Human T-Lymphotropic Virus Type 1
Human T-lymphotropic virus type 1 (HTLV-1) is a retrovirus that is endemic in Japan, the Caribbean islands, and parts of Central and South America. It accounts for approximately 1% of uveitis cases in Japan. The diagnosis is made by serologic testing.
The major target cell of HTLV-1 is the CD4+ T cell. HTLV-1 infection is the established cause of adult T-cell leukemia/lymphoma (ATL), HTLV-1–associated myelopathy/tropical spastic paralysis (HAM/TSP), and HTLV-1 uveitis (HU). HU is defined as uveitis of undetermined origin in an HTLV-1 carrier. Additional ocular manifestations of HTLV-1 infection include retinal infiltrates caused by secondary ATL (Fig 11-17), retinal degeneration, optic neuropathy, and keratopathy, as well as keratoconjunctivitis sicca in patients with HAM/TSP.
Figure 11-17 Ocular findings in human T-cell lymphotropic virus type 1–associated T-cell leukemia/lymphoma. A, Fundus photograph showing HTLV-1–associated retinal and vascular infiltrates. B, Anterior segment photograph of HTLV-1–associated keratopathy.
(Courtesy of H. Nida Sen, MD/National Eye Institute.)
Most cases of HU (75%) are classified as an intermediate uveitis. Patients present with blurred vision and floaters caused by a mild granulomatous anterior uveitis (20%), unilateral vitritis (60%), membranous vitreous opacities, and/or “snowballs.” Retinal vasculitis (60%), exudative retinal lesions (25%), optic disc abnormalities (20%), and uveitic macular edema (3%) may also be observed. Retinal vasculitis is responsive to corticosteroids.
For cases that progress despite therapy, the clinician must consider a masquerade syndrome, as retinal infiltration caused by ATL (see Fig 11-17) and retinal degeneration associated with HAM/TSP may mimic HU. HTLV-1–associated keratopathy (previously referred to as HTLV-1–related chronic interstitial keratitis) has been described in Brazilian and Caribbean patients but has not been found among Japanese patients. These corneal lesions likely represent lymphoplasmacytic infiltrates and are asymptomatic.
Although HU responds to topical, periocular, or systemic steroids, one-half of patients may experience recurrent disease.
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Goto H, Mochizuki M, Yamaki K, Kotake S, Usui M, Ohno S. Epidemiological survey of intraocular inflammation in Japan. Jpn J Ophthalmol. 2007;51(1):41–44.
Excerpted from BCSC 2020-2021 series: Section 9 - Uveitis and Ocular Inflammation. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.