LAUSR

Alemtuzumab, a monoclonal antibody against CD52, is a highly effective treatment of relapsing–remitting multiple sclerosis (RRMS), but it is known to cause secondary autoimmunity in 40% of patients [1]. We present a case of a RRMS patient treated with alemtuzumab who developed acute posterior multifocal placoid pigment epitheliopathy (APMPPE). A 34-year-old male patient, diagnosed with RRMS aged 26, experienced multiple disabling relapses per year whilst on treatment with interferon β-1a (Rebif) and was enrolled in a clinical trial for alemtuzumab (CAMMS 32400507). Six months after his first cycle of treatment, he had experienced no new relapses, but in the context of an enterococcal urinary tract infection with exacerbation of his RRMS symptoms, he awoke one morning to discover a ‘multicoloured blob’ obscuring the central field of his left eye. On examination, visual acuity was 6/9, pinholing to 6/6, on the right and better than 6/6 on the left. Three left-eye scotomata were evident on Amsler grid plotting and fundoscopy revealed numerous pale-yellow lesions bilaterally at the level of the retinal pigment epithelium and choriocapillaris, with some showing early hyperpigmentation (Fig. 1a). Fluorescein angiography showed early hypofluorescence and late hyperfluorescence of some lesions (Fig. 1b). Inflammatory markers were normal and a full blood count showed only a marginally low lymphocyte count (0.95 × 109/L). An autoimmune screen showed normal immunoglobulin, serum angiotensin converting enzyme (ACE) and complement levels, and was negative for antinuclear antibodies. Infection was ruled out by serological testing (including for syphilis), analysis of aqueous humour obtained by anterior chamber paracentesis, and a T-spot test for tuberculosis. Additionally, a CT of the chest, abdomen and pelvis was unremarkable, making lymphoma unlikely. Over the next weeks, he demonstrated continual evolution of chorioretinal lesions bilaterally (Fig. 1a). There were no symptoms of neurological involvement. Accordingly, an MRI scan of the head showed no new lesions and a lumbar puncture was unremarkable. An empirical course of acyclovir treatment was commenced even though his presentation was not typical of herpetic disease and his symptoms began resolving after 2 months. APMPPE is a self-limiting idiopathic inflammatory chorioretinopathy, believed to be secondary to a hypersensitivity-induced obstructive vasculitis affecting the choriocapillaris [2, 3]. Associations of the disease with preceding viral infections and vaccinations, as well as with human leukocyte antigen (HLA) haplotypes DR2 and B7, support an immune aetiology for APMPPE [4]. There is no single diagnostic investigation, but the exclusion of other causes and the characteristic appearance make APMPPE the most likely diagnosis in this case. Moreover, the timing of the occurrence of symptoms coincides with the earlier stages of B-cell reconstitution following alemtuzumab: the time period during which patients are at highest risk of autoimmune disease [5]. The coincident timing of * Jiali Gao [email protected]