Hepatitis C virus/human T lymphotropic virus 1/2 co-infection: Regional burden and virological outcomes in people who inject drugs

A review of the influence of environmental pollutants (microplastics, pesticides, antibiotics, air pollutants, viruses, bacteria) on animal viruses

Microorganisms, especially viruses, cause disease in both humans and animals. Environmental chemical pollutants including microplastics, pesticides, antibiotics sand air pollutants arisen from human activities affect both animal and human health. This review assesses the impact of chemical and biological contaminants (virus and bacteria) on viruses including its life cycle, survival, mutations, loads and titers, shedding, transmission, infection, re-assortment, interference, abundance, viral transfer between cells, and the susceptibility of the host to viruses. It summarizes the sources of environmental contaminants, interactions between contaminants and viruses, and methods used to mitigate such interactions. Overall, this review provides a perspective of environmentally co-occurring contaminants on animal viruses that would be useful for future research on virus-animal-human-ecosystem harmony studies to safeguard human and animal health.

HTLV-2 Enhances CD8+ T Cell-Mediated HIV-1 Inhibition and Reduces HIV-1 Integrated Proviral Load in People Living with HIV-1

People living with HIV-1 and HTLV-2 concomitantly show slower CD4⁺ T cell depletion and AIDS progression, more frequency of the natural control of HIV-1, and lower mortality rates. A similar beneficial effect of this infection has been reported on HCV coinfection reducing transaminases, increasing the spontaneous clearance of HCV infection and delaying the development of hepatic fibrosis. Given the critical role of CD8⁺ T cells in controlling HIV-1 infection, we analysed the role of CD8⁺ T cell-mediated cytotoxic activity in coinfected individuals living with HIV-1. One hundred and twenty-eight individuals living with HIV-1 in four groups were studied: two groups with HTLV-2 infection, including individuals with HCV infection (N = 41) and with a sustained virological response (SVR) after HCV treatment (N = 25); and two groups without HTLV-2 infection, including individuals with HCV infection (N = 25) and with a sustained virological response after treatment (N = 37). We found that CD8⁺ T cell-mediated HIV-1 inhibition in vitro was higher in individuals with HTLV-2. This inhibition activity was associated with a higher frequency of effector memory CD8⁺ T cells, higher levels of granzyme A and granzyme B cytolytic enzymes, and perforin. Hence, cellular and soluble cytolytic factors may contribute to the lower HIV-1 pre-ART viral load and the HIV-1 proviral load during ART therapy associated with HTLV-2 infection. Herein, we confirmed and expanded previous findings on the role of HTLV-2 in the beneficial effect on the pathogenesis of HIV-1 in coinfected individuals.

Biomarkers in a Cohort of HIV-Infected Patients Single- or Co-Infected with HTLV-1, HTLV-2, and/or HCV: A Cross-Sectional, Observational Study

HIV, HTLV-1/-2, and HCV share routes of transmission, and such virus co-infections could account for worse outcomes of associated diseases. Measuring cytokines/chemokines, CD4 and CD8 T cells, and HIV viral load (VL) in HIV single-infected and co-infected individuals has prognostic value. We analyzed such biomarkers in 129 blood samples of HIV-infected individuals matched for age and sex and divided into six groups (G1 (69 HIV); G2 (9 HIV/HTLV-1); G3 (6 HIV/HTLV-2); G4 (11 HIV/HCV); G5 (19 HIV/HCV/HTLV-1); and G6 (15 HIV/HCV/HTLV-2)). Eight cytokines/chemokines from fifteen analytes could be compared. The highest levels of Th1 and pro-inflammatory cytokines were detected in G2 (IFN-γ) and G6 (IL-6 and IL1-β) and of chemokines in G1 (MIG, IP10, RANTES), G4 (MCP1), and G6 (MIP1-β). The highest CD4 cells number and the lowest HIV VL were identified in G3 and the opposite results in G2. Positive correlations between CD4 and CD8 cells counts and IL-6 levels were detected in G2 and G5 and of HIV VL and RANTES in G4. Negative correlations were detected between CD8 and IFN-γ in G4 and HIV VL and RANTES in G6. Despite the small number of the cohort analyzed, and although the cross-sectional study design does not allow firm conclusions, the homogeneity of the characteristics of HIV/HTLV-co-infected individuals regarding age, time and route of HIV acquisition, and criteria for introducing ART enable us to suggest a negative impact of HTLV-1 and a possible protective role of HTLV-2 in HIV infection progression in such patients.

HTLV-1 and Co-infections

Human T lymphotropic virus type 1 (HTLV-1) is a retrovirus that causes lifelong T-cell infection in humans, impacting the host immune response. This virus causes a range of clinical manifestations, from inflammatory conditions, including neuronal damage (HTLV-1 associated myelopathy, HAM) to life-threatening leukemia (adult T-cell leukemia, ATL). Human T lymphotropic virus type 1 is also associated with increased risk of all-cause mortality, but the mechanisms remain unclear. As a blood-borne and sexually transmitted infection (STI), HTLV-1 shares transmission routes to many other pathogens and although it has worldwide distribution, it affects mainly those in low- and middle-income tropical areas, where the prevalence of other infectious agents is high. These factors contribute to a high incidence of co-infections in people living with HTLV-1 (PLHTLV). This comprehensive review addresses the impact of HTLV-1 on several co-infections and vice-versa. There is evidence of higher rates of HTLV-1 infection in association with other blood borne (HCV, HBV) and sexually transmitted (Syphilis, Chlamydia, HPV, HSV) infections but whether this represents increased susceptibility or opportunity is unclear. Higher frequency of Mycobacterium tuberculosis (MTb) and Mycobacterium leprae (M. leprae) is observed in PLHTLV. Reports of opportunistic infections and high frequency of crusted scabies in patients with HTLV-1 points to immune impairment in those individuals. Human T lymphotropic virus type 1 may influence the persistence of pathogens, exemplified by the higher rates of Schistosoma mansoni and Strongyloides stercoralis (St. stercoralis) treatment failure observed in PLHTLV. This retrovirus is also associated with increased tuberculosis (TB) severity with some evidence pointing to a deleterious impact on leprosy outcome as well. These findings are supported by immune alterations observed in those co-infected individuals. Although the role of HTLV-1 in HCV outcome is debatable, most data indicate that HTLV may negatively impact the clinical course of hepatitis C. Co-infections may also influence the risk of developing HTLV-1 associated disease, but data are still limited. The impact of HTLV-1 on the response to more common infections, might contribute to the increased mortality rate of HTLV-1. Large scale prospective controlled studies on the prevalence and impact of HTLV-1 in co-infections and vice-versa are needed. Human T lymphotropic virus type 1 impact in public health is broad. Measures to increase awareness and to prevent new infections are needed.

The reasons to include the serology of human T-lymphotropic virus types 1 and 2 (HTLV-1 and HTLV-2) in the clinical follow-up of patients with viral hepatitis B and C in Brazil

Background

The WHO established targets for 2030 to globally reduce new viral hepatitis B and C infections by 90% and deaths by 65% and recommends searching for coinfections that increase the progression of chronic liver infections towards cirrhosis and hepatocellular carcinoma.

Aims and methodology

This study aimed to add information concerning the influence of human T-lymphotropic virus type 1 (HTLV-1) and type 2 (HTLV-2) infections in hepatitis B and C, since in Brazil, these human retroviruses are endemic but neglected. Serum samples from 1,910 patients with hepatitis B and 1,315 with hepatitis C from São Paulo, southeast Brazil, that were previously tested and grouped for HIV and HTLV-1/-2 coinfections were analyzed for hepatitis B virus (HBV) and hepatitis C virus (HCV) loads measurements and subsequent clearance using data from laboratory records.

Key results

Briefly, the lowest HBV viral load (VL) was detected in HBV/HTLV-2 coinfected patients, regardless of whether they were infected with HIV (all comparisons p<0.05). In contrast, higher HCV VL was detected in HCV/HIV, HCV/HIV/HTLV-1/-2 coinfected patients (all p<0.05), and the lowest HCV VL was detected in HCV/HTLV-2 coinfected patients. Curiously, 61.1% of the patients with HBV/HTLV-2 coinfection had an undetectable HBV VL at the beginning of the study versus 21.4% in the patients with HBV/HTLV-1 coinfection. Although the percentages of undetectable HCV loads in HCV/HTLV-1 and HCV/HTLV-2 coinfected patients were quite similar, during follow-up, more HCV clearance was detected in patients with HCV/HTLV-2 coinfection [OR 2.65; 95% IC (1.17–5.99)].

Major conclusions

HTLV-2 positively impacts HBV and HCV viral loads and HCV clearance, while HIV and/or HTLV-1 negatively impacts HCV viral load. Thus, the search for HTLV-1/-2 in viral hepatitis B and C infected patients has virological prognostic value, which is a strong reason to suggest including HTLV serology in the follow-up of patients.

The human T-lymphotropic viruses type 1 (HTLV-1) and type 2 (HTLV-2) are endemic and neglected in Brazil, and although these viruses were considered to have prognostic value when associated with HIV, e.g., HTLV-1 has been associated with fast progression and death to AIDS and more cases of lymphoma and neurological disorders, and HTLV-2 has been associated with slow progression to AIDS, their impact on hepatitis B virus (HBV) and hepatitis C virus (HCV) outcomes remain unknown. The present study analyzed the influence of HTLV-1 and HTLV-2 coinfection on HBV and HCV virological outcomes (viral load levels and virus clearance during follow-up) in serum samples from 1,910 patients with hepatitis B and 1,315 patients with hepatitis C from São Paulo, southeast Brazil. The results obtained confirmed the positive impact of HTLV-2 on HBV and HCV virological outcomes (lower HBV and HCV viral loads and increased HCV clearance when compared with HCV-monoinfected patients) and the opposite effect of HTLV-1; these findings are similar to the effects observed in HIV/AIDS patients. Taking into consideration these results and the differential impact of HTLV-1 and HTLV-2 in viral hepatitis B and C, we suggest including the serology of HTLV-1/2 in the follow-up of such patients in Brazil.

Neurological Aspects of HIV-1/HTLV-1 and HIV-1/HTLV-2 Coinfection

Simultaneous infection by human immunodeficiency viruses (HIV) and human T-lymphotropic viruses (HTLV) are not uncommon since they have similar means of transmission and are simultaneously endemic in many populations. Besides causing severe immune dysfunction, these viruses are neuropathogenic and can cause neurological diseases through direct and indirect mechanisms. Many pieces of evidence at present show that coinfection may alter the natural history of general and, more specifically, neurological disorders through different mechanisms. In this review, we summarize the current evidence on the influence of coinfection on the progression and outcome of neurological complications of HTLV-1/2 and HIV-1.

Surveillance of human retroviruses in blood samples from patients with hepatitis B and C in São Paulo, Brazil

INTRODUCTION

Human retroviruses and the hepatitis B and C viruses (HBV and HCV, respectively) share routes of transmission; thus, coinfections occur and could alter subsequent disease outcomes. A preliminary study on human T-lymphotropic virus types 1 and 2 (HTLV-1/2) in serum samples from HBV- and HCV-infected individuals in São Paulo revealed 1.3% and 5.3% rates of coinfection, respectively. These percentages were of concern since they were detected in HTLV-endemic regions and in high-risk individuals in Brazil. The present study was conducted to extend and confirm these data.

METHODS

HTLV-1/2 and human immunodeficiency virus (HIV) infection status were identified in 1,984 sera for HBV and HCV viral load quantification - 1,290 samples from HBV-infected individuals (53.3% men, mean age: 47.1 years) and 694 samples from HCV-infected individuals (56.3% men, mean age: 50.1 years). HTLV-1/2 antibodies were detected by enzyme immunoassay, followed by western blotting and line immunoassay; HIV infection was detected by enzyme immunoassay.

RESULTS

HTLV-1/-2 infection was detected in 1.9% HBV-infected individuals (0.7% HTLV-1 and 1.2% HTLV-2) and in 4.0% (2.4% HTLV-1 and 1.6% HTLV-2) HCV-infected individuals; HIV infection was detected in 9.2% and 14.5%, respectively. Strong associations with HTLV and HIV, male sex, and older age were found in HBV/HTLV and HCV/HTLV-coinfected individuals (p<0.05).

CONCLUSIONS

HTLV-1 and HTLV-2 were confirmed to be prevalent in individuals with HBV and HCV in São Paulo; coinfected individuals deserve further clinical and laboratory investigation.

Hepatitis C viral load in HCV-monoinfected and HCV/HIV-1-, HCV/HTLV-1/-2-, and HCV/HIV/HTLV-1/-2-co-infected patients from São Paulo, Brazil

Co-infections of hepatitis C virus (HCV) and either human immunodeficiency virus type 1 (HIV-1), human T-cell lymphotropic virus type 1 (HTLV-1) or type 2 (HTLV-2) have been described as having an impact on HCV viremia and subsequent disease progression. HCV load in serum samples from 622 patients (343 males, 279 females; median age 50.8 years) from São Paulo/southeast Brazil was analyzed using the Abbott Real Time HCV assay (Abbott Molecular Inc., IL, USA). Samples were obtained from HCV-monoinfected (n = 548), HCV/HIV-1- (n = 41), HCV/HTLV-1- (n = 16), HCV/HTLV-2- (n = 8), HCV/HIV/HTLV-1- (n = 4), and HCV/HIV/HTLV-2-co-infected (n = 5) patients, and results were compared among the groups and according to sex. The median HCV load in HCV-monoinfected patients was 5.23 log₁₀ IU/mL and 0.31 log₁₀ higher in men than in women. Increases in viral load of 0.51 log₁₀, 0.54 log₁₀, and 1.43 log₁₀ IU/mL were detected in HCV/HIV-1-, HCV/HTLV-1- and HCV/HIV/HTLV-1-co-infected individuals, respectively, compared with HCV-monoinfected counterparts. In contrast, compared to HCV/HIV co-infected patients, HCV/HTLV-2-co-infected patients had an HCV load of 5.0 log₁₀ IU/mL, whereas HCV/HIV/HTLV-2-co-infected patients had a median load 0.37 log₁₀ IU/mL lower. Significant differences in HCV loads were detected, with males and HCV/HIV-1- and HCV/HIV/HTLV-1-co-infected patients presenting the highest values. Conversely, females and HCV/HTLV-2-co-infected patients exhibited lower HCV loads. Overall, HCV viremia is increased in HIV and/or HTLV-1-co-infection and decreased in HTLV-2 co-infection.

Making the invisible visible: searching for human T-cell lymphotropic virus types 1 and 2 (HTLV-1 and HTLV-2) in Brazilian patients with viral hepatitis B and C

With this study, the authors hope to alert clinicians regarding the presence of human T-cell lymphotropic virus type 1 and 2 (HTLV-1/-2) infections in patients with viral hepatitis B and C in Brazil. HTLV-1/-2 were detected in 1.3% of hepatitis B virus (HBV)- and 5.3% of hepatitis C virus (HCV)-infected blood samples sent for laboratory viral load measurements. A partial association of human immunodeficiency virus (HIV)-1 and HTLV-1/-2 infection was detected in patients with HCV (HIV+, 27.3%), whereas this association was almost 100% in HBV-infected patients (HIV+, all except one). The high prevalence of HTLV-1/-2 infection among patients with hepatitis C was of concern, as HTLV-1/-2 could change the natural course of subsequent liver disease. The authors suggest including HTLV-1/-2 serology in the battery of tests used when following patients with viral hepatitis in Brazil, regardless of the HIV status.

Human T-lymphotropic virus type 1 infection and disease in Spain

: Human T-lymphotropic virus type 1 (HTLV-1) infection is a neglected disease despite roughly 15 million people are chronically infected worldwide. Lifelong less than 10% of carriers develop life-threatening diseases, mostly a subacute myelopathy known as tropical spastic paraparesis (TSP) and a lymphoproliferative disorder named adult T-cell leukemia (ATL). HTLV-1 is efficiently transmitted perinatally (breastfeeding), sexually (more from men to women) and parenterally (transfusions, injection drug user (IDU), and transplants). To date there is neither prophylactic vaccine nor effective antiviral therapy. A total of 327 cases of HTLV-1 infection had been reported at the HTLV-1 Spanish registry until December 2016, of whom 34 had been diagnosed with TSP and 25 with ATL. Overall 62% were Latin American immigrants and 13% were persons of African origin. The incidence of HTLV-1 in Spain has remained stable for nearly a decade with 20-25 new cases yearly. Of the 21 newly diagnosed HTLV-1 cases during year 2016, one was a native Spaniard pregnant woman, and four presented with symptomatic disease, including three with ATL and one with TSP. Underdiagnosis of HTLV-1 in Spain must be high (iceberg model), which may account for the disproportionate high rate of symptomatic cases (almost 20%) and the late recognition of preventable HTLV-1 transmissions in special populations, such as newborns and transplant recipients. Our current estimate is of 10 000 persons living with HTLV-1 infection in Spain. Given the large flux of immigrants and visitors from HTLV-1 endemic regions to Spain, the expansion of HTLV-1 screening policies is warranted. At this time, it seems worth recommending HTLV testing to all donor/recipient organ transplants and pregnant women regardless place of birth. Although current leukoreduction procedures largely prevent HTLV-1 transmission by blood transfusions, HTLV testing of all first-time donors should be cost-effective contributing to unveil asymptomatic unaware HTLV-1 carriers.

Hepatitis B virus and human T-cell lymphotropic virus type 1 co-infection in the Northern Territory, Australia

OBJECTIVE

To establish the relationship between hepatitis B virus (HBV) and human T-cell lymphotropic virus type 1 (HTLV-1) serological markers in the Northern Territory, Australia.

METHODS

A retrospective serological study of patients presenting to public healthcare facilities in the Northern Territory between 2008 and 2015 was performed in order to determine the presence and relationships of serological markers of HBV and HTLV-1.

RESULTS

Seven hundred and forty individual patients were found to be serologically positive for HTLV-1 in the Northern Territory over the 8-year period. Hepatitis B results were available for 521 of these patients. Hepatitis B surface antigen (HBsAg) positivity was demonstrated in 15.9% (83/521) of this cohort, which was significantly different to the HTLV-1-negative group (3.7%, 125/3354) (p<0.001). Excluding individuals with isolated hepatitis B surface antibody (anti-HBs), those in the HTLV-1-positive group had a higher HBV exposure history (67.5%, 352/521) when compared to HTLV-1-negative individuals (37.8%, 1259/3354) (p<0.001). HTLV-1-positive individuals had a lower prevalence of HBV combined anti-HBs and hepatitis B core antibody (anti-HBc) positive markers compared to those who were HTLV-1-negative (56.3% (198/352) versus 73.8% (937/1269), respectively; p<0.001).

CONCLUSIONS

A significantly higher prevalence rate of HBV was found in HTLV-1-positive individuals from the Northern Territory. When considering the higher exposure to HBV in HTLV-1-positive individuals, the clearance of HBV appears lower than in those individuals testing HTLV-1-negative. A lower prevalence of clearance in HTVL-1-positive individuals than in HTLV-1-negative individuals, as signified by formation of HBVcAb and HBVsAb in HTVL-1 positive individual's may equate to higher prevalence of ongoing coinfection.

HTLV infection in HCV-antibody positive patients in Spain

Since hepatitis C virus (HCV) and human T-lymphotropic virus (HTLV) share transmission routes, dual infection could be frequent. In Spain, HTLV underdiagnosis is highlighted by the high proportion of patients presenting either with tropical spastic paraparesis (TSP) or adult T-cell leukemia (ATL) at first diagnosis. We examined whether the renewed efforts for expanding HCV testing may provide a sentinel population that might selectively be targeted to unveil asymptomatic HTLV carriers. The presence of anti-HTLV antibodies was examined in 3,838 consecutive individuals with reactive HCV serology attended during the last three years at 13 hospitals distributed across the Spanish geography. Overall 71% were male and the median age was 41-years old. Foreigners represented 9% of the study population. A total of 50 individuals (1.3%) were seroreactive for HTLV, being 30 confirmed as HTLV-2 and two as HTLV-1 (0.12%). The remaining 18 had indeterminate Western blot patterns. Most individuals with HTLV-2 and HTLV indeterminate serology were HIV-positive, former injection drug users and native Spaniards. In contrast, the two HTLV-1 infections were found in men coming from Brazil and the Dominican Republic, respectively. In summary, the overall prevalence of HTLV infection in individuals living in Spain seropositive for HCV is 1.3%, more than 10-fold greater than in general outclinics in Spain. However, immigrants from HTLV-1 endemic regions and former injection drug users with HTLV-2 infection are by far the major contributory groups in HCV patients. Therefore, testing for HTLV in newly diagnosed HCV individuals would not contribute much to improve late HTLV diagnosis in Spain.

Family Aggregation of Human T-Lymphotropic Virus 1-Associated Diseases: A Systematic Review

Human T-lymphotropic virus 1 (HTLV-1) is a retrovirus that produces a persistent infection. Two transmission routes (from mother to child and via sexual intercourse) favor familial clustering of HTLV-1. It is yet unknown why most HTLV-1 carriers remain asymptomatic while about 10% of them develop complications. HTLV-1 associated diseases were originally described as sporadic entities, but familial presentations have been reported. To explore what is known about family aggregation of HTLV-1-associated diseases we undertook a systematic review. We aimed at answering whether, when, and where family aggregation of HTLV-1-associated diseases was reported, which relatives were affected and which hypotheses were proposed to explain aggregation. We searched MEDLINE, abstract books of HTLV conferences and reference lists of selected papers. Search terms used referred to HTLV-1 infection, and HTLV-1-associated diseases, and family studies. HTLV-1-associated diseases considered are adult T-cell leukemia/lymphoma (ATLL), HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), HTLV-1-associated uveitis, and infective dermatitis. Seventy-four records reported HTLV-1-associated diseases in more than one member of the same family and were included. Most reports came from HTLV-1-endemic countries, mainly Japan (n = 30) and Brazil (n = 10). These reports described a total of 270 families in which more than one relative had HTLV-1-associated diseases. In most families, different family members suffered from the same disease (n = 223). The diseases most frequently reported were ATLL (115 families) and HAM/TSP (102 families). Most families (n = 144) included two to four affected individuals. The proportion of ATLL patients with family history of ATLL ranged from 2 to 26%. The proportion of HAM/TSP patients with family history of HAM/TSP ranged from 1 to 48%. The predominant cluster types for ATLL were clusters of siblings and parent-child pairs and for HAM/TSP, an affected parent with one or more affected children. The evidence in the literature, although weak, does suggest that HTLV-1-associated diseases sometimes cluster in families. Whether familial transmission of HTLV-1 is the only determining factor, or whether other factors are also involved, needs further research.