Abstract
Purpose: :
Rituximab is a chimeric mouse/human monoclonal antibody that acts against the B cell antigen CD20. This antigen is expressed by all B cells until they differentiate into mature plasma cells. Treatment with rituximab results in a marked, sustained reduction in the number of both normal and malignant B cells . Recently, few studies published on the use of 1 mg/0.1 ml intravitreal rituximab for vitreoretinal lymphoma and demonstrated its effective treatment. Although clinical observations from a small number of patients do not point to retinal toxicity, no study has yet been published addressing this fundamental aspect. Our aim was to evaluate retinal toxicity of intravitreal rituximab in a rabbit model.
Methods: :
Seven New Zealand white rabbits were used. The Right eye of each rabbit was injected with 1 mg/0.1 ml rituximab solution (Experimental eye) and the left eye was injected with 0.1 ml saline (control eye). Electroretinogram (ERG) and Visual Evoked Potential (VEP) were recorded at 3 hr, 3 days, 1, 2 and 4 weeks. Histological preparations and GFAP immunostaining were made throughout the follow-up period. In addition, slit lamp examination was performed in all time points.
Results: :
No differences in the b-wave maximal (saturating) amplitude (Vmax), the luminance for reaching 50% of Vmax (σ) or the light-adapted amplitude ERG were found between experimental and control rabbit eyes. Similar flash VEP responses were found in experimental and control rabbit eyes. Morphology and GFAP expression of retinas in eyes exposed to the rituximab solution was normal. No abnormal findings were noticed on slit lamp examinations.
Conclusions: :
A dose of 1 mg/0.1 ml of rituximab, the clinically used dose, did not cause measurable or morphological toxic effects to the rabbit retina. These findings may lay the ground for its safety intraocular use.
Keywords: electrophysiology: non-clinical • immunohistochemistry • retina