Atypical corneal immunoglobulin deposition in a patient with dysproteinemia

Immunohistochemical staining of immunoglobulin G in healthy equine, canine, and feline corneas

Objective

Establishing an immunohistochemical approach for semi‐quantitative assessment of the presence of immunoglobulin G (IgG) in equine, canine, and feline corneas.

Procedures

Healthy corneas of horses, dogs, and cats, euthanized because of a fatal disease or an unrecoverable trauma unrelated to and without a history of ophthalmic disease were formalin‐fixed, paraffin‐embedded, and determined to be pathomorphologically healthy by light microscopy. Automated immunohistochemistry was performed using primary antibodies against IgG, biotin‐conjugated secondary antibodies, and streptavidin‐peroxidase, as well as diaminobenzidine for visualization. After counterstaining with hematoxylin, epithelium, stroma, Descemet´s membrane (DM), and endothelium were semi‐quantitatively scored for the presence of IgG on a 4‐grade scale (0 = no, 1 = faint, 2 = medium, 3 = strong staining) by light microscopy.

Results

Corneal specimens of 20 horses (40 eyes) with a median age of 15.5 years (range 2–31 years), 12 dogs (21 eyes) with a median age of 10.0 years (range 4–16), and 13 cats (24 eyes) with a median age of 10.0 years (range 2–18) were included in the study. Different sexes and breeds were represented. In all corneas (100%), significant medium signal intensity in the stroma was observed. Variable immunosignal was obtained in epithelium, DM, and endothelium.

Conclusion

This method reproducibly allows for the detection of IgG in healthy equine, canine, and feline corneas, particularly stroma. Semi‐quantitative results evidence medium presence of IgG in the corneal stroma. Further research is needed to evaluate IgG presence in diseased corneas.

Monoclonal gammopathy of "ocular" significance

Purpose

Diagnostic criteria for monoclonal gammopathy of undetermined significance (MGUS) do not currently include ocular phenotypic changes. Here, we offer a new diagnostic approach that is useful in patients with posteriorly located corneal depositions and present evidence to support the theory that the aqueous humor is a source for monoclonal proteins accumulated in the cornea.

Observations

A 77-year-old woman presented to the clinic with a gradual decrease in visual acuity over 6 months. Slit lamp examination revealed bilateral central guttae consistent with Fuchs corneal dystrophy, peripheral circular band-like corneal opacities in the deep stroma, and bilateral nuclear sclerotic and cortical cataracts. Anterior segment optical coherence tomography confirmed corneal opacities in the posterior stroma and Descemet membrane. Immunological studies revealed increased serum IgG levels of 3220 mg/dL and serum electrophoresis showed an abnormal monoclonal band of 2.4 g/dL identified as IgG lambda by immunofixation electrophoresis. The patient was referred to the hematology clinic where she underwent further systemic workup and was diagnosed with MGUS. Immunofixation electrophoresis of aqueous sampling, which was performed at the time of cataract surgery, confirmed the presence of the IgG lambda gammopathy in the anterior chamber.

Conclusions and importance

Monoclonal gammopathy, although rare, should be included in the differential diagnosis of corneal opacities, as the ocular finding can be the initial manifestation of a systemic disease that can potentially be life-threatening. When corneal biopsy is not feasible due to the location of corneal pathology, aqueous sampling may be an alternative approach towards a clinical diagnosis. We propose a new terminology, “monoclonal gammopathy of ocular significance,” for patients diagnosed with MGUS, however, their only significant clinical finding is ocular manifestation.

Crystalline keratopathy due to intravenous immunoglobulin in a 12-year-old girl with Kawasaki disease

Kawasaki disease (KD) is an acute, self-limiting, medium-vessel vasculitis that occurs predominantly in young children. The treatment of KD consists of intravenous immunoglobulin (IVIG) along with aspirin and, in IVIG-resistant cases, corticosteroids. Crystalline keratopathy with corneal deposition of the immunoglobulin is a rare complication of IVIG therapy. We report the case of a 12-year-old girl who received IVIG for KD and developed visual complaints, which were attributable to crystalline keratopathy and corneal edema. Cessation of IVIG and treatment with topical and systemic corticosteroids reversed the finding. At final follow-up, vision in both eyes was normal.

Ocular toxicity from systemically administered xenobiotics

INTRODUCTION

The eye is considered as the most privileged organ because of the blood-ocular barrier that acts as a barrier to systemically administered xenobiotics. However, there has been a significant increase in the number of reports on systemic drug-induced ocular complications. If such complications are left untreated, then it may cause permanent damage to vision. Hence, knowledge of most recent updates on ever-increasing reports of such toxicities has become imperative to develop better therapy while minimizing toxicities.

AREAS COVERED

The article is mainly divided into anterior and posterior segment manifestations caused by systemically administered drugs. The anterior segment is further elaborated on corneal complications where as the posterior segment is focused on optic nerve, retinal and vitreous complications. Furthermore, this article includes recent updates on acute and chronic ocular predicaments, in addition to discussing various associated symptoms caused by drugs.

EXPERT OPINION

Direct correlation of ocular toxicities due to systemic drug therapy is evident from current literature. Therefore, it is necessary to have detailed documentation of these complications to improve understanding and predict toxicities. We made an attempt to ensure that the reader is aware of the characteristic ocular complications, the potential for irreversible drug toxicity and indications for cessation.