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Dry eye disease caused by viral <strong>in</strong>fection: review<br />

The potential pathogenic mechanisms to DED associated to the<br />

viral <strong>in</strong>fection <strong>in</strong> the lacrimal gl<strong>and</strong> are the follow<strong>in</strong>g:<br />

HTLV<br />

The human T-cell lymphotropic virus (HTLV) <strong>in</strong>fection is endemic<br />

<strong>in</strong> Japan, the Caribbean bas<strong>in</strong>, Central <strong>and</strong> South America <strong>and</strong> Africa.<br />

It is transmitted through sexual <strong>in</strong>tercourse, breast-feed<strong>in</strong>g, blood<br />

transfusion <strong>and</strong> shar<strong>in</strong>g of contam<strong>in</strong>ated syr<strong>in</strong>ges <strong>and</strong> <strong>needle</strong>s. HTLV<br />

is characterized by asymptomatic <strong>in</strong>fection <strong>in</strong> most of seropositive<br />

cases. Although 90% of the approximately 20 million <strong>in</strong>fected people<br />

worldwide rema<strong>in</strong> asymptomatic carriers dur<strong>in</strong>g their lives, HTLV<br />

<strong>in</strong>fection is also associated with systemic <strong>and</strong> ocular complications (14) .<br />

HTLV <strong>in</strong>fection is etiologically l<strong>in</strong>ked to two potential fatal<br />

diseases: 1) the malignant proliferation of T cell caus<strong>in</strong>g the adult<br />

leukemia/lymphoma (ATL) <strong>and</strong> 2) a neuromyelopathy known as<br />

tro pical spastic paraparesis (TSP). ATL is considered an aggressive lym -<br />

phoproliferative malignancy with short survival <strong>in</strong> its acute form,<br />

occurr<strong>in</strong>g <strong>in</strong> less than 5% <strong>in</strong> HTLV <strong>in</strong>fected people. TSP is a chronic<br />

men<strong>in</strong>gomyelitis <strong>in</strong> the sp<strong>in</strong>al cord, with demyel<strong>in</strong>ation <strong>and</strong> axonal<br />

degeneration lead<strong>in</strong>g to the development of a slowly progressive<br />

spastic paraparesis, high impairment of gait, autonomic dysfunction<br />

<strong>and</strong> profound repercussions on abilities <strong>and</strong> quality of life of the<br />

patients (15,16) . HTLV also causes dermatitis, pneumonia, polymyositis,<br />

thyroiditis <strong>and</strong> Sjögren’s like syndrome (16) .<br />

HTLV ocular lesions may present as uveitis, dry eye, keratitis <strong>and</strong><br />

ret<strong>in</strong>al vasculitis (17) . The prevalence of uveitis is controversial <strong>in</strong> different<br />

parts of the world. In Japan, for <strong>in</strong>stance, a 35.4% prevalence of<br />

uveitis <strong>in</strong> patients <strong>in</strong>fected with HTLV was observed, while <strong>in</strong> Mart<strong>in</strong>ique,<br />

the prevalence was 14.5% (18) . The <strong>in</strong>cidence of dry eye <strong>in</strong> seropositive<br />

patients was 36.4% <strong>in</strong> study conducted <strong>in</strong> the region of highest<br />

prevalence of HTLV <strong>in</strong>fection <strong>in</strong> Brazil. Moreover, 54.4% of DED <strong>in</strong> TSP<br />

patients <strong>and</strong> 20.3% <strong>in</strong> asymptomatic seropositives. In those patients<br />

immunophenotyp<strong>in</strong>g analysis shown high levels of both CD4+ <strong>and</strong><br />

CD8+ (19) . Another study, evaluat<strong>in</strong>g 200 <strong>in</strong>fected patient found 37% of<br />

DES accompanied by lymphoplasmocytoid <strong>in</strong>filtration of secondary<br />

salivar gl<strong>and</strong> (20,21) .<br />

Serological studies demonstrated the prevalence of antibodies<br />

to HTLV <strong>in</strong> Sjögren patients rang<strong>in</strong>g from 23-36%, significantly higher<br />

than that among blood donors. Salivary IgA antibodies to HTLV were<br />

found <strong>in</strong> seropositive HTLV patients with SS (22,23) . Indeed, two <strong>in</strong>dependent<br />

studies confirmed the presence of HTLV genome <strong>in</strong> salivary<br />

gl<strong>and</strong>s samples from patients with Sjögren (24,25) .<br />

HIV<br />

HIV (human immunodeficiency virus) <strong>in</strong>fection may present with<br />

a large variety of primary <strong>and</strong> secondary (caused by opportunistic<br />

<strong>in</strong>fections) ocular manifestations, some of those have threaten<strong>in</strong>g<br />

potential to vision <strong>and</strong> life quality. The <strong>in</strong>cidence <strong>and</strong> presentation of<br />

the AIDS epidemic <strong>and</strong> its correlated complications have dramatically<br />

changed s<strong>in</strong>ce the <strong>in</strong>troduction of the potent antiretroviral therapies<br />

(also know as highly active antiretroviral therapy, or HAART), but<br />

rema<strong>in</strong>s as a dramatic public health <strong>in</strong> very low <strong>in</strong>come countries.<br />

DED appears to be much more prevalent among <strong>in</strong>dividuals with<br />

AIDS (21.4-38.8% of HIV-<strong>in</strong>fected men, 16.9% of HIV-<strong>in</strong>fected women)<br />

than <strong>in</strong> the general population (13,26,27) . Burt<strong>in</strong> et al. evaluated the ocular<br />

surface <strong>and</strong> DED compla<strong>in</strong>s <strong>in</strong> a group of HIV positive patients. Accord<strong>in</strong>g<br />

to this study, 70% of them had compla<strong>in</strong>ed of DED symptoms,<br />

85% present at least one cl<strong>in</strong>ical sign of ocular surface dysfunction<br />

tested through Schirmer test, tear break-up time <strong>and</strong> lissam<strong>in</strong>e sta<strong>in</strong><br />

<strong>and</strong> the impression cytology revealed a decrease <strong>in</strong> the number of<br />

dendritic cells (28) .<br />

Geier et al. showed that decreased tear production occurs <strong>in</strong><br />

ap proximately 20% to 25% of patients with HIV <strong>in</strong>fection without<br />

correlation with the CD4+v lymphocites blood count, or to the severity<br />

of HIV disease, <strong>in</strong> a group of 144 HIV patients (29) . Although the<br />

entire pathogenesis of the aqueous tear deficiency <strong>in</strong> HIV-<strong>in</strong>fected<br />

rema<strong>in</strong> unclear, it may be associated with lymphocytic <strong>in</strong>filtration <strong>and</strong><br />

destruction of the lacrimal gl<strong>and</strong> ac<strong>in</strong>i <strong>and</strong> ducts.<br />

In fact, a Sjögren’s syndrome-like picture may be present <strong>in</strong> HIV<br />

-<strong>in</strong>fected patients who develop the diffuse <strong>in</strong>filtrative lymphocytosis<br />

syndrome (DILS). Thus, it is an exclusion criteria for <strong>in</strong>dividuals under<br />

<strong>in</strong>vestigation for Sjögren syndrome (30) . DILS is a disorder <strong>in</strong> patients<br />

with HIV <strong>in</strong>fection that is characterized by the enlargement of salivary<br />

<strong>and</strong> lacrimal gl<strong>and</strong>s <strong>and</strong> a vary<strong>in</strong>g <strong>in</strong>tensity of DED symptoms. In addition,<br />

DILS is accompanied by persistent circulat<strong>in</strong>g <strong>and</strong> <strong>in</strong>filtration of<br />

CD8-positive lymphocytes. DILS may mimic Sjögren’s syndrome <strong>in</strong><br />

Table 1. Major characteristics of virus associated to dry eye disease<br />

Virus Type Major cl<strong>in</strong>ical manifestation<br />

HTLV Retrovirus (Oncornavirus) Adult T-cell leukemia/lymphoma<br />

Neuromyelopathy<br />

Major ocular<br />

manifestation<br />

Uveitis<br />

Dry eye<br />

Transmission<br />

Blood <strong>and</strong> blood products transfusion,<br />

breastfeed<strong>in</strong>g; sexual <strong>in</strong>tercourse<br />

HIV Retrovirus (Lentivirus) Acquired immunodeficiency syndrome Dry eye Sexual <strong>in</strong>tercourse; blood <strong>and</strong> blood products<br />

transfusion; maternal fetal; <strong>in</strong>jection drug users;<br />

HCV<br />

RNA virus<br />

(Flavivirus)<br />

Hepatitis<br />

Cirrhosis<br />

Liver failure<br />

Hepatocellular carc<strong>in</strong>oma<br />

Extrahepatic manifestations (e.g. gl<strong>and</strong>ular, renal,<br />

dermatological, hematological, jo<strong>in</strong>ts)<br />

EBV DNA virus (Herpesvirus) Infectious mononucleosis<br />

Burkitt’s lymphoma<br />

Nasophar<strong>in</strong>geal carc<strong>in</strong>oma<br />

Ret<strong>in</strong>opathy<br />

Scleritis<br />

Keratitis<br />

Dry eye<br />

Dry eye<br />

Injection drug users; blood <strong>and</strong> blood products<br />

transfusion; <strong>needle</strong>stick <strong>in</strong>juries <strong>in</strong> health care<br />

sett<strong>in</strong>gs; sexual <strong>in</strong>tercourse (rare); maternal fetal<br />

(rare); contam<strong>in</strong>ated <strong>needle</strong>s <strong>and</strong> <strong>in</strong>struments<br />

(tattoo, pierc<strong>in</strong>gs)<br />

Exchang<strong>in</strong>g of saliva<br />

Direct contact<br />

HSV-1 DNA virus (Herpesvirus) Mucocutaneous lesions<br />

(typical oral <strong>and</strong> sk<strong>in</strong> watery blisters)<br />

Men<strong>in</strong>gitis, encephalitis, Bell’s palsy<br />

Keratitis<br />

Blepharitis<br />

Conjunctivitis<br />

Uveitis<br />

Ret<strong>in</strong>itis<br />

Direct contact<br />

HTLV= human T-cell lymphotropic virus; HIV= human immunodeficiency virus; HCV= hepatitis C virus; EBV= Epste<strong>in</strong>-Barr virus; HSV-1= herpes simplex virus-1.<br />

130 Arq Bras Oftalmol. 2013;76(2):129-32

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