Concluding Remarks for Special Issue HTLV-HIV Co-Infections

During the early 1980s, the first 3 human retroviruses were identified: human T-lymphotropic virus 1 and 2 (HTLV-1 and HTLV-2) and human immunodeficiency virus (HIV) [...].

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.

Visceral leishmaniasis as an independent cause of high immune activation, T-cell senescence, and lack of immune recovery in virologically suppressed HIV-1-coinfected patients

OBJECTIVES

Different immune alterations have been described in HIV-infected patients with visceral leishmaniasis (VL). We aimed to identify the immunological factors involved in the lack of immunological recovery and VL relapses in HIV-infected patients with VL, by comparison with other HIV-infected patients.

METHODS

We carried out a cross-sectional study of 55 patients receiving suppressive combination antiretroviral therapy (cART) for at least 1 year: nine with previous relapsing VL, 20 with an immunodiscordant response (IDR) to cART (CD4 count < 200 cells/μL) and no previous VL, and 26 with a concordant response (CR) to cART (CD4 count > 350 cells/μL) without VL. Immunosenescence was investigated by analysing CD57(+) CD28(-) levels, immune activation by analysing CD38(+) HLA-DR(+) levels, inflammation by analysing interleukin (IL)-6 levels, and microbial translocation by analysing lipopolysaccharide (LPS) and soluble CD14 (sCD14) levels.

RESULTS

In VL patients, the median time since VL diagnosis was 42 months, and all patients had had at least one relapse despite suppressive cART for a median time of 43 months. Patients with previously diagnosed VL had a higher CD8 T-cell activation level (P < 0.001) than those with IDR. Also, levels of IL-6, LPS and especially sCD14, associated with bacterial translocation and additional monocyte activation, were significantly increased in patients with previous VL compared with patients with IDR (P = 0.048, P = 0.049 and P < 0.001, respectively). In addition, patients with previous VL had higher levels of CD8 T-cell senescence. Notably, the levels of immune activation and inflammation in patients with previous VL were not related to the time of VL diagnosis, the number of VL relapses, or hepatitis C virus (HCV) coinfection.

CONCLUSIONS

Our data demonstrate that VL patients had an even worse immunological status than patients with IDR, which was probably associated with increased microbial translocation and additional monocyte/macrophage activation. These data explain the observed lack of immunological recovery and the occurrence of VL relapses in HIV-infected patients with previous VL.

High levels of CD4⁺ CTLA-4⁺ Treg cells and CCR5 density in HIV-1-infected patients with visceral leishmaniasis

Visceral leishmaniasis (VL) in HIV-1-infected patients has been associated with poor immunological recovery and frequent disease relapses. The aim of this study was to analyse the role of T cell populations, Treg cells and CCR5 density in patients with VL compared to HIV-1-infected patients without leishmaniasis. A cross-sectional study of nine Leishmania-HIV-1-coinfected (LH) patients with VL receiving suppressive cART for at least 1 year were compared to 16 HIV-1-infected patients with non-immunological response (NIR, CD4 count below 250 cells/mm(3)) and 26 HIV-1-infected patients with immunological response (IR, CD4 count above 500 cells/mm(3)) without leishmaniasis. LH patients had a deep depletion of naïve T cells (p = 0.002), despite similar levels of effector T cells compared to NIR patients. CD4 Treg cells were similar compared to NIR patients, but higher compared to IR patients (p < 0.001). Interestingly, CD4 Treg CTLA-4(+) cells were higher in LH patients compared to either NIR or IR patients (p = 0.022 and p < 0.001, respectively), and the CD4 Treg/TEM ratio was similar to NIR patients, but higher compared to IR patients (p = 0.017). CCR5(+) T cell levels were higher compared to IR patients (p < 0.001), while CCR5 density on T cells were higher compared to both NIR and IR patients (p < 0.005 in both cases). Higher levels of CD4(+) CTLA-4(+) Treg cells and CCR5 density on CD8(+) T cells are strongly associated with VL in HIV-1-infected patients. Also, these patients have a poor immunological profile that might explain the persistence and relapse of the pathogen.

Expression of gut-homing β7 receptor on T cells: surrogate marker for microbial translocation in suppressed HIV-1-infected patients?

OBJECTIVES

In view of the fact that mucosal damage associated with HIV-1 infection leads to microbial translocation despite successful antiretroviral treatment, we analysed microbial translocation and expression of the gut-homing β7 receptor on peripheral T cells in HIV-1-infected individuals.

METHODS

Fifteen long-term suppressed HIV-1-infected patients, of whom seven had their treatment intensified with maraviroc and eight with raltegravir, were included in the study. Samples at baseline, at week 48 of intensification, and at weeks 12 and 24 after deintensification were analysed for soluble CD14, lipopolysaccharide (LPS), LPS-binding protein, gut-homing β7 receptor and T-cell subsets.

RESULTS

The increases in both microbial translocation and expression of the gut-homing β7 receptor on activated CD8 T cells found during maraviroc intensification were reduced after deintensification. Moreover, the correlations between activated β7(+) T cells and LPS levels found during intensification with maraviroc (P = 0.036 and P = 0.010, respectively) were lost during deintensification. In contrast, microbial translocation was stable during raltegravir intensification, with the exception of decreased LPS levels and activated CD4 β7(+) T cells, which reverted to baseline values after deintensification.

CONCLUSIONS

Microbial translocation is an important factor in gut immune activation and mucosa inflammation, as evidenced by the association between the dynamics of microbial translocation and activated T cells expressing the gut-homing β7 receptor. The recruitment of activated β7(+) T cells to the gut tract when alteration of microbial translocation is maximum may be the major mechanism for recovery of mucosal integrity.

CD8 TCR β chain repertoire expansions and deletions are related with immunologic markers in HIV-1-infected patients during treatment interruption

BACKGROUND

HIV-1-infected individuals progressively loss CD4(+) T cells leading to immunosuppression and raising the risk of opportunistic infections. CD8(+) T-cells play an important role in the immune response against virus infections through their TCR.

OBJECTIVE

To evaluate the CD8-TCR repertoire and immunologic markers in HIV-1-infected patients.

STUDY DESIGN

Ten chronic HIV-1-infected individuals on prolonged effective antiretroviral treatment (ART) were analyzed at baseline (before treatment interruption), after at least one year of treatment interruption (TI) and after at least one year from ART resume (TR). Twenty-four TCR-Vβ gene families were analyzed by a modified CDR3 spectratyping method in isolated CD8(+) T-cells. Immune activation, exhaustion and subpopulation markers were analyzed by flow cytometry.

RESULTS

Expansion of Vβ10, Vβ14 and Vβ15 families, associated with low cell activation and stable exhaustion markers, were found at TI. Moreover, an increment of effector memory cells was found. Besides, depletion of Vβ20, Vβ28, and Vβ29 families, associated with an increase in cell activation and exhaustion markers, at TI were also found. These alterations seemed to be more pronounced in patients who had longer time from diagnosis. ART seemed to restore altered CD8(+) T-cell repertoire and most of the immunologic markers.

CONCLUSIONS

During TI (that was more pronounced in patients with longer HIV-1 infection) it was observed the expansion of Vβ families correlated with decreased cell activation, while Vβ families correlated with cell activation and exhaustion were depleted. These specific repertoire alterations reverted after ART resume.

Prevalence and resistance mutations of non-B HIV-1 subtypes among immigrants in Southern Spain along the decade 2000-2010

Background

Most of the non-B HIV-1 subtypes are predominant in Sub-Saharan Africa and India although they have been found worldwide. In the last decade, immigration from these areas has increased considerably in Spain. The objective of this study was to evaluate the prevalence of non-B subtypes circulating in a cohort of HIV-1-infected immigrants in Seville, Southern Spain and to identify drug resistance-associated mutations.

Methods

Complete protease and first 220 codons of the reverse transcriptase coding regions were amplified and sequenced by population sequencing. HIV-1 subtypes were determined using Stanford University Drug Resistance Database, and phylogenetic analysis was performed comparing multiple reported sequences. Drug resistance mutations were defined according to the International AIDS Society-USA.

Results

From 2000 to 2010 a total of 1,089 newly diagnosed HIV-1-infected patients were enrolled in our cohort. Of these, 121 were immigrants, of which 98 had ethical approval and informed consent to include in our study. Twenty-nine immigrants (29/98, 29.6%) were infected with non-B subtypes, of which 15/29 (51.7%) were CRF02-AG, mostly from Sub-Saharan Africa, and 2/29 (6.9%) were CRF01-AE from Eastern Europe. A, C, F, J and G subtypes from Eastern Europe, Central-South America and Sub-Saharan Africa were also present. Some others harboured recombinant forms CRF02-AG/CRF01-AE, CRF2-AG/G and F/B, B/C, and K/G, in PR and RT-coding regions. Patients infected with non-B subtypes showed a high frequency of minor protease inhibitor resistance mutations, M36I, L63P, and K20R/I. Only one patient, CRF02_AG, showed major resistance mutation L90M. Major RT inhibitor resistance mutations K70R and A98G were present in one patient with subtype G, L100I in one patient with CRF01_AE, and K103N in another patient with CRF01_AE. Three patients had other mutations such as V118I, E138A and V90I.

Conclusions

The circulation of non-B subtypes has significantly increased in Southern Spain during the last decade, with 29.6% prevalence, in association with demographic changes among immigrants. This could be an issue in the treatment and management of these patients. Resistance mutations have been detected in these patients with a prevalence of 7% among treatment-naïve patients compared with the 21% detected among patients under HAART or during treatment interruption.