Studies on the allostimulatory function of dendritic cells from HCV-HIV-1 co-infected patients

There is increasing recognition of the potential morbidity and mortality associated with HIV- 1 and hepatitis C (HCV) co-infection. HIV appears to adversely affect HCV disease while the reciprocal effect of HCV on HIV remains controversial.We therefore studied the effect of co-infection on dendritic cell function versus HIV infection alone, as previous work has shown that HCV impairs dendritic cell (DC) function. HIV-1 positive individuals with HCV were matched for CD4 count, HIV-1 RNA viral load and therapy, to HIV-1 positive patients without HCV. Monocyte-derived DC were generated and mixed leukocyte reactions were performed. We assessed allostimulatory capacity with and without administration of exogenous Thl cytokines, using thymidine uptake and cell division analyses with the vital dye CFSE. We found that monocyte-derived DC from co-infected individuals showed no significant differences in allostimulatory capacity to ex vivo generated DC from HIV-1 infected individuals without HCV. Unlike the situation with HCV infection alone, this impairment was not reversed by increasing concentrations of either interleukin-2 or -12. Monocyte-derived DC from HIV- 1 and HCV co-infected individuals have a similar allostimulatory capacity to DC from matched patients with HIV-1 alone. These findings are compatible with results of prior clinical studies that found no evidence that HCV co-infection altered HIV disease progression and has implications for immunotherapeutic approaches in co-infected individuals.     

Relationship of HLA-A, -Cw Polymorphisms with HIV/AIDS in Chinese Yi Ethnic Group of Sichuan Province1

The relationship of HLA-A, -Cw alleles on HIV infection and AIDS disease progression in the Chinese Yi ethnic group of Sichuan province were investigated. The genetic polymorphisms of HLA-A, -Cw alleles of 102 unrelated healthy Chinese Yi ethnic individuals, 68 HIV-1 infected and 21 HIV positive long-time survivors were typed by PCR-SSP assay. Statistic signifiance was determined by the χ^2 test with the SPSS software. No significant differences were observed between the HLA-A, -Cw alleles of the 68 HIV-1 infected and 102 non-infected Chinese Yi control individuals. Whereas the prevalence of A＊3601,Cw＊14（01-03）and Cw＊0304 was significantly higher in 21 long time survivors compared with 102 healthy controls with P values of 0.016, 0.016 and 0.000 by χ^2 or the Fisher exact test respectively. The result implies that A＊3601,Cw＊14（01-03） and Cw＊0304 may be associated with slow AIDS disease progression in the Chinese Yi ethnic group, further studies on this association may yield insight on the pathogenesis of HIV-1 infection.     

HIV and HCV： from Co-infection to Epidemiology, Transmission, Pathogenesis, and Treatment

Human immunodeficiency virus (HIV) is the infectious agent causing acquired immu-nodeficiency syndrome (AIDS),a deadliest scourge of human society. Hepatitis C virus (HCV) is a major causative agent of chronic liver disease and infects an estimated 170 million people worldwide,resulting in a serious public health burden. Due to shared routes of transmission,co-infection with HIV and HCV has become common among individuals who had high risks of blood exposures. Among hemophiliacs the co-infection rate accounts for 85%; while among injection drug users (IDU) the rate can be as high as 90%. HIV can accelerate the progression of HCV-related liver disease,particularly when immunodeficiency has developed. Although the effect of HCV on HIV infection is controversial,most studies showed an increase in mortality due to liver disease. HCV may act as a direct cofactor to fasten the progression of AIDS and decrease the tolerance of highly active antiretroviral therapy (HARRT). Conversely,HAART-related hepatotoxicity may enhance the progression of liver fibrosis. Due to above complications,co-infection with HCV and HIV-1 has imposed a critical challenge in the management of these patients. In this review,we focus on the epidemiology and transmission of HIV and HCV,the impact of the two viruses on each other,and their treatment.     

Roles of HIV-1 auxiliary proteins in viral pathogenesis and host-pathogen interactions

Active host-pathogen interactions take place during infection of human immunodeficiency virus type 1 （HIV-1）. Outcomes of these interactions determine the efficiency of viral infection and subsequent disease progression. HIV-infected cells respond to viral invasion with various defensive strategies such as innate, cellular and humoral immune antiviral mechanisms. On the other hand, the virus has also developed various offensive tactics to suppress these host cellular responses. Among many of the viral offensive strategies, HIV-1 viral auxiliary proteins （Tat, Rev, Nef, Vif, Vpr and Vpu） play important roles in the host-pathogen interaction and thus have significant impacts on the outcome of HIV infection. One of the best examples is the interaction of Vif with a host cytidine deaminase APOBEC3G. Although specific roles of other auxiliary proteins are not as well described as Vif-APOBEC3G interaction, it is the goal of this brief review to summarize some of the preliminary findings with the hope to stimulate further discussion and investigation in this exhilarating area of research.     

Binding of HIV-1 virions to α_4β_7 expressing cells and impact of antagonizing α_4β_7 on HIV-1 infection of primary CD4~+ T cells

HIV-1 envelope glycoprotein is reported to interact with α4β7, an integrin mediating the homing of lymphocytes to gut-associated lymphoid tissue, but the significance of α4β7 in HIV-1 infection remains controversial. Here, using HIV-1 strain Ba L, the gp120 of which was previously shown to be capable of interacting with α4β7, we demonstrated that α4β7 can mediate the binding of whole HIV-1 virions to α4β7-expressing transfectants. We further constructed a cell line stably expressing α4β7 and confirmed the α4β7-mediated HIV-1 binding. In primary lymphocytes with activated α4β7 expression, we also observed significant virus binding which can be inhibited by an anti-α4β7 antibody. Moreover, we investigated the impact of antagonizing α4β7 on HIV-1 infection of primary CD4+ T cells. In α4β7-activated CD4+ T cells, both anti-α4β7 antibodies and introduction of shorthairpin RNAs specifically targeting α4β7 resulted in a decreased HIV-1 infection. Our findings indicate that α4β7 may serve as an attachment factor at least for some HIV-1 strains. The established approach provides a promising means for the investigation of other viral strains to understand the potential roles of α4β7 in HIV-1 infection.     

Binding of HIV-1 virions to α4β7 expressing cells and impact of antagonizing α4β7 on HIV-1 infection of primary CD4+ T cells

HIV-1 envelope glycoprotein is reported to interact with α4β7, an integrin mediating the homing of lymphocytes to gut-associated lymphoid tissue, but the significance of α4β7 in HIV-1 infection remains controversial. Here, using HIV-1 strain Ba L, the gp120 of which was previously shown to be capable of interacting with α4β7, we demonstrated that α4β7 can mediate the binding of whole HIV-1 virions to α4β7-expressing transfectants. We further constructed a cell line stably expressing α4β7 and confirmed the α4β7-mediated HIV-1 binding. In primary lymphocytes with activated α4β7 expression, we also observed significant virus binding which can be inhibited by an anti-α4β7 antibody. Moreover, we investigated the impact of antagonizing α4β7 on HIV-1 infection of primary CD4+ T cells. In α4β7-activated CD4+ T cells, both anti-α4β7 antibodies and introduction of shorthairpin RNAs specifically targeting α4β7 resulted in a decreased HIV-1 infection. Our findings indicate that α4β7 may serve as an attachment factor at least for some HIV-1 strains. The established approach provides a promising means for the investigation of other viral strains to understand the potential roles of α4β7 in HIV-1 infection.     

＂Unconventional＂ Neutralizing Activity of Antibodies Against HIV

Neutralizing antibodies are recognized to be one of the essential elements of the adaptive immune response that must be induced by an effective vaccine against HIV. However,only a limited number of antibodies have been identified to neutralize a broad range of primary isolates of HIV-1 and attempts to induce such antibodies by immunization were unsuccessful. The difficulties to generate such antibodies are mainly due to intrinsic properties of HIV-1 envelope spikes,such as high sequence diversity,heavy glycosylation,and inducible and transient nature of certain epitopes. In vitro neutralizing antibodies are identified using "conventional" neutralization assay which uses phytohe-magglutinin (PHA)-stimulated human PBMCs as target cells. Thus,in essence the assay evaluates HIV-1 replication in CD4 T cells. Recently,several laboratories including us demonstrated that some monoclonal antibodies and HIV-1-specific polyclonal IgG purified from patient sera,although they do not have neutralizing activity when tested by the "conventional" neutralization assay,do exhibit potent and broad neutralizing activity in "unconventional" ways. The neutralizing activity of these antibodies and IgG fractions is acquired through post-translational modifications,through opsonization of virus particles into macrophages and immature dendritic cells (iDCs),or through expression of antibodies on the surface of HIV-1-susceptible cells. This review will focus on recent findings of this area and point out their potential applications in the development of preventive strategies against HIV.     

NKT cells in HIV-1 infection

Natural killer T （NKT） cells are a unique T cell population that have important immunoregulatory functions and have been shown to be involved in host immunity against a range of microorganisms. It also emerges that they might play a role in HIV-1 infection, and therefore be selectively depleted during the early stages of infection. Recent studies are reviewed regarding the dynamics of NKT depletion during HIV-1 infection and their recovery under highly active antiretroviral treatment （HAART）. Possible mechanisms for these changes are proposed based on the recent developments in HIV pathogenesis. Further discussions are focused on HIV＇s disruption of NKT activation by downregulating CDld expression on antigen presentation cells （APC）. HIV-1 protein Nefis found to play the major role by interrupting the intracellular trafficking of nascent and recycling CDld molecules.     

The role of monocyte-lineage cells in human immuno-deficiency virus persistence: mechanisms and progress

Human immunodeficiency virus type 1(HIV-1) persistence is a major barrier to the successful treatment and eradication of acquired immunodeficiency syndrome(AIDS).In addition to resting CD4+ T cells,a significant long-lived compartment of HIV-1 infection in vivo includes blood monocytes and tissue macrophages.Studying HIV-1 persistence in monocyte-lineage cells is critical because these cells are important HIV-1 target cells in vivo.Monocyte-lineage cells,including monocytes,dendritic cells(DCs) and macrophages,play a significant role in HIV-1 infection and transmission.These cells have been implicated as viral reservoirs that facilitate HIV-1 latency and persistence.A better understanding of HIV-1 interactions with monocyte-lineage cells can potentially aid in the development of new approaches for intervention.This minireview highlights the latest advances in understanding the role of monocyte-lineage cells in HIV-1 persistence and emphasizes new insights into the mechanisms underlying viral persistence.     

Downregulation of CD4＋CD25＋ regulatory T cells may underlie enhanced Th1 immunity caused by immunization with activated autologous T cells

Regulatory T cells （Treg） play important roles in immune system homeostasis, and may also be involved in tumor immunotolerance by suppressing Th1 immune response which is involved in anti-tumor immunity. We have previously reported that immunization with attenuated activated autologous T cells leads to enhanced anti-tumor immunity and upregulated Thl responses in vivo. However, the underlying molecular mechanisms are not well understood. Here we show that Treg function was significantly downregulated in mice that received immunization of attenuated activated autologous T cells. We found that Foxp3 expression decreased in CD4＋CD25＋ T cells from the immunized mice. Moreover, CD4＋CD25＋Foxp3＋ Treg obtained from immunized mice exhibited diminished immunosuppression ability compared to those from naive mice. Further analysis showed that the serum of immunized mice contains a high level ofanti-CD25 antibody （about 30 ng/ml, p〈0.01 vs controls）. Consistent with a role ofanti-CD25 response in the downregulation of Treg, adoptive transfer of serum from immunized mice to naive mice led to a significant decrease in Treg population and function in recipient mice. The triggering of anti-CD25 response in immunized mice can be explained by the fact that CD25 was induced to a high level in the ConA activated autologous T cells used for immunization. Our results demonstrate for the first time that immunization with attenuated activated autologous T cells evokes anti-CD25 antibody production, which leads to impeded CD4＋CD25＋Foxp3＋ Treg expansion and function in vivo. We suggest that dampened Treg function likely contributes to enhanced Thl response in immunized mice and is at least part of the mechanism underlying the boosted anti-tumor immunity.     

Frequency and Absolute Number of FoxP3+ Regulatory T Cells Correlate with Disease Progression of Chronic HIV-1 Infection

CD4+CD25+ Regulatory T cells (Treg) have been found to down-regulate immune activation in HIV-1 infection. However, whether the depletion of Treg benefits to the disease status of HIV infection remains undefined. To address this issue, we enumerated the Treg absolute counts and frequency in 75 antiviral-na(i)ve HIV-1-infected individuals in this study. It was found that HIV-infected patients displayed a significant decline in Treg absolute counts but a significant increase in Treg frequency. In addition, with disease progression indicated by CD4 T-cell absolute counts, circulating Treg frequency gradually increased; while Treg absolute counts were gradually decreased, suggesting that the alteration of Treg number closely correlated with disease progression in HIV infection.Functional analysis further showed that Treg efficiently inhibit both CD4 and CD8 T cell proliferation in vitro. Thus, our findings indicates that Treg actively participate in pathogenesis of chronic HIV infection,influencing the disease progression.     

Frequency and absolute number of FoxP3<Superscript>+</Superscript> regulatory T cells correlate with disease progression of chronic HIV-1 infection

CD4⁺CD25⁺ Regulatory T cells (Treg) have been found to down-regulate immune activation in HIV-1 infection. However, whether the depletion of Treg benefits to the disease status of HIV infection remains undefined. To address this issue, we enumerated the Treg absolute counts and frequency in 75 antiviral-naïve HIV-1-infected individuals in this study. It was found that HIV-infected patients displayed a significant decline in Treg absolute counts but a significant increase in Treg frequency. In addition, with disease progression indicated by CD4 T-cell absolute counts, circulating Treg frequency gradually increased; while Treg absolute counts were gradually decreased, suggesting that the alteration of Treg number closely correlated with disease progression in HIV infection. Functional analysis further showed that Treg efficiently inhibit both CD4 and CD8 T cell proliferation in vitro. Thus, our findings indicates that Treg actively participate in pathogenesis of chronic HIV infection, influencing the disease progression.     

CD39/adenosine pathway is involved in AIDS progression

HIV-1 infection is characterized by a chronic activation of the immune system and suppressed function of T lymphocytes. Regulatory CD4+ CD25(high) FoxP3+CD127(low) T cells (Treg) play a key role in both conditions. Here, we show that HIV-1 positive patients have a significant increase of Treg-associated expression of CD39/ENTPD1, an ectoenzyme which in concert with CD73 generates adenosine. We show in vitro that the CD39/adenosine axis is involved in Treg suppression in HIV infection. Treg inhibitory effects are relieved by CD39 down modulation and are reproduced by an adenosine-agonist in accordance with a higher expression of the adenosine A2A receptor on patients' T cells. Notably, the expansion of the Treg CD39+ correlates with the level of immune activation and lower CD4+ counts in HIV-1 infected patients. Finally, in a genetic association study performed in three different cohorts, we identified a CD39 gene polymorphism that was associated with down-modulated CD39 expression and a slower progression to AIDS.     

GBV-C/HIV共感染对AIDS疾病进程和HIV病毒复制的影响

近年来,一些研究发现,GBV-C/HIV共感染可延缓HIV感染疾病的进程,然而也有一些研究得出不同的结论.本研究收集我国安徽省阜阳市HIV血清学阳性的既往献血员血浆标本,对其进行GBV-C感染的检测,研究GBV-C/HIV共感染与HIV病毒载量和CD4 T淋巴细胞绝对计数的关系.用RT-PCR和酶联免疫法检测,在203人中检出GBV-C感染52例,显示该人群GBV-C的感染率为25.6%,男性感染者(35例,67.3%)高于女性感染者(17例,32.7%).分析发现,GBV-C感染与未感染两组患者的CD4 T淋巴细胞绝对计数和HIV病毒载量数据均无统计学差异.本研究中的HIV-1感染者均未接受ART治疗,因而排除了治疗对疾病进展的影响.研究结果显示,在HIV-1感染晚期的献血人群,GBV-C/HIV共感染对CD4细胞和病毒复制水平无显著影响.由于本研究对象中无HIV-1早期感染者,因而不能判断GBV-C在HIV-1感染的早期对疾病进展有无影响.     

Human immunodeficiency virus type 1 Nef in human monocyte-like cell line THP-1 expands treg cells via toll-like receptor 2

CD4(+) CD25(+) regulatory T cells (Tregs) represent a unique T-cell lineage that is endowed with the ability to actively suppress immune responses in order to inhibit pathogenic damage resulting from over activation of the immune system. In human immunodeficiency virus-1 (HIV-1) infection, suppression of the immune response by Tregs appears to play an opposing role that promotes chronic viral infection. Treg expansion is known as a marker of the severity of HIV infection and as a potential prognostic marker of disease progression. HIV-1 Nef is one of the earliest expressed viral regulatory genes whose expression may play an important role in regulating Treg cells. We established a THP-1 cell line stably expressing HIV-1 Nef and showed that Nef protein was a potent factor for increasing Treg numbers in vitro. We further found that TLR2 plays a critical role in the increase in Treg cells induced by Nef using TLR2-specific siRNA. Our results suggest new strategies for therapeutic and preventive interventions of HIV infection.     

Plasma concentrations of transforming growth factor beta 1 in non-progressive HIV-1 infection correlates with markers of disease progression

The human immunodeficiency virus (HIV) infection shows variable rate of disease progression. The underlying biological and molecular mechanisms involved in determining progression of HIV infection are not fully understood. The aims of this study were to determine plasma concentrations of active TGF β 1, Th1 and Th2 cytokines in patients with non-progressive and those with progressive HIV-1 infection, as well as to determine if there is an association of these cytokines to disease progression. In a cross-sectional study of 61 HIV-1 infected individuals categorized according to disease progression as having non-progressive HIV-1 infection (n = 14) and progressive infection (n = 47), plasma levels of active TGF β 1, INF-γ, TNF-α, IL-10, IL-1β, IL-12p70 and IL-13 were compared with HIV uninfected healthy controls (n = 12). Plasma concentration of these cytokines was measured using a highly sensitive luminex200 XMAP assay. Pearson correlation test was used to assess the correlation of cytokines with CD4+ and CD8+ T cells, CD4:CD8 ratio and plasma HIV-1 RNA in the different study groups. Plasma concentrations of TGF β 1 and IL-10 were significantly decreased while IL-1β, IL-12p70 and TNF-α were increased in patients with non-progressive HIV-1 infection compared to patients with progressive infection. Plasma levels of TGF β 1 and IL-10 showed an inverse correlation with CD8+ T cell counts and CD4:CD8 ratios in patients with non-progressive HIV-1 infection, while plasma HIV-1 RNA positively correlated with CD4+ T cell counts. Plasma levels of TNF-α, IL-1β, IL-12p70 and IL-13 positively correlated with CD4+ T cell counts and inversely correlated with plasma HIV-1 RNA, CD8+ T cell count and CD4:CD8 ratio in patients with non-progressive infection. The correlation of cytokines to the state of T-lymphocyte and plasma HIV-1 RNA found in this study may provide insight into the role of cytokines in both progressive and non-progressive HIV-1 infection. Additionally, these findings may have implications for systemic cytokine-based therapies in HIV-1 infection.     

Comprehensive analysis of frequency and phenotype of T regulatory cells in HIV infection: CD39 expression of FoxP3+ T regulatory cells correlates with progressive disease

There are conflicting data about the frequency and role of regulatory T cells (Tregs) during the course of HIV infection. Peripheral blood of a large cohort of HIV-infected patients (n = 131) at different stages of disease, including 15 long-term nonprogressors and 21 elite controllers, was analyzed to determine the frequency and phenotype of Tregs, defined as CD4(+), CD25(high), CD127(low), FoxP3(high) cells. A significantly increased relative frequency of Tregs within the CD4(+) compartment of HIV(+) patients compared to that of healthy controls (P < 0.0001) was observed. Additionally, the relative frequency of Tregs directly correlated with HIV viral load and inversely with CD4(+) counts. However, the absolute Treg number was reduced in HIV-infected patients versus healthy controls (P < 0.0001), with the exception of elite controllers (P > 0.05). The loss of absolute Treg numbers coincided with rising markers of immune activation (P < 0.0006). The initiation of antiviral therapy significantly increased absolute Treg numbers (P < 0.0031). We find that the expression of CD39, a newly defined ectonucleotidase with immunomodulatory functions on Tregs, correlated with progressive HIV disease, HIV viral load, and immune activation. Of note, when tested in peripheral blood mononuclear cells of healthy volunteers, the in vitro capacity to suppress T-cell proliferation was limited to CD4(+), CD25(high), CD39(+) T cells. Interestingly, Tregs of elite controllers exhibited not only the highest expression of CCR5, CTLA-4, and ICOS but also the lowest level of CD39. The data presented here reconcile the seemingly contradictory results of previous studies looking at Tregs in HIV and highlight the complexity of Treg-mediated immunoregulation during human viral infections.     

Analysis of Suppressor and Non-Suppressor FOXP3+ T Cells in HIV-1-Infected Patients

Recently, it was shown that peripheral blood FOXP3+CD4+ T cells are composed of three phenotypic and functionally distinct subpopulations. Two of them having in vitro suppressive effects were characterized as resting Treg cells (rTregs) and activated Treg cells (aTregs). A third subset, identified as FOXP3+ non-Tregs, does not display any suppressor activity and produce high levels of Th1 and Th17 cytokines upon stimulation. In the present study we focus on the characteristics of these three subsets of FOXP3+CD4+ T cells in untreated HIV-1-infected patients. We found that the absolute counts of rTregs, aTregs and FOXP3+ non-Tregs were reduced in HIV-1 patients compared with healthy donors. The relative frequency of rTregs and aTregs was similar in HIV-1 patients and healthy donors, while the frequency of FOXP3+ non-Tregs was significantly higher in HIV-1 patients, reaching a maximum in those patients with the lower values of CD4 counts. Contrasting with the observations made in FOXP3- CD4+ T cells, we did not find a negative correlation between the number of rTregs, aTregs or FOXP3+ non-Tregs and virus load. Studies performed with either whole PBMCs or sorted aTregs and FOXP3+ non-Tregs cells showed that these two populations of FOXP3+ T cells were highly permissive to HIV-1 infection. Upon infection, FOXP3+ non-Tregs markedly down-regulates its capacity to produce Th1 and Th17 cytokines, however, they retain the ability to produce substantial amounts of Th2 cytokines. This suggests that FOXP3+ non-Tregs might contribute to the polarization of CD4+ T cells into a Th2 profile, predictive of a poor outcome of HIV-1-infected patients.     

High CCR5 Density on Central Memory CD4+ T Cells in Acute HIV-1 Infection Is Mostly Associated with Rapid Disease Progression

CD4+ central memory T cells play a critical role in the pathogenesis of simian immunodeficiency virus disease, and the CCR5 density on the surface of CD4 T cells is an important factor in human immunodeficiency virus (HIV)-1 disease progression. We hypothesized that quantifying central memory cells and CCR5 expression in the early stages of HIV-infection could provide useful prognostic information. We enrolled two different groups of acute HIV-infected subjects. One group progressed to CD4 T cell numbers below 250 cells/µl within 2 years (CD4 Low group), while the other group maintained CD4 cell counts above 450 cells/µl over 2 years (CD4 High group). We compared the CCR5 levels and percentage of CD4 subsets between the two groups during the 1st year of HIV infection. We found no differences between the two groups regarding the percentage of naïve, central memory and effector memory subsets of CD4 cells during the 1st year of HIV-1 infection. CCR5 levels on CD4+ CM subset was higher in the CD4 Low group compared with the CD4 High group during the 1st year of HIV-1 infection. High CCR5 levels on CD4 central memory cells in acute HIV infection are mostly associated with rapid disease progression. Our data suggest that low CCR5 expression on CD4 central memory cells protects CD4 cells from direct virus infection and favors the preservation of CD4⁺ T cell homeostasis.     

Acute Plasma Biomarkers of T Cell Activation Set-Point Levels and of Disease Progression in HIV-1 Infection

T cell activation levels, viral load and CD4⁺ T cell counts at early stages of HIV-1 infection are predictive of the rate of progression towards AIDS. We evaluated whether the inflammatory profile during primary HIV-1 infection is predictive of the virological and immunological set-points and of disease progression. We quantified 28 plasma proteins during acute and post-acute HIV-1 infection in individuals with known disease progression profiles. Forty-six untreated patients, enrolled during primary HIV-1 infection, were categorized into rapid progressors, progressors and slow progressors according to their spontaneous progression profile over 42 months of follow-up. Already during primary infection, rapid progressors showed a higher number of increased plasma proteins than progressors or slow progressors. The plasma levels of TGF-β1 and IL-18 in primary HIV-1 infection were both positively associated with T cell activation level at set-point (6 months after acute infection) and together able to predict 74% of the T cell activation variation at set-point. Plasma IP-10 was positively and negatively associated with, respectively, T cell activation and CD4⁺ T cell counts at set-point and capable to predict 30% of the CD4⁺ T cell count variation at set-point. Moreover, plasma IP-10 levels during primary infection were predictive of rapid progression. In primary infection, IP-10 was an even better predictor of rapid disease progression than viremia or CD4⁺ T cell levels at this time point. The superior predictive capacity of IP-10 was confirmed in an independent group of 88 HIV-1 infected individuals. Altogether, this study shows that the inflammatory profile in primary HIV-1 infection is associated with T cell activation levels and CD4⁺ T cell counts at set-point. Plasma IP-10 levels were of strong predictive value for rapid disease progression. The data suggest IP-10 being an earlier marker of disease progression than CD4⁺ T cell counts or viremia levels.