Retinal vasculitis in human T-lymphotropic virus type I associated myelopathy

Advances in the treatment of human T-cell lymphotropic virus type-I associated myelopathy

INTRODUCTION

Nearly 2-3% of those 10 to 20 million individuals infected with the Human T-cell lymphotropic virus type-1 (HTLV-1); are predisposed to developing HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). It is a neuro-inflammatory disease; differentiated from multiple sclerosis based on the presence of typical neurologic symptoms, confirmation of HTLV-1 infection, and other molecular biomarkers.

AREAS COVERED

A brief review of the epidemiology, host immune responses, and molecular pathogenesis of HAM/TSP is followed by detailed discussions about the host-related risk factors for developing HAM/TSP and success/failure stories of the attempted management strategies.

EXPERT OPINION

Currently, there is no effective treatment for HAM/TSP. Anti-retroviral therapy, peculiar cytokines (IFN-α), some anti-oxidants, and allograft bone marrow transplantation have been used for treating these patients with limited success. Under current conditions, asymptomatic carriers should be examined periodically by a neurologist for early signs of spinal cord injury. Then it is crucial to determine the progress rate to adapt the best management plan for each patient. Corticosteroid therapy is most beneficial in those with acute myelitis. However, slow-progressing patients are best managed using a combination of symptomatic and physical therapy. Additionally, preventive measures should be taken to decrease further spread of HTLV-1 infection.

Differential diagnosis of retinal vasculitis

Retinal vaculitis is a sight-threatening inflammatory eye condition that involves the retinal vessels. Detection of retinal vasculitis is made clinically, and confirmed with the help of fundus fluorescein angiography. Active vascular disease is characterized by exudates around retinal vessels resulting in white sheathing or cuffing of the affected vessels. In this review, a practical approach to the diagnosis of retinal vasculitis is discussed based on ophthalmoscopic and fundus fluorescein angiographic findings.

Retinal Vasculitis

Retinal vasculitis is a sight-threatening intraocular inflammation affecting the retinal vessels. It may occur as an isolated ocular condition, as a manifestation of infectious or neoplastic disorders, or in association with a systemic inflammatory disease. The search for an underlying etiology should be approached in a multidisciplinary fashion based on a thorough history, review of systems, physical examination, and laboratory evaluation. Discrimination between infectious and noninfectious etiologies of retinal vasculitis is important because their treatment is different. This review is based on recently published articles on retinal vasculitis and deals with its clinical diagnosis, its link with systemic diseases, and its laboratory investigation.

A Novel NF-κB Pathway Involving IKKβ and p65/RelA Ser-536 Phosphorylation Results in p53 Inhibition in the Absence of NF-κB Transcriptional Activity

Nuclear factor kappaB (NF-kappaB) plays an important role in regulating cellular transformation and apoptosis. The human T-cell lymphotropic virus type I protein, Tax, which is critical for viral transformation, modulates the transcription of several cellular genes through activation of NF-kappaB. We have demonstrated previously that Tax inhibits p53 activity through the p65/RelA subunit of NF-kappaB. We now present evidence that suggests that the upstream kinase IKKbeta plays an important role in Tax-induced p53 inhibition through phosphorylation of p65/RelA at Ser-536. First, mouse embryo fibroblast (MEF) IKKbeta-/-cells did not support Tax-mediated p53 inhibition, whereas MEFs lacking IKKalpha allowed Tax inhibition of p53. Second, transfection of IKKbeta wild type (WT), but not a kinase-dead mutant, into IKKbeta-/-cells rescued p53 inhibition by Tax. Third, the IKKbeta-specific inhibitor SC-514 decreased the ability of Tax to inhibit p53. Fourth, we show that phosphorylation of p65/RelA at Ser-536 is important for Tax inhibition of p53 using MEF p65/RelA-/-cells transfected with p65/RelA WT or mutant plasmids. Moreover, Tax induced p65/RelA Ser-536 phosphorylation in WT or IKKalpha-/- cells but failed to induce the phosphorylation of p65/RelA Ser-536 in IKKbeta-/-cells, suggesting a link between IKKbeta and p65/RelA phosphorylation. Consistent with this observation, blocking IKKbeta kinase activity by SC-514 decreases the phosphorylation of p65/RelA at Ser-536 in the presence of Tax in human T-cell lymphotropic virus type I-transformed cells. Finally, the ability of Tax to inhibit p53 is distinguished from the NF-kappaB transcription activation pathway. Our work, therefore, describes a novel Tax-NF-kappaB p65/RelA pathway that functions to inhibit p53 but does not require NF-kappaB transcription activity.

[Vasculitis associated with viral infections]

VIRUSES, THE CAUSE OF VASCULITIS: Although the majority of systemic vasculitis are of unknown causes, the responsibility of a viral infection has been formally demonstrated in some of them and specific treatment can permanently cure them. Each virus incriminated accounts for a particular type of vasculitis. HEPATITIS B VIRAL INFECTION (HBV): Is the cause of polyarteritis nodosa in 36 to 50% of cases. The onset of the symptomatology is acute, usually within a few months following the infection; it is comparable to that observed in the absence of HBV infection. CRYOGLOBULINEMIA RELATED TO THE HEPATITIS C VIRUS (HCV): The clinical manifestations are those of systemic vasculitis with particular tropism for the skin (involvement generally inaugural and almost constant), peripheral nerves and the glomerula. They occur fairly late during the infection. VASCULITIS ASSOCIATED WITH HIV INFECTION: There is strong tropism for the peripheral (multi-neuritis) and central nervous system. During acute parvovirus B19 infection Vasculitis lesions have occasionally been reported following the viremic phase, generally limited to one or several flares of vascular purpura predominating on the lower limbs. FOLLOWING VARICELLA-HERPES ZOSTER INFECTION: Vasculitis occasionally develops in the form of a central neurological deficiency (locomotor deficiency with or without aphasia around one month after an ophthalmologic herpes zoster) or involving the retina or, more rarely, the skin or the kidneys. VASCULITIS ASSOCIATED WITH CYTOMEGALOVIRAL INFECTION: Predominantly observed in immunodepressed patients, vasculitis after CMV infection is diffuse and basically involving the digestive tube, notably the colon, the central nervous system and the skin. A RARE COMPLICATION OF AN HTLV1 INFECTION: Vasculitis of the retina often in the form of necrotic retinitis is often associated with spasmodic paraparessia.

THERAPEUTIC STRATEGY

For many vasculitis of viral origin, corticosteroid and immunosuppressive treatments are only indicated in second intention following failure with antiviral agents and the combination of antivirals and plasma exchanges.

Immunopathogenesis of HTLV-I-associated myelopathy/tropical spastic paraparesis

The main pathological feature of human T-lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is chronic inflammation of the spinal cord characterized by perivascular cuffing of mononuclear cells accompanied by parenchymal lymphocytic infiltration. Although the exact mechanism of the pathogenesis of HAM/TSP is still obscure, immunological abnormalities arising from a high HTLV-I proviral load in peripheral blood lymphocytes (PBL) play an important role in the pathological process of spinal cord lesions in HAM/TSP patients. The relationship between HLA haplotype and the risk of the occurrence of HAM/TSP will be elucidated by results from studies of HLA allele typing. In addition, recent data indicate that HTLV-I and its expression are localized in infiltrated lymphocytes within the spinal cord lesions of HAM/TSP patients rather than in resident central nervous system (CNS) parenchymal cells. Although a bystander damage of the surrounding CNS tissues, in which CD8+ HTLV-I-specific cytotoxic T lymphocyte (CTL) attack HTLV-I-infected lymphocytes, might be involved in the pathological events of the spinal cords of HAM/ TSP patients as one of the actual pathogenetic mechanisms, heightened transmigrating activity of HTLV-I-infected CD4+ T lymphocytes to the CNS tissues may have a key role in the development of HAM/TSP. Therefore, although the exact mechanism underlying the high HTLV-I proviral load in PBL in HAM/TSP patients is still unknown, we must consider therapeutic approaches in HAM/TSP that eliminate HTLV-I-infected CD4+ T lymphocytes.

Importance of immune deviation toward Th1 in the early immunopathogenesis of human T-lymphotropic virus type I-associated myelopathy

Although the principal neuropathological feature of human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM) is chronic inflammation of the spinal cord, characterized by perivascular cuffing of mononuclear cells accompanied by parenchymal lymphocytic infiltration, the precise mechanisms by which HTLV-I infection causes chronic inflammation of the spinal cord are still obscure. In patients with HAM, peripheral blood CD4(+)T lymphocytes, particularly HTLV-I-infected CD4(+)T lymphocytes, have increased adherent activity to endothelial cells and transmigrating activity through basement membranes. In addition, the profile of cytokine expression suggests increased numbers of Th1 cells in peripheral blood CD4(+)T lymphocytes of patients with HAM. These findings strongly suggest that immune deviation toward Th1, which might be based on high viral load of HTLV-I, plays an important role in tissue damage in the central nervous system of patients with HAM. We herein emphasize the importance of activated Th1 cells as the first trigger in the immunopathogenesis of HAM.

Molecular pathologic analysis of the tonsil in HTLV-I-infected individuals

Little is known about the role of the tonsils in HTLV-I infection. We performed molecular pathologic studies of tonsils in individuals positive or negative for anti-HTLV-I antibodies (HTLV-I-Ab) to clarify histologic characteristics of tonsils in HTLV-I infection. We collected tonsils and peripheral blood samples from patients who underwent tonsillectomy in a prospective manner. HTLV-I-Ab in serum was examined and presence of HTLV-I provirus was detected by polymerase chain reaction (PCR) in extracted DNA of both peripheral blood and tonsils. Histopathologic and immunohistochemical evaluations of tonsils were performed. HTLV-I seropositivity and PCR detection of HTLV-I provirus matched perfectly. Tonsil samples from seropositive individuals showed atrophy of the mantle zone and high numbers of T cells in the marginal zone compared with findings in HTLV-I-negative samples. HTLV-I provirus could be detected only from extracted DNA of extrafollicular areas. PCR in situ hybridization also showed positive signals in some mononuclear cells located in the marginal zone. There was a significant correlation between HTLV-I proviral load in tonsils and in peripheral blood. These results suggest the presence of characteristic histologic changes and deviated localization of HTLV-I-infected cells in the tonsils of individuals positive for HTLV-I.

On the etiology of tropical spastic paraparesis and human T-cell lymphotropic virus-I-associated myelopathy

The purpose of this review is to present some concepts on the etiology of tropical spastic paraparesis or human T-cell lymphotropic virus-I (HTLV-I)-associated myelopathy (TSP/HAM). The large number of syndromes that have been associated with HTLV-I (60 to date), the existence of TSP/HAM cases associated with other retroviruses (human immunodeficiency virus-2 [HIV-2], HTLV-II), the existence of many TSPs without HTLV-I, and the evidence of clear epidemiologic contradictions in TSP/HAM indicate that the etiopathogenesis of TSP/HAM is not yet clear. Tropical spastic paraparesis/HAM affects patients of all human ethnic groups, but usually in well localized and relatively isolated geographic regions where HTLV-I has been endemic for a long time. Environmental factors and geographic locations appear to be critical factors. Because the neuropathology of TSP/HAM suggests a toxometabolic, rather than a viral cause, it is proposed that an intoxication similar to neurolathyrism could account for some of TSP/HAM cases, mainly in tropical and subtropical countries. If this were the case, HTLV-I could be a cofactor or act as a bystander. it is possible that co-infection with another agent is necessary to produce TSP/HAM and most of the syndromes associated with HTLV-I.

Phosphorylation of p53: a novel pathway for p53 inactivation in human T-cell lymphotropic virus type 1-transformed cells

Inhibition of p53 function, through either mutation or interaction with viral or cellular transforming proteins, correlates strongly with the oncogenic potential. Only a small percentage of human T-cell lymphotropic virus type 1 (HTLV-1)-transformed cells carry p53 mutations, and mutated p53 genes have been found in only one-fourth of adult T-cell leukemia cases. In previous studies, we demonstrated that wild-type p53 is stabilized and transcriptionally inactive in HTLV-1-transformed cells. Further, the viral transcriptional activator Tax plays a role in both the stabilization and inactivation of p53 through a mechanism involving the first 52 amino acids of p53. Here we show for the first time that phosphorylation of p53 inactivates p53 by blocking its interaction with basal transcription factors. Using two-dimensional peptide mapping, we demonstrate that peptides corresponding to amino acids 1 to 19 and 387 to 393 are hyperphosphorylated in HTLV-1-transformed cells. Moreover, using antibodies specific for phosphorylated Ser15 and Ser392, we demonstrate increased phosphorylation of these amino acids. Since HTLV-1 p53 binds DNA in a sequence-specific manner but fails to interact with TFIID, we tested whether phosphorylation of the N terminus of p53 affected p53-TFIID interaction. Using biotinylated peptides, we show that phosphorylation of Ser15 alone inhibits p53-TFIID interaction. In contrast, phosphorylation at Ser15 and -37 restores TFIID binding and blocks MDM2 binding. Our studies provide evidence that HTLV-1 utilizes the posttranslational modification of p53 in vivo to inactivate function of the tumor suppressor protein.

HTLV-I-associated myelopathy associated with multi-organ inflammatory disease: a case report

We report a 73-year-old man with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM) complicated with multi-organ inflammatory disease, including Sjögren's syndrome, interstitial cystitis, and uveitis. The presence of HTLV-I proviral DNA in peripheral blood mononuclear cells (PBMC), cerebrospinal fluid, salivary gland, mucosa of urinary bladder, and aqueous humor was confirmed by polymerase chain reaction using HTLV-I pX region primer. Western blot analysis revealed the presence of anti-HTLV-I antibodies in serum, CSF, saliva, and urine, suggesting replication of HTLV-I in each tissue. A high load of HTLV-I proviral DNA (20 copies out of 100 PBMC) was present, associated with increased spontaneous proliferation of peripheral blood lymphocytes (24,747 cpm). Our results suggest that the high load of HTLV-I in patients with HAM may potentially induce systemic inflammation in several organs.

HAM/TSP: recent perspectives in Japan

Neurologic diseases associated with human T-cell lymphotropic virus type I (HTLV-I) infection have a clinical spectrum that includes myelopathy (HTLV-I-associated myelopathy/tropical spastic paraparesis, HAM/TSP) as the central manifestation. Many clinical signs of involvement outside the central nervous system (CNS) have been described in some patients with HAM/TSP and have triggered and advanced the discovery of some HTLV-I-associated concepts in HTLV-I-infected individuals without signs of CNS involvement. Most of these HTLV-I-associated diseases exhibit common viroimmunologic characteristics that include a distributional bias of HTLV-I activation between the blood flow and the affected lesions and accumulated cellular immune responses in the lesions. These facts suggest that the vulnerable tissue(s) in some HTLV-I-infected individuals may not be defined by an exclusive tissue specificity, but that common steps of HTLV-I-versus-host interactions may have an important role in the pathologic process(es) in these diseases. This review summarizes the recent perspectives of the clinical spectrum and the pathogenesis of HAM/TSP in Japan. Furthermore, the feasible pathogenic involvement of cellular interactions between infected cells and responding immunocompetent cells in the affected tissues is emphasized.

HTLV-I uveitis

Human T-cell lymphotropic virus type I (HTLV-I) is known to cause adult T-cell leukemia/T-cell lymphoma and tropical spastic paraparesis/HTLV-I-associated myelopathy. Recent seroepidemiologic, clinical, and virologic studies indicate that the virus is also related to a certain type of uveitis, which has been classified as uveitis without defined etiologies or idiopathic uveitis. According to the seroepidemiologic survey, the seroprevalence of HTLV-I in patients with idiopathic uveitis was significantly higher than that of two control groups, that is, patients with uveitis with defined etiologies and patients with nonuveitic ocular diseases. Clinically, the uveitis seen in HTLV-I carriers is characterized by moderate to severe cellular infiltration in the eye and by moderate retinal vasculitis, and the intraocular inflammation responds well to corticosteroid therapy. Interestingly, 25% of female patients with the disease had a previous history of Graves disease with hyperthyroidisms. The following virologic, molecular biologic findings suggest that cytokines produced by HTLV-I-infected T cells in the eye play the central role in the pathogenic mechanisms of the uveitis: (a) the virus load in the peripheral blood monocytes analyzed by the quantitative polymerase chain reaction methods was significantly greater in patients with the uveitis than in asymptomatic carriers, (b) the proviral DNA of HTLV-I and the gene expression of the virus at the mRNA level was detected in the infiltrating cells from the eyes of the patients, (c) the virus particles were detected by electron-microscopic examination in the T-cell clones established from the intraocular fluid of the patients, and (d) the HTLV-I-infected T cells produced a variety of cytokines without any stimuli, such as interleukin (IL)-1 alpha, IL-2, IL-3, IL-6, IL-8, IL-10, tumor necrosis factor alpha, interferon-gamma, and granulocyte-macrophage colony-stimulating factor. Based on the seroepidemiologic, clinical, and virologic data, the uveitis seen in HTLV-I carriers is considered to be a distinct clinical entity related to HTLV-I infection, and the disease is designated as HTLV-I uveitis.

Prevalence of HTLV-I-associated uveitis in the Kanto Plain, Japan

BACKGROUND

Seroprevalence of antibody to human T-lymphotropic virus type I (HTLV-I) is high in the island of Kyushu, Japan. Reports on the etiological analysis of HTLV-I in patients with uveitis primarily document cases in this island. We studied the seroprevalence of HTLV-I at the Department of Ophthalmology in Yokohama City University Hospital and in Odawara Municipal Hospital, which are in the Kanto Plain on the island of Honshu, Japan.

METHODS

The subjects were 741 patients who visited the two hospitals. The presence of serum antibodies against HTLV-I was assessed using the method of particle agglutination.

RESULTS

Of 454 patients with nonuveitic ocular diseases, 9 (1.98%) were seropositive. Of 143 patients with definite diagnosis of uveitis, 1 (0.70%) was seropositive. Of 144 patients with non-specific uveitis (etiology undefined), 8 (5.56%) were seropositive. Thus, the prevalence of serum antibodies to HTLV-I was higher in patients with non-specific uveitis than in patients with specific uveitis or nonuveitic ocular diseases. Common ocular symptoms of 8 HTLV-I-infected patients with non-specific uveitis were compatible with the clinical features of uveitis described as HTLV-I-associated uveitis (HAU).

CONCLUSION

It is important to suspect HAU in patients with uveitis of unknown etiology, even outside known areas of prevalence.

Expression of human T lymphotropic virus type 1 (HTLV-1) tax/rex gene in fresh bronchoalveolar lavage cells of HTLV-1-infected individuals

Accumulating evidence has suggested the involvement of HTLV-1 in the inflammatory lesions of various organs, including the lung. However, the causal relationship between HTLV-1 and inflammatory responses in the organs remains to be elucidated. In order to evaluate the expression of HTLV-1 and its effects in the lung, we examined the expression of mRNA for the HTLV-1 tax/rex gene in fresh bronchoalveolar lavage cells (BALC) and peripheral blood mononuclear cells (PBMC) of 23 seropositive individuals, including six patients with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), by use of an improved method of reverse transcription-polymerase chain reaction (RT-PCR). The tax/rex mRNA was more frequently detected in BALC than in PBMC. All the HAM/TSP patients and eight of 17 carriers without neurological symptoms showed the expression of tax/rex mRNA in the BALC. IgM class antibodies to HTLV-1 were preferentially detected in sera of the tax/rex mRNA-positive individuals. The detection of tax/rex mRNA correlated closely with the presence of lymphocytosis accompanied by an elevated proportion of IL-2 receptor-bearing T cells in the BALC. Our findings indicate the crucial role of viral expression in the inflammatory response in the lung in HTLV-1-infected individuals.

Human T lymphotropic virus type 1 uveitis

The human retroviruses, HTLV-I and HIV, are playing clinically important roles in a variety of ocular disorders, particularly in uveitis. Both viruses are integrated in the genome of infected T cells. HIV-I infection causes the death of the infected T cells, thereby affecting the host defence system and causing AIDS. Subsequent opportunistic infections of ocular tissues, such as CMV retinitis, are a serious problem in clinical ophthalmology all over the world. Another human retrovirus, HTLV-I, has been known as the causative agent of T cell malignancies (ATL and T cell lymphoma) and chronic myelopathy (HAM/TSP), and is now recognised as a causative agent for a specific type of intraocular inflammation characterised by vitreous opacities with mild iritis and mild retinal vasculitis (HTLV-I uveitis). The mechanism by which HTLV-I causes uveitis is still unknown, but our recent data suggest that it is most probably an immune mediated mechanism by activated CD4 T cells infected with the virus. HTLV-I uveitis, therefore, may implicate a significant role of retroviruses in autoimmune diseases and further the pathogenesis of diseases with infection/autoimmune overlap.

Ocular manifestations of adult T-cell leukemia/lymphoma. A clinicopathologic study

BACKGROUND

Adult T-cell leukemia/lymphoma (ATLL) is a recently described distinct clinicopathologic entity characterized by an extremely aggressive clinical course, a leukemic or lymphomatous proliferation of hyperlobulated peripheral T cells, and an association with infection by a retrovirus, human T-lymphotropic virus type I (HTLV-I). The authors present a patient with ATLL who initially had clinical features of severe uniocular intraocular inflammation, simulating acute retinal necrosis or herpetic retinitis, but results of histopathologic examination of the globe showed ATLL.

PATIENT

A 38-year-old man had severe unilateral intraocular inflammation associated with widespread diffuse retinitis. Two weeks later, a focal retinitis with vasculitis developed nasal to the optic disc in the opposite eye. Shortly thereafter, mental disturbance developed, and the patient died less than 3 months after onset of the ocular symptoms.

RESULTS

Results of postmortem examination showed atypical lymphocytic infiltration in the eyes, brain, and other systemic organs. Results of histopathologic and immunohistochemical studies showed that the atypical cells infiltrating the ocular tissues were ATLL cells.

CONCLUSIONS

Patients infected with HTLV-I initially can have intraocular T-cell lymphoma that simulates acute retinal necrosis or herpetic retinitis.

Clinical features of HTLV-I associated uveitis

The prevalence of human T cell lymphoma virus type 1 (HTLV-I) was studied among patients with endogenous uveitis. Twelve (15.8%) of 76 uveitis patients with known aetiology or clinical entity were seropositive, the prevalence being comparable with that in the general population of the southwestern area of Japan where HTLV-I is highly endemic. In the comparison, 32 (41.0%) of 78 patients with aetiology or entity undefined uveitis were seropositive for HTLV-I, which indicated a significantly higher seroprevalence than controls matched for sex and age. The 32 cases of clinical entity undefined, HTLV-I positive uveitis were characterised by acute granulomatous or non-granulomatous uveal reactions which were accompanied by vitreous opacities and retinal vasculitis. The uveal inflammatory and retinal vascular changes responded well to topical and/or systemic corticosteroids and resolved in a few weeks in the majority of cases with favourable visual outcome. The disease affected one or both eyes, and eight cases (25%) showed recurrence within a year. The general condition of the patients remained well otherwise during a follow up study (mean follow up time 15.4 months), except for three cases with a possible association of hyperthyroidism. These findings provide additional information favouring an association between HTLV-I and isolated uveitis, a new disease entity which should be termed HTLV-I-associated uveitis.

Retinal vasculitis in a mother and her son with human T-lymphotropic virus type 1 associated myelopathy

A 53-year-old woman had difficulty in walking, raised titres to human T-lymphotropic virus type 1 (HTLV-1) in serum and cerebrospinal fluid, and yellowish white retinal lesions and vasculitis in the right eye. Her 20-year-old son also had difficulty in walking, raised titres to HTLV-1 in serum and cerebrospinal fluid, and retinal vasculitis and multiple whitish vitreoretinal spots in both eyes.

Seroprevalence of antibodies to HTLV-I in patients with ocular disorders

Human T-lymphotropic virus type 1 (HTLV-I) has been shown to spread worldwide and to be responsible for distinct systemic diseases, namely adult T-cell leukaemia and HTLV-I-associated myelopathy. Immune-mediated, inflammatory lesions in the lungs, joints, and lacrimal glands (Sjögren's syndrome) are also suggested to be associated with the retrovirus. We studied seroprevalence of antibodies to HTLV-I in patients with various ocular disorders who are residents of south-west Japan, one of the endemic areas of HTLV-I. Of 310 patients with ocular disease 72 (23.2%) were seropositive. This seroprevalence did not differ significantly from that of the general population of the area. As regards individual ocular diseases, aetiologically undefined nonspecific uveitis showed a significantly high seropositivity for HTLV-I. Of 44 patients 18 (40.9%) were seropositive. Their clinical features were acute or subacute, transient and sometimes recurrent, and granulomatous changes in the anterior uvea. Patients with isolated cotton-wool spot of the retina, non-familial retinitis pigmentosa, or keratoconjunctivitis sicca did not show any significantly high prevalence of HTLV-I infection.