GNAQ and GNA11 mutations and downstream YAP activation in choroidal nevi.

BACKGROUND: Mutations in GNAQ/11 genes are considered an early event in the development of uveal melanoma that may derive from a pre-existing nevus. The Hippo pathway, by way of YAP activation, rather than MAP kinase, has a role in the oncogenic capacity of GNAQ/11 mutations. METHODS: We investigated 16 nevi from 13 human eyes for driver GNAQ/11 mutations using droplet digital PCR and determined whether nevi are clonal by quantifying mutant nevus cell fractions. Immunohistochemistry was performed on 15 nevi to analyse YAP activation. RESULTS: For 15 out of 16 nevi, a GNAQ/11 mutation was detected in the nevus cells albeit at a low frequency with a median of 13%. Nuclear YAP, a transcriptional co-activator in the Hippo tumour-suppressor pathway, was detected in 14/15 nevi. CONCLUSIONS: Our analysis suggests that a mutation in GNAQ/11 occurs in a subset of choroidal nevus cells. We hypothesise that GNAQ/11 mutant-driven extracellular mitogenic signalling involving YAP activation leads to accumulation of wild-type nevus cells.

Differences in anti-endothelial and anti-retinal antibody titers: implications for the pathohysiology of acute and chronic central serous chorioretinopathy.

The aim of the study was to evaluate the prevalence of serum anti-retinal (ARAs) and anti-endothelial cell antibodies (ACEAs) in patients with acute and chronic central serous chorioretinopathy (CSC). We enrolled 28 patients with acute CSC, 42 patients with chronic CSC, and 40 healthy controls. The presence of ARAs was determined by indirect immunofluorescence using monkey retina as an antigen substrate, while the presence of AECAs was determined using cultivated human umbilical vein endothelial cells (HUVECs) and primate skeletal muscle according to the manufacturer's instructions (Euroimmun AG). There were no differences in the prevalence of antibodies against rods, cones, cytoplasmic components of retinal nuclear layer cells, and retinal vessels between the acute and chronic CSC groups and the control group (P = 0.27, P = 0.16, P = 0.71, and P = 0.06, respectively). However, AECAs reactive with HUVECs were observed in 46% of patients with acute CSC, 45% of those with chronic CSC, and 22% of controls, whereas AECAs reactive with the skeletal muscle were present in 46%, 45%, and 15%, respectively (difference between groups: P = 0.045 for HUVECs and P = 0.005 for the skeletal muscle). Furthermore, AECA titers were higher in CSC patients than in controls (P = 0.004). This study provides evidence for the possible involvement of an autoimmune process directed against vessel antigens in the pathogenesis of CSC. AECAs may be more important than ARAs in this disease and may be involved in endothelial damage in the choroidal vessels and choriocapillaris, leading to hyperpermeability, which is central to the pathophysiology of CSC.

Episodic Src activation in uveal melanoma revealed by kinase activity profiling.

BACKGROUND: The RAS/RAF/MEK/ERK pathway is involved in the balance between melanocyte proliferation and differentiation. The same pathway is constitutively activated in cutaneous and uveal melanoma (UM) and related to tumour growth and survival. Whereas mutant BRAF and NRAS are responsible for the activation of the RAS/RAF/MEK/ERK pathway in most cutaneous melanoma, mutations in these genes are usually absent in UM. METHODS: We set out to explore the RAS/RAF/MEK/ERK pathway and used mitogen-activated protein kinase profiling and tyrosine kinase arrays. RESULTS: We identified Src as a kinase that is associated with ERK1/2 activation in UM. However, low Src levels and reduced ERK1/2 activation in metastatic cell lines suggest that proliferation in metastases can become independent of Src and RAS/RAF/MEK/ERK signalling. Inhibition of Src led to the growth reduction of primary UM cultures and cell lines, whereas metastatic cell line growth was only slightly reduced. CONCLUSION: We identified Src as an important kinase and a potential target for treatment in primary UM. Metastasis cell lines seemed largely resistant to Src inhibition and indicate that in metastases treatment, a different approach may be required.

IL-10 promotor haplotypes associated with susceptibility to and severity of bacterial corneal ulcers.

Interleukin-10 plays an important role in modulating inflammation and antimicrobial defences. In animal models for bacterial corneal ulcers, high IL-10 levels were associated with a better clinical outcome. We investigated whether IL-10 promotor haplotypes, known to determine IL-10 expression in vitro, are associated with susceptibility to and/or clinical outcome of bacterial corneal ulcers in patients. IL-10 promotor polymorphisms C-819T, G-1082A, A-2763C, and A-2849G for 83 patients with bacterial corneal ulcers and 115 healthy controls were determined by restriction fragment length PCR analysis. For 63 patients and all healthy controls the most frequently occurring IL-10 promotor haplotypes were inferred from these data using the program SNPHAP. A significant underrepresentation of the A-2849A genotype was observed in patients as compared to healthy controls. Both the -2763A allele and the IL-10.1 promotor haplotype were associated with a poor clinical outcome, whereas a favourable clinical outcome was seen in patients carrying the IL-10.2 promotor haplotype. Together, IL-10 promotor haplotypes associated with low IL-10 levels seem to protect against the onset of bacterial corneal ulcers. Once a corneal ulcer has developed, patients carrying IL-10 haplotypes associated with a high IL-10 expression may have a favourable outcome.

Cutaneous allergy testing in patients suspected of an allergic reaction to eye medication.

PURPOSE: Our aim was to determine the usefulness of allergy testing in patients with possible allergic reactions to an eye medication. METHODS: This retrospective study analyzed the usefulness of allergy testing in 90 patients who on the basis of their complaints were under suspicion of having an allergic response to eye medication. RESULTS: Among the 90 patients suspected of an allergic reaction to eye medication, the most common complaint was itching, while hyperemic conjunctivae were the most common symptom. Skin testing revealed an allergy to eye medication in 32 (36%) of the patients tested, which seemed to be the causal factor of the complaints in 22 cases (24%). The most frequent medication-associated allergies were directed against tobramycin, neomycin sulfate and thimerosal. Clinically relevant non-drug-related allergies occurred in 26 cases and were directed against nickel sulfate, Myroxylon pereirae and fragrance mix. Twenty-three patients were atopic and had positive skin prick tests against inhalation allergens such as house dust mites or dogs. CONCLUSION: Allergy testing was helpful to obtain a diagnosis of a clinically relevant allergy in 48 of the 90 patients who were referred under suspicion of having a contact allergy to eye medication.

Immunophenotypic markers to differentiate between benign and malignant melanocytic lesions.

BACKGROUND/AIMS: The authors investigated the expression of S100A1, S100A6, S100B, MelanA, and CEA in conjunctival naevi, primary acquired melanosis (PAM), conjunctival melanoma, and uveal melanoma in order to assess their potential usefulness in the pathological differential diagnosis of these entities. METHODS: Paraffin embedded sections of 18 conjunctival naevi, 14 PAM, 16 conjunctival melanomas, and 20 uveal melanomas were immunostained for S100A1, S100A6, S100B, MelanA, and CEA, and expression was scored semiquantitatively. RESULTS: Expression of S100A1 differed significantly between conjunctival naevi and conjunctival melanoma, with percentages of positive cells of 30.6% and 71.4%, respectively. Conjunctival melanomas had high average scores for S100A1 and S100B (71.4%, 62.9%, respectively), while uveal melanomas also had high S100A1 but low S100B scores (88.5%, 18.5%, respectively). MelanA was highly variable; naevi and uveal melanoma had higher average scores than conjunctival melanoma. CEA was hardly detectable in all four groups. CONCLUSION: S100A1 seems to be a possible candidate to differentiate conjunctival naevi from conjunctival melanoma. S100B seems to differentiate between uveal melanoma and conjunctival melanoma. However, the study size was small and therefore the data have to be confirmed by others.

Successful immunotherapy of an intraocular tumor in mice.

Immune privilege in the eye is considered essential in the protection against local sight-threatening inflammatory responses. However, the deviant immune responses in the eye may also provide an ideal opportunity to uncontrolled growth of viruses or tumors by inhibiting intraocular immunological attack. To establish to what extent immune privilege interferes with T cell-mediated antitumor immunotherapy, we established a new ocular tumor model in the mouse and tested whether well-defined tumor-specific CTLs can eradicate an immunogenic intraocularly growing tumor. Tumor cells, transformed by human adenovirus type 5 early region 1 (Ad5E1), injected s.c. in a dose of 10(7) cells, did not induce s.c. tumor growth in C57BL/6 mice. However, an injection of 0.3 x 10(6) of these cells into the anterior chamber of the eye led to intraocular tumor growth in 95% of mice (n = 20). Tumor growth in the eye did not induce systemic tumor-specific tolerance, because 70% of the mice were able to eradicate the tumor spontaneously after 5 weeks. Mice vaccinated s.c. with irradiated tumor cells were protected against intraocular tumor challenge, indicating that preactivated memory T cells are able to protect against intraocular tumor growth. Moreover, an i.v. injection of an Ad5E1-specific CTL clone was able to eradicate established intraocular Ad5E1-transformed tumors, whereas the anatomy of the eye remained intact. These results demonstrate that tumor-specific, CTL-mediated immunity can be used successfully for the prevention and eradication of tumors growing in the immune-privileged anterior chamber of the eye, without detectable destruction of the eye.

Promoter hypermethylation: a common cause of reduced p16(INK4a) expression in uveal melanoma.

Tumors often display unrestricted cell cycling attributable to a dysfunctional G(1)-S checkpoint. One of the mechanisms leading to such a defect is the inactivation of the cyclin-dependent kinase inhibitor p16(INK4a). Although inactivation of p16(INK4a) is observed in a wide range of tumors, including cutaneous melanoma, genetic alteration of p16(INK4a) is reportedly uncommon in uveal melanoma. Here we show that the p16(INK4a) promoter is hypermethylated in 6 of 12 uveal melanoma cell lines and in 7 of 22 primary uveal melanomas analyzed. Five of seven patients with a methylated primary tumor died of metastatic disease compared with 2 of 15 patients with a nonmethylated primary tumor. We also show that all uveal melanoma cell lines with a hypermethylated p16(INK4a) promoter have lost p16(INK4a) expression but have maintained the expression of p14(ARF). Treatment of uveal melanoma cell lines with 5-aza-2'-deoxycytidine results in demethylation of p16(INK4a) and in reexpression of p16(INK4a) mRNA, which is maintained upon withdrawal of the 5-aza-2'-deoxycytidine. In conclusion, p16(INK4a) promoter methylation appears to be a common event in uveal melanoma and is accompanied by the loss of p16(INK4a) expression.

CT and MR Imaging in the Diagnosis of Scleritis.

Scleritis is a rare, underdiagnosed vision-threatening condition that can occur isolated or in association with other orbital abnormalities. The etiology of scleritis is mainly inflammatory noninfectious, either idiopathic or in the context of systemic disease. Ultrasonography remains the criterion standard in diagnostic imaging of this condition but might prove insufficient, and studies on the diagnostic value of CT and MR imaging are lacking. We retrospectively analyzed 11 cases of scleritis in which CT and/or MR imaging were performed during the active phase of disease and assessed the diagnostic utility of these techniques. The most important imaging findings of scleritis were scleral enhancement, scleral thickening, and focal periscleral cellulitis. MR imaging is the recommended imaging technique, though posterior scleritis also can be accurately diagnosed on CT. It is important for the radiologist to be acquainted with these findings because being able to diagnose scleritis is of clinical significance and might be vision-saving.

Biocompatibility of a fish scale-derived artificial cornea: Cytotoxicity, cellular adhesion and phenotype, and in vivo immunogenicity.

PURPOSE: To determine whether a fish scale-derived collagen matrix (FSCM) meets the basic criteria to serve as an artificial cornea, as determined with in vitro and in vivo tests. METHODS: Primary corneal epithelial and stromal cells were obtained from human donor corneas and used to examine the (in)direct cytotoxicity effects of the scaffold. Cytotoxicity was assessed by an MTT assay, while cellular proliferation, corneal cell phenotype and adhesion markers were assessed using an EdU-assay and immunofluorescence. For in vivo-testing, FSCMs were implanted subcutaneously in rats. Ologen(®) Collagen Matrices were used as controls. A second implant was implanted as an immunological challenge. The FSCM was implanted in a corneal pocket of seven New Zealand White rabbits, and compared to sham surgery. RESULTS: The FSCM was used as a scaffold to grow corneal epithelial and stromal cells, and displayed no cytotoxicity to these cells. Corneal epithelial cells displayed their normal phenotypical markers (CK3/12 and E-cadherin), as well as cell-matrix adhesion molecules: integrin-α6 and ß4, laminin 332, and hemi-desmosomes. Corneal stromal cells similarly expressed adhesion molecules (integrin-α6 and ß1). A subcutaneous implant of the FSCM in rats did not induce inflammation or sensitization; the response was comparable to the response against the Ologen(®) Collagen Matrix. Implantation of the FSCM in a corneal stromal pocket in rabbits led to a transparent cornea, healthy epithelium, and, on histology, hardly any infiltrating immune cells. CONCLUSION: The FSCM allows excellent cell growth, is not immunogenic and is well-tolerated in the cornea, and thus meets the basic criteria to serve as a scaffold to reconstitute the cornea.

Microarray Gene Expression Analysis to Evaluate Cell Type Specific Expression of Targets Relevant for Immunotherapy of Hematological Malignancies.

Cellular immunotherapy has proven to be effective in the treatment of hematological cancers by donor lymphocyte infusion after allogeneic hematopoietic stem cell transplantation and more recently by targeted therapy with chimeric antigen or T-cell receptor-engineered T cells. However, dependent on the tissue distribution of the antigens that are targeted, anti-tumor responses can be accompanied by undesired side effects. Therefore, detailed tissue distribution analysis is essential to estimate potential efficacy and toxicity of candidate targets for immunotherapy of hematological malignancies. We performed microarray gene expression analysis of hematological malignancies of different origins, healthy hematopoietic cells and various non-hematopoietic cell types from organs that are often targeted in detrimental immune responses after allogeneic stem cell transplantation leading to graft-versus-host disease. Non-hematopoietic cells were also cultured in the presence of IFN-γ to analyze gene expression under inflammatory circumstances. Gene expression was investigated by Illumina HT12.0 microarrays and quality control analysis was performed to confirm the cell-type origin and exclude contamination of non-hematopoietic cell samples with peripheral blood cells. Microarray data were validated by quantitative RT-PCR showing strong correlations between both platforms. Detailed gene expression profiles were generated for various minor histocompatibility antigens and B-cell surface antigens to illustrate the value of the microarray dataset to estimate efficacy and toxicity of candidate targets for immunotherapy. In conclusion, our microarray database provides a relevant platform to analyze and select candidate antigens with hematopoietic (lineage)-restricted expression as potential targets for immunotherapy of hematological cancers.

Normal HLA class I, II, and MICA gene distribution in uveal melanoma.

PURPOSE: The molecules of the HLA class I and II molecules as well as the MHC class I chain-related gene A (MICA), a polymorphic and stress-induced cell surface molecule, are involved in T-cell and natural killer-cell (NK-cell) mediated immune responses. In this study we looked for any genetic susceptibility contributed by HLA class I, class II, or MICA genes with regard to the development of uveal melanoma. METHODS: Between 1998 and 2001, 159 uveal melanoma patients were typed for HLA class I and II, and 168 uveal melanoma patients were evaluated for MICA by microsatellite typing. The HLA antigen and MICA allele frequencies were compared with control groups of, respectively, 2,440 and 247 healthy Dutch individuals. RESULTS: HLA class I, HLA class II, and MICA gene frequencies in uveal melanoma patients and healthy Dutch controls showed no significant deviations after correction for the number of comparisons. CONCLUSIONS: We conclude that there is no genetic susceptibility or increased risk attributed to any HLA class I, class II, and MICA polymorphism with regard to the development of uveal melanoma.

Matching for Human Leukocyte Antigens (HLA) in corneal transplantation - to do or not to do.

As many patients with severe corneal disease are not even considered as candidates for a human graft due to their high risk of rejection, it is essential to find ways to reduce the chance of rejection. One of the options is proper matching of the cornea donor and recipient for the Human Leukocyte Antigens (HLA), a subject of much debate. Currently, patients receiving their first corneal allograft are hardly ever matched for HLA and even patients undergoing a regraft usually do not receive an HLA-matched graft. While anterior and posterior lamellar grafts are not immune to rejection, they are usually performed in low risk, non-vascularized cases. These are the cases in which the immune privilege due to the avascular status and active immune inhibition is still intact. Once broken due to infection, sensitization or trauma, rejection will occur. There is enough data to show that when proper DNA-based typing techniques are being used, even low risk perforating corneal transplantations benefit from matching for HLA Class I, and high risk cases from HLA Class I and probably Class II matching. Combining HLA class I and class II matching, or using the HLAMatchmaker could further improve the effect of HLA matching. However, new techniques could be applied to reduce the chance of rejection. Options are the local or systemic use of biologics, or gene therapy, aiming at preventing or suppressing immune responses. The goal of all these approaches should be to prevent a first rejection, as secondary grafts are usually at higher risk of complications including rejections than first grafts.

The genetic basis of uveal melanoma.

Uveal melanoma (UM) is the most common intraocular malignancy in adults with an incidence of about 1/100,000 new cases per year in the Western world. Risk factors are having a light skin, blond hair and blue eyes. As some UM patients have a young age at diagnosis or an affected family history for UM or other malignancies, there may be an underlying genetic basis. This review discusses known or suspected risk factors for UM, the cancer risk in UM patients and their family members, and the genes that have been reported to predispose to UM (germline mutations) and tumor development (somatic mutations).

Are atypical nevi a risk factor for uveal melanoma? A case-control study.

Atypical nevi and other potential risk factors for uveal melanoma were studied in 109 uveal melanoma patients and 149 controls. Information concerning employment, medical history, drug use, family history of cancer, excess sun exposure, and blistering sunburn before and after the age of 15 was obtained. A total skin examination was performed and skin type, hair color, eye color, freckles, actinic damage, the total number of common acquired nevi, and the number of clinically atypical nevi were noted. More atypical nevi were found in uveal melanoma patients than in controls (age- and sex-adjusted odds ratio of 2.9 [95% confidence interval 1.2-6.3] for one or two atypical nevi versus none; odds ratio of 5.1 [95% CI 1.3-20.0] for three or more atypical nevi versus none). Light skin types and freckling also prevailed in uveal melanoma cases. In our study, atypical nevi are more common in uveal melanoma patients than in controls. Further studies will have to indicate whether risk factors comparable to those for cutaneous melanoma really exist for uveal melanoma.

Lack of effect of different cytokines on expression of membrane-bound regulators of complement activity on human uveal melanoma cells.

Tumor cells are protected from antibody-dependent complement-mediated lysis by membrane-bound regulators of complement activation (m-RCA). m-RCA are expressed on uveal melanoma cells. We determined whether cytokine treatment affects expression of m-RCA on these cells in vitro. m-RCA expression on uveal melanoma cell lines was studied by flow cytometry, using monoclonal antibodies directed against CD46, CD55, and CD59. Cytokines studied were interferon-alpha (IFN-alpha), IFN-gamma, interleukin-1B (IL-1B), IL-12, and tumor necrosis factor-alpha (TNF-alpha). All three m-RCA were expressed on the uveal melanoma cell lines (CD59>>CD46>CD55), although in variable amounts. With a few exceptions, the cytokines had no effect on m-RCA expression. CD55 expression was not influenced by any of the cytokines. IFN-gamma downregulated expression of CD46 on one cell line (p < 0.01). TNF-alpha upregulated CD59 expression on two of the five cell lines (p < 0.012 and p < 0.001, respectively), which effect was dose dependent. IFN-alpha, IFN-gamma, IL1-beta, IL12, and TNF-alpha had limited effects on m-RCA expression on uveal melanoma cells in vitro.

Comparison of techniques for the detection of monocyte specific antigens.

Monocyte specific antigens are relevant in renal and bone marrow transplantation, but a reproducible monocyte-antigen system has not yet been recognized. In order to establish a sensitive test system with reproducible results in monocyte serology, 3 different monocyte cytotoxicity techniques were compared. In our hands the two-colour fluorescence test on post-Ficoll total leukocyte suspensions fulfilled the criteria. This technique was used to screen sera from multiparous women and renal transplant recipients for the presence of monocyte specific antibodies. By testing sera on cells from individuals who were HLA compatible with the serum donors, anti-HLA reactions were excluded. Several promising sera containing monocyte specific antibodies were identified, thus indicating the success of our approach.

Changes in the immune response against BCP 54 following corneal transplantation in man.

Bovine corneal protein (BCP) 54 is the major soluble protein of the cornea. Immune responses against this protein can be observed in patients with corneal disease or inflammatory disease of the anterior chamber of the eye. We wanted to determine whether an immune response against this corneal protein plays a role in corneal transplantation. A cell-mediated immune response against BCP 54 was therefore determined in 46 patients prior to and on several occasions during the first year following corneal transplantation. The presence of an anti-BCP 54 response before transplantation was not associated with any clinical parameters or with rejection following transplantation. The highest frequency of positive responses was observed three months after transplantation. Transplantation may have stimulated a temporary immune response against a previously sequestered antigen, but this tissue-specific immune response did not necessarily lead to rejection. Therefore, no prognostic value can be attributed to the anti-BCP 54 response.

Human leukocyte antigen class I expression. Marker of poor prognosis in uveal melanoma.

PURPOSE: Because the expression of human leukocyte antigen (HLA) antigens is important for immunologic recognition of tumor cells, we determined expression of locus-specific HLA class I antigens in uveal melanoma and tested whether the level of HLA expression was related to prognosis or associated with known prognostic parameters. METHODS: Expression of HLA-A and -B antigens was determined on 30 formalin-fixed and paraffin-embedded sections of uveal melanoma by immunohistochemistry with locus-specific monoclonal antibodies and scored semiquantitatively. RESULTS: The level of expression of HLA-A and -B varied between uveal melanomas. Expression levels of HLA-A and -B were significantly correlated (P = 0.02). High HLA-B expression was significantly correlated with the presence of epithelioid cells (P = 0.04) in the tumor. Expression levels of HLA-A as well as of HLA-B, cell type, mitotic rate, Mib-1 score, and largest tumor diameter were significant predictive factors for survival. High expression of HLA-A and -B was associated with a decreased survival. Multiple Cox regression analysis with stepwise selection of covariates showed that the contribution of HLA-A expression to survival (P = 0.0003) exceeded that of tumor diameter (P = 0.02) and Mib-1 score (P = 0.04). CONCLUSIONS: Lack of expression of HLA-A as well as of HLA-B antigens on uveal melanoma is correlated with a better patient survival. Our data suggest that shedding of uveal melanoma micrometastases with a low expression of HLA class I into the systemic circulation may facilitate their removal and prevent the development of metastases. These findings support a protective role for natural killer cells in the development of metastatic disease in uveal melanoma.

Association between NM23-H1 gene expression and metastasis of human uveal melanoma in an animal model.

PURPOSE: To evaluate the role of nm23 gene expression in the development of metastases of human uveal melanomas in an animal model. METHODS: Seven human uveal melanoma cell lines and two murine skin melanoma cell lines were subjected to Northern blot analysis for the detection of nm23-H1 mRNA and to immuno-histochemistry to detect nm23 antigen. Each tumor cell line was transplanted intracamerally into nude mice, and the metastatic behavior was evaluated by histopathologic analysis of the livers and by determining host survival times. RESULTS: There was a strong inverse correlation between the levels of nm23 mRNA expression and nm23 antigen expression and the development of metastases of all seven human uveal melanomas and both murine skin melanomas transplanted intracamerally. Host survival time also was correlated with the degree of nm23 gene expression. CONCLUSIONS: The expression of nm23 mRNA and nm23 antigen in human uveal melanomas is correlated closely with reduced metastatic behavior in experimental animals and may serve as a sensitive prognostic indicator of malignancy and survival in patients with uveal melanomas.