Immunohistochemical characterization of feline lymphoplasmacytic anterior uveitis

Abstract

AbstractObjectiveTo characterize the immune cells present in different forms of feline anterior uveitis.SamplesEyes were obtained from 49 cats diagnosed with chronic idiopathic lymphoplasmacytic anterior uveitis, 7 cats with feline infectious peritonitis (FIP), and 9 cats euthanized for nonocular disease.MethodsH&E sections were scored on the level of infiltrate in the anterior uvea. Immunohistochemistry was performed for FoxP3,CD3, andIL‐17A, and positive cells were quantified in multiple images of each sample. A generalized estimating equation tested for an association between the level of inflammation and the prevalence of these cell types.ResultsCells stained positive forIL‐17A in idiopathic uveitis but not inFIPsamples. We found significantly fewer FoxP3+andCD3+cells in low‐grade compared with high‐grade inflammation in idiopathic uveitis orFIPsamples (Pvalues all <.005), but no difference betweenFIPand high‐grade samples.ConclusionsIdiopathic, but notFIP‐associated, uveitis appears to have Th17 cell involvement. The numbers of FoxP3+andCD3+T‐cells present appear directly correlated; thus, the severity of disease does not appear directly determined by the numbers of regulatory cells.