False negative antibody-based HLA-A29 typing in two patients with birdshot chorioretinopathy

Abstract

A strong association between birdshot chorioretinopathy and HLA-A29 expression has been well established.1 In fact, some have suggested that HLA-A29 expression is essential to make the diagnosis of birdshot chorioretinopathy. Such a strong association makes accurate HLA-A29 subtyping quite important in patients suspected of having this entity. Herein, we describe two patients with birdshot chorioretinopathy in whom initial testing for HLA-A29 expression using antibody-based methods was negative and subsequent testing using more sensitive and specific PCR-based techniques was positive. A 45-year-old Caucasian man with a history of psoriatic skin lesions presented with worsening vision, floaters, and nyctalopia affecting both eyes for 2 months prior to presentation. Best corrected visual acuity was 20/25 …