Prevention and control of HIV/AIDS in China: lessons from the past three decades.

ABSTRACT: In the past 37 years, human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) has undergone various major transmission routes in China, with the world most complex co-circulating HIV-1 subtypes, even the prevalence is still low. In response to the first epidemic outbreak of HIV in injecting drug users and the second one by illegal commercial blood collection, China issued the Anti-Drug Law and launched the Blood Donation Act and nationwide nucleic acid testing, which has avoided 98,232 to 211,200 estimated infections and almost ended the blood product-related infection. China has been providing free antiretroviral therapy (ART) since 2003, which covered >80% of the identified patients and achieved a viral suppression rate of 91%. To bend the curve of increasing the disease burden of HIV and finally end the epidemic, China should consider constraining HIV spread through sexual transmission, narrowing the gaps in identifying HIV cases, and the long-term effectiveness and safety of ART in the future.

IP-10 Promotes Latent HIV Infection in Resting Memory CD4+ T Cells via LIMK-Cofilin Pathway.

A major barrier to HIV eradication is the persistence of viral reservoirs. Resting CD4+ T cells are thought to be one of the major viral reservoirs, However, the underlying mechanism regulating HIV infection and the establishment of viral reservoir in T cells remain poorly understood. We have investigated the role of IP-10 in the establishment of HIV reservoirs in CD4+ T cells, and found that in HIV-infected individuals, plasma IP-10 was elevated, and positively correlated with HIV viral load and viral reservoir size. In addition, we found that binding of IP-10 to CXCR3 enhanced HIV latent infection of resting CD4+ T cells in vitro. Mechanistically, IP-10 stimulation promoted cofilin activity and actin dynamics, facilitating HIV entry and DNA integration. Moreover, treatment of resting CD4+ T cells with a LIM kinase inhibitor R10015 blocked cofilin phosphorylation and abrogated IP-10-mediated enhancement of HIV latent infection. These results suggest that IP-10 is a critical factor involved in HIV latent infection, and that therapeutic targeting of IP-10 may be a potential strategy for inhibiting HIV latent infection.

Elevated CD54 Expression Renders CD4+ T Cells Susceptible to Natural Killer Cell-Mediated Killing.

BACKGROUND: Natural killer (NK) cells are an important type of effector cell in the innate immune response, and also have a role in regulation of the adaptive immune response. Several studies have indicated that NK cells may influence CD4+ T cells during HIV infection. METHODS: In total, 51 HIV-infected individuals and 15 healthy controls participated in this study. We performed the flow cytometry assays and real-time PCR for the phenotypic analysis and the functional assays of NK cell-mediated deletion of CD4+ T cells, phosphorylation of nuclear factor-κB (NF-κB/p65) and the intervention of metformin. RESULTS: Here we detected high CD54 expression on CD4+ T cells in HIV-infected individuals, and demonstrate that upregulated CD54 is associated with disease progression in individuals infected with HIV. We also show that CD54 expression leads to the deletion of CD4+ T cells by NK cells in vitro, and that this is modulated by NF-κB/p65 signaling. Further, we demonstrate that metformin can suppress CD54 expression on CD4+ T cells by inhibiting NF-κB/p65 phosphorylation. CONCLUSIONS: Our data suggest that further studies to evaluate the potential role of metformin as adjunctive therapy to reconstitute immune function in HIV-infected individuals are warranted.

Rapid CD4+ T-cell decline is associated with coreceptor switch among MSM primarily infected with HIV-1 CRF01_AE in Northeast China.

OBJECTIVE: CRF01_AE is the most prevalent HIV-1 subtype among MSM in China. However, the characteristics and underlying mechanism of the accelerated CD4 T-cell decline in CRF01_AE-infected MSM remain incompletely understood. DESIGN: A long-term prospective follow-up study was conducted with 1388 MSM at risk of HIV-1 infection in Northeast China. MSM with primary HIV-1 CRF01_AE infection were identified and followed for 3-6 years to explore the determinants of rapid CD4 T-cell decline. METHODS: Tropism was determined in primary infection by both single genome amplification-based genotypic prediction using four different algorithms and phenotypic determination using clinical isolates. Serial isolates were used to determine phenotype of coreceptor switch. Human leukocyte antigen genotypes and T-cell activation markers were determined. RESULTS: Fifty-nine MSM primarily infected with HIV-1 CRF01_AE were discovered and recruited for the follow-up study. CCR5-utilizing (R5) viruses accounted for up to 98% of HIV-1 CRF01_AE infections in Northeast China. Survival analysis indicated 39.5% of the patients underwent coreceptor switch within 3 years after infection. After adjustment for other potential risk factors, linear mixed-effect models demonstrated patients experienced R5 to CXCR4-utilizing/dual-tropic (X4/DM) coreceptor switch within 3 years after infection underwent a faster CD4 T-cell decline compared to those without coreceptor switch. CONCLUSIONS: Primary HIV-1 CRF01_AE infection among MSM in Northeast China is characterized by R5 viral infection and early R5 to X4/DM coreceptor switch, which is associated with rapid CD4 T-cell decline. The findings highlight the importance of immediate treatment among the CRF01_AE-infected MSM.

Alteration of CCR6+CD95+CD4+ naïve T cells in HIV-1 infected patients: Implication for clinical practice.

The profound deficiency of Th17 cells contributes to HIV disease progression. The mechanisms of their perturbation remain unclear. Recently, CCR6+CD95+CD4+ naïve T cells (CCR6+CD95+CD4+ TNA), identified as pre-committed Th17 precursors, were recognized as a subpopulation of CD4+ T cells with stem cell properties. Following phenotypical identification, we evaluated their level in patients during chronic HIV infection and following antiretroviral therapy (ART) using flow cytometry. The levels of CCR6+CD95+CD4+ TNA were decreased during chronic HIV infection and correlated with CD4+ T cell counts. Immunological responders harbored higher frequency of CCR6+CD95+CD4+ TNA, which was associated with CD4/CD8 T cell ratio. Immunological non-responders with lower frequency of CCR6+CD95+CD4+ TNA failed to exhibit a correlation between CCR6+CD95+CD4+ TNA and CCR6+CD95+CD4+ TCM, and displayed elevated ratio of CCR6+CD95+CD4+ TCM/TNA. The number of CCR6+CD95+CD4+ TNA was increased following early ART. These findings shed light on the importance of targeting pre-committed Th17 precursors that enhance immune reconstitution.

AID recruits the RNA exosome to degrade HIV-1 nascent transcripts through interaction with the Tat-P-TEFb-TAR RNP complex.

Activation-induced cytidine deaminase (AID), a member of the APOBEC family that induces antibody diversification, has been shown to inhibit the replication of hepatitis B virus, Kaposi's sarcoma-associated herpesvirus, and retro-transposons. However, whether AID can inhibit human immunodeficiency virus 1 (HIV-1) replication remains unclear. Here, we report that AID impairs the synthesis of HIV-1 components by interacting with the complex of Tat. This interaction recruits the RNA exosome to degrade the nascent HIV-1 transcript. AID also targets the HIV-1-integrated genome via the Tat-P-TEFb-TAR complex. Thus, we propose a novel function for AID as an adaptor protein that represses viral transcription. Our findings provide insights into developing anti-HIV therapeutics and understanding how host cells restrict integrated virus replication.

Low CD1c + myeloid dendritic cell counts correlated with a high risk of rapid disease progression during early HIV-1 infection.

BACKGROUND: During early HIV-1 infection (EHI), the interaction between the immune response and the virus determines disease progression. Although CD1c + myeloid dendritic cells (mDCs) can trigger the immune response, the relationship between CD1c + mDC alteration and disease progression has not yet been defined. METHODS: EHI changes in CD1c + mDC counts, surface marker (CD40, CD86, CD83) expression, and IL-12 secretion were assessed by flow cytometry in 29 patients. RESULTS: When compared with the normal controls, patients with EHI displayed significantly lower CD1c + mDC counts and IL-12 secretion and increased surface markers. CD1c + mDC counts were positively correlated with CD4+ T cell counts and inversely associated with viral loads. IL-12 secretion was only positively associated with CD4+ T cell counts. Rapid progressors had lower counts, CD86 expression, and IL-12 secretion of CD1c + mDCs comparing with typical progressors. Kaplan-Meier analysis and Cox regression models suggested patients with low CD1c + mDC counts (<10 cells/µL) had a 4-fold higher risk of rapid disease progression than those with high CD1c + mDC counts. However, no relationship was found between surface markers or IL-12 secretion and disease progression. CONCLUSIONS: During EHI, patients with low CD1c + mDC counts were more likely to experience rapid disease progression than those with high CD1c + mDC counts.

Transcriptomic analysis of peripheral blood mononuclear cells in rapid progressors in early HIV infection identifies a signature closely correlated with disease progression.

BACKGROUND: A substantial percentage (10%-15%) of HIV-infected individuals experience a sharp decline in CD4(+) T-cell counts and progress to AIDS quickly after primary infection. Identification of biomarkers distinguishing rapid progressors (RPs) vs chronic progressors (CPs) is critical for early clinical intervention and could provide novel strategies to facilitate vaccine design and immune therapy. METHODS: mRNA and microRNA (miRNA) expression profiles in the peripheral blood mononuclear cells (PBMCs) of RPs and CPs were investigated at 111 (22) days [mean (SD)] of HIV infection. The association of mRNA and miRNA expression with disease progression was examined by ROC analysis and Kaplan-Meier survival analysis. RESULTS: Pathway enrichment analysis showed that genes with deregulated expression in RPs were primarily involved in apoptosis pathways. Furthermore, we found that 5 miRNAs (miR-31, -200c, -526a, -99a, and -503) in RPs were significantly decreased compared to those in CPs (P < 0.05). The decreased expression of these miRNAs was associated with a rapid disease of progression of HIV infection with a 94% predictive value as measured by the area under the curve. The upregulated predicted targets from the 5 signature miRNAs and all upregulated genes identified from mRNA microarray analysis converged to the apoptosis pathway. Moreover, overexpression of miR-31 in primary human T cells promoted their survival. CONCLUSIONS: Our results have identified a distinct transcriptomic signature in PBMCs of RPs and provided novel insights to the pathogenesis of HIV infection.

Identification and characterization of broadly cross-reactive neutralizing antibodies in patients infected with HIV-1 B'/C recombinant (CRF07_BC).

The identification of broadly cross-reactive neutralizing (BCN) antibodies is essential for the development of a more universally effective vaccine for human immunodeficiency virus (HIV). In this study, CRF07_BC serum was analyzed for cross-clade antibody reactivity and neutralization. A total of 117 HIV-1 sera (CRF07_BC) were screened for their capacity to neutralize three primary HIV-1 isolates. A total of 18 out of 117 sera cross-neutralized all three viruses, and were tested along with eight randomly selected non-BCN sera against seven primary HIV-1 isolates and two laboratory strains that represented different clades and tropisms. BCN sera neutralized eight or all nine of these primary isolates. Non-BCN sera did not display any broadly cross-reactive neutralizing responses. BCN sera neutralized with higher frequency and geometric mean titers compared to non-BCN sera. Sera from asymptomatic individuals on average neutralized a significantly greater number of the three key isolates than sera from symptomatic individuals. Our data indicate that the three HIV-1 isolated strains are sufficient to screen broad cross-neutralizing sera, and that BCN responses may contribute to protection from infection and disease progression. The neutralizing antibody response demonstrated extensive cross-neutralization, suggesting that neutralizing antibodies induced by vaccines will have a relatively low epitope diversity to overcome in patients infected with HIV-1 B'/C recombinant (CRF07_BC).

R-848 triggers the expression of TLR7/8 and suppresses HIV replication in monocytes.

BACKGROUND: Toll-like receptors (TLR) 7 and 8 are important in single-stranded viral RNA recognition and may play a role in HIV infection and disease progression. We analyzed TLR7/8 expression and signaling in monocytes from HIV-infected and uninfected subjects to investigate a pathway with new potential for the suppression of HIV replication. METHODS: Eighty-one HIV-infected and uninfected subjects from Liaoning and Henan provinces in China participated in this study. Monocytes were isolated from subjects' peripheral blood mononuclear cells by magnetic bead selection. TLR7 and TLR8 mRNA was measured using quantitative real-time reverse transcriptase PCR. R-848 (resiquimod) was used as a ligand for TLR7 and TLR8 in order to 1) assess TLR7/8-mediated monocyte responsiveness as indicated by IL-12 p40 and TNF-α secretion and 2) to examine HIV replication in cultured monocytes in the presence of R-848. RESULTS: We found that expression of TLR7/8 mRNA in peripheral blood monocytes decreased with disease progression. TLR7 expression was decreased with stimulation with the TLR7/8 agonist, R-848, in vitro, whereas TLR8 expression was unaffected. Following R-848 stimulation, monocytes from HIV-infected subjects produced significantly less TNF-α than those from uninfected subjects, but trended towards greater production of IL-12 than stimulated monocytes from uninfected subjects. R-848 stimulation also suppressed HIV replication in cultured monocytes. CONCLUSIONS: Our study provides evidence that the TLR7 and TLR8 triggering can suppress HIV replication in monocytes and lead to postpone HIV disease progression, thereby offering novel targets for immunomodulatory therapy.

Rapid disease progression in HIV-1-infected men who have sex with men is negatively correlated with peripheral plasmacytoid dendritic cell counts at the early stage of primary infection.

To explore the relationship between absolute dendritic cell (DC) counts at the early stage of primary human immunodeficiency virus type 1 (HIV-1) infection (PHI) and subsequent disease progression, we performed a prospective study of 16 rapid progressors (RPs) and 12 typical progressors (TPs) from a PHI cohort of men who have sex with men. Significantly decreased plasmacytoid DC (pDC) and myeloid DC (mDC) counts in the blood of RPs were observed at study entry as compared with TPs and healthy HIV-1-negative subjects. Low baseline pDC counts were significantly associated with rapid disease progression after adjustment for baseline CD4(+) T cell counts, mDC counts, and HIV-1 load. Kaplan-Meier survival analysis showed that low pDC counts were strongly associated with rapid disease progression. Our findings demonstrated the predictive value of blood absolute pDC counts at baseline in PHI for HIV-1 disease progression. Further studies are required to confirm this notion.

The associations of hA3G and hA3B mRNA levels with HIV disease progression among HIV-infected individuals of China.

OBJECTIVE: To explore correlations between mRNA (hA3G, hA3F, and hA3B) levels and CD4 T-cell counts and HIV-1 viral loads to evaluate their respective roles in disease progression. METHODS: Real-time polymerase chain reaction was used to quantify the mRNA levels of hA3G, hA3B, and hA3F in peripheral blood mononuclear cells from slow progress patients (SP), asymptomatic HIV-infected patients (AS), AIDS patients, and HIV-negative controls. RESULTS: The levels of hA3G and hA3B mRNA correlated positively with CD4 T-cell counts (r = 0.436, P = 0.002, r = 0.334, P = 0.025), and negatively with HIV-1 viral loads (r = -0.306, P = 0.038, r = -0.301 P = 0.044). The levels of hA3G and hA3B mRNA in HIV-infected subjects were lower than in HIV-negative controls (P < 0.05), and hA3G and hA3B mRNA levels were significantly higher in SP than in AIDS patients (P < 0.05). There was no correlation between the hA3F mRNA level and CD4 T-cell counts or between the hA3F mRNA level and HIV-1 viral loads. CONCLUSIONS: Higher expression levels of hA3G and hA3B mRNA in the peripheral blood mononuclear cells of Chinese HIV-infected individuals were found to be associated with slower HIV disease progression, suggesting their potential roles in antiviral innate immunity.

[Resistance to HIV-1 infection of CD4 + T lymphocytes in vitro from chinese HIV-1 exposed seronegative individuals].

OBJECTIVE: To determine the relative resistance to HIV-1 infection of CD4 + T lymphocytes in HIV-exposed seronegative individuals (ESNs) in China. METHODS: HIV primary isolates were obtained from peripheral whole blood of HIV-infected persons. CD4 + T lymphocytes of Chinese ESNs were separated from peripheral blood mononuclear cells with magnetic cell sorting (MACS). The purified CD4 + T lymphocytes were cocultured with HIV primary isolates. The p24 level was detected and the culture medium was refreshed every 3 days within 2 weeks. RESULTS: For M tropic HIV strains, p24 level was significantly lower in ESN group than in control group (P < 0.05); for some M tropic HIV strains, even no p24 replicated in ESN group. However, T tropic virus strains had no significant difference between these two groups (P > 0.05). CONCLUSION: CD4 + T lymphocytes of Chinese ESNs may possess relative resistance to M tropic HIV strains, which may be one of the main influencing factors that result in ESN.