Integrated omics analysis of sweat reveals an aberrant amino acid metabolism pathway in Vogt-Koyanagi-Harada disease

Vogt-Koyanagi-Harada (VKH) disease is an autoimmune disease leading to visual impairment. Its pathogenic mechanisms remain poorly understood. Our purpose was to investigate the distinctive protein and metabolic profiles of sweat in patients with VKH disease. In the present study, proteomics and metabolomics analysis was performed on 60 sweat samples (30 VKH patients and 30 normal controls) using liquid chromatography tandem mass spectrometry. Parallel reaction monitoring (PRM) analysis was used to validate the results of our omics analysis. In total, we were able to detect 716 proteins and 175 metabolites. Among them, 116 proteins (99 decreased and 17 increased) were observed to be significantly different in VKH patients when compared to controls. Twenty-one differentially expressed metabolites were identified in VKH patients, of which 18 included choline, L-tryptophan, betaine and L-serine were reduced, while the rest were increased. Our multi-omics strategy reveals an important role for the amino acid metabolic pathway in the pathogenesis of VKH disease. Significant differences in proteins and metabolites were identified in the sweat of VKH patients and, to some extent, an aberrant amino acid metabolism pathway may be a pathogenic factor in the pathogenesis of VKH disease.

Identification of susceptibility SNPs in CTLA-4 and PTPN22 for scleritis in Han Chinese

The aim of this study was to determine the association between 13 single nucleotide polymorphisms (SNPs) in the cytotoxic T lymphocyte-associated antigen-4 (CTLA4) and protein tyrosine phosphatase non-receptor type 22 (PTPN22) genes with scleritis in a Chinese Han population. We recruited 432 scleritis patients and 710 healthy controls. Four tag SNPs of CTLA4 and nine tag SNPs of PTPN22 were selected using Haploview. Genotyping was performed with the Sequenom MassArray® iPLEX GOLD Assay. Genotype and allele frequency differences were analyzed by χ² test and Bonferroni correction. Haplotype analysis was performed to further evaluate the association of these two genes with scleritis. In this study, CTLA4/rs3087243 G allele frequency and GG genotype frequency were significantly increased in scleritis patients compared to healthy controls [corrected P-value (Pc) = 0·02, odds ratio (OR) = 1·475, 95% confidence interval (CI) = 1·175-1·851; Pc = 0·04, OR = 1·546, 95% CI = 1·190-2·008, respectively]. None of the tested SNPs in the PTPN22 gene showed an association with scleritis. Haplotype analysis revealed a lower frequency of a CTLA4 TCAA haplotype (order of SNPs: rs733618, rs5742909, rs231775, rs3087243) (Pc = 4·26 × 10^-3 , OR = 0·618, 95% CI = 0·540-0·858) and a higher frequency of a PTPN22 TTATACGCG haplotype (order of SNPs: rs3789604, rs150426536, rs1746853, rs1217403, rs1217406, rs3789609, rs1217414, rs3789612, rs2488457) (Pc = 2·83 × 10^-4 , OR = 1·457, 95% CI = 1·210-1·754) in scleritis patients when compared to healthy controls. In conclusion, our findings indicate that CTLA4 and PTPN22 might confer genetic susceptibility to scleritis in a Chinese Han population.

The Role of Mitochondria-Associated Reactive Oxygen Species in the Amyloid β Induced Production of Angiogenic Factors b y ARPE-19 Cells

OBJECTIVE

This study aimed to investigate the mechanisms whereby Amyloidbeta (Aβ) induces the production of angiogenic factors by a human retinal pigment epithelial cell line (ARPE-19) cells.

METHODS

ARPE-19 cells obtained from the American Type Culture Collection (ATCC) were utilized in this study. The expression level of vascular endothelial growth factor (VEGF), Interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1) and complement activation fragments C3a and C5a were measured by Real-time quantitative PCR (RT-PCR) and Enzyme-linked immunosorbent assay (ELISA). The production of mitochondria-associated reactive oxygen species (ROS) was measured by flow cytometry.

RESULTS

The expression of VEGF, IL-8, MCP-1, C3a and C5a was significantly increased in Aβ-treated ARPE-19 cells. Mitochondria-associated ROS production was also significantly increased when exposed to Aβ. Inhibition of mitochondrial ROS with Diphenyleneiodonium chloride (DPI) markedly decreased the Aβ induced production of VEGF, IL-8, MCP-1, C3a and C5a by ARPE-19 cells. Anti-C3a or anti-C5a neutralizing antibodies did not have a detectable influence on the secretion of VEGF, IL-8 and MCP-1 by ARPE-19 cells upon stimulation with Aβ.

CONCLUSION

Our results support the hypothesis that Aβ is involved in the pathogenesis of choroidal neovascularization (CNV) formation by promoting the production of the angiogenic cytokines VEGF, IL-8 and MCP-1 by RPE cells. Mitochondrial ROS was shown to play a role in the regulation of Aβ induced expression of these cytokines.

ERAP1/ERAP2 and RUNX3 polymorphisms are not associated with ankylosing spondylitis susceptibility in Chinese Han

Previous studies show that endoplasmic reticulum‐associated aminopeptidase (ERAP1/ERAP2) and runt‐related transcription factor 3 (RUNX3) gene polymorphisms are associated with AS (ankylosing spondylitis) in European Caucasians. However, contradictory results were reported in different Asian populations. The purpose of this study was to determine whether eleven candidate single nucleotide polymorphisms (SNPs) in ERAP1/ERAP2 and six in RUNX3 genes confer susceptibility to AS with or without acute anterior uveitis (AAU) [AS⁺AAU⁺ or AS⁺AAU^–] in Chinese Han. Therefore, a case–control association study was performed in 882 AS⁺AAU^–, 884 AS⁺AAU⁺ and 1727 healthy controls. Genotyping was performed using the iPLEXGold genotyping assay. A meta‐analysis was performed to assess the association of polymorphisms of ERAP1 with AS susceptibility in Asian populations. No association was found between SNPs of ERAP1/ERAP2/RUNX3 and susceptibility of AS with or without AAU. A case–control study between patients with human leucocyte antigen HLA‐B27‐positive and healthy controls also failed to demonstrate an association of the tested SNP with AS with or without AAU. Moreover, a meta‐analysis showed that there was no association of rs30187, rs27037, rs27980, rs27434 and rs27582 in ERAP1 with AS in Chinese Han. Taken together, 17 SNPs in ERAP1/ERAP2 and RUNX3 genes did not confer disease susceptibility to AS in Chinese Han.

Higher Expression of NOD1 and NOD2 is Associated with Vogt-Koyanagi-Harada (VKH) Syndrome But Not Behcet's Disease (BD)

NOD1 and NOD2 have been found to play a significant regulatory role in autoimmune disease. To analyze the role of NOD1 and NOD2 in the pathogenesis of Vogt- Koyanagi-Harada (VKH) syndrome and Behcet's disease (BD). We analyzed the expression of NOD1 and NOD2 from PBMCs by RT-PCR and Western Blot. PBMCs and DCs were cultured with NOD receptor ligands iE-DAP (NOD1) or MDP (NOD2) and cells and supernatants were analyzed by flow cytometry (FCM) and enzyme-linked immunosorbent assay (ELISA). DCs and CD4+T cells were co-cultured with or without stimulation and cells and supernatants were analyzed by FCM and ELISA. A higher expression of NOD1 and NOD2 was observed in patients with active VKH syndrome as compared with controls. However, no significant differences were found between BD patients and controls. Activation of NOD1 and NOD2 with iE-DAP or MDP markedly increased the level of IL-6, TNF-α and IL-1β in PBMCs and DCs and induced the expression of CD40, CD80, CD83, CD86 and HLA-DR on DCs. Activation of NOD1 and NOD2 in DCs promoted the differentiation and proliferation of CD4(+)T cells. In conclusion, activation of NOD1 or NOD2 increased the production of pro-inflammatory cytokines in PBMCs and promoted the maturation and activation of human DCs in association with stimulation of Th1 and Th17 cells. Our results suggest that over-expression of NOD1 and NOD2 may be involved in the pathogenesis of VKH syndrome.

TLR3 and TLR4 But not TLR2 are Involved in Vogt-Koyanagi- Harada Disease by Triggering Proinflammatory Cytokines Production Through Promoting the Production of Mitochondrial Reactive Oxygen Species

Vogt-Koyanagi-Harada (VKH) disease is considered to be an autoimmune disease possibly triggered by an abnormal response to infection. Activation of TLRs signaling pathways by microbial products can drive inflammatory responses and adaptive immunity. In the present study, we investigated the role of TLRs in the pathogenesis of VKH disease. We showed that the expression of TLR3 and TLR4, but not TLR2, was significantly increased in monocyte-derived macrophages (MDMs) from VKH patients with active uveitis compared to controls. VKH patients with active uveitis showed an elevated level of IL-1β, IL-6, IL-8, TNF-α and reactive oxygen species (ROS) in MDMs. IL-1β, IL-6, IL-8 and TNF-α production could be significantly upregulated and downregulated by a ROS activator or inhibitor, respectively. Downregulation of the NLRP3 inflammasome significantly inhibited the production of IL-1β but not IL-6, IL-8 and TNF-α. The phosphorylation levels of p38 and ERK1/2 were significantly higher in MDMs from active VKH patients compared to controls. Inhibition of p38 or ERK1/2 significantly decreased IL-1β, IL-6, IL-8 and TNF-α expression. These results suggest that the increased expression of TLR3/4 in MDMs may be involved in the pathogenesis of VKH disease by the induction of inflammatory cytokines which is mediated by enhanced production of ROS.

Activation of the aryl hydrocarbon receptor affects activation and function of human monocyte-derived dendritic cells

Aryl hydrocarbon receptor (AhR) is well known for mediating the toxic effects of dioxin-containing pollutants, but has also been shown to be involved in the natural regulation of the immune response. In this study, we investigated the effect of AhR activation by its endogenous ligands 6-formylindolo[3,2-b]carbazole (FICZ) and 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) on the differentiation, maturation and function of monocyte-derived DCs in Behçet's disease (BD) patients. In this study, we showed that AhR activation by FICZ and ITE down-regulated the expression of co-stimulatory molecules including human leucocyte antigen D-related (HLA-DR), CD80 and CD86, while it had no effect on the expression of CD83 and CD40 on DCs derived from BD patients and normal controls. Lipopolysaccharide (LPS)-treated dendritic cells (DCs) from active BD patients showed a higher level of interleukin (IL)-1β, IL-6, IL-23 and tumour necrosis factor (TNF)-α production. FICZ or ITE significantly inhibited the production of IL-1β, IL-6, IL-23 and TNF-α, but induced IL-10 production by DCs derived from active BD patients and normal controls. FICZ or ITE-treated DCs significantly inhibited the T helper type 17 (Th17) and Th1 cell response. Activation of AhR either by FICZ or ITE inhibits DC differentiation, maturation and function. Further studies are needed to investigate whether manipulation of the AhR pathway may be used to treat BD or other autoimmune diseases.

Recent developments in the treatment of posterior uveitis

Uveitis is an intraocular inflammation that can be caused by infection, autoimmune disease, trauma or malignancy. It is a serious cause of visual handicap and therapy is targeted at: removal of possible infectious agents, the immunological processes that lead to or sustain the inflammation and finally to prevent or treat the destructive effects of the inflammation on the delicate ocular structures. In this review the latest developments concerning the treatment of posterior uveitis are illuminated, e. g., new approaches concerning the treatment of infectious uveitis including the therapy of herpes virus (VZV, HSV and CMV), bacterial and toxoplasma infections of the eye. Several new ways to influence the immune response and inflammation are described including the use of interferons, modulation of cytokines, soft steroids, other new immunosuppressive drugs and treatment of autoimmune uveitis by oral tolerization. An overview is given to illustrate new ways to administer drugs into eyes, such as intravitreal devices. Finally new developments in the field of the treatment of the various complications of uveitis (cystoid macular edema) are described.

Food safety in free-range and organic livestock systems: risk management and responsibility

Animal production systems that offer outdoor access to the animals have become increasingly popular in the Western world due to the growing general discontent of consumers with conventional bioindustrial farming practices. These open production systems offer improved animal welfare but may create new problems for animal health, resulting in increased food safety risks from bacterial, viral, or parasitic infections or environmental contaminants. Examples of these new problems include increased Toxoplasma gondii infections in pigs and high dioxin levels in eggs from free-range hens. In this review, the relation between positive and negative points of free-range and organic livestock production systems is discussed with reference to production in The Netherlands. We investigated how proponents of more animal welfare friendly systems deal with potential negative issues in public and whether any risk communication is used. Generally, we found that the existence of a dilemma is disputed or avoided in communication with the consumer. This avoidance could be detrimental for public trust in alternative animal production systems, should problems occur. To prevent future problems, it will be necessary to communicate about the relevant types and sources of the food safety risks to the consumers. The responsibility for protecting food safety should be properly divided among the various parties involved: producers, processors, governments, nongovernmental organizations, and consumers.

Inhibitory effect of rapamycin and dexamethasone on production of IL-17 and IFN-gamma in Vogt-Koyanagi-Harada patients

AIMS

To evaluate the effect of rapamycin (RAPA) and dexamethasone (DEX) on the production of IL-17 and IFN-gamma by peripheral blood mononuclear cells (PBMCs) from Vogt-Koyanagi-Harada (VKH) patients and healthy individuals.

METHODS

Blood samples were drawn from 10 active VKH patients and 10 healthy individuals. PBMCs were cultured with or without anti-CD3 and anti-CD28 antibodies in the presence or absence of different concentrations of RAPA or DEX for 72 h. IL-17 and IFN-gamma concentrations in the supernatants were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The expression of IL-17 and IFN-gamma was significantly increased in active VKH patients compared with that in healthy controls. Both RAPA and DEX were able to significantly inhibit the production of IL-17 and IFN-gamma by PBMCs from patients and healthy controls. RAPA was able to completely inhibit IL-17 production at a dosage of 10 ng/ml but only partially suppressed IFN-gamma production even at a much higher concentration (1000 ng/ml). DEX inhibited the production of both IL-17 and IFN-gamma by approximately 70%.

CONCLUSIONS

This study indicates that both RAPA and DEX inhibit the production of IL-17 and IFN-gamma by PBMCs. RAPA is much stronger in inhibiting the production of IL-17 than DEX.

Aqueous flare and cells in Fuchs syndrome

PURPOSE

To quantitatively evaluate aqueous flare and cells in patients with Fuchs syndrome.

METHODS

The medical records of 40 patients (47 eyes) diagnosed with Fuchs syndrome between February 2006 and January 2007 at the Uveitis Study Center of Sun Yat-sen University were retrospectively reviewed. Aqueous flare and cells were clinically evaluated and quantified with laser flare-cell meter. Statistical analysis was performed to investigate the relationship between flare values and cell counts, and clinical parameters including patients' age, sex, duration of disease, best-corrected visual acuity, keratic precipitate, iris depigmentation, intraocular pressure, and posterior subcapsular lens opacities.

RESULTS

Aqueous flare values (photon counts/ms) were significantly higher in Fuchs syndrome (9.40+/-5.85) than in normal controls (5.77+/-1.89, P=0.000). Aqueous cell counts (cells/0.5 mm(3)) were also significantly higher in Fuchs syndrome (5.09+/-4.84) than in normal controls (1.14+/-1.03, P=0.000). The flare values were positively correlated with the cell counts (r=0.331, P=0.001). Both flare values and cell counts were higher in eyes with keratic precipitates scored 2+ or 3+ as compared to those with a 1+ score. Higher flare values and cell counts were also observed in eyes with a 2+ or 3+ iris depigmentation score as compared to those with a 1+ score. No difference was found between flare values and cell counts and other parameters.

CONCLUSION

Breakdown of blood-aqueous barriers and increased cell counts are present in the affected eyes in patients with Fuchs syndrome. These changes are positively associated with the degree of keratic precipitates and iris depigmentation.

Longitudinal quantification of aqueous flare and cells in Vogt-Koyanagi-Harada disease

AIMS

To quantitatively evaluate the changes of aqueous flare and cells in eyes with Vogt-Koyanagi-Harada (VKH) disease.

METHODS

This prospective study included 35 initial-onset VKH patients (70 eyes) and 46 recurrent VKH patients (92 eyes) following immunotherapy. Aqueous flare and cells were quantified using the laser flare-cell meter before treatment, 2 weeks, 1, 3, 6 and 9 months after treatment.

RESULTS

Before treatment, mean aqueous flare (ph/ms) in initial-onset and recurrent VKH eyes were 8.1 (SD 4.1) vs 43.6 (20.7) (p = 0.000). Following treatment, recurrent VKH eyes showed a significantly higher flare value than initial-onset VKH eyes at 2 weeks, 1, 3 and 6 months. Prior to treatment, mean cell counts (cells/0.5 mm3) in initial-onset and recurrent VKH eyes were 2.0 (1.9) vs 39.4 (23.1) (p = 0.000). Following treatment, recurrent VKH eyes showed significantly higher cell counts than initial-onset VKH eyes at 2 weeks, 1 and 3 months.

CONCLUSIONS

Our study shows that recurrent VKH patients displayed a more striking and long-lasting breakdown of the BAB and more severe inflammation than initial-onset VKH patients. Our study also indicates that the disruption of BAB lasted longer than aqueous cells either in initial-onset or in recurrent VKH patients.

Effect of Flock Size on Dioxin Levels in Eggs from Chickens Kept Outside

To decrease dioxin uptake by the general population the European Union (EU) has set limits to the dioxin content of many foodstuffs including eggs. Eggs from free foraging chickens are known to have a higher dioxin content compared with confined laying hens, and the question is whether these eggs can adhere to current EU regulations. The aim of the study was to investigate parameters that are involved in the contamination of eggs from chickens raised under organic conditions. Samples from 34 organic farms including soil and earthworm samples were collected between September and December of the year 2003. Dioxin levels were assayed by gas chromatography-mass spectrometry. Various parameters were collected by on farm interviews. Egg dioxin content varied between 0.4 and 8.1 pg of toxic equivalents (TEQ)/g of egg fat with a mean of 2.2 pg of TEQ/g of egg fat. Nine out of 34 farms exceeded the EU limit of 3 pg of TEQ/g of egg fat. In addition, dioxin-like polychlorinated biphenyls (DL-PCB) were measured, and 8 samples exceeded the limit for the sum of dioxins and DL-PCB. Overall, egg samples from 10 farms were noncompliant with the dioxin or total TEQ limits. No statistically significant relation could be observed between egg dioxin levels and the concentration observed in soil or earthworms. A statistically significant association was observed between flock size and egg dioxin and DL-PCB content. This effect is most likely attributable to the fact that flock size is related to the time chickens spend outside. Restricting outdoor run use on one of the farms resulted in a decrease of the egg dioxin content to a level that was within the EU limits. This demonstrates that the most likely contamination source is the soil or soil organisms but that the behavior of the hens determines the extent of the contamination. Following the completion of this study, a dioxin monitoring protocol has been set up in the Netherlands to prevent marketing of eggs with raised dioxin levels.

Questionnaire survey of disease prevalence and veterinary treatments in organic layer husbandry in the Netherlands

Disease prevalence and veterinary treatments in organic animal production differ from those in conventional systems. In order to gather information about current practices in organic layer husbandry, 33 organic egg producers of 16 small, 12 medium-sized, and 5 large farms were asked to complete a questionnaire on disease prevalence and treatments. On these farms, the mean mortality was 9% and the mean laying percentage was 79%. In contrast with the regulations for organic farming, the use of chemotherapeutics was not recorded on 30% of the farms. One third of the farmers were not aware of the type of vaccination given to their hens, and on the other farms hens had been vaccinated as pullets against nine or more viral and bacterial diseases. Several health problems were mentioned, such as feather pecking, red mites, helminths, infectious bronchitis, colibacillosis, and coccidiosis. On 19 farms, diseases were treated with homeopathic, phytotherapeutic, or other alternative medicines; on 10 of these farms chemotherapeutics were also used. On 4 farms only chemotherapeutics were used, on 10 farms no products were used, and on some farms up to seven products were used. Although quite a large number of organic layer farmers in the Netherlands used homeopathic, phytotherapeutic, or other alternative medicines, the use of chemotherapeutics is currently inevitable to prevent animal suffering or distress in organic husbandry.

Cats and goat whey associated with Toxoplasma gondii infection in pigs

In organic livestock production systems, farm-management factors are thought to play an important role in the on-farm prevalence of Toxoplasma gondii. Serological results and the results of an HACCP analysis were combined to determine important risk factors for the prevalence of this protozoan parasite. Mathematical analysis demonstrated that feeding goat whey to pigs and the presence of a high number of cats were positively correlated to T. gondii seroprevalence in pigs. Not covering roughage and the farmers' assumption that pigs can come into contact with cat feces also showed a positive relationship. In order to decrease the risk of T. gondii infecting their pigs, farmers should limit the access and number of cats on their farms and refrain from feeding goat whey to their pigs.

Selective blockade of phosphodiesterase types 2, 5 and 9 results in cyclic 3'5' guanosine monophosphate accumulation in retinal pigment epithelium cells

AIM

To investigate which phosphodiesterase (PDE) is involved in regulating cyclic 3'5' guanosine monophosphate breakdown in retinal pigment epithelium (RPE) cells.

METHODS

cGMP content in the cultured RPE cells (D407 cell line) was evaluated by immunocytochemistry in the presence of non-selective or isoform-selective PDE inhibitors in combination with the particulate guanylyl cyclase stimulator atrial natriuretic peptide (ANP) or the soluble guanylyl cyclase stimulator sodium nitroprusside (SNP). mRNA expression of PDE2, PDE5 and PDE9 was studied in cultured human RPE cells and rat RPE cell layers using non-radioactive in situ hybridisation.

RESULTS

In the absence of PDE inhibitors, cGMP levels in cultured RPE cells are very low. cGMP accumulation was readily detected in cultured human RPE cells after incubation with Bay60-7550 as a selective PDE2 inhibitor, sildenafil as a selective PDE5 inhibitor or Sch51866 as a selective PDE9 inhibitor. In the presence of PDE inhibition, cGMP content increased markedly after stimulation of the particulate guanylyl cyclase. mRNA of PDE2,PDE5 and PDE9 was detected in all cultured human RPE cells and also in rat RPE cell layers.

CONCLUSIONS

PDE2, PDE5 and PDE9 have a role in cGMP metabolism in RPE cells.

Presence of Salmonella and Campylobacter spp. in wild small mammals on organic farms

The presence of Salmonella and Campylobacter spp. in rodents and insectivores (n = 282) was investigated on organic farms. Infections were encountered in house mice (8 of 83 Campylobacter positive and 1 of 83 Salmonella sp. strain Livingstone positive) and brown rats (1 of 8 Campylobacter positive) but not in other species. No shared Campylobacter genotypes were found between rodent and pig manure isolates. Effective on-farm rodent management is recommended.

Upregulation of T-bet expression in peripheral blood mononuclear cells during Vogt-Koyanagi-Harada disease

AIM

To test the hypothesis that T-bet expression is altered in patients with Vogt-Koyanagi-Harada (VKH) disease.

METHODS

Peripheral blood was withdrawn from 16 VKH patients before and after immunosuppressive treatment and from 16 healthy individuals. IFN-gamma, IL-2, and IL-4 in the serum and the supernatants of peripheral blood mononuclear cells (PBMC) cultured with or without phytohaemagglutinin (PHA) were measured by ELISA. T-bet mRNA and protein expression in PBMC cultured with or without PHA was detected by RT-PCR and western blot, respectively.

RESULTS

The level of IFN-gamma, but not IL-2 and IL-4, was significantly higher in the supernatants of stimulated PBMC in patients than in controls. A significantly increased T-bet mRNA was found in VKH patients during an active uveitis episode, but not in quiescent patients, compared to controls. T-bet protein was detectable in VKH patients during an active uveitis episode, but not in quiescent patients nor in the healthy controls. Stimulation of PBMC with PHA resulted in a marked upregulation of T-bet mRNA and protein expression for both patients and controls with no significant difference between the two groups.

CONCLUSIONS

Upregulation of T-bet may be associated with the development of a Th1 mediated immune response in VKH disease.

Immunological factors in the pathogenesis and treatment of age-related macular degeneration

Recent findings indicate that immunological factors are involved not only in the pathogenesis of age-related macular degeneration (AMD), but also in its treatment. Earlier data showing the presence of inflammatory cells in affected areas of AMD retinas support this statement. Although a possible role for autoimmunity was initially suggested, it has never reached general acceptance. Microorganisms have also been implied in the pathogenesis of AMD. Both serum antibacterial antibody levels and positive DNA tests from neovascular membranes have pointed to a possible role for Chlamydia pneumoniae in the pathogenesis of AMD. New data is providing evidence for the hypothesis that deposits between Bruch's membrane and the retinal pigment epithelium (RPE) cell layer may act as a stimulus for the local activation of the complement system. This may lead to a further growth of the deposits due to the strong chemotactic activity of certain complement activation products (such as C5a) with an influx of inflammatory cells. The buildup of cells and extracellular deposits may lead to local ischemia resulting in the activation of RPE cells. These activated RPE cells are thought to release angiogenic stimuli leading to choroidal neovascularization, which is the most serious complication of AMD. The fact that immunosuppressive drugs such as triamcinolone acetonide and anecortave acetate are capable of inhibiting choroidal neovascularization is consistent with an inflammatory component in the pathogenesis of AMD. Specific immunotherapy directed at certain cytokines or growth factors is now being investigated at both the animal and patient levels. Various clinical trials involving engineered antibodies are now being applied to block angiogenic factors such as the vascular endothelial growth factor (VEGF). An approach using gene therapy to influence angiogenesis by inducing the production of the pigment epithelium-derived factor (PEDF) was able to block neovascularization in an experimental murine model. Besides trying to block ongoing processes in AMD, retinal transplantation is now also being investigated as a treatment option. The fact that the retina is possibly an immunoprivileged tissue in combination with experimental data showing that the subretinal space is an immunoprivileged site is an indication that transplantation would not suffer from the rejection process. A larger obstacle is the question whether transplanted retinal tissue will regain its functional properties.

Long-Term Changes in Corneal Endothelial Morphology After Discontinuation of Low Gas-Permeable Contact Lens Wear

PURPOSE

Low gas-permeable contact lens wear of polymethyl methacrylate or hydroxyethyl methacrylate material is known to cause morphologic abnormalities in the corneal endothelial cell layer. These lenses were widely prescribed and successfully worn until their use was actively discouraged in the late 1980s and early 1990s. This study was designed to investigate whether discontinuation of low gas-permeable contact lens wear leads to an improvement of corneal endothelial cell morphology.

METHODS

At the time of discontinuation and at least 5 years after discontinuation of low gas-permeable contact lens wear, noncontact specular photographs of the central corneal endothelium were made in 66 patients (14 male and 52 female, mean age 37.7 +/- 8.4, range 24.6-69.0). By computer analysis of endothelial photographs, parameters for polymegethism and pleomorphism were calculated, as well as cell density.

RESULTS

Mean follow-up time between photographs was 6.8 years (SD 1.1). Sixty-one patients were refitted with rigid high gas-permeable contact lenses or high-water-content soft lenses, and 5 patients switched to spectacle wear. A small but significant recovery of the corneal endothelial cell morphology was found for the mean coefficient of variation of cell area, from 37.5 to 35.7 (P = 0.022), and for the coefficient of variation of the number of sides, from 13.1 to 12.4 (P = 0.004). The mean percentage of hexagonal cells increased from 54.2 to 56.2 (P = 0.013). Although the corneal endothelial cell morphology improved significantly on cessation of LGP contact lens wear, the values did not return to levels observed in normal, non-contact lens wearing individuals. During follow-up, the mean endothelial cell density decreased significantly (P = 0.001) from 2994 to 2890 (a 3.5% cell loss in 6.8 years), which is similar to the known normal age-related cell loss of 0.6% per year in non-contact lens wearing healthy individuals.

CONCLUSION

Endothelial polymegethism and pleomorphism caused by PMMA or HEMA contact lens wear is partly reversible.

T-bet expression is upregulated in active Behçet's disease

AIM

To investigate T-bet mRNA and protein expression on peripheral blood mononuclear cells (PBMC) in patients with Behçet's disease with active uveitis.

METHODS

Blood samples were taken from 24 patients with Behçet's disease who had active uveitis and 16 healthy individuals. PBMC were subjected to analysis of T-bet mRNA and protein expression using semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and western blot, respectively. The products from PCR were sequenced. In order to determine the influence of activation on T-bet expression, the phytohaemagglutinin (PHA) stimulated PBMC from each sample were also evaluated for expression of T-bet mRNA and protein.

RESULTS

A significantly increased T-bet mRNA accumulation was detected in the samples from patients with active Behçet's disease compared with that in controls. A 62 kDa band was detectable in patients with active Behçet's disease, but not in controls. No difference was found between patients with Behçet's disease who had active uveitis and normal controls concerning the expression of either T-bet mRNA or its protein after stimulation with PHA for 72 hours.

CONCLUSION

Behçet's disease is associated with an upregulation of T-bet expression, which supports a role for the Th1 subset of T cells in the pathogenesis of this disease.

Characterization of Toxoplasma gondii-specific T cells recovered from vitreous fluid of patients with ocular toxoplasmosis

PURPOSE

The mechanisms involved in reactivations of latent ocular Toxoplasma gondii (Tg) infections in immunocompetent patients are poorly understood. In view of the possible role of T cells in the immunopathogenesis of the disease, ocular infiltrating T cells obtained from patients with recurrent ocular toxoplasmosis were characterized phenotypically and functionally.

METHODS

Ocular infiltrating T cells were recovered from vitreous fluid (VF) samples of 10 patients with active recurrent ocular toxoplasmosis. Two patients with uveitis of other origins were included as control subjects. T-cell lines (TCLs) were generated by mitogenic stimulation and tested for reactivity to Tg and human retinal protein extracts. The TCLs of three patients were cloned by limiting dilution. Tg-reactive T-cell clones (TCCs) were characterized with respect to their phenotype, T-cell receptor variable (TCR V)-beta gene usage, HLA restriction, and cytokine secretion profile.

RESULTS

Reactivity to Tg could be detected only in the TCLs of patients with ocular toxoplasmosis. None of the TCLs showed reactivity to human retinal antigens. All tested intraocular Tg-specific TCCs (n = 23) were CD3+CD4+ and displayed differential TCR Vbeta usage. Twenty-one TCCs were HLA-DR restricted and two TCCs were restricted by HLA-DP. The majority of the intraocular Tg-specific TCCs showed a bias toward a T-helper (Th)0-Th2 cytokine profile.

CONCLUSIONS

The data indicate that T cells specific for the triggering microorganism infiltrate the eye of patients with recurrent ocular toxoplasmosis. The functional characteristics of the VF-derived Tg-specific T cells and their presence at the site of inflammation suggest their involvement in the local inflammatory response of ocular toxoplasmosis.

Disturbed expression of Fas/FasL on CD4(+) and CD8(+)T cells in Behcet's disease, Vogt-Koyanagi-Harada syndrome, and idiopathic anterior uveitis

AIMS

To evaluate the expression of Fas/FasL antigen on peripheral blood T lymphocytes in patients with Behcet's disease, Vogt-Koyanagi-Harada (VKH) syndrome, and idiopathic anterior uveitis.

METHODS

The expression of Fas and FasL on peripheral blood T lymphocytes was determined using flow cytometry in 26 patients with Behcet's disease (BD), 17 patients with VKH syndrome, 25 patients with idiopathic anterior uveitis, and 43 healthy individuals (controls).

RESULTS

A higher proportion of CD4(+) T cells expressing Fas was noted in patients with Behcet's disease (25.70 +/- 7.32%), VKH syndrome (19.60 +/- 11.02%), and idiopathic anterior uveitis (20.81+/- 7.40%) compared with controls (14.02 +/- 6.30%). The expression of Fas on CD8(+) cells from patients with Behcet's disease (9.47 +/- 6.97%) and VKH syndrome (6.84+/- 5.5%) was also higher than that seen in controls (3.47+/- 2.75%). There was no difference in FasL expression on T cells between patients and controls except that a lower expression of FasL on CD8(+) T cells was noted in patients with idiopathic anterior uveitis.

CONCLUSION

A disturbed expression of Fas and FasL on T cells is present in patients with Behcet's disease, VKH syndrome, and idiopathic anterior uveitis, which may be involved in the perpetuation and recurrence of uveitis.

The role of cytokines in corneal immunopathology

Cytokines play an important role in the pathogenesis of various corneal diseases and during corneal graft rejection. Furthermore, cytokines may also play a role in the maintenance of the integrity of the normal cornea. This review focuses on the effects of several cytokines in corneal immunopathology, including the type of the corneal immune response, angiogenesis, chemotaxis, apoptosis, wound healing, corneal disease, and transplantation. It may provide clues for the future treatment of corneal disease and corneal transplantation rejection.

Longitudinal analysis of varicella-zoster virus DNA on the ocular surface associated with herpes zoster ophthalmicus

PURPOSE

Longitudinal analysis of varicella-zoster virus DNA on the ocular surface of patients with herpes zoster ophthalmicus.

METHODS

Clinical specimens were obtained from the bulbar conjunctival surface with a cotton-tipped swab at weekly intervals for 6 consecutive weeks from 21 patients with acute ophthalmic zoster with a skin rash duration of less than 7 days. All patients received oral valacyclovir 1000 mg three times daily for 10 days without additional corticosteroids. The swabs were analyzed by means of polymerase chain reaction for the presence of varicella-zoster virus and herpes simplex virus type 1 DNA. Conjunctival swabs were also obtained from a control group of 20 patients with cataract.

RESULTS

On inclusion, varicella-zoster virus DNA was present on the ocular surface of 19 of the 21 patients. Six varicella-zoster virus DNA-positive patients had no signs of ocular inflammation. All control swabs were negative for both varicella-zoster virus and herpes simplex virus DNA. The duration of varicella-zoster virus DNA detection from rash onset varied from 2 to 34 days. The number of days between the onset of herpes zoster skin rash and the latest positive varicella-zoster virus DNA test was significantly longer in patients whose age was equal to or above the median age of 66 years than in the younger patients (Mann-Whitney test: P =.0004). At 6-week follow-up, all conjunctival swabs were negative for varicella-zoster virus DNA. However, at that time, the eyes of seven patients were still inflamed.

CONCLUSION

The duration of varicella-zoster virus DNA shedding in herpes zoster ophthalmicus is highly variable and age dependent, and is probably related to the host immune response.

Retinal pigment epithelium-immune system interactions: cytokine production and cytokine-induced changes

Vision is dependent on proper function of several intraocular structures. Immune responses to eliminate invading pathogens from the eye may threat vision by causing damage to these structures. Therefore, immunological defence of the eye should be carefully balanced between efficacy and maintenance of functional integrity. The eye is equipped with several regulatory mechanisms to prevent certain immune and inflammatory responses and is, therefore, regarded as an immune privileged site. The retinal pigment epithelium (RPE) contributes to the immune privileged status of the eye as part of the blood-eye barrier and by the secretion of immunosuppressive factors inside the eye. RPE cells, however, may also play an important role in the development of immune and inflammatory responses in the posterior part of the eye. During the last decade it has become clear that RPE cells are highly sensitive to a variety of inflammatory cytokines. Under inflammatory conditions, RPE cells produce a myriad of cytokines that may activate the resident ocular cells or attract and activate leukocytes. Cytokine stimulation of RPE cells causes profound effects, including nitric oxide secretion, cell surface expression of MHC class II and adhesion molecules and abrogation of barrier function. This article provides a comprehensive review of the literature concerning RPE cells and cytokines.

Analysis of the cellular infiltrate in the iris during experimental autoimmune encephalomyelitis

PURPOSE

Previous studies have shown that experimental autoimmune encephalomyelitis (EAE) and anterior uveitis (AU) develop in Lewis rats immunized with myelin basic protein (MBP). The purpose of this study was to characterize the dynamics, distribution, and phenotype of infiltrating cells in the iris during EAE-associated AU.

METHODS

Lewis rats were immunized with MBP emulsified in complete Freund's adjuvant (CFA) or with CFA alone. Cellular infiltration of the iris was analyzed at various time points by immunohistochemistry of wholemounts, flow cytometry, and immunoelectron microscopy, by using monoclonal antibodies specific for monocytes/macrophages (ED1), T lymphocytes (R73, W3.25, OX8), T-cell activation markers (OX39, OX40), granulocytes (HIS48), major histocompatibility complex (MHC) class II (OX6), and neurofilament (2H3).

RESULTS

MBP-immunized rats showed development of characteristic monophasic EAE, followed, after resolution of paralysis, by mild self-limited AU. Initially, focal infiltrates of round MHC class II(+) and ED1(+) cells were found in the iris. During the course of AU, the midiris became massively infiltrated with ED1(+) monocytes-macrophages, R73(+) T cells, granulocytes (HIS48(+)), and MHC class II(+) cells. The influx of T cells consisted of CD4(+) and CD8(+) cells, of which only a small fraction (<14 and 11%, respectively) expressed activation markers. The infiltrating cells accumulated in proximity to myelinated and nonmyelinated nerve bundles and in the vicinity of blood vessels in the iris. No evidence was found for demyelination or nerve degradation. Neither EAE nor AU developed in CFA-treated control rats.

CONCLUSIONS

These data show that EAE-associated AU is characterized by a transient mixed cellular infiltrate consisting of monocytes-macrophages, granulocytes, and CD4 and CD8 T cells. The preferential accumulation of inflammatory cells in the vicinity of nerve fibers suggests that AU in this model may result from autoreactivity to nerve antigens.

Localization and characterization of immunocompetent cells in the human retina

PURPOSE

Recent studies have shown that experimental uveitis can be induced by the appropriate administration of various retinal antigens. Little is known about the in-situ interactions between immune cells in the retina as a prerequisite for understanding the mechanisms involving the presentation of antigens by local antigen-presenting cells (APC) to invading T cells. The study described here was therefore designed to investigate the presence of immunocompetent cells with a focus on the characterization of retinal APCs.

MATERIALS AND METHODS

Retinal wholemounts, cytospins, and ocular sections were prepared from eyebank eyes obtained within 24 hours postmortem. Immunohistochemistry (single staining and double staining) was performed on the retinal wholemounts, cytospins, and the ocular sections using monoclonal antibodies specific for HLA-DR (MHC class II), CD45 (leukocytes), CD68 (macrophages), CD22 (B cells), CD3 (T cells), and CD1a (dendritic cells).

RESULTS

CD68-positive macrophages were observed in one layer of the retina, whereas HLA-DR(+) and CD45(+) cells were seen in two distinct planes: one mainly at the level of the inner nuclear layer to outer plexiform layer (deep layer) and the other mainly at the nerve fiber and ganglion cell layer (shallow layer). There was a significant difference between the different parts of the retina with regard to the density of these cells. Cell density decreased when going from the peripheral to the posterior areas of the retina. The positive cells in the deep layer were frequently associated with blood vessels, whereas the cells in the shallow layer were distributed evenly throughout the retina. Most positive cells displayed a dendritiform appearance, whereas few cells showed a pleiomorphic morphology. Very few CD1a-positive cells were noted in the retina. Neither T cells (CD3) nor B cells (CD22) could be detected in the normal human retina. Double staining showed that the majority (83. 7%) of the CD45(+) cell population was HLA-DR-positive, whereas approximately half (56.8%) the CD68(+) cell population was HLA-DR-positive.

CONCLUSIONS

This study shows that the human retina contains a number of different microglia populations, some of which express HLA-DR and could thus be involved in antigen presentation. Marked differences in cell density can be observed within the retina, with the most abundant presence seen in the peripheral retina. The normal retina contains few professional antigen-presenting cells (CD1(+)).

Topical ophthalmic beta blockers may cause release of histamine through cytotoxic effects on inflammatory cells

AIM

To evaluate the effects of beta blockers used in ophthalmology on the release of histamine from mixed cell preparations containing human leucocytes and basophils.

METHODS

A mixed leucocyte and basophil preparation was obtained from venous blood of healthy non-atopic volunteers. Cell preparations were then incubated with betaxolol, metipranolol, timolol, or carteolol. After incubation for 1 hour the histamine content of the supernatant was analysed by automated fluorometric analysis. Cell viability was tested by measuring lactate dehydrogenase (LDH) concentrations.

RESULTS

Betaxolol and metipranolol in concentrations between 10(-2) M and 10(-3) M liberated histamine from human blood cells in a dose dependent manner. Carteolol and timolol had no effect on histamine at these concentrations. At the same concentrations LDH was also detected in the supernatants of cell suspensions incubated with metipranolol or betaxolol.

CONCLUSIONS

Betaxolol and metipranolol induce substantial histamine release from human leucocytes, probably as a result of their cytotoxic effect.

Interleukin 10 treatment does not prolong experimental corneal allograft survival

In view of the known anti-inflammatory activities of interleukin (IL) 10, we investigated whether the administration of recombinant murine IL-10 prolonged corneal graft survival. A major histocompatibility complex mismatched rat model with AO rats as recipients of PVG donor corneas was used. A total of 39 corneal allografts was included in this study and divided into 7 groups for different treatments. Group I (n = 6), II (n = 8), III (n = 6) and IV (n = 7) were injected subconjunctivally with saline (control), 0. 5 ng, 5 ng or 50 ng of IL-10, respectively, on the day of transplantation and then on postoperative days (POD) 2, 4, 6, 8 and 10. Group V (n = 4) and group VI (n = 4) were injected intraperitoneally with saline (control) or 1 microg of IL-10, respectively, on the day before surgery, the day of grafting and then on POD 2, 4 and 6. Finally, group VII (n = 4) was injected with both subconjuctival 5 ng of IL-10 and intraperitoneal 1 microg of IL-10 on the same days as the previous groups. The median days for corneal rejection in the various groups were: group I, 11.3 +/- 0.9; group II, 11.5 +/- 0.9; group III, 11.6 +/- 0.8, and group IV, 10 +/- 1.0. Statistical analysis revealed a trend towards rejection (p = 0.08) in group IV (compared to group I). In groups V and VI, corneal rejection was evident on day 12 and in group VII the median time for rejection was 10.5 +/- 0.8 days. These results indicate that IL-10 treatment does not prolong corneal allograft survival and may even accelerate rejection.

Incidence of ocular side effects of topical beta blockers in the Netherlands

BACKGROUND

Several ocular side effects including uveitis, have been reported following topical beta blocker treatment for glaucoma and ocular hypertension. The incidence of these side effects was investigated in the Netherlands.

METHODS

A prospective observational design was used whereby monthly questionnaires were sent to all practising ophthalmologists in the Netherlands during 3 consecutive months. Questionnaires were returned at the end of each month. Any patient whose topical beta blocker therapy was altered because of an ocular reaction was noted on this questionnaire. Ophthalmologists who did not return their questionnaires were interviewed by telephone at the end of the study period. The number of patients using topical beta blockers was derived from drug sales figures.

RESULTS

70% (328/467) of the ophthalmologists in the Netherlands participated in the study. During the 3 month study period 34 cases were reported: 15 patients had periorbital dermatitis, in eight patients eyelids and conjunctiva were affected, in seven patients the conjunctiva was affected, and four patients had punctate keratitis. The calculated incidence of ocular side effects during topical beta blocker therapy was 1.51 cases/1000 patient years.

CONCLUSION

Topical beta blocker therapy is associated with few clinically important ocular side effects. No cases of uveitis were reported.

IgA antibodies to Toxoplasma gondii in human tears

PURPOSE

To investigate whether mucosal immune responses directed against the ubiquitous parasite Toxoplasma gondii can be detected in tears of healthy humans.

METHODS

Nonstimulated tears and blood were obtained from 62 healthy humans (mean age, 35 +/- 10 [SD] years). Serum anti-T. gondii immunoglobulin titers were determined by Sabin-Feldman (SF) dye test. Western blot analysis was used to compare the anti-T. gondii repertoire in tears and serum, and antibody avidity was determined by urea elution. Diluted tear and serum samples were incubated with the intact parasite to determine whether the antibodies found in tears and serum are capable of binding to surface exposed antigens of T. gondii.

RESULTS

Eighty-one percent of the individuals tested had an anti-T. gondii IgA response in their tears, whereas only 23% had evidence of systemic immunity against the parasite. There was no apparent relation between chronic infection and presence of anti-T. gondii IgA in tears. Characteristically, the antigens recognized by the IgA antibodies in tears were often limited to at least one of four antigens with molecular weights of 74, 70, 49, and 34 kDa. The avidity of the anti-T. gondii IgA antibodies in tears was similar to the avidity of serum IgG antibodies. IgA antibodies directed against the 49- and 74-kDa antigens recognized epitopes exposed on the surface of the parasite.

CONCLUSIONS

A major finding of this study is that tears of many individuals, chronically infected or not, contain IgA antibodies against T. gondii. It is not known whether these frequently observed antibody responses are the result of common mucosal immune responses against T. gondii or represent the natural antibody repertoire.

Apoptosis of infiltrating cells in experimental autoimmune uveoretinitis

OBJECTIVE

To investigate the cellular phenotype and apoptosis of infiltrating cells involved in experimental autoimmune uveoretinitis (EAU).

METHODS

Immunohistochemical staining and in situ apoptosis staining were performed using monoclonal antibodies to monocytes and macrophages (ED1), major histocompatibility complex (MHC) class-II antigen (OX6), T lymphocytes (R73) and TACS 1 Klenow kit on both ocular sections and wholemounts from Lewis rats after immunization with interphotoreceptor retinoid-binding protein (IRBP).

RESULTS

EAU was induced in 12 of 16 Lewis rats with a mean clinical inflammation score of 1.29 +/- 0.7. Influx of monocytes, lymphocytes and MHC class II-positive cells into the uvea and retina was noted after immunization with IRBP. Apoptosis of infiltrating cells was observed in the uvea and retina, and more apoptotic cells were present in the iris and ciliary body compared with those in the choroid and retina.

CONCLUSION

Apoptosis of infiltrating cells occurs at the early stage of EAU, which may greatly contribute to the rapid regression of the inflammation induced by IRBP.

Anterior uveitis with sectoral iris atrophy in the absence of keratitis: a distinct clinical entity among herpetic eye diseases

OBJECTIVE

To determine the cause and describe the clinical features of unilateral anterior uveitis with sectoral atrophy of the iris in the absence of associated keratitis.

DESIGN

Retrospective, observational case series.

PARTICIPANTS

Thirty-one patients with unilateral anterior uveitis with sectoral iris atrophy and without (previous) keratitis.

METHODS

The patients were selected from our database of 592 patients with anterior uveitis.

MAIN OUTCOME MEASURES

We reviewed the clinical data on the 31 patients and the results of diagnostic anterior chamber fluid analysis for 24 of the 31 patients. Specifically, production of local antibodies against herpes simplex virus (HSV) and varicella zoster virus (VZV) was determined and the polymerase chain reaction was performed to demonstrate the DNA of HSV, VZV, and cytomegalovirus (CMV) in the aqueous samples.

RESULTS

Main clinical characteristics of anterior uveitis with iris atrophy included unilateral involvement with a prolonged course and recurrent exacerbations in all cases. Elevated intraocular pressure during intraocular inflammation occurred in 90% of patients (28 of 31). Visual outcome was favorable because 29 of 31 patients (94%) retained a visual acuity of 20/32 or more. The causal agent was identified as HSV in 83% (20 of 24) and VZV in 13% (3 of 24) and was inconclusive in one case. The patients with HSV uveitis were younger than those with VZV uveitis (mean age at onset 34 and 65 years, respectively; P = 0.0056).

CONCLUSIONS

Unilateral anterior uveitis with sectoral atrophy of the iris without associated (previous) keratitis is a distinct entity among herpetic eye diseases. Recurrent unilateral anterior uveitis with iris atrophy and/or elevated intraocular pressure has most likely been caused by HSV.

Changes in cytokine mRNA levels in experimental corneal allografts after local clodronate-liposome treatment

PURPOSE

Corneal allograft rejection in rats can be prevented by subconjunctival injections of liposomes containing dichloromethylene diphosphonate (clodronate-LIP), which selectively eliminate macrophages. In this study, the effect of clodronate-LIP treatment on cytokine mRNA levels in corneal allografts was examined.

METHODS

AO rats received corneal grafts of PVG rats. Rats were either not treated or injected subconjunctivally with clodronate-LIP on the day of transplantation and on postoperative days (PODs) 2, 4, 6, and 8. RNA was isolated from the graft and rim of corneas at different times after transplantation and from normal controls. Interleukin (IL)-1beta, IL-1 receptor antagonist (IL-1RA), IL-2, IL-4, IL-6, IL-10, IL-12p40, tumor necrosis factor (TNF)-alpha, TNF-beta/lymphotoxin (LT), interferon (IFN)-gamma, monocyte chemotactic protein 1 (MCP-1), and macrophage inflammatory protein 2 (MIP-2) mRNA levels were analyzed by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Corneal rejection, observed in all untreated rats by POD 12, was associated with increased mRNA levels of all cytokines investigated in grafts and rims. Clodronate-LIP treatment prevented allograft rejection and strongly decreased the levels of IL-1beta, IL-1RA, IL-2, IL-4, IL-6, IL-10, IFN-gamma, TNF-beta/LT, MCP-1, and MIP-2 mRNA in grafts and IL-1 beta, IL-2, IL-4, IL-6, and IFN-gamma mRNA in rims. Interleukin-12p40 mRNA levels were unaltered in clodronate-treated rats, except for a transient increase in grafts at POD 3. TNF-alpha mRNA levels were increased by clodronate-LIP in grafts and rims early after transplantation (PODs 3 and 7). Despite a normal appearance, long-term accepted corneal grafts (POD 100) contained mRNA for IL-10, IL-12p40, TNF-alpha, MCP-1, and MIP-2.

CONCLUSIONS

Clodronate-liposome treatment markedly altered the mRNA levels of all cytokines investigated in corneal allografts. These results may explain in part the mechanism by which clodronate-LIP treatment prevents corneal allograft rejection.