitis was measured with a specific bioassay using the murine hybridoma cell line B9. Sixteen patients had Fuchs' heterochromic cyclitis (FHC) and 8 had toxoplasma uveitis (TU). Sixty-three percent of each of the FHC and TU groups had raised levels of IL-6 in their aqueous (mean: 543 and 19,228 units/ml respectively). Thirteen control aqueous samples, obtained at surgery for senile cataract, showed IL-6 levels of less than 10 units/ml. Serum obtained at the same time as each aqueous humor sample also showed IL-6 levels of less than 10 units/ml, indicating that the raised levels of IL-6 found in the aqueous of uveitis patients did not result from serum leakage, but from local production. This is the first report on intraocular IL-6 levels, and indicates that IL-6 may play a role as an inflammatory mediator in uveitis.

Aqueous humour analysis in Fuchs' heterochromic cyclitis

Aqueous humor from 23 patients with Fuchs' heterochromic cyclitis (FHC) was analysed by a number of immunological methods. Intraocular IgG synthesis was found in 65% of patients and oligoclonal IgG bands, mainly of the IgG1 subclass, identified in 57%. There was a relative increase in IgG1 (P less than 0.01) as compared to patients with senile cataract. Local production of the cytokine Interleukin-6 was demonstrated in 63% of patients (P less than 0.01). Analysis of aqueous by HPLC and SDS-PAGE failed to reveal any abnormalities specific for FHC. These findings add further evidence to the theory of immune dysregulation in this condition.

[The possibilities for predicting and preventing postoperative inflammatory complications in intraocular correction]

Measurements of unsaturated fatty acid diene conjugates in the anterior chamber humor are recommended to predict postoperative inflammatory complications. If their levels are increased, antioxidants should be included in the therapeutic scheme along with antibiotics and corticosteroids.