Seroprevalence of HTLV-I and HTLV-II among a cohort of HIV-infected women and women at risk for HIV infection. Women's Interagency HIV Study

Pseudotyping of HIV-1 with Human T-Lymphotropic Virus 1 (HTLV-1) Envelope Glycoprotein during HIV-1-HTLV-1 Coinfection Facilitates Direct HIV-1 Infection of Female Genital Epithelial Cells: Implications for Sexual Transmission of HIV-1

Female genital epithelial cells cover the genital tract and provide the first line of protection against infection with sexually transmitted pathogenic viruses. These cells normally are impervious to HIV-1. We report that coinfection of cells by HIV-1 and another sexually transmitted virus, human T-lymphotropic virus 1 (HTLV-1), led to production of HIV-1 that had expanded cell tropism and was able to directly infect primary vaginal and cervical epithelial cells. HIV-1 infection of epithelial cells was blocked by neutralizing antibodies against the HTLV-1 envelope (Env) protein, indicating that the infection was mediated through HTLV-1 Env pseudotyping of HIV-1. Active replication of HIV-1 in epithelial cells was demonstrated by inhibition with anti-HIV-1 drugs. We demonstrated that HIV-1 derived from peripheral blood of HIV-1-HTLV-1-coinfected subjects could infect primary epithelial cells in an HTLV-1 Env-dependent manner. HIV-1 from subjects infected with HIV-1 alone was not able to infect epithelial cells. These results indicate that pseudotyping of HIV-1 with HTLV-1 Env can occur in vivo Our data further reveal that active replication of both HTLV-1 and HIV-1 is required for production of pseudotyped HIV-1. Our findings indicate that pseudotyping of HIV-1 with HTLV-1 Env in coinfected cells enabled HIV-1 to directly infect nonpermissive female genital epithelial cells. This phenomenon may represent a risk factor for enhanced sexual transmission of HIV-1 in regions where virus coinfection is common.IMPORTANCE Young women in certain regions of the world are at very high risk of acquiring HIV-1, and there is an urgent need to identify the factors that promote HIV-1 transmission. HIV-1 infection is frequently accompanied by infection with other pathogenic viruses. We demonstrate that coinfection of cells by HIV-1 and HTLV-1 can lead to production of HIV-1 pseudotyped with HTLV-1 Env that is able to directly infect female genital epithelial cells both in vitro and ex vivo Given the function of these epithelial cells as genital mucosal barriers to pathogenic virus transmission, the ability of HIV-1 pseudotyped with HTLV-1 Env to directly infect female genital epithelial cells represents a possible factor for increased risk of sexual transmission of HIV-1. This mechanism could be especially impactful in settings such as Sub-Saharan Africa and South America, where HIV-1 and HTLV-1 are both highly prevalent.

Human T-lymphotropic Virus Co-infections in Adults Infected With Human Immunodeficiency Virus

INTRODUCTION

Human T-lymphotropic virus type 1 or 2 (HTLV-1/2) co-infection in patients infected with the human immunodeficiency virus (HIV) can lead to increased morbidity. Because HTLV-1/2 shares a similar transmission route with HIV, HTLV-1/2 infection may be more prevalent in HIV-infected individuals. However, rates of HTLV-1/2 co-infection among HIV-infected individuals have not been studied recently in the United States.

MATERIALS AND METHODS

We conducted a cross-sectional study using serum from 292 HIV-infected subjects from one clinic in Virginia. Serum samples were tested for co-infection with HTLV-1/2 by commercial ELISA; positive results were then confirmed via western blot, which also differentiated between HTLV-1 and -2.

RESULTS

Seven (2.4%) of the subjects were co-infected with HTLV-2. One subject (among the seven co-infected with HTLV-2) was co-infected with HTLV-1 (0.3%). The only demographic factor significantly associated with HTLV-2 infection was history of intravenous drug abuse (p=0.002).

CONCLUSIONS

While our results are limited to a single city, our low rates of co-infection do not support routine screening for HTLV-1/2 co-infection among HIV-infected individuals in the United States.

Hepatitis C virus and human T-lymphotropic virus coinfection: epidemiological, clinical, laboratory and histopathological features

Twenty-four hepatitis C virus patients coinfected with human T-lymphotropic virus type 1 were compared with six coinfected with HTLV-2 and 55 with HCV alone, regarding clinical, epidemiological, laboratory and histopathological data. Fischer's discriminant analysis was applied to define functions capable of differentiating between the study groups (HCV, HCV/HTLV-1 and HCV/HTLV-2). The discriminant accuracy was evaluated by cross-validation. Alcohol consumption, use of intravenous drugs or inhaled cocaine and sexual partnership with intravenous drug users were more frequent in the HCV/HTLV-2 group, whereas patients in the HCV group more often reported abdominal pain or a sexual partner with hepatitis. Coinfected patients presented higher platelet counts, but aminotransferase and gamma-glutamyl transpeptidase levels were higher among HCV-infected subjects. No significant difference between the groups was seen regarding liver histopathological findings. Through discriminant analysis, classification functions were defined, including sex, age group, intravenous drug use and sexual partner with hepatitis. Cross-validation revealed high discriminant accuracy for the HCV group.

Modulation of infection and type 1 cytokine expression parameters by morphine during in vitro coinfection with human T-cell leukemia virus type I and HIV-1

Infection of injection drug users (IDUs) with the human T-cell leukemia viruses (HTLVs) or HIV is considerably higher than in the non-IDU population. Also, coinfection with HIV-1 and HTLV type I (HTLV-I) occurs more frequently. There is little or no information on the effects of opiates (i.e., morphine) on HTLV infection alone or on coinfection of HTLV-I-infected cells with HIV-1. Therefore, in this report, we analyzed the in vitro effects of morphine on HIV or HTLV infection alone as well as on dual infection with HTLV-I and HIV-1. Morphine decreased the in vitro levels of interferon-gamma (IFN gamma) and IL-2 during single infections, and this effect was reversed by the addition of the opioid antagonist naloxone. In contrast, treatment with morphine resulted in a 31% and 36% increase in IFN gamma and IL-2 levels, respectively, during dual infection. In addition, naloxone had an apparent additive effect on the morphine-associated enhancement of IFN gamma and IL-2 expression in the dual-infection model. Despite the high levels of IFN gamma expression, the viability of the coinfected cells in the presence of morphine was maintained. Importantly, morphine treatment was associated with augmented viral reverse transcription activity in dually infected cultures, apparently to the benefit of HTLV-I. If a similar putative morphine-induced advantage for HTLV-I production also occurs during in vivo coinfection, opiates such as morphine could contribute to the observed increased rate of HIV-1/HTLV-I infection in the IDU population in a more direct fashion than was previously believed.

Immune response and virus population composition: HIV as a case study

Based on the current understanding of the immune response, we present what we believe to be a new model of intrahost virus dynamics. The model takes into account the relationship between virus replication rate and the level of antigen displayed by infected cells, and shows how the cell-directed immune response controls both virus load and virus replication rate. In contrast to conventional wisdom, it shows that the predominant virus variant does not necessarily have the highest replication rate. A strong immune response produces a selective advantage for latent viruses, whereas a deteriorating immune response invites in viruses of higher replication rates. The model is analysed in light of the well-studied HIV/AIDS disease progression, and shows how a wide range of major, seemingly unrelated issues in the study of HIV may be accounted for in a simple and unified manner.

Seroprevalence and demographic characteristics of HTLV-I among blood donors in Taiwan: 1996-1999

Screening for the human T-cell lymphotropic virus type I (HTLV-I) and-II in blood donors was implemented in Taiwan beginning in February 1996. The purpose of the present study was to investigate the changes in HTLV-I seroprevalence in all unpaid blood donors in Taiwan during the period from February 1996 to December 1999 and to determine the influence of age and sex on the HTLV-I seropositivity of donors. HTLV-I and HTLV-II screening was performed using combined HTLV-I/II immunoassay. Repeated reactive samples were confirmed by Western blot analysis. Of a total of 3,701,087 donors in all 6 blood centers in Taiwan, 2,311 (0.058%) were seropositive for HTLV-I. The HTLV-I seropositivity was 0.130%, 0.063%, 0.044%, and 0.032% in the years 1996, 1997,1998, and 1999, respectively. There was a linear increase of HTLV-I seropositivity with advancing age. The HTLV-I carrier rate for female donors was twice that for the male donors. Ninty-seven percent of HTLV-I seropositive results came from first-time donors. Our findings suggest that Taiwan is a low-prevalence nonendemic area for HTLV-I infection. The large-scale HTLV-I screening program has decreased HTLV-I seropositivity among blood donors and is useful for preventing HTLV-I transmission via blood transfusion.

HTLV-1 and HTLV-2 infections in HIV-infected individuals from Santos, Brazil: seroprevalence and risk factors

Because HTLV-I, HTLV-2, and HIV share identical modes of transmission, simultaneous or subsequent infections with these retroviruses are to be expected. The population of Santos, the largest port in Latin America, includes large numbers of female commercial sex workers and intravenous drug users, presumably having been exposed to retroviral infection. To evaluate the seroprevalence of HTLV infection and their associated risk factors, a cross-sectional survey was carried out in 499 HIV-infected individuals from Santos, Brazil. HTLV testing consisted of enzyme immunoassays for serologic screening and confirmatory Western blot testing. Overall HTLV-I and HTLV-2 seroprevalences were 6.0% (95% confidence interval [CI], 3.9-8.1) and 7.4% (95% CI, 5.1-9.7), respectively. Multivariate logistic regression for statistical analysis revealed HTLV-I infection to be independently associated with: intravenous drug use (IDU) (odds ratio [OR]. 2.99; 95% CI, 1.09-8.20), seropositivity to hepatitis C virus (HCV) (OR, 3.03; 95% CI, 1.02-9.01) and < 3 years of education (OR, 4.73; 95% CI, 1.56-14.41). HTLV-2 infection was associated with: IDU (OR, 3.22; 95% CI, 1.33-7.84), HCV seropositivity (OR, 5.40; 95% CI, 1.86-15.66) and nonwhite race (OR, 3.32; 95% CI, 1.58-7.00). Results indicate that HIV-infected individuals living in Santos are at similarly high risk of being exposed to HTLV-1 and HTLV-2. IDU constitutes the main risk factor for HTLV acquisition in this population, and there is no significant risk associated with sexual practice.