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.

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.

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.

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 β4, laminin 332, and hemi-desmosomes. Corneal stromal cells similarly expressed adhesion molecules (integrin-α6 and β1). 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.

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.

Combined PKC and MEK inhibition in uveal melanoma with GNAQ and GNA11 mutations

Uveal melanoma (UM) is a genetically and biologically distinct type of melanoma, and once metastatic there is no effective treatment currently available. Eighty percent of UMs harbor mutations in the Gαq family members GNAQ and GNA11. Understanding the effector pathways downstream of these oncoproteins is important to identify opportunities for targeted therapy. We report consistent activation of the protein kinase C (PKC) and MAPK pathways as a consequence of GNAQ or GNA11 mutation. PKC inhibition with AEB071 or AHT956 suppressed PKC and MAPK signalling and induced G1 arrest selectively in melanoma cell lines carrying GNAQ or GNA11 mutations. In contrast, treatment with two different MEK inhibitors, PD0325901 and MEK162, inhibited the proliferation of melanoma cell lines irrespective of their mutation status, indicating that in the context of GNAQ or GNA11 mutation MAPK activation can be attributed to activated PKC. AEB071 significantly slowed the growth of tumors in an allograft model of GNAQ(Q209L)-transduced melanocytes, but did not induce tumor shrinkage. In vivo and in vitro studies showed that PKC inhibitors alone were unable to induce sustained suppression of MAP-kinase signaling. However, combinations of PKC and MEK inhibition, using either PD0325901or MEK162, led to sustained MAP-kinase pathway inhibition and showed a strong synergistic effect in halting proliferation and in inducing apoptosis in vitro. Furthermore, combining PKC and MEK inhibition was efficacious in vivo, causing marked tumor regression in a UM xenograft model. Our data identify PKC as a rational therapeutic target for melanoma patients with GNAQ or GNA11 mutations and demonstrate that combined MEK and PKC inhibition is synergistic, with superior efficacy compared to treatment with either approach alone.

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.

New therapeutic agents in uveal melanoma

Uveal melanoma is the most common primary intraocular malignant tumour in adults. Five, ten and fifteen years after primary tumour treatment, up to 25%, 34% and 50% of patients may develop metastases, respectively. There are only a few systemic therapies that have been approved for uveal melanoma, all with doubtful efficacy. As the molecular knowledge over cancer has improved, new therapies are being developed. Several drugs, such as bortezomib, celecoxib, dacarbazine, anti-angiogenic agents (such as bevacizumab, sorafenib and sunitinib), temsirolimus, mitogen-activated protein kinase kinase (MEK) inhibitors, ipilimumab and AEB071 are candidate drugs, and studies are underway to determine the therapeutic effects of these drugs in uveal melanoma.

Clinical presentation and outcome of perforating ocular injuries due to BB guns: a case series

PURPOSE

To describe the clinical presentations and treatment modalities of a series of BB gun-related perforating ocular injuries.

METHODS

Clinical records of all consecutive cases of perforating BB gun injuries to the globe seen between September 2004 and September 2008 were reviewed retrospectively. At the time of the trauma and after final treatment, all patients underwent a complete ocular examination, including visual acuity,applanation tonometry for intraocular pressure, slit lamp biomicroscopy, indirect ophthalmoscopy and fundus photography, if possible. In all cases, primary globe repair was performed in the first session, and then appropriate surgery took place based on the individual situation.

RESULTS

In this study, 13 patients (11 males and 2 females) with a mean age of 20.8 years (range 9–50 years) were enrolled. The mean follow-up period was 7.2 4.3 months (range 1–25 months). Initial visual acuity (VA) ranged from no-light perception (NLP) to finger counting (CF). Vitreous haemorrhage and retinal detachment were present in all involved eyes. Hyphema (30.76%), uveal and retinal prolapse (30.8%), retinalin carceration (30.8%) and retinal haemorrhage (53.8%) were other ocular findings. VA remained stable in 46.2% of the patients (6 cases). The best achieved final VA was CF at 2 min one case after 6 months follow-up.After several surgical procedures, enucleation was necessary in only 2/13 (15.4%) cases.

CONCLUSION

Despite several surgical procedures which decreased the number of enucleations, BB gunperforating ocular injuries still lead to a grim visual outcome. This implies the importance of political strategies targeting on education of parents and restriction for children to access to these guns.

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.

Expression and distribution of MMPs and TIMPs in human uveal melanoma

Matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) are involved in tumour invasion, metastasis and angiogenesis, and have been implicated as progression markers in uveal melanoma, although their topographical expression has not been fully described. In this study we compared the distribution and specificity of several classes of MMPs (MMP-1, -2, -9, -19, and MT1-MMP) and physiological MMP inhibitors (TIMP-2 and -3) in different regions of the tumour microenvironment and adjacent choroid in a series of primary uveal melanomas. Paraffin sections of untreated uveal melanomas (n=18, 3/18 spindle; 11/18 mixed, and 4/18 epithelioid) were examined for MMP-1 (collagenase 1), MMP-2 and MMP-9 (gelatinases A and B), MT1-MMP (membrane-type 1-MMP), MMP-19, TIMP-2 and TIMP-3 (tissue inhibitors of MMPs), using indirect peroxidase immunohistochemistry. The distribution and intensity of immunolabelling was graded semi-quantitatively (0-3) by 2 independent observers. Non-parametric analyses were used to test for associations between tumour cell type, and the average grade of MMP or TIMP expression. Immunostaining for MMP-1, -9, -19 and MT1-MMP was > or =Grade 2 in more than 70% of specimens, and a heterogeneous pattern of MMP-1, -9, MT1-MMP and TIMP-3 expression was observed. At the tumour-scleral interface (TSI), melanoma cells had a flattened morphology and a much reduced MMP and TIMP expression, with a high expression in tumour areas adjacent to the TSI. Tumour vasculature and stromal cells strongly expressed MMP-2. We also observed heterogeneous immunostaining of the vasculature by MMP-1, -9, MT1-MMP and TIMP-2 antibodies, and of the extravascular matrix by MMP-9 antibody. The distinct immunostaining patterns observed for MMPs and TIMPs within uveal melanoma are consistent with their involvement in tumour growth and angiogenesis. In particular, the heterogeneous expression within regions of the tumours, and the localized expression in vasculature and stromal cells emphasises the importance of the tumour microenvironment in the pathogenesis of uveal melanoma (and other tumours).

Lactoferrin Glu561Asp polymorphism is associated with susceptibility to herpes simplex keratitis

Lactoferrin plays an important role in the defense against infections, including herpes simplex virus (HSV) keratitis. We studied the impact of three single nucleotide polymorphisms in the human lactoferrin gene on the susceptibility to HSV infections of the eye and the severity of such infections. Lactoferrin gene polymorphisms were determined by PCR combined with restriction fragment length analysis in 105 HSV keratitis patients and 145 control subjects. Bilateral tear samples were harvested from 50 patients and 40 healthy controls and tear lactoferrin concentrations were determined by ELISA. Patients' records were used to acquire information about the severity of the HSV keratitis. The frequencies of the Glu561Asp polymorphism, but not those of the Ala11Thr and Lys29Arg polymorphisms, differed significantly between patients and control subjects with an under-representation of the Asp561 allele in the patient group. Furthermore, the values for best corrected visual acuity, frequency of recurrences since onset, and average duration of clinical episodes did not differ among patients with various lactoferrin genotypes. In addition, tear lactoferrin concentrations were the same in patients with HSV keratitis and healthy controls and also did not differ among patients with various lactoferrin genotypes. Lactoferrin Glu561Asp polymorphism is associated with the susceptibility to HSV keratitis with a protective role for lactoferrin variants comprising Asp561. However, no beneficial effects of this lactoferrin variant on the clinical outcome of ocular HSV keratitis were noted.

Mechanisms of local immunosuppression in cutaneous melanoma

Cutaneous melanoma is highly immunogenic, yet primary melanomas and metastases develop successfully in otherwise immunocompetent patients. To investigate the local immunosuppressive microenvironment, we examined the presence of suppressor T lymphocytes and tolerising dendritic cells (DCs), the expression of immunosuppressive cytokines (IL-10, TGFβ1 and TGFβ2) and the enzyme indoleamine 2,3-dioxygenase (IDO) using qRT–PCR and immunohistochemistry in primary skin melanomas, negative and positive sentinel lymph nodes (SLN), and lymph nodes with advanced metastases. Our results indicate that tolerogenic DCs and suppressor T lymphocytes are present in melanoma at all stages of disease progression. They express transforming growth factor β receptor 1 (TGFβR1), and are therefore susceptible to TGFβ1 and TGFβ2 specifically expressed by primary melanoma. We found that expression of IDO and interleukin 10 (IL-10) increased with melanoma progression, with the highest concentration in positive SLN. We suggest that negative SLN contain immunosuppressive cells and cytokines, due to preconditioning by tolerogenic DCs migrating from the primary melanoma site to the SLN. In primary melanoma, TGFβ2 is likely to render peripheral DCs tolerogenic, while in lymph nodes IDO and TGFβ1 may have a major effect. This mechanism of tumour-associated immunosuppression may inhibit the immune response to the tumour and may explain the discrepancy between the induction of systemic immunity by anti-melanoma vaccines and their poor performance in the clinic.

S-100B protein and melanoma inhibitory activity protein in uveal melanoma screening. A comparison with liver function tests

AIM

Our purpose was to determine whether S-100B or melanoma inhibitory activity (MIA) concentrations in the serum of patients with large uveal melanomas were better markers for the presentation of metastases than liver function tests. We also investigated whether increased marker levels were related to known clinical and histopathological prognostic parameters.

METHODS

Total S-100B (A1B + BB) and MIA concentrations were measured in the sera from 104 patients with uveal melanoma prior to enucleation and in the sera from 50 healthy controls. Concentrations were also determined in the sera from 30 patients with known uveal melanoma metastases. Liaison Sangtec 100, an automated immunoluminometric assay measuring the total S-100B, and Roche MIA ELISA were used to quantify these proteins in serum. Results were compared with liver function tests [alkaline phosphatase, lactate dehydrogenase (LD), aspartate aminotransferase, alanine aminotransferase and gamma-glutamyl transpeptidase].

RESULTS

The mean S-100B and MIA concentrations were significantly higher in patients with metastases compared to melanoma patients without metastases. At the time of enucleation, S-100B and MIA were not prognostic for metastases in uveal melanoma, but S-100B and LD were the best tests to predict the occurrence of metastatic disease during the follow-up period.

CONCLUSIONS

In our study, the S-100B and MIA serum concentrations were not correlated with any tested established prognostic parameter. S-100B and LD showed better performance in identifying melanoma metastases than gamma-glutamyl transpeptidase and MIA. A prospective follow-up study is needed to evaluate S-100B and MIA in identifying early micrometastasis in uveal melanoma.

A new model for limbal transplantation using E-GFP for follow-up of transplant survival

Limbal transplants in humans show a high rate of rejection even under local and systemic immunotherapy. In order to test immunomodulatory treatments a new limbal transplant model in the rat was developed using enhanced green fluorescent protein (E-GFP) as marker for follow-up. Sixty E-GFP-positive limbal transplants from Sprague-Dawley TgN(act-EGFP)Osb4 rats were transplanted onto 18 wild-type inbred Sprague-Dawley (isografts) rats, six wild-type litter mate Sprague-Dawley (sibling) rats, 18 Fischer 344 (allografts) rats, and 18 Fischer 344 rats depleted from monocytes and macrophages by subconjunctival treatment with clodronate liposomes. All rats were monitored three times a week with fluorescence microscopy, until fluorescence had disappeared. At postoperative days 6, 9, 12, and 15, three rats of all groups were killed for immunohistochemical analysis of infiltrating cells. Using a modified digital fluorescence microscope, we were able to monitor transplant behavior over time without disturbance of the ocular surface. The average days of rejection were 14 days in the isograft group, the sibling group, and the untreated allograft group. However, the average day of rejection in the allogeneic macrophage-depleted group was 27 days. Marked infiltration of macrophages and lymphocytes was seen in the untreated isografts and allografts. In the clodronate liposome-treated allografts infiltration was minor. A successful new limbal transplant model is described. The transplant can be accurately followed up in vivo by E-GFP labeling of the donor tissue without disturbing the corneal surface. Although E-GFP itself proved to be immunogenic, local clodronate liposome injections significantly increased graft survival. So the model seems to be useful for testing immunosuppressive or modulatory agents in limbal transplantation studies.

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.

Ciliary tissue transplantation in the rabbit

Irreversible damage of the ciliary body can be responsible for prolonged ocular hypotony and phthisis bulbi, which, currently, cannot be treated. The aim of this study was to achieve survival of morphologically normal ciliary tissue (CT) transplants in the anterior chamber of a rabbit's eye. Outbred female New Zealand albino rabbits received CT allografts, which were placed on to the surface of the host iris. We evaluated the influence of ciclosporin (CsA), VEGF and donor perfusion on graft survival. Operated eyes were assessed clinically and histologically, and revascularization of the grafts was determined by fluorescein angiography. All grafts became dark and ischemic during the first five to seven days after transplantation. Reperfusion of the grafted tissue was complete at approximately ten days after transplantation. In untreated animals, transplants became infiltrated by inflammatory cells, which led to destruction of the tissue. This was prevented by systemic use of CsA. Transplants treated with VEGF prior to transplantation had fewer ischemic areas but epithelial cell survival was not improved. Whole body donor perfusion prior to preparation of the grafts resulted in less inflammation and, histologically, in a better quantity and quality of the epithelial cells in the CT transplants. Ciliary tissue can be successfully transplanted but the ciliary epithelium suffers from ischemia and in untreated animals the whole transplant is rejected in the classical fashion. If the donor is perfused and the host immunosuppressed, histologically normal ciliary epithelium can be preserved together with rapid revascularization, minimal inflammation and good survival of the transplant, although fibrosis continued to occur during the two months after transplantation.

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.

Activation of the MAPK pathway is a common event in uveal melanomas although it rarely occurs through mutation of BRAF or RAS

In contrast to cutaneous melanoma, there is no evidence that BRAF mutations are involved in the activation of the mitogen-activated protein kinase (MAPK) pathway in uveal melanoma, although there is increasing evidence that this pathway is activated frequently in the latter tumours. In this study, we performed mutation analysis of the RAS and BRAF genes in a panel of 11 uveal melanoma cell lines and 19 primary uveal melanoma tumours. In addition, Western blot and immunohistochemical analyses were performed on downstream members of the MAPK pathway in order to assess the contribution of each of these components. No mutations were found in any of the three RAS gene family members and only one cell line carried a BRAF mutation (V599E). Despite this, mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK), ERK and ELK were constitutively activated in all samples. These data suggest that activation of the MAPK pathway is commonly involved in the development of uveal melanoma, but occurs through a mechanism different to that of cutaneous melanoma.

The efficacy and safety of topical polymyxin B, neomycin and gramicidin for treatment of presumed bacterial corneal ulceration

AIM

To evaluate the clinical efficacy and safety of topical polymyxin B, neomycin, and gramicidin for the treatment of suspected bacterial corneal ulceration at the Leiden University Medical Center.

METHODS

Patients with a diagnosis of a suspected bacterial corneal ulcer between April 1995 and February 2002 were retrospectively identified and reviewed; clinical and microbiological features and response to therapy were analysed. All patients were treated with Polyspectran eye drops.

RESULTS

In total, 91 patients were included in this analysis. Bacteriological cultures of 46 patients (51%) were positive and revealed 51 microorganisms. Staphylococcus aureus (29.4%) and Pseudomonas aeruginosa (23.5%) were the most frequently encountered bacteria. Eighteen patients switched therapy before complete healing of the corneal ulceration, four patients were lost to follow up. Of the 69 patients who completed Polyspectran treatment, re-epithelialisation occurred in 68 patients (99%) and on average took 12.6 (median 8) days. Among 91 patients, there were four perforations and one evisceration. Seven toxic or allergic reactions were reported.

CONCLUSION

This study shows that the combination of polymyxin B, neomycin, and gramicidin is an effective and safe treatment of suspected corneal ulceration.

Gene expression profiling identifies tumour markers potentially playing a role in uveal melanoma development

Microarray is a powerful tool to compare the gene expression of different tumour specimens and cell lines simultaneously and quantitatively. To get a better insight into genes that are involved in uveal melanoma tumorigenesis, we compared the gene expression profiles of 12 different uveal melanoma cell lines with three melanocyte cell cultures obtained from healthy donor eyes. Gene expression profiles were obtained by nylon filter arrays, containing 1176 gene spots related to cancer development. The expression levels of selected genes were validated on cell lines and primary uveal melanomas by real time RT–PCR, and were subsequently included in cluster analysis. Four candidate tumour markers, Laminin Receptor 1, Endothelin 2, Von Hippel Lindau Binding protein 1 and Cullin 2, have been selected from genes that were differentially expressed in the uveal melanoma cell lines compared to the normal uveal melanocytes. In primary uveal melanomas, these four markers could discriminate between two classes of uveal melanoma, which may be indicative of a differential disease process.

[HLA class I antigen expression correlates with histological cell type in uveal melanoma]

PURPOSE

The prognosis of uveal melanoma is correlated with its histologic cell type. The epithelioid cell type is associated with a higher metastatic rate than the spindle cell type. The Human Leucocyte Antigen Class I (HLA-I) expression of the melanoma also correlates with the prognosis. In this study, we analyzed HLA-I antigen expression of uveal melanomas to determine whether a relationship exist between antigenic expression and melanoma cell type.

METHODS

Formalin-fixed, paraffin-embedded spindle cell type (n = 11) and epithelioid cell type (n = 11) uveal melanomas were immunostained with the HC10 antibody (1:80) for HLA-I antigen expression with appropriate positive and negative controls. Sections were assessed semiquantitatively according to the percentage of stained cells.

RESULTS

Among the spindle cell type melanomas, 2 out of 11 (18%) stained with HC10 antibodies. The staining intensity was less than 25% of the cells in these two melanomas. Among the epithelioid cell type melanomas, 9 out of 11 (82%) stained with HC10. The staining intensity was more than 25% of the cells in 5 of these 9 melanomas.

CONCLUSIONS

It is unknown why spindle and epithelioid cell type uveal melanomas have different prognoses. Human uveal melanoma cell lines with low HLA-I expression are susceptible to NK cell-mediated lysis in vitro and in murine studies. The prognostically more favorable spindle cell type melanoma expresses less HLA-I than the epithelioid cell type melanoma. These results stress the role of NK cells in the rejection of uveal melanoma.

Uveal melanoma: no expression of HLA-G

PURPOSE

To investigate whether uveal melanoma cells express HLA-G, a nonclassical HLA class I molecule that has been shown to be a critical mediator in the inhibition of natural killer (NK) cell-mediated cytolysis.

METHODS

Eleven human uveal melanoma cell lines were analyzed for the expression of HLA-G by flow cytometry, immunocytochemistry, Western blot analysis, and RT-PCR followed by Southern blot analysis. Two HLA-G-specific monoclonal antibodies were used, 87G and MEM-G/1. In addition, HLA-G expression was determined on frozen tissue sections of 17 primary uveal melanomas.

RESULTS

With all HLA-G detection methods, no evidence for HLA-G expression by uveal melanoma cells was found. In contrast, the trophoblast cell line JEG-3 clearly expressed HLA-G transcripts and protein in all cases. Furthermore, interferon-gamma did not induce HLA-G expression in the uveal melanoma cell lines. Notably, all cell lines expressed HLA-E, and this expression was significantly enhanced by interferon-gamma.

CONCLUSIONS

Because none of the uveal melanoma cell lines nor any of the primary uveal melanomas displayed expression of HLA-G, it is unlikely that HLA-G plays a role, direct or indirect, in the modulation of cellular immunity against uveal melanoma tumors.

Rejection of intraocular tumors by CD4(+) T cells without induction of phthisis

Immune privilege of the eye protects against sight-threatening inflammatory events, but can also permit outgrowth of otherwise nonlethal immunogenic tumors. Nonetheless, ocular tumor growth can be controlled by cellular immune responses. However, this will normally result in phthisis of the eye, in case tumor rejection is mediated by a delayed-type hypersensitivity response orchestrated by CD4(+) T cells. We now show that intraocular tumors can be eradicated by CD4(+) Th cells without inducing collateral damage of neighboring ocular tissue. Injection of tumor cells transformed by the early region 1 of human adenovirus type 5 in the anterior chamber of the eye leads to intraocular tumor formation. Tumor growth is transient in immunocompetent mice, but lethal in immunodeficient nude mice, indicating that T cell-dependent immunity is responsible for tumor clearance. Tumor rejection has all the characteristics of a CD8(+) T cell-mediated immune response, as the tumor did not express MHC class II and only tumor tissue was the subject of destruction. However, analysis of the molecular and cellular mechanisms involved in tumor clearance revealed that perforin, TNF-alpha, Fas ligand, MHC class I, and CD8(+) T cells did not play a crucial role in tumor eradication. Instead, effective tumor rejection was entirely dependent on CD4(+) Th cells, as CD4-depleted as well as MHC class II-deficient mice were unable to reject their intraocular tumor. Taken together, these observations demonstrate that CD4(+) T cells are able to eradicate MHC class II-negative tumors in an immune-privileged site without affecting surrounding tissues or the induction of phthisis.

Characterization of melanocortin-1 receptor gene variants in uveal melanoma patients

PURPOSE

Allelic variations of the melanocortin-1 receptor (MC1R) gene have been linked to red hair and sun-sensitive skin types and may play a role in the susceptibility to develop cutaneous malignant melanoma (CMM). To define the role of MC1R gene in uveal melanoma, a case control study was performed, in which the presence of MC1R gene variations in uveal melanoma patients was compared with that of healthy controls.

METHODS

MC1R gene variants were analyzed in 162 uveal melanoma patients and 255 healthy controls. After genomic DNA was isolated from venous blood, the MC1R gene was amplified by polymerase chain reaction (PCR) and examined for the presence of variants by single-strand conformation polymorphism (SSCP) analysis. Participants were asked to complete a questionnaire regarding skin type, eye color, and hair color.

RESULTS

No disparity was found between the distribution of the MC1R gene variants in both groups. Furthermore, no associations between MC1R genotype and pigment phenotype were found. In contrast to CMM, uveal melanoma patients did not show specific MC1R gene variants. Compared with controls, most uveal melanoma patients had blue eyes (65%, P = 0.060) and skin type III (56%); however, in the uveal melanoma group the presence of dark blond hair was significantly elevated (46%, P = 0.030). These findings are in contrast with studies on CMM, where most patients have skin type II and red/fair hair.

CONCLUSIONS

These data suggest that MC1R variants do not play a role in the susceptibility to develop uveal melanoma. Furthermore, most uveal melanoma patients share phenotypic characteristics that differ from findings in CMM patients.

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.

Adoptive T cell immunotherapy of human uveal melanoma targeting gp100

HLA-A*0201-restricted CTL against human gp100 were isolated from HLA-A*0201/K(b) (A2/K(b))-transgenic mice immunized with recombinant canarypox virus (ALVAC-gp100). These CTL strongly responded to the gp100(154-162) epitope, in the context of both the chimeric A2/K(b) and the wild-type HLA-A*0201- molecule, and efficiently lysed human HLA-A*0201(+), gp100(+) melanoma cells in vitro. The capacity of the CTL to eradicate these tumors in vivo was analyzed in A2/K(b)-transgenic transgenic mice that had received a tumorigenic dose of human uveal melanoma cells in the anterior chamber of the eye. This immune-privileged site offered the unique opportunity to graft xenogeneic tumors into immunocompetent A2/K(b)-transgenic mice, a host in which they otherwise would not grow. Importantly, systemic (i.v.) administration of the A2/K(b)-transgenic gp100(154-162)-specific CTL resulted in rapid elimination of the intraocular uveal melanomas, indicating that anti-tumor CTL are capable of homing to the eye and exerting their tumoricidal effector function. Flow cytometry analysis of ocular cell suspensions with HLA-A*0201-gp100(154-162) tetrameric complexes confirmed the homing of adoptively transferred CTL. Therefore, the immune-privileged state of the eye permitted the outgrowth of xenogeneic uveal melanoma cells, but did not protect these tumors against adoptive immunotherapy with highly potent anti-tumor CTL. These data constitute the first direct indication that immunotherapy of human uveal melanoma may be feasible.

Expression of epidermal growth factor receptor: risk factor in uveal melanoma

PURPOSE

To investigate the prognostic significance of the expression of epidermal growth factor receptor (EGFR) in uveal melanoma. EGFR is a transmembrane glycoprotein, and its expression has been correlated with the development of metastases in various malignancies.

METHODS

Frozen sections from 22 primary uveal melanomas were examined for EGFR expression by a three-step immunoperoxidase staining, using a mouse anti-human EGFR IgG2b monoclonal antibody. The results were compared with patient survival and clinical and histopathologic parameters.

RESULTS

EGFR expression could not be determined on one tumor due to excessive pigmentation. Two patients died of causes unrelated to melanoma, and two patients were lost to follow-up. Out of 21 tumors, six tumors showed immunoreactivity for EGFR. Five of these six patients (83%) died due to metastases, compared with 2 (17%) of 12 patients with no EGFR expression (Kaplan-Meier analysis P = 0.0004). EGFR-positive tumors tended to have a greater tumor prominence and a higher mitotic rate.

CONCLUSIONS

The expression of EGFR was significantly correlated with death due to metastatic disease and therefore can be regarded as an important prognostic factor in human uveal melanoma.

High frequency of allele-specific down-regulation of HLA class I expression in uveal melanoma cell lines

Uveal melanoma is the most common primary intra-ocular tumor in adults and has a high mortality rate due to liver metastases, for which no effective treatment is available. To investigate whether immunotherapy might be feasible in uveal melanoma, the HLA class I surface expression of 6 uveal melanoma cell lines was analyzed by flow cytometry using a broad panel of allele-specific monoclonal antibodies. To up-regulate HLA expression, cells were also cultured with IFN-alpha or -gamma. In general, expression of HLA-A alleles was high (except for cell line EOM-3) and could be further up-regulated by both IFN-alpha and -gamma. In cell line EOM-3, IFN-gamma treatment resulted in significant HLA-A expression while IFN-alpha treatment did not. Expression of HLA-B alleles was low or even negative. Variable effects were observed after IFN treatment. In 3 cell lines, expression of some HLA-B alleles could not be induced by IFN-alpha or -gamma: HLA-B44 in cell line 92-1, HLA-B15 in cell line OCM-1 and HLA-B5 in cell line MEL-202. The other B alleles of these cell lines showed enhanced expression levels upon IFN stimulation. In OMM-1 cells, IFN-alpha and -gamma increased the expression of HLA-A but did not induce expression of the 2 B alleles, indicating an HLA-B locus-specific loss. We thus found a high frequency of allele-specific and locus-specific down-regulation of HLA expression in uveal melanoma cell lines. Some of these defects were not restored by IFN-alpha or -gamma treatment. The lack of HLA expression may explain why uveal melanoma cells escape immune surveillance by cytotoxic T cells and complicate the development of immunotherapy in uveal melanoma.

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.

Expression of angiogenic and immunosuppressive factors by uveal melanoma cell lines

Dissemination of uveal melanomas is almost exclusively haematogenous, making angiogenesis of the tumour a prerequisite for the formation of metastases. Uveal melanomas must employ strategies to evade the immune system in order to escape immune surveillance. We therefore determined the expression of the following angiogenic and immunosuppressive factors in seven human uveal melanoma cell lines using reverse transcriptase-polymerase chain reaction (RT-PCR): secreted interleukin-1 receptor antagonist (sIL-1ra), interleukin (IL)-6, IL-8, IL-10, transforming growth factor (TGF)-alpha, TGFbeta, vascular endothelial growth factor (VEGF), platelet derived growth factor (PDGF), basic fibroblast growth factor (bFGF), angiopoietin-1 and angiopoietin-2. In addition, the secretion of sIL-1ra, IL-6, IL-8, IL-10, TGFbeta and VEGF was assayed by enzyme linked immunosorbent assay (ELISA). The potential of uveal melanoma cell lines to convert plasminogen to angiostatin was tested in an in vitro assay. All the factors except angiopoietin-1 were determined in one or more cell lines using RT-PCR, although these results were not necessarily confirmed by ELISA. Expression of VEGF and angiopoietin-2 was found in all seven cell lines. Production of angiostatin was observed in one cell line. All seven cell lines examined expressed angiogenic factors and most cell lines expressed immunosuppressive factors. The expression of VEGF and angiopoietin-2 in combination with a lack of angiopoietin-1 expression suggest high vascular remodelling capacity and could be of great relevance for the metastatic potential of uveal melanoma.

Frequent loss of heterozygosity on chromosome 6p in uveal melanoma

Lack of expression of HLA class I antigens is frequently observed on primary uveal melanoma, and is correlated with improved patient survival. Several mechanisms may contribute to the observed loss of HLA class I expression, including changes at the DNA level. In this study, we used microsatellite analysis as a molecular genetic approach to examine loci on chromosome 6p for loss of heterozygosity (LOH). Three pairs of microsatellite markers were used to screen 20 formalin-fixed, paraffin-embedded uveal melanomas for LOH on the short arm of chromosome 6. In all cases, normal adjacent scleral tissue was used as a control. We identified LOH in eleven cases from microsatellite locus D6S105 to the telomere, in eight cases from microsatellite locus D6STNFa to the telomere (area includes D6S105), and in seven cases from microsatellite locus D6S291 to the end of chromosome 6p (includes D6STNFa and D6S105). In seven cases, retention of heterozygosity was found at all three loci using these primers. Our results suggest that loss of heterozygosity on chromosome 6p is a common feature in uveal melanoma. We did not find a correlation between the presence of LOH and locus-specific HLA-A and -B expression.

Effects of transpupillary thermotherapy on immunological parameters and apoptosis in a case of primary uveal melanoma

Transpupillary thermotherapy (TTT) is a new treatment modality for uveal melanoma. We studied whether application of TTT influences the immunogenicity of the tumour cells in vivo or the expression of molecules related to apoptosis. Immunohistochemistry using monoclonal antibodies directed against HLA molecules, HMB45, P53, Fas ligand (FasL), Fas, Bcl-2 and tumour-infiltrating cells was applied to sections of an enucleated eye containing a uveal melanoma that received TTT 1 week before enucleation. The innermost part of the tumour which had been exposed directly to the laser treatment showed no staining for HLA antigens, nor for Fas or FasL epitopes. The intermediate part of the tumour showed a wet necrosis and HLA expression similar to the expression in the peripheral tumour. A large number of macrophages were observed in the necrotic as well as the intact tumour tissue, especially bordering the wet necrotic area. FasL and Bcl-2 were only expressed in the viable, outer part of the tumour. This immunological evaluation of one case of uveal melanoma treated with TTT revealed that TTT may not only have a direct destructive effect on the primary tumour, but may also influence the immunogenicity of uveal melanoma cells, induce infiltration of macrophages into the tumour, and induce apoptosis. The presence of many macrophages suggests that they play a role in the removal of the TTT-treated tumour tissue by phagocytosis.

Macrophage control of herpes simplex virus type 1 replication in the peripheral nervous system

After corneal infection, herpes simplex virus type 1 (HSV-1) invades sensory neurons with cell bodies in the trigeminal ganglion (TG), replicates briefly, and then establishes a latent infection in these neurons. HSV-1 replication in the TG can be detected as early as 2 days after corneal infection, reaches peak titers by 3-5 days after infection, and is undetectable by 7-10 days. During the period of HSV-1 replication, macrophages and gammadelta TCR+ T lymphocytes infiltrate the TG, and TNF-alpha, IFN-gamma, the inducible nitric oxide synthase (iNOS) enzyme, and IL-12 are expressed. TNF-alpha, IFN-gamma, and the iNOS product nitric oxide (NO) all inhibit HSV-1 replication in vitro. Macrophage and gammadelta TCR+ T cell depletion studies demonstrated that macrophages are the main source of TNF-alpha and iNOS, whereas gammadelta TCR+ T cells produce IFN-gamma. Macrophage depletion, aminoguanidine inhibition of iNOS, and neutralization of TNF-alpha or IFN-gamma all individually and synergistically increased HSV-1 titers in the TG after HSV-1 corneal infection. Moreover, individually depleting macrophages or neutralizing TNF-alpha or IFN-gamma markedly reduced the accumulation of both macrophages and gammadelta TCR+ T cells in the TG. Our findings establish that after primary HSV-1 infection, the bulk of virus replication in the sensory ganglia is controlled by macrophages and gammadelta TCR+ T lymphocytes through their production of antiviral molecules TNF-alpha, NO, and IFN-gamma. Our findings also strongly suggest that cross-regulation between these two cell types is necessary for their accumulation and function in the infected TG.

Corneal transplantation in antibody-deficient hosts

PURPOSE

To examine the role of donor-specific antibodies, with or without complement, in rejection of orthotopic corneal transplants by using mice as recipients in which the genes for the heavy chain of immunoglobulin or the third complement component have been eliminated by homologous recombination.

METHODS

BALB/c corneas were transplanted into eyes of B-cell-deficient (n=17) or wild-type control C57BL/6 (n=30) mice and into eyes of complement (C3)-deficient (n=15) or wild-type control 129-C57BL/6 (n=13) mice. After surgery all grafts were evaluated over 8 weeks in a masked manner by biomicroscopy for signs of rejection.

RESULTS

The rates of corneal transplant rejection were similar among B-cell-deficient and C3-deficient mice compared with rejection rates in their respective wild-type control subjects. This similarity applied to the time course of rejection and to cumulative survival rates.

CONCLUSIONS

Neither donor-specific antibody nor the third component of complement play essential roles in acute rejection of orthotopic corneal allografts in mice.

Role of mucosal IgA in the resistance to Acanthamoeba keratitis

PURPOSE

To determine whether oral immunization with Acanthamoeba castellanii antigens elicits mucosal antibodies of the IgA isotype and whether mucosal antibodies affect parasite adhesion to the corneal epithelium.

METHODS

Chinese hamsters were immunized with 100 microg aqueous Acanthamoeba antigen mixed with cholera toxin (Ac-CT) and subsequently challenged with parasite-laden contact lenses that were applied to abraded corneal surfaces. Tears and stool samples were examined for the presence of Acanthamoeba-specific IgA antibodies by enzyme-linked immunosorbent assay (ELISA). The effect of mucosal antibody on trophozoite binding to corneal epithelium and viability of trophozoites was examined in vitro.

RESULTS

Hamsters immunized orally with Ac-CT showed significantly lower infection rates than did control groups (21.4% versus 72.6%). ELISA analysis of mucosal specimens showed the presence of parasite-specific IgA in stool samples and tears from hamsters orally immunized with Ac-CT, but not in control animals. In vitro assays showed that anti-Acanthamoeba IgA did not affect parasite viability. However, mucosal anti-Acanthamoeba IgA profoundly inhibited (>75%) the binding of parasites to corneal epithelial cells in vitro.

CONCLUSIONS

Oral immunization with Ac-CT induces the production of parasite-specific IgA in mucosal secretions and prevents corneal infection. Mucosal antibody does not affect the viability of Acanthamoeba trophozoites but seems to prevent infection by inhibiting parasite binding to the corneal epithelium.

Distribution of tumors in the retina in hereditary retinoblastoma patients

We have compared the location of the ocular tumors in hereditary retinoblastoma in relation to the age of the patients at time of diagnosis. Eighty fundus drawings were analyzed from 59 hereditary patients containing I 59 tumors. At the time of diagnosis, indirect ophthalmoscopy was performed under general anaesthesia in all patients and standard drawings of the retina were made depicting the number and relative location of all tumors. The distance between the center of the tumor and the center of the macula was measured and plotted against the age of the patients at time of diagnosis. The results show that the distance between the center of the tumor and the center of the macula at time of diagnosis increases with age during the first seven months after birth.

A small molecular weight factor in aqueous humor acts on C1q to prevent antibody-dependent complement activation

PURPOSE

Aqueous humor inhibits activation of the classic complement pathway; however, the mechanism of this inhibition is unknown. We have examined at the molecular level potential factors responsible for the inhibition, and we have tried to determine where in the complement pathway the inhibition takes place.

METHODS

Fresh rabbit aqueous humor was size fractionated by centrifuge concentrators and by size exclusion column chromatography, and each fraction was assayed for inhibition of the classic complement pathway in a standard CH50 hemolytic assay. Fractions with inhibitory activity were assayed for protein and the presence of ascorbic acid and were subjected to heat treatment. To identify where in the pathway the inhibitor(s) function, the expression of activated complement components bound to the surface of antibody-coated erythrocytes was analyzed by flow cytometry using fluorescein isothiocyanate-labeled antibodies to specific complement components. In addition, hemolytic assays were performed for the function of individual complement components.

RESULTS

The most potent inhibition of the classic pathway was in a fraction of aqueous humor of less than 1.3 kDa. The inhibitory activity in the fraction was unassociated with detectable protein or ascorbic acid, and it remained present after heat treatment. The functional analysis through flow cytometry and hemolytic assays for individual complement components showed that the inhibitor in the less than 1.3-kDa fraction caused a blockade in the complement pathway at the level of C1q.

CONCLUSIONS

The aqueous humor contains a unique potent anticomplementary factor that has a molecular weight less than 1.3 kDa. This heat-stable inhibitory factor inhibits the classic pathway at the level of C1q. These results imply that within the eye the complement pathway is inhibited at the earliest steps of its initiation. Such inhibition would prevent production of complement products that mediate inflammation and chemotaxis of inflammatory cells. Therefore, as part of the adaptation of immune privilege, the ocular microenvironment is protected from inflammation induced by antigen-antibody complexes.

Occurrence of cutaneous and uveal melanoma in patients with uveal melanoma and their first degree relatives

Uveal and cutaneous melanomas are rare tumours, but have been described to occur together in one patient or in members of the same family. A group of 109 consecutive uveal melanoma patients from one specialized ocular tumour clinic were investigated dermatologically. The patient's own history and medical data and the family history of skin or eye problems were recorded. A total of three cutaneous melanomas were found as a result of this study--two in ocular melanoma patients and one in a first-degree relative. Four patients had first-degree relatives with a skin melanoma (in three of these families dysplastic naevus syndrome was also found), and one patient had a first-degree relative with an uveal melanoma. To find cutaneous and uveal melanoma coexisting in two cases and cutaneous melanoma in first-degree relatives in four cases out of a total of 109 uveal melanoma patients seems more than a coincidence. A linking factor in three cases was the familial atypical multiple mole melanoma syndrome, suggesting a common genetic predisposition to both malignancies in these families. In our only family with familial uveal melanoma, cutaneous melanoma and atypical naevi did not occur. A different genetic mechanism for these cases is probable.

Expression of MAGE, gp100 and tyrosinase genes in uveal melanoma cell lines

In order to determine the possible use of uveal melanoma cell lines as stimulators in immunotherapy, we evaluated the expression of the human genes for MAGE-1, -2 and -3, gp100 and tyrosinase in uveal melanoma cell lines. mRNA expression of the MAGE-1, -2 and -3, gp100 and tyrosinase genes and the HLA class I specificity were determined in five primary and three metastatic uveal melanoma cell lines. Expression of the examined genes was heterogeneous in the primary and metastatic cell lines. The cell lines OCM-1 and OMM-1 expressed MAGE-1, -2 and -3, whereas EOM-3, MEL202, 92-1 and OMM-3 were negative for these antigens. gp100 was expressed in all cell lines, and tyrosinase in all but three (EOM-29, OMM-2 and OMM-3). Except for EOM-3, the HLA-A type of all the cell lines could be determined by complement-dependent microlymphocytotoxicity assay. Since at least two melanoma-associated antigens can be found in uveal melanoma cell lines, as well as the HLA class I molecules, these cell lines may be applicable as immunogens for specific immunotherapy against metastatic uveal melanoma.

Systemic immune response to Acanthamoeba keratitis in the Chinese hamster

Recrudescence is a common and troubling feature of Acanthamoeba keratitis and suggests that corneal infection with this organism fails to stimulate the systemic immune apparatus. The present study examined the cell-mediated and humoral immune responses to Acanthamoeba keratitis in the Chinese hamster. Corneal infection with A. castellanii failed to induce either delayed-type hypersensitivity (DTH) or serum IgG antibody against parasite antigens. The failure to induce cell-mediated and humoral immunity did not result in anergy or tolerance since subsequent intramuscular (i.m.) immunization with parasite antigens elicited robust DTH and IgG antibody responses. The inability of corneal infections to induce primary cell-mediated immune responses was due to the absence of resident antigen-presenting cells in the central cornea because induction of Langerhans cell (LC) migration into the central cornea prior to infection with Acanthamoeba promoted the development of parasite-specific DTH. Although the presence of resident LC did not promote the development of a primary humoral immune response, subsequent i.m. immunization elicited heightened parasite-specific IgG antibody production which was indicative of an anamnestic response. Collectively, the results indicate that in the absence of resident antigen-presenting cells, corneal infection with Acanthamoeba fails to stimulate primary cell-mediated or humoral immunity. Induction of peripheral LC into the central corneal epithelium promotes the development of parasite-specific DTH, but does not exacerbate corneal disease.

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.

HLA expression in a primary uveal melanoma, its cell line, and four of its metastases

BACKGROUND

The level of HLA expression on a tumour may influence the immunological response against this tumour, and vice versa. HLA expression was determined in a primary uveal melanoma, its metastases, and on a cell line derived from this melanoma, and the presence and type of infiltrate in tissue sections were also studied.

METHODS

Immunohistochemistry with monoclonal antibodies (MAbs) against HLA class I and II, T cells, NK cells, and macrophages.

RESULTS

Primary and metastatic lesions, as well as the cell line showed high levels of expression of the monomorphic determinants of HLA class I. Expression of the polymorphic HLA-A2 and HLA-A3 antigens was decreased on metastases to the skin and liver. HLA-Bw4 expression was low on all lesions, as well as expression of HLA class II. Tumour infiltrating cells consisted mainly of CD3, CD4, and CD8 positive cells. Expression on the cell line corresponded to expression on the primary tumour.

CONCLUSION

The primary uveal melanoma as well as the cell line showed a high expression of monomorphic and polymorphic HLA-A antigens, while metastases showed a high expression of monomorphic and a lower expression of polymorphic antigens. This variation in expression may support tumour cell escape from NK cells as well as CTL mediated lysis.

Multidrug resistance-related proteins in primary choroidal melanomas and in vitro cell lines

PURPOSE

Metastatic uveal melanoma is strongly resistant to chemotherapy, and multidrug resistance (MDR) may be involved. To investigate the role of MDR, the presence of the MDR-associated proteins P-glycoprotein (Pgp), MRP, and lung resistance protein (LRP) was determined on primary choroidal melanomas and cell lines.

METHODS

A panel of primary choroidal melanomas was examined for the presence of MDR-associated proteins by immunohistochemical analysis. In cell lines established from four primary choroidal melanomas and one metastatic choroidal melanoma, the expression of MDR-associated proteins was determined with monoclonal antibodies in cytospin preparations and flow cytometry. In addition, the functional capacities of transporter proteins Pgp and MRP as adenosine triphosphate-driven efflux pumps were determined by measuring the cellular accumulation and efflux of the fluorescent dyes rhodamine 123 and calcein-AM, with and without the presence of specific pump inhibitors PSC833 and probenecid.

RESULTS

Low levels of Pgp and MRP were detected in most primary tumors and in some cell lines. Measurable transporter function of Pgp could be determined in cell line OCM-1. Lung-resistance protein was present in all primary tumors and cell lines and showed high expression levels.

CONCLUSIONS

This study revealed the involvement of LRP and at least a minor role of Pgp and MRP in chemoresistance of choroidal melanoma. Compared with cutaneous melanomas, uveal melanomas appear to express slightly higher levels of Pgp. These findings provide insights into the drug-resistant phenotype of this disease and can aid in the design of therapeutic protocols.

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.

Effect of hyperthermia on expression of histocompatibility antigens and heat-shock protein molecules on three human ocular melanoma cell lines

Hyperthermia is used as a new treatment modality for ocular melanoma. We wondered whether this treatment would affect the antigenicity of melanoma cells and studied the effect of hyperthermia on the expression of histocompatibility antigens (HLA), beta 2-microglobulin, as well as heat-shock proteins (HSP-60 and HSP-70) on choroidal melanoma cells. Uveal melanoma cell lines were exposed to different temperatures (39-45 degrees C) in a waterbath. Antigen expression was determined with fluorescence-activated cell sorting analysis, using monoclonal antibodies against HLA and HSP. In a 51Cr-release cytotoxicity assay we studied the effect of heat on natural killer (NK) cell susceptibility. Exposure to 45 degrees C for 30 min reduced expression of HLA class I antigens and beta 2-microglobulin. A greater reduction was observed after longer exposure times. Expression of HSP-70 was increased after exposure to 45 degrees C at all time intervals, while expression of HSP-60 was not induced by heat treatment. We did not find a significant difference in the NK cell susceptibility between heated and unheated cells. Hyperthermia has a time- and temperature-dependent effect on expression of HLA class I and HSP-70 molecules on the cell surface of uveal melanoma cells. Hyperthermia did not alter the susceptibility to NK cell lysis.

Decreased expression of HLA class I on ocular melanoma cells following in vitro photodynamic therapy

Our objective was to investigate whether photodynamic therapy (PDT) influences the expression of HLA Class I and beta 2-microglobulin molecules on cultured uveal melanoma cells. Uveal melanoma cells were incubated with hematoporphyrin esters (HPE) and illuminated using red light. HLA expression on cells was determined by flowcytometry. PDT treatment induced an immediate reduction in expression of HLA Class I and beta 2-microglobulin, followed by a transient increase in expression after 2 h. Normalization occurred after 6 h. Treatment of ocular melanoma cells with PDT temporally alters the expression of HLA Class I and beta 2-microglobulin, which may affect anti-tumor-immune responses.