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Background: The aim of this study was to assess the impact of the ratio between the graft and host corneal size (RGH) on postoperative complications, such as immune reactions, re-bubbling rate and endothelial cell loss (ECL) after Descemet membrane endothelial keratoplasty (DMEK)., Patients and Methods: Retrospectively, 457 patient eyes were included which had undergone surgery between 2016 and 2019 in the Department of Ophthalmology, Saarland University Medical Center in Homburg/Saar using DMEK or triple DMEK, diagnosed as Fuchs' endothelial dystrophy (n = 431), pseudophakic bullous keratopathy (n = 9) and others (n = 17). The follow-up period extended until the end of 2020. Main outcome measures included immune reaction (IR), re-bubbling rate and the postoperative endothelial cell loss (ECL) at 6 weeks, 6 months and 12 months and whether these measures depended on the RGH., Results: The RGH in this study ranged from 0.35 to 0.62 (0.46 ± 0.04). There were 33 (7.2%) postoperative IRs (DMEK n = 25; triple DMEK n = 8). The average RGH without IR (0.46 ± 0.04) was significantly (p = 0.038) smaller than in the group with IR (0.47 ± 0.05). Re-bubbling was necessary in 159 of 457 (34.8%) patient eyes. The RGH in patient eyes with re-bubbling (0.47 ± 0.04) was significantly (p = 0.014) higher than that in eyes without re-bubbling (0.45 ± 0.04). The mean preoperative endothelial cell count (ECD) was 2603 ± 251 cells/mm 2 (min: 2161, max: 3500 cells/mm 2 ). It was shown that a larger RGH had no positive influence on endothelial cell loss (r = 0.001; p = 0.974)., Conclusion: Our results suggest that a larger graft diameter compared to host corneal size is associated with an increased rate of immune reactions and a higher re-bubbling rate after DMEK. Otherwise, a larger RGH had no positive influence on endothelial cell loss after DMEK. Accordingly, the graft size for DMEK should not be unnecessarily large, especially in eyes with Fuchs' endothelial dystrophy., (© 2024. The Author(s).)

Mononuclear phagocytes are derived from bone marrow precursor cells and are part of the innate immune system. These cells circulate in the blood as monocytes but differentiate in the peripheral circulation into tissue macrophages and dendritic cells under the influence of various cytokines. In addition to antimicrobial properties, macrophages also participate in wound healing; however, they also support degenerative and inflammatory processes. In cases of acute corneal allograft rejection, mononuclear cells initially form the main component of the cellular anterior chamber infiltrate. How monocytes are recruited into the anterior chamber is currently uncertain. Furthermore, no information is available about the possible cytotoxic effects on corneal endothelial cells. Gaining insight into these mechanisms may lead to potential pharmacological interventions.

Background: ABO blood group antigens are only expressed by the epithelial cells of normal human corneas. Since AB0 blood group antigens are also known to be expressed on stromal and endothelial cells of inflamed corneas, this study aimed to investigate the extend of ABO blood group antigen expression in corneal allograft failures., Material and Methods: Twenty-two failed corneal allografts of 22 patients were examined. In 12 cases the patients had clinically proven corneal allograft rejection. In 10 cases there was no evident history of allograft rejection and the diagnosis graft failure due to chronic endothelial cell loss was made. Immunohistochemical staining of paraffin embedded sections was performed with monoclonal mouse antibodies to human blood group antigen A or B using the streptavidin-biotin-peroxidase complex technique., Results: Blood group antigens A or B were expressed by stromal keratocytes in 5 out of 12 and by endothelial cells in 7 out of 12 corneas with clinically proven immunologic graft rejection. Corneal transplants with chronic endothelial cell loss expressed blood group antigens A and/or B on the endothelial cells in three out of ten cases., Conclusion: The results of this study show that ABO blood group antigens can be up-regulated in cases of corneal allograft failure, especially in cases of immune mediated graft rejection. This phenomenon might play a role in corneal allograft rejection.

Background: Tumor necrosis factor (TNF)-alpha as a proinflammatory cytokine is of great importance during the development of herpes simplex virus-1 keratitis (HSK). In this study the local administration of antisense oligonucleotides (ASON) targeting TNF-alpha was examined for its usefulness in ameliorating this disease., Methods: Uptake and efficacy of the oligonucleotides were studied in vitro by fluorescence microscopy and flow cytometry. Substance- and sequence-specific influences on the development of HSK were scrutinized in an animal model., Results: Quick and stable uptake of FITC-labeled ASON by isolated spleen and lymph node cells was proved. The production of TNF-alpha by these cells after stimulation with HSV antigen or concanavalin A (ConA) was clearly downregulated after addition of ASON. In vivo, incidence and development of HSK were ameliorated after subepithelial corneal injection of ASON targeting TNF-alpha. When buffer and control oligonucleotides were given, no significant influence on the disease was found., Conclusion: The ASON effectively reduced TNF-alpha secretion in vitro and suppressed the development of experimental HSK in vivo.

Purpose: The immune mediated HSV-1 stromal keratitis (HSK) rapidly improves after amniotic membrane transplantation (AMT). This study investigated whether AMT modulates the T cell response and whether the anti-inflammatory action of AMT is due to local or systemic effects., Methods: Corneas of BALB/c mice were infected with 10(5) (PFU) of HSV-1. Animals with ulcerating keratitis on day 14 post-infection were divided into 4 groups: group 1 ( n=12): right eye AMT;group 2 ( n=12): right eye tarsorrhaphy; group 3 ( n=8): right eye tarsorrhaphy, left eye AMT;group 4 ( n=8): both eyes tarsorrhaphy. The mice were examined for clinical signs of HSV keratitis after 2 days. Corneal sections were studied histologically and the inflammatory cell infiltration was studied by immunohistochemical staining. DTH response and the HSV-specific 3H-thymidin-uptake were compared between the groups., Results: Compared to group 2, ulceration and stromal inflammation was profoundly improved in group 1 ( p<0.01). The corneas in the AMT mice had fewer inflammatory cells, CD3+,CD4+ and CD8+ cells than the control mice ( p<0.01). There were no significant differences between groups 1 and 2 with respect to the delayed type hypersensitivity reaction (DTH response) and the HSV-specific 3H-thymidin uptake. AMT or tarsorrhaphy on the left eyes in groups 3 and 4 had no influence on the course of keratitis or the T cell response., Conclusions: Ulcerating herpetic keratitis markedly improves after AMT. Our observations indicate that this is caused predominantly by local and not by systemic AMT-related effects.

Background: Herpes simplex virus (HSV-1) stromal keratitis is an immune-mediated disease. Recently, it has been shown that infection of cells with HSV-1 induces apoptosis. In this study we investigated the presence of apoptotic cell death in keratectomy specimens from patients with HSV-1 stromal keratitis., Patients and Methods: Keratectomy specimens from six patients with HSV-1 non-necrotizing stromal keratitis were chosen and compared to healthy corneas. Paraffin sections were analyzed histologically and cryosections were studied by the immunoperoxidase technique for the presence of HSV-1, Fas and FasLigand (FasL) antigens. Apoptosis was assessed by TUNEL assay (TdT-mediated dUTP nick-end labeling)., Results: In healthy corneas, Fas was detected in the epithelium, keratocytes and endothelium; FasL was present in the epithelium and endothelium; TUNEL-positive cells were only found in the superficial epithelial cells. In contrast, inflammatory cells and scars were found in all HSV-diseased corneas; HSV-1 antigen was detected in only one specimen. Cells within inflammatory infiltrations and epithelium were apoptotic. Fas was detected in all corneal cell layers and inflammatory cells. FasL was restricted to areas of inflammation., Conclusions: The data suggest that apoptosis plays a role in the pathogenesis of HSV keratitis. The Fas-FasL system appears to be involved in the induction of apoptosis. Apoptosis could be involved in the depletion of inflammatory cells in the cornea and may limit the extension of viral replication to the eye.

Background: Macular corneal dystrophy can be classified into three different immunophenotypes according to presence and distribution of sulfated keratan sulfate (SKS) in the cornea and serum levels of SKS. Immunophenotype I A has yet only been reported in patients with macular corneal dystrophy from Saudi Arabia., Material and Methods: Case report of a patient with macular corneal dystrophy type I A from Germany. Indirect immunohistochemistry for sulfated keratan sulfate was performed on the corneal buttons obtained after perforating keratoplasty (monoclonal antibodies 3D12/H7 and 5-D-4). The serum concentration of SKS was determined using the monoclonal antibody 5-D-4 in a serum antigen-inhibition assay. Immunogold labeling with the 5-D-4 antibody was performed to allow ultrastructural localization of SKS in the cornea., Results: The patient demonstrated the typical clinical picture of macular corneal dystrophy. Serum levels of SKS were not detectable. Positive immunohistochemistry for SKS was found only within single keratocytes of both corneae without staining of the stroma (3D12/H7 and 5-D-4). Immunogold labeling localized SKS within stromal keratocytes and proved this patient to suffer from macular corneal dystrophy immunophenotype I A., Conclusion: Macular corneal dystrophy immunophenotype I A can be found outside Saudi Arabia in a German patient. All three immunophenotypes of macular corneal dystrophy are present in corneal buttons from German patients.

Background: Corneal HLA-DR antigens are going to be lost during organ culture storage. This study investigated if this phenomenon is based on down-regulation of the HLA-DR antigen, or on a loss of the HLA-DR-positive corneal Langerhans cells (LCs)., Material and Methods: Corneal LCs were stained in situ by the method of fluorescence-associated immunohistochemistry, and the organ culture mediums underwent flow cytometric analysis for HLA-DR-positive corneal LC at the end of the storage period., Results: All stored corneas were negative for HLA-DR after 14 days and HLA-DR antigens could be detected in culture medium at the end of the storage time., Conclusion: Flow cytometry showed that organ culture storage leads to loss of HLA-DR-positive cells and not only to a loss of antigen presentation.

Background: Keratitis, retinitis and secondary cataract are well known complications of ocular herpes simplex infection. We report on a case of herpetic keratouveitis and cataract. Acute and inflammatory pathogenesis of cataract formation resemble a phacoanaphylactic reaction., Case Report: A 15-year-old girl with recurrent herpes keratitis was referred for acute spontaneous cataract formation accompanied by iridocyclitis and hypotony. Visual acuity was decreased from 0.4 to light projection. During cataract extraction the anterior chamber was tabbed for immunological analysis. The thickened anterior lens capsule was examined by light microscopy. We found a significant local synthesis of herpes antibodies in the aqueous. Histologically the lens capsule depicted a defect and a granulomatous inflammatory infiltrate towards the basal membrane material. The specimen was not suitable to judge on eventual additional phacoanaphylaxis. After cataract extraction and systemic acyclovir and corticosteroids the keratouveitis subsided. Visual acuity improved to 0.4, but was limited by the disciform corneal scar., Conclusion: The granulomatous response towards lens capsule shown here, resembles the granulomatous reaction towards Descemet's membrane in advanced herpetic corneal ulcer. We speculate on the pathogenesis of the lens capsule defect as a, so far unknown, herpes-associated autoimmun response against the basal membrane material of the lens. The acuteness of cataract formation may be a consequence of contact of aqueous with lens fibres. Additional phacoanaphylaxis combined with secondary glaucoma is possible.

Noninfectious ulceration of the peripheral cornea remains a major diagnostic and therapeutic challenge. The pathogenesis in most of these disorders is unclear, however, on the basis of systemic connective tissue diseases, autoimmune mechanisms are most likely involved. The peripheral cornea has distinct morphological and immunological characteristics that predispose for inflammatory reactions. Major differences exist regarding humoral and cellular components of the immune system. In the peripheral cornea there is more high-molecular IgM and initial complement component C1 than in the central cornea and may predispose for immune complex formation. The close contact to the conjunctival vasculature provides the basis necessary to generate an immune response. Langerhans cells and macrophages as important antigen presenting and processing cells are present in higher number in the peripheral cornea. Autoimmune diseases that affect the peripheral cornea include collagen vascular diseases and Mooren's ulcer. Although this association is obvious in advanced rheumatoid arthritis more subtle forms of polyarteritis nodosa or systemic lupus erythematosus require careful medical evaluation and workup. Ocular manifestations may present as the initial clinical signs and require careful workup in these potentially lethal disorders.

We are reporting a case of a 23-year-old patient suffering from measles despite vaccination during childhood. He presented with bilateral punctate keratitis without conjunctival reaction 10 days after the onset of rash. We assume a late immunological reaction, possibly related to earlier vaccination.

Various conjunctival and corneal biopsies of eyes with chronic inflammation of the outer segment (e.g., following chemical burns, chronic proliferative conjunctival alterations) were examined using monoclonal antibodies. Class II antibodies were found in both epithelial and stromal conjunctival cells, indicating that there may be some etiological significance to an autoimmune process in altered tissue.

Between September 1986 and June 1988 310 penetrating keratoplasties were performed and prospectively analyzed. The purpose of this prospective study was the evaluation of graft rejections and the underlying corneal diseases. The mean follow-up time was 6.9 months. We found early graft rejections in 5.8% of the eyes. The increased rate of graft rejection in eyes with herpetic corneal ulcers was remarkable.

The incidence of allograft rejection was determined for 740 penetrating keratoplasties performed between 1980 and 1987. All 740 cases were followed up for at least 1 year. The reaction forms of allograft rejection were grouped according to biomicroscopic appearance. The incidence and progression of symptoms are described. Rejection types are subdivided into patients with favorable versus poor prognosis. Of the patients 37.9% demonstrated an immune response (including discrete forms). Clear reaction patterns within the two groups of patients became apparent when reaction variations were carefully differentiated. Epithelial immune reaction was found in 5.2%/10.5% and subepithelial infiltration in 1.7%/4.8% of the patients with favorable/poor prognosis. The largest disparity in frequency occurred in progressive endothelial reaction; 3.8% in patients with favorable versus 36.7% in patients with poor prognosis. Focal endothelial reactions occurred in both groups with comparable frequencies (14.1%/13.3%). The large percentage of immunological reactions, including late manifestations (approximately 12% after 1 year) and some with irreversible progression, warrants continuing efforts to treat and prevent this complication.

Immune reactions against corneal transplants cause most of the graft failures during the first 24 months after keratoplasty. This is partly due to inadequate diagnosis and therapy. After a short discussion of the experimental and clinical background, different kinds of characteristic immune reactions are demonstrated by case descriptions and photos. The importance of immune reactions is substantiated by an evaluation of 88 recently performed keratoplasties. Finally, detailed suggestions are made for prophylaxis and therapy of postkeratoplasty immune reactions.

Foxes that were positive by the fluorescent antibody test on brain were also positive by the corneal test. The corneal test gave a false-negative results only when the specimen was in a macerated state. Out of 133 foxes in which rabies virus was demonstrated in the optic nerve by animal inoculation, only one was negative to the corneal test - this may have been a case of centripetal spread of the infection which was examined at a stage when virus was present in the optic nerve but not in the cornea or the brain. Hence it is possible that the virus may be absent from the cornea. False-positive results seem unlikely to occur, for only one fox was negative upon inoculation of animals with optic nerve and vitreous humour, while the fluorescent antibody test of corneal cells was positive. Animal tests revealed virus inhibitors in the vitreous humour of this animal. All the other cornea-test positive foxes were also positive in tests on brain, lacrimal gland and optic nerve.

Seven cases of immune reactions against donor endothelium after penetrating keratoplasty were analyzed in a prospective study. Cell loss during the immune reaction period varied between 25% and 81% and seemed to continue thereafter, though much more slowly. The authors discuss the complex etiology of post-keratoplasty endothelial cell loss and make suggestions for the diagnosis and treatment of classic endothelial immune reactions with special reference to specular microscopy.

Two pathogenic mechanisms are discussed as possibly being responsible for destruction of the corneal tissue in the course and corneal infections caused by Pseudomonas aeruginosa. One involves bacterial exoenzymes and the other polymorphonuclear (PNM)-derived lysosomal enzymes. The objective of the present study was (1) to show the relative importance of the two mechanisms and (2) to evaluate the effect of active immunization against Pseudomonas aeruginosa exoenzymes on ocular damage. Rabbits were immunized against Pseudomonas aeruginosa alkaline protease (AP) or elastase (Ela) and challenged with the respective enzymes. Corneal damage was studied by light photography. In another group rabbits were immunized against AP, Ela and exotoxine A and challenged with Pseudomonas aeruginosa strain PA 01 und PA 103. Corneal damage was studied by light photography, light microscopy and electron microscopy. Immunized animals were totally protected against purified Pseudomonas aeruginosa exoenzymes. Less corneal damage was found in immunized rabbits than in non-immunized ones. 12 and 24 h after infection with whole bacteria. However, after 48 h corneal damage was comparable in both groups. These results show that corneal damage by lysosomal enzymes from stimulated PMN ist more important in Pseudomonas aeruginosa than direct damage by bacterial exoenzymes.

Using the indirect immunofluorescence technique, IgG and IgA antibodies against human cornea and IgG antibodies against human inner ear tissue (stria vascularis, Reissner's membrane, spiral ligament, dark cell area) were demonstrated in the serum of a patient with cogan's syndrome. Sera of controls (healthy individuals) did not show positive reactions. Additionally the serum of two patients suffering from "idiopathic" progressive sensorineural hearing loss contained antibodies (IgG) which reacted with human inner ear tissue only but not with human cornea. A possible autoimmune mechanism in Cogan's syndrome is discussed.

Changes of the serumimmunoglobulins concentrations could be established after keratoplasty. Especially the fluctuations of the Ig-M-level was characteristically, which could be of prognostic meaning.

Conjunctival and corneal tissue samples from nine patients with severe changes after acid and alkali burns were examined immunohistochemically. Epithelial HLA Class II antigen expression was present in three of five conjunctival samples, and all of the antigen markers examined in the conjunctival stroma could be stained. HLA Class II expression was demonstrated in four out of five corneal tissue samples. The results show that in Grade III or IV chemical burns, with the diverse changes of the external eye that they produce, immunological and possibly also autoimmune mechanisms can influence the clinical course.

On the basis of follow-up examinations of 236 penetrating keratoplasties the different forms of immune reaction were analyzed with special regard to their relationship to indication and prognosis. An immune reaction was observed in 42.8% of the cases. An epithelial Khodadoust line occurred in 17 transplants (7.2%). Nine of these were early reactions within the first two months after reoperation. Subepithelial infiltrates occurred in 14 grafts (5.9%), usually as late complications except after reoperation. Special risk factors are anterior synechiae, chronic inflammation and regrafts. The lower risk group differs from the high risk group with regard to a) the epithelial Khodadoust line (2.9% vs. 10.6%), b) the severs forms of endothelial immune reactions (4.8% vs. 32.6%), and c) the irreversible immune reactions (0% vs. 23.5%). Subepithelial infiltrates and mild forms of precipitates occurred about equally in both groups. The different forms of endothelial immune reactions are of prognostic value only in connection with the individual diagnosis and indication. About 50% of the late immune reactions were of iatrogenic origin. Misalignment of the graft can lead to a typical Khodadoust line. In one patient an irreversible immune reaction of the diffuse type was caused by YAG laser treatment of a secondary membrane.

After sensitization of a rabbit with soluble human cornea proteins a hetero-keratoplasty (man-rabbit) is performed with exactly determined antibody titer. Light-microscopic investigations showed that the epithelium of the transplant is involved in this severe humoral immune-reaction mainly. In the area between receptor's and donor's cornea impressive changes could be observed.

Ultrastructural changes of the receptor's cornea of a rabbit by experimentally induced immune-reaction were communicated. The finding of plasma-cells proves the generation of humoral antibodies. Granulocytic elements are shown in the transplant or react with diffusing antigen-antibody-complexes already in the stroma of the receptor's cornea.