抗病毒治疗早期艾滋病病人CD4+ T细胞亚群与免疫重建的关系

目的研究抗病毒治疗(ART)早期阶段,艾滋病(AIDS)病人CD4+T细胞亚群的变化及其与免疫重建的关系。方法前瞻性分析21例接受ART规律治疗的艾滋病病人,收集病人服药前及服药第2、4、8、12周时的静脉血,采用流式细胞仪染色技术检测CD4+T细胞的水平,分析其在治疗过程中的变化规律,以及与免疫活化间的相关性。结果 ART后,CD4中心记忆细胞(CD4CM)和CD4幼稚细胞两种形式的CD4+T细胞增加,且在前4周治疗增长迅速。治疗4周时CD4CM的变化与治疗12周时CD4+T细胞的变化呈正相关关系,而与CD8+CD3+8T细胞的变化呈负相关关系。结论 ART能有效地重建AIDS病人的T淋巴细胞免疫,并且CD4CM可能是免疫重建的早期指标。     

CD4+ and CD8+ T cell receptor repertoire perturbations with normal levels of T cell receptor excision circles in HIV-infected,therapy-naive adolescents

Our objective was to determine whether treatment-naive HIV-infected adolescents manifest abnormalities in thymus function and peripheral T cell repertoire, and to assess relationships of these immunologic characteristics with each other, with plasma HIV virus load, and T cell surface markers. TCR Vbeta repertoire was determined by CDR3 length spectratyping in purified CD4(+) and CD8(+) T cells of high-risk, HIV-negative adolescents and of treatment-naive, HIV-infected adolescents. Thymus function was investigated by the simultaneous examination of T cell receptor excision circles (TRECs) in the CD4(+) and CD8(+) T cell subsets. HIV-infected adolescents exhibited significantly greater perturbations in their TCR Vbeta repertoire in comparison with HIV-negative subjects. Perturbations in the CD8(+) T cell compartment were more profound in comparison with CD4(+) T cells. The CD4(+) TCR Vbeta perturbations were negatively correlated with the total and phenotypically naive CD4(+) T cells, and with CD4(+) TRECs. CD8(+) TRECs, although not correlated with CD8(+) TCR Vbeta perturbations, showed negative correlation with memory and activated CD8(+) T cells. Interestingly, TRECs in CD4(+) and CD8(+) T cells were not significantly different between HIV-infected and uninfected adolescents. The TCR Vbeta repertoire in adolescents is profoundly perturbed even in early stages of HIV infection, when total CD4(+) cell counts in most subjects are within normal limits. The correlative analyses demonstrating negative association of CD4(+) cell TRECs with CD4(+) TCR Vbeta perturbations and of CD8(+) TRECs with CD8(+) cell activation markers provide evidence of the intense activation of the central and peripheral immune compartments in this study population.     

CD38 expression on CD8 T cells has a weak association with CD4 T-cell recovery and is a poor marker of viral replication in HIV-1-infected patients on antiretroviral therapy

OBJECTIVE: The aim of the study was to determine whether the expression of CD38 on CD8 T cells can identify patients with virological failure on antiretroviral therapy (ART). DESIGN: This was a cross-sectional study of patients attending a single HIV clinic in London. METHODS: The expression of CD38 on CD8 T cells was assessed using a biologically calibrated flow cytometry protocol. Patients were characterized by lymphocyte subset and viral load measurements. Characteristics including historical CD4 T cell counts, therapeutic history, co-infections and demographics were obtained from medical records. RESULTS: Elevated levels of CD8 CD38(high) T cells were found in HIV-1-infected patients who failed to suppress viral replication with ART; however, this parameter lacked sufficient sensitivity and specificity to replace viral load testing in assessing the efficacy of ART. Increased levels of CD8 CD38(high) cells were associated with reduced CD4 T cell counts in HIV-1-infected patients on ART after correcting for known determinants of CD4 T-cell recovery. CONCLUSIONS: The expression of CD38 on CD8 T cells lacks sufficient sensitivity and specificity to be used as a surrogate marker for viral load to monitor HIV-1 infection. T-cell activation is associated with reduced CD4 T-cell reconstitution in patients receiving ART.     

Protease inhibitor therapy in HIV-infected children

We reviewed the short-term response to and safety of protease inhibitor (PI) therapy in HIV-infected children by performing a retrospective chart review of open-label PI containing combination therapy at two urban pediatric HIV centers. Seventy HIV-infected children received 101 PI containing antiretroviral therapy (ART) combinations. Main outcome measures were follow-up CD4 counts, viral loads, and patient or caregiver reported compliance. During follow-up, treatment with PI ART was associated with a mean maximal increase in CD4+ lymphocyte count of 454 x 10(6)/L and a mean maximal decrease in viral load of 1.76 log units. Of the 32 patients who achieved undetectable viral loads, 28 (87.5%) remained undetectable through a mean follow-up of 8.9 months. Patients who reported good compliance achieved a higher rate of response (92.6%) than those who reported poor compliance (61.5%). Of 14 changes made to a second PI because of treatment failure, 11 (78.6%) resulted in a positive response to the second regimen. Nineteen of 101 courses of PI therapy resulted in significant side effects, including renal complications in 8 of 21 patients treated with indinavir. PI ART was associated with substantial short-term improvement in immunological and virological parameters in this heavily pretreated cohort, with 40% of patients maintaining an undetectable viral load after 9 months of therapy. Patients who failed one PI regimen usually responded to a second regimen. There was a significant rate of side effects from PI treatment.     

Combination antiretroviral therapy results in a rapid increase in T cell receptor variable region beta repertoire diversity within CD45RA CD8 T cells in human immunodeficiency virus-infected children

Human immunodeficiency virus (HIV) type 1 disrupts the T cell receptor (TCR) variable region (V) beta repertoire in CD8 T cells by impairing thymic capacity and skewing postthymic cellular maturation. The TCR repertoire was examined using spectratyping of CDR3 length diversity within CD45RA and CD45RO CD8 T cells in HIV-infected and healthy children. In healthy children, CDR3 lengths displayed Gaussian distribution in both CD45RA and CD45RO subsets. Vbeta families in HIV-infected children displayed a large proportion of perturbations in both subsets. High virus load and advanced immunosuppression correlated with increased perturbations within CD45RA but not CD45RO CD8 T cells. After therapy and virus suppression, there was rapid reestablishment of Gaussian distributions in CD45RA cells. HIV-1-induced disruption of TCR diversity within CD45RA CD8 T cells correlates with disease progression. Suppression of viral replication by treatment results in the rapid correction of TCR diversity in this CD8 subset because of emergence of new T cells from the thymus.     

Virological phenotype switches under salvage therapy with lopinavir-ritonavir in heavily pretreated HIV-1 vertically infected children

OBJECTIVE: To investigate the effects of salvage therapy with lopinavir-ritonavir on HIV-1 phenotype in heavily antiretroviral experienced HIV-infected children. DESIGN: Twenty antiretroviral experienced HIV-infected children were studied during a mean of time of 16.1 months from initiation of the treatment with lopinavir-ritonavir. METHODS: Besides CD4 T cells, viral load and clinical status, we analyzed 91 serial viral isolates to study the phenotype, and biological clones derived from co-cultivation techniques. RESULTS: We observed an increase in CD4 T cells, a statistically significant decrease in viral load and clinical benefits from 3 months after treatment. Ninety per cent of children had SI/X4 bulk isolates in peripheral blood mononuclear cells at study entry. The viral phenotype changed to non syncitium-inducing (NSI)/R5 in 94% of the children after a mean of 5.7 months (95% confidence interval, 2.1-9.3 months) of salvage therapy. The remaining 10% of children had NSI/R5 isolates at entry and at all follow-up study. Similar results were found at the clonal level. Thus, at study entry in PBMC of three children with bulk syncitium-inducing (SI) phenotype, we recovered 65 biologic clones, 56 being SI and nine NSI. After salvage therapy bulk isolates changed to NSI and of 40 biologic clones recovered only five were SI and the rest were NSI. CONCLUSIONS: Our data suggest that lopinavir-ritonavir salvage therapy led not only to a viral load decrease but also to a phenotypic change. X4 virus appeared to be preferentially suppressed. Shifts in co-receptor usage may thereby contribute to the clinical efficacy of anti-HIV drugs in vertically infected infants.     

Immunological changes after highly active antiretroviral therapy with lopinavir-ritonavir in heavily pretreated HIV-infected children

We evaluated the effect of salvage antiretroviral therapy with lopinavir/ritonavir (LPV/r) on the immune system of heavily antiretroviral pretreated HIV-infected children. We carried out a longitudinal study in 20 antiretroviral experienced HIV-infected children to determine the changes in several immunological parameters (T cell subsets, thymic function) every 3 months during 18 months of follow-up on salvage therapy with LPV/r. Statistical analyses were performed with the Wilcoxon test, taking as a reference the basal value at the entry in the study. HIV-infected children showed an increase of CD4+ T cells, a decrease in CD8+ T cells, and an increase in T cell rearrangement excision circle (TRECs) levels. The percentage of HIV children with undetectable viral load (VL < or = 400 copies/ml) increased significantly (p = 0.007) and the percentage with SI viral phenotype decreased significantly (p = 0.002) at the end of the study. Thus, the viral phenotype changed to NSI/R5 after salvage therapy with LPV/r. Interestingly, we observed a significant decrease of memory (CD4+ CD45RO+) and a moderate decrease of activated (CD4+ HLA-DR+, CD4+ HLA-DR+CD38, CD4+, CD45RO+HLA-DR+) CD4+ T cells during the follow-up. On the other hand, memory (CD8+ CD45RO+ and CD8+ CD45RO+CD38+), activated (CD8+ HLA-DR+CD38+, CD8+ HLA-DR+, CD8+ CD38+), and effector (CD8+ CD57+, CD8+ CD28(-)CD57+) CD8+ T cells had a very significant decrease during follow-up. Our data indicate an immune system reconstitution in heavily pretreated HIV-infected children in response to salvage therapy with LPV/r as a consequence of a decrease in immune system activation and an increase in thymic function.     

Proportions of circulating T cells with a regulatory cell phenotype increase with HIV-associated immune activation and remain high on antiretroviral therapy

OBJECTIVE: To examine the relationships between blood CD4 natural regulatory T (Treg) cells, plasma HIV RNA level, CD4 T-cell count and immune activation in untreated HIV-infected patients and immunodeficient patients beginning antiretroviral therapy (ART), using a novel phenotype to define Treg cells (CD25CD127CD4). Data were compared with established Treg cell markers (FoxP3, CTLA-4 and GITR). METHODS: Twenty-nine untreated HIV-infected patients with CD4 T-cell counts of < 300 or > 400/microl were compared in a cross-sectional study and 12 patients beginning combination ART with < 100 CD4 T cells/mul were followed for 1 year on therapy. Three- and four-colour flow cytometry was used to quantitate proportions of Treg cells. RESULTS: In control donors and patients with high CD4 T-cell counts, 28-89% (median 60%) of CD25CD127CD4 cells were FoxP3, but < 10% expressed GITR or CTLA-4. Immunodeficient patients also had CD4-negative lymphocytes with the phenotype FoxP3CD127. Proportions of CD25CD127 cells and activated (HLA-DR) cells in the CD4 T-cell population were increased in patients with low CD4 T cell counts. The proportion of CD25CD127CD4 T cells correlated positively with plasma HIV RNA level and CD4 T-cell activation, but inversely with CD4 T-cell count. Longitudinal studies of 12 patients receiving ART in two distinct cohorts (Western Australia and Malaysia) showed that the proportion of CD25CD127CD4 cells decreased slightly over time, but remained above levels seen in non-HIV controls. CONCLUSIONS: Proportions of circulating T cells with a regulatory cell phenotype increase with HIV-associated immune activation and remain high after 1 year on ART.     

Discontinuation of potent antiretroviral therapy: predictive value of and impact on CD4 cell counts and HIV RNA levels.

OBJECTIVE: To characterize predictors and consequences of discontinuing antiretroviral therapy (ART) in terms of CD4 cell count, HIV RNA, and reported side-effects in a large cohort of HIV-infected women. DESIGN: Cohort study. METHODS: A total of 1058 HIV-infected women initiated potent ART before September 1999. For each 6 month period after October 1996 we determined the proportion of potent ART users who downshifted to non-potent ART and who discontinued all ART. We examined the role of CD4 cell count and HIV RNA with regard to ART discontinuation. RESULTS: Between October 1996 and September 1999, 1058 individuals contributed 3362 visits at which potent ART was reported in the previous 6 months. Overall rates of 6 month downshifting and discontinuation were 10.0% and 6.7%. The proportion of individuals discontinuing all ART increased from 2.9% in late 1996 to 9.1% in mid 1999 (P < 0.001). Individuals with high HIV RNA levels were more likely to discontinue (P < 0.05). Compared to those who continued on potent ART, individuals who discontinued experienced large declines (P < 0.001) in CD4 cell counts and were more than three times more likely (P < 0.001) to experience HIV RNA increases. However, over one-third of those discontinuing ART reported side-effects and this subset had smaller CD4 cell count declines as compared to discontinuers not reporting side-effects (P = 0.147). CONCLUSIONS: In a large cohort of HIV-infected women, an increasing proportion of potent ART users discontinued ART over 3 years. Higher HIV RNA levels predicted discontinuation. Immediate immunological/virological deleterious consequences were observed. Side-effects were the most common reason for discontinuation and CD4 cell count declines were larger among those who did not cite side-effects as the reason for discontinuation.     

Oligoclonal expansions of CD4+ and CD8+ T-cells in the target organ of patients with biliary atresia

BACKGROUND & AIMS: Biliary atresia is an inflammatory, fibrosclerosing neonatal cholangiopathy, characterized by a periductal infiltrate composed of CD4(+) and CD8(+) T cells. The pathogenesis of this disease has been proposed to involve a virus-induced, subsequent autoreactive T cell-mediated bile duct injury. Antigen-specific T-cell immunity involves clonal expansion of T cells expressing similar T-cell receptor (TCR) variable regions of the beta-chain (Vbeta). We hypothesized that the T cells in biliary atresia tissue expressed related TCRs, suggesting that the expansion was in direct response to antigenic stimulation. METHODS: The TCR Vbeta repertoire of T cells from the liver, extrahepatic bile duct remnants, and peripheral blood of biliary atresia and other cholestatic disease controls were characterized by fluorescent-activated cell sorter analysis, and TCR junctional region nucleotide sequencing was performed on expanded TCR Vbeta regions to confirm oligoclonality. RESULTS: FACS analysis revealed Vbeta subset expansions of CD4(+) and CD8(+) T cells from the liver or bile duct remnant in all patients with biliary atresia and only 1 control. The CD4(+) TCR expansions were limited to Vbeta3, -5, -9, and -12 T-cell subsets and the CD8(+) TCR Vbeta expansions were predominantly Vbeta20. Each Vbeta subset expansion was composed of oligoclonal populations of T cells. CONCLUSIONS: Biliary atresia is associated with oligoclonal expansions of CD4(+) and CD8(+) T cells within liver and extrahepatic bile duct remnant tissues, indicating the presence of activated T cells reacting to specific antigenic stimulation. Future studies entail identifying the specific antigen(s) responsible for T-cell activation and bile duct injury.     

Short communication: CD8(+) T cell polyfunctionality profiles in progressive and nonprogressive pediatric HIV type 1 infection

Pediatric HIV-1 infection is characterized by rapid disease progression and without antiretroviral therapy (ART), more than 50% of infected children die by the age of 2 years. However, a small subset of infected children progresses slowly to disease in the absence of ART. This study aimed to identify functional characteristics of HIV-1-specific T cell responses that distinguish children with rapid and slow disease progression. Fifteen perinatally HIV-infected children (eight rapid and seven slow progressors) were longitudinally studied to monitor T cell polyfunctionality. HIV-1-specific interferon (IFN)-γ(+) CD8(+) T cell responses gradually increased over time but did not differ between slow and rapid progressors. However, polyfunctional HIV-1-specific CD8(+) T cell responses, as assessed by the expression of four functions (IFN-γ, CD107a, TNF-α, MIP-1β), were higher in slow compared to rapid progressors (p=0.05) early in infection, and was associated with slower subsequent disease progression. These data suggest that the quality of the HIV-specific CD8(+) T cell response is associated with the control of disease in children as has been shown in adult infection.     

Functionally competent antigen-specific CD127(hi) memory CD8+ T cells are preserved only in HIV-infected individuals receiving early treatment

The importance of functional CD4+ T cells and antigen control in the maintenance of CD127 expression on antigen-specific CD8+ T cells is poorly understood in humans. We compared CD127 expression on antigen-specific CD8+ T cells in 4 groups of human immunodeficiency virus (HIV)-infected patients. This analysis demonstrated that HIV-specific CD8+ CD127(hi) T cells are maintained as long-lived memory cells only in HIV-infected individuals treated early with antiretroviral therapy (ART). This population of CD127(hi) T cells fluctuates with viral load (VL) such that the antigen-specific T cell pool oscillates from a CD127(hi) memory to a CD127(lo) effector phenotype depending on the levels of plasma VL. In individuals with chronic infection, the CD127(hi) pool diminishes or is lost with time despite virologic control while receiving ART. These studies show that functionally competent subsets of antigen-specific memory CD8+ T cells in HIV-infected individuals are maintained but only if control of viremia is attained early during the course of infection.     

The role of targeted viral load testing in diagnosing virological failure in children on antiretroviral therapy with immunological failure

Objectives To determine the improvement in positive predictive value of immunological failure criteria for identifying virological failure in HIV‐infected children on antiretroviral therapy (ART) when a single targeted viral load measurement is performed in children identified as having immunological failure. Methods Analysis of data from children (<16 years at ART initiation) at South African ART sites at which CD4 count/per cent and HIV‐RNA monitoring are performed 6‐monthly. Immunological failure was defined according to both WHO 2010 and United States Department of Health and Human Services (DHHS) 2008 criteria. Confirmed virological failure was defined as HIV‐RNA >5000 copies/ml on two consecutive occasions <365 days apart in a child on ART for ≥18 months. Results Among 2798 children on ART for ≥18 months [median (IQR) age 50 (21–84) months at ART initiation], the cumulative probability of confirmed virological failure by 42 months on ART was 6.3%. Using targeted viral load after meeting DHHS immunological failure criteria rather than DHHS immunological failure criteria alone increased positive predictive value from 28% to 82%. Targeted viral load improved the positive predictive value of WHO 2010 criteria for identifying confirmed virological failure from 49% to 82%. Conclusion The addition of a single viral load measurement in children identified as failing immunologically will prevent most switches to second‐line treatment in virologically suppressed children.     

Characterization of murine Th1 clones specific to egg antigen of Schistosoma japonicum and their interaction with cytokines

T cell clones (B1, B21, B7, A25) specific to the soluble egg antigen (SEA) of Schistosoma japonicum were established from C3H/He mice immunized with SEA. These clones belonged to CD3+, CD4+ and CD8-Th1 cells, showing TCR-gamma delta-, TCR-alpha beta+ and Vbeta10b+. The molecular weights of target antigens recognized by the clones ranged from 51 to 80 kDa. Interleukin-2 (IL-2) and IL-12 could vigorously increase the proliferation response of the T clones to SEA; while IL-10 and transforming growth factor-beta1 (TGF-beta1) strongly inhibited the response. IL-12 activity was detected in the culture supernatant of T clones stimulated with SEA in the presence of APC (antigen presenting cells). This stimulation also upregulated the expression of the IL-12 receptor on the T clones. IL-12 from APC served as a costimulatory factor for the SEA induced proliferation of the T clone cells. Clone B1 was able to induce granuloma formation both in vivo and in vitro. These data provide further insight into the complicated interaction among SEA, T cell and cytokine at a clonal level in S. japonicum infection.     

Determinants of CD4+ T cell recovery during suppressive antiretroviral therapy: association of immune activation, T cell maturation markers, and cellular HIV-1 DNA

BACKGROUND: Suboptimal CD4+ T cell recovery during antiretroviral therapy (ART) is a common clinical dilemma. METHODS: We analyzed viral and immunologic predictors of CD4+ T cell recovery in 116 human immunodeficiency virus type 1 (HIV-1)-infected subjects who had suppressed viremia (< or = 50 copies/mL) while receiving ART. Successive measurements of T cell immunophenotypes and cellular HIV-1 DNA levels were obtained before and during receipt of ART. On the basis of increases in the CD4+ T cell count, subjects were classified as immunologically concordant (demonstrating an increase of > or = 100 CD4+ T cells/mm3) or discordant (demonstrating an increase of <100 CD4+ T cells/mm3) after 48 weeks of ART. RESULTS: In adjusted analyses, CD4+ and CD8+ T cell activation at baseline was negatively associated with immunologic concordance at week 48 of ART (odds ratio [OR], 0.80 [P = .04] and 0.67 [P = .02], respectively). High memory (CDRA(-)CD62L-) CD8+ T cell counts at baseline (OR, 0.33 [P = .05]) predicted less CD4+ T cell recovery, whereas increased naive CD4+ T cell counts were associated with higher increases in CD4+ T cells (OR, 1.19 [P = .052]). Neither the cell-associated HIV-1 DNA level at baseline (P = .32) nor the cell-associated HIV-1 DNA level at week 48 of ART (P = .42) was associated with immunologic concordance during ART. CONCLUSIONS: These results support the potential clinical usefulness of the baseline determination of immune activation and maturation subsets in the prediction of CD4+ T cell recovery during viral suppression. Furthermore, identification of individuals with reduced potential for CD4+ T cell recovery during ART may provide a rationale for the initiation of early therapy for some patients.