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Editor,—The progressive retinal outer necrosis syndrome (PORN) is a recognised variant of necrotising herpetic retinopathy, presumably caused by the varicella zoster virus.1 2 The syndrome is characterised by minimal intraocular inflammation, rapidly spreading multifocal deep retinal lesions without vascular involvement (until late in the disease), bilateral involvement in the majority of the cases, and poor visual prognosis irrespective of treatment.2 So far, the majority of the described cases were related to HIV disease. We present a HIV seronegative immunocompromised patient with normal CD4 counts, who developed PORN and responded well to aciclovir.
A 29 year old man with cutaneous non-Hodgkin’s T cell lymphoma (Sézary syndrome) for 4 years, developed a progressive loss of vision of his right eye within 5 days. Five weeks previously, he had had a thoracic zoster that responded well to orally administered aciclovir (5 × 800 mg per day). On admission, the visual acuity of the right eye was 0.4 and a central subcapsular posterior cataract was present. Intraocular cells were absent, and remained absent thereafter. Extensive central and peripheral oedematous and white necrotic lesions, including the macula were observed with sparing of the perivascular region (Fig 1). Slight optic oedema and a few scattered retinal haemorrhages were also found. The left eye exhibited no abnormalities. A diagnostic aqueous tap was performed and intravenous aciclovir, 10 mg/kg body weight three times per day, was immediately initiated. Treatment with chlorambucil 4 mg and prednisone 22.5 mg daily for the non-Hodgkin’s lymphoma was continued. CD4 counts were normal (390×106/l, reference range 350–1500×106/l), CD8 counts, however, were low (14.8×106/l) resulting in high CD4/CD8 ratio (26, reference range 1.1–2.5). Microparticle enzyme immunoassay (IMX 8B3220, Abbott, CA, USA) demonstrated HIV seronegativity.
After 3 days, resolution of the peripheral lesions started but progression into the posterior pole occurred. Fluorescein angiography disclosed retinal necrotic lesions with perivascular sparing and areas of resolution with arteriolar attenuation. Because of the development of phlebitis along the cannula intravenously administered aciclovir was temporarily switched to oral aciclovir (5 × 800 mg per day) from day 8 until day 13. Nevertheless, resolution of the necrotic lesions continued, resulting in opaque chorioretinal scarring and optic atrophy by the end of the second week (Fig 2). After a month patient was discharged with a maintenance therapy (5 × 800 mg aciclovir orally per day). Visual acuity in the right eye stabilised at 0.2 for the following 11 months; however, the patient developed a mature cataract, leading to light perception only. Retinal detachment did not occur (shown by ultrasound biomicroscopy) and the left eye remained uninvolved until his death (due to respiratory failure) at 18 months’ follow up.
Aqueous humour analysis revealed low Goldmann–Witmer coefficients (<3.0) and no DNA of varicella zoster virus (VZV), herpes simplex virus, and cytomegalovirus (polymerase chain reaction negative) was detected. High serum IgG levels (1:8192) against VZV might have contributed to the low Goldmann–Witmer coefficients.
Our patient was immunocompromised by the cutaneous non-Hodgkin’s lymphoma and the accompanying therapy, but in contrast with AIDS patients CD4 counts were, albeit low, within the normal limits. Characteristically for the Sézary syndrome however, the CD4/CD8 ratio was elevated due to low counts of CD8 cells. Compared with HIV seropositive patients or AIDS patients with PORN,2 our patient responded well to aciclovir treatment. Furthermore, notwithstanding the optic atrophy, he retained useful visual acuity and retinal detachment did not develop. As suggested earlier, the degree1 and probably the type of immune deficiency might be responsible for the differences in clinical picture, and therapy outcome.
Five cases with PORN in HIV seronegative, but otherwise immunocompromised, individuals were reported. In contrast with our patient, none of these cases displayed all typical features of PORN as described originally in AIDS patients1: two patients had moderate or pronounced intraocular inflammation,3 4 and the third patient showed ophthalmological lesions resembling bilateral acute retinal necrosis syndrome.5 Two other cases were only briefly mentioned but not described.4 Recently, PORN was described in a HIV seronegative patient following bone marrow transplantation with poor visual outcome despite preventive antiviral treatment; however, this patient had low CD4 counts.6
Our case demonstrates that PORN may develop in HIV seronegative, immunocompromised patients with normal CD4 but low CD8 counts.