Simple Method for Quantifying Alpha-Tocopherol in Low-Density+Very-Low-Density Lipoproteins and in High-Density Lipoproteins

We assessed the distribution of alpha-tocopherol in serum lipoprotein samples after separating the lipoprotein fractions by either sequential ultracentrifugation or selective precipitation with sodium phosphotungstate-magnesium chloride reagent. alpha-Tocopherol concentrations were determined by reversed-phase high-performance liquid chromatography. After ultracentrifugation, we found that in men, low- and very-low-density serum lipoproteins (LDL-VLDL) contained 53.6% of alpha-tocopherol vs 46.4% in high-density lipoproteins (HDL). In women, serum LDL-VLDL contained 45.6% alpha-tocopherol after ultracentrifugation vs 54.4% in HDL. After selective precipitation, the proportions of alpha-tocopherol in men were 56.1% in LDL-VLDL vs 43.9% in HDL, and in women, 45.4% in LDL-VLDL vs 54.6% in HDL. After selective precipitation, alpha-tocopherol recovery from whole lipoprotein fractions was 97% to 100% vs 80% after ultracentrifugation, thus allowing more accurate alpha-tocopherol quantification than after separation by ultracentrifugation.

Non-AIDS-related malignancies: expert consensus review and practical applications from the multidisciplinary CANCERVIH Working Group

Malignancies represent a major cause of morbidity and mortality in human immunodeficiency virus (HIV)-infected patients. The introduction of combined antiretroviral therapy has modified the spectrum of malignancies in HIV infection with a decreased incidence of acquired immunodeficiency syndrome (AIDS) malignancies such as Kaposi's sarcoma and non-Hodgkin's lymphoma due to partial immune recovery and an increase in non-AIDS-defining malignancies due to prolonged survival. Management of HIV-infected patients with cancer requires a multidisciplinary approach, involving both oncologists and HIV physicians to optimally manage both diseases and drug interactions between anticancer and anti-HIV drugs. The French CANCERVIH group presents here a review and an experience of managing non-AIDS malignancies in HIV-infected individuals.

Soluble biomarkers of immune activation and inflammation in HIV infection: impact of 2 years of effective first-line combination antiretroviral therapy

OBJECTIVES

The aim of the study was to assess the impact of rapid and sustained viral control produced by combination antiretroviral therapy (cART) on HIV-associated immune activation and inflammation.

METHODS

In this longitudinal observational study, we examined changes in interleukin-6 (IL-6), interferon-γ-inducible protein-10 (IP-10), monokine induced by interferon-γ (MIG) and soluble CD14 (sCD14) levels during 2 years of effective first-line cART. Biomarker levels before and after cART were compared with those observed in healthy subjects, using the Wilcoxon signed rank test. Elevated biomarker levels were defined with respect to values for healthy subject (mean + 2 standard deviations). Factors associated with persistently elevated biomarker levels after 2 years of cART were identified by logistic regression.

RESULTS

We included in the study 139 patients with a median HIV-1 RNA level of 4.8 log10 HIV-1 RNA copies/mL and a median CD4 cell count of 294 cells/μL at cART initiation [day 0 (D0)]. At D0, all biomarker levels were higher than in healthy subjects (P < 0.05). After 2 years of cART, IL-6, IP-10 and MIG levels fell significantly, by a median of 0.54, 420 and 1107 pg/mL, respectively (all P < 0.001), and were no longer elevated in > 75% of patients. In contrast, sCD14 levels did not change significantly (0.18 × 10(6)  pg/mL; P = 0.102) and remained elevated. Older age was associated with elevated levels of IP-10 [odds ratio (OR) 1.60 per 10 years older; P = 0.047] and MIG (OR 1.92 per 10 years older; P = 0.007) after 2 years of cART.

CONCLUSIONS

The rapid and sustained viral suppression produced by first-line cART reduced IL-6, IP-10 and MIG to normal levels, while sCD14, a marker of monocyte activation, remained elevated. High levels of IP-10 and MIG tended to persist in older patients.

QuantiFERON-TB gold cut-off value: implications for the management of tuberculosis-related ocular inflammation

PURPOSE

To evaluate the accuracy of QuantiFERON-TB Gold testing in patients with presumptive tuberculosis-ocular inflammation.

DESIGN

Prospective nonrandomized case series and clinical laboratory investigation.

METHODS

Ninety-six consecutive patients presenting with ocular inflammation between January and October 2007 were tested using QuantiFERON-TB Gold. Positive patients received a 6-month anti-tuberculosis treatment. Patient follow-up ranged from 12 months to 24 months. Treatment was considered effective at the end of follow-up, in cases of no or a 2-point decrease of ocular inflammation (SUN criteria) and systemic corticosteroids stopped or tapered to 10 mg/day.

RESULTS

Mean age was 51 ± 17 years. Types of ocular inflammation included scleritis (n = 7), panuveitis (n = 34), and posterior (n = 15), intermediate (n = 14), and anterior uveitis (n = 15). QuantiFERON-TB Gold was positive in 42 cases (44%), negative in 51 cases (53%), and undetermined in 3 cases (3%). Among positive QuantiFERON-TB Gold patients, 25 received a full anti-tuberculosis treatment, which was effective in 15 cases (60%). Associated systemic steroids were given to 6 patients and tapered to 10 mg/day or less in all cases. Median QuantiFERON-TB Gold value was significantly higher in the group with a successful therapeutic response (7.67 IU/mL [0.46 to 33.37]) compared to the group with treatment failure (1.22 IU/mL [0.61 to 4.4]), P = .026.

CONCLUSION

Results of anti-tuberculosis treatment were encouraging in QuantiFERON-TB Gold-positive ocular inflammation, especially with values over 2 IU/mL in our study, suggesting that a higher cut-off value than that given by the manufacturer should be considered to better identify ocular inflammation that can benefit from full anti-tuberculosis treatment.

[Enhancing immune restoration in human immunodeficiency virus infection]

The primary objective of antiretroviral therapy has recently evolved from a virologic endpoint towards the achievement of normal CD4T cell count (greater than 500/mm(3)) to avoid progression to AIDS. This shift in the primary objective is supported by many clinical and epidemiological studies. Recent data have shown that HIV-infected adults with a CD4T cell count greater than 500cells/mm(3) on long-term combination antiretroviral therapy reach same mortality rates as the general population. However, less than 50% of patients receiving long-term suppressive antiretroviral combination reach such a CD4T cell level. New antiretroviral strategies to improve immune reconstitution, such as specific or non-specific immune-based therapy on one hand and the use of novel antiretroviral drugs from new classes on the other hand are currently under investigation. Here we review several current strategies that may improve immune reconstitution, keeping in mind that the best way to reach normal CD4T cell count is an early treatment initiation.

Fetal death as a result of placental immune reconstitution inflammatory syndrome

A 26-year-old woman was HIV-1 diagnosed at 11 weeks of pregnancy (CD4 = 7/mm(3), HIV-1 RNA = 108,000 copies/mL) with immunity against toxoplasmosis (Toxoplasma IgG = 1800 UI/mL). A fetal death was diagnosed 7 weeks after starting HAART (CD4 = 185/mm(3), HIV-1 RNA = 391 copies/mL) with a positive Toxoplasma PCR on fetal tissues and amniotic fluid. The absence of severe toxoplasmic foetopathy, the very exaggerated and atypical placental inflammation and the immune restoration context led to the diagnosis of placental IRIS associated with Toxoplasma gondii reactivation. This outcome remains undescribed and could represent an issue in resource-limited settings where HIV-pregnant patients are often severely immunodeficient and infected with opportunistic pathogens.

Anti-PGL-Tb1 responses as an indicator of the immune restoration syndrome in HIV-TB patients

A prospective and multi-centre study has allowed us to analyse antibody responses and Mycobacterium tuberculosis clinical isolate genotypes on 24 consecutive HIV-TB co-infected patients treated with Highly Active Antiretroviral Therapy (HAART) who either went on to develop a TB Immune Restoration Syndrome (TB-IRS), or not. Circulating free and immune-complexed antibodies against ManLAM, ESAT-6/CFP10 and PGL-Tb1 in HIV-TB co-infected patients were measured by ELISA at the initiation of anti-TB treatment, at the date of HAART initiation and thereafter. Presence of circulating B cells was also monitored by in vitro antibody production (IVAP) against ESAT-6/CFP10 and PGL-Tb1. Finally, 16 out of 24M. tuberculosis clinical isolates from patients with TB-IRS were genotyped using spoligotyping and MIRUs-VNTR typing. Eleven patients (45.8%) experienced TB-IRS (TB-IRS+). Significantly, lower anti-PGL-Tb1 antibody levels were identified in TB-IRS+ compared to TB-IRS-negative patients prior to TB-IRS development. These very low levels were neither related to CD4 counts nor with complexed antibodies. No difference in antibody levels was observed with the other tested antigens. In addition, no specific strain genotype was associated with TB-IRS. The presence of specific anti-PGL-Tb1 antibodies only in TB-IRS-negative patients represents for the first time an indicator of a potential protective response or a diagnostic biomarker for the detection of non-progression to TB-IRS in HIV-TB co-infected patients starting HAART.

[Déplétion du compartiment muqueux de cellules T CD4+ mémoires au cours de l'infection par le virus de l'immunodéficience humaine (VIH) : causes et conséquences]

The gradual depletion of peripheral blood CD4+ T cells, a major prognostic marker of the disease, is the principal hallmark of HIV infection. However, most CD4+ T cells reside within the gastrointestinal tract and other lymphatic tissues rather than in peripheral blood. Compared with circulating lymphocytes a greater percentage of these mucosal CD4+ T cells express the CCR5 chemokine receptor and are preferential targets of viral replication. So, an important depletion occurs preferentially within these cells during primary infection by SIV or HIV. Consequently, the total-body CD4+ T cell number is severely and rapidly depleted. This initial depletion is mainly a direct or indirect consequence of CD4+ T cell infection. Secondarly several mechanisms such as hyperactivation and alteration of lymphocyte homeostasis take part in its persistence and aggravation. In contrast to blood, recovery of intestinal CD4+ T cell numbers is highly variable among patients and is dependent of time of treatment initiation.

Modulation of interleukin-7 receptor expression characterizes differentiation of CD8 T cells specific for HIV, EBV and CMV

OBJECTIVES

To further understand differentiation and homeostasis of CD8 T cells specific for HIV, Epstein-Barr Virus (EBV) and cytomegalovirus (CMV) during HIV infection, we investigated interleukin-7 receptor alpha (IL-7Ralpha) expression on those virus-specific T cells.

METHODS

Microarrays and cytometry analyses were performed on peripheral blood mononuclear cells (PBMC), total and tetramer-binding virus-specific CD8 T cells from 66 HIV-infected patients.

RESULTS

Microarray analysis revealed reduced levels of IL-7Ralpha and increased levels of perforin with disease progression in total PBMC. This loss of IL-7Ralpha expression was observed on CD8 T cells and was inversely related to perforin expression. The relative expression of both molecules defined three new subsets: IL-7Ralpha(pos)Perforin(neg); IL-7Ralpha(loneg)Perforin(lo); and IL-7Ralpha(loneg)Perforin(hi) corresponding to naive and effector-memory CD8 differentiation, as assessed by CD45RA/CD11a. The IL-7Ralpha expression decreased along the CD8 differentiation pathway defined by CD27 and CD28. In contrast, IL-7Ralpha expression was down-modulated on all the CD8 T cells specific for HIV, EBV and CMV that were almost exclusively IL-7Ralpha(lo/neg)Perforin(lo) and was parallel with the CD27 expression. In addition, this low IL-7Ralpha expression on HIV-specific CD8 T cells was independent of virus load and T-cell activation and remained stable during the first 6 months of antiretroviral therapy despite successful control of HIV replication.

CONCLUSION

The relative expression of IL-7Ralpha, perforin reveals new aspects of virus-specific CD8 T cell differentiation, independently of T-cell activation and virus load. This opens new perspectives for understanding homeostasis of those cells and immune-based therapeutic strategies.

A systematic comparison of methods to measure HIV-1 specific CD8 T cells

Several methods are now available to evaluate the frequencies of virus-specific CD8 T cells but require a systematic comparison to help at choosing the best strategy for evaluation. First, we compared the ELISpot-IFNgamma assay, intracellular IFNgamma staining and HLA class I tetramer-binding assay to quantify the HIV-specific CD8 T cells. Second, we determined the frequency of recognition of HIV antigens and evaluated whether the mode of antigen presentation might influence the results: We compared HIV antigen presentation in the same ELISpot-IFNgamma assays by using recombinant vaccinia viruses (rVVs) encoding for HIV-LAI Gag, Pol, Env, Nef, Tat and Vif proteins, or a panel of 49 synthetic 8-11 amino acid length peptides tested either individually or pooled. Third, we compared the antigens recognized by memory CTL analysis using chromium release assay (CRA) on CTL lines and by effector CD8 cell analysis using ELISpot assay. Our results show that: (1) Flow cytometry and ELISpot assay measuring IFNgamma production give the same frequency of HIV-specific CD8 T cells; (2) tetramer-binding assay detects more HIV-specific CD8 T cells than other methods; (3) pools of optimal peptides and sum frequencies of individual optimal peptides give similar results in ELISpot assay; (4) ELISpot assays using peptides are more sensitive than those using rVV; and (5) CRA and ELISpot assay when using rVV provide a comparable profile of HIV antigen recognition by memory CTLs (CRA) and effector CTLs (ELISpot) in two thirds cases. These results have important implications for the choice of immunological methods to evaluate CD8 T cells responses to vaccines.

Re-occurrence of HIV-1 drug mutations after treatment re-initiation following interruption in patients with multiple treatment failure

Antiretroviral treatment interruption in 20 extensively pre-treated HIV-1 patients with treatment failure led to genotype viral reversion of at least one class of drug-mutation resistance in half of the patients. The only predictive factor of reversion was found to be the duration of interruption. The outgrowth of residual wild-type virus seems not to be a true genetic reversion because drug mutations are detected rapidly at salvage therapy re-initiation.

Reconstitution of CD4+ T lymphocytes in HIV-infected individuals following antiretroviral therapy

Immune reconstitution during antiretroviral therapy has recently been shown to depend upon multiple factors at work in T cell homeostasis, amongst which the reduction of thymus dysfunction and of immune hyperactivation are instrumental. The optimism that has been raised by the restoration of hosts' defenses against opportunistic pathogens is, however, balanced by the poor immunity restored against HIV; thus, innovative immune interventions are required.

HIV dynamics and T-cell immunity after three structured treatment interruptions in chronic HIV-1 infection

OBJECTIVE

To evaluate whether controlled re-exposures to autologous HIV-1 could boost HIV-specific immunity and limit virus replication in patients with chronic HIV-1 infection.

PATIENTS AND DESIGN

Subjects with at least 2 years virus suppression during antiretroviral therapy and a CD4 : CD8 ratio > 1 were randomly assigned to interrupt highly active antiretroviral treatment (HAART) three times (n = 12) or to continue their previous HAART (n = 14).

RESULTS

In 10/12 interrupter patients a rebound of HIV-1 RNA was detected in all three structured treatment interruptions (STI). Plasma virus doubling time was shorter during the first STI than in the second and third STI, corresponding to an average 13% reduction in viral basic reproductive rate. However, the mean time before plasma viral load rose to > 50 copies/ml was significantly shorter in the second and third STI. The average frequency of HIV-specific CD8 T cells in the interrupter patients at the end of the third STI cycle was significantly higher compared with the baseline and the end of the first STI. A substantial increase in HIV-specific CD8 T cell frequencies was found in four interrupter patients, whereas there were no changes in all 14 non-interrupter individuals. A weak p24-specific T helper response developed in 5/12 interrupter patients compared with no response in non-interruptors, but these responses were transient and disappeared rapidly.

CONCLUSION

The increase in the control of viral replication, and positive effects of STI on immune responses in this population should encourage the further development of HIV-specific immune-based therapeutic strategies.

Discontinuation of maintenance therapy for cytomegalovirus retinitis in HIV-infected patients receiving highly active antiretroviral therapy

OBJECTIVE

To study the safety of discontinuing cytomegalovirus (CMV) maintenance therapy among patients with cured CMV retinitis receiving highly active antiretroviral therapy (HAART).

METHODS

Patients with a history of CMV retinitis who were receiving anti-CMV maintenance therapy and who had a CD4 cell count > 75 x 10(6) cells/l and a plasma HIV RNA level < 30000 copies/ml while on HAART were included in a multicentre prospective study. Maintenance therapy for CMV retinitis was discontinued at enrolment and all the patients were monitored for 48 weeks by ophthalmological examinations and by determination of CMV markers, CD4 cell counts and plasma HIV RNA levels. T helper-1 anti-CMV responses were assessed in a subgroup of patients. The primary study endpoint was recurrence of CMV disease.

RESULTS

At entry, the 48 assessable patients had been taking HAART for a median of 18 months. The median CD4 cell count was 239 x 10(6) cells/l and the median HIV RNA load was 213 copies/ml. Over the 48 weeks, 2 of the 48 patients had a recurrence of CMV disease. The cumulative probability of CMV retinitis relapse was 2.2% at week 48 (95% confidence interval, 0.4-11.3) and that of all forms of CMV disease 4.2%. CMV blood markers remained negative throughout follow-up. The proportion of patients with CMV-specific CD4 T cell reactivity was 46% at baseline and 64% at week 48.

CONCLUSIONS

CMV retinitis maintenance therapy may be safely discontinued in patients with CD4 cell counts above 75 x 10(6) cells/l who have been taking HAART for at least 18 months.

Transient mobilization of human immunodeficiency virus (HIV)-specific CD4 T-helper cells fails to control virus rebounds during intermittent antiretroviral therapy in chronic HIV type 1 infection

Immune control of human immunodeficiency virus (HIV) is not restored by highly active antiretroviral therapies (HAART) during chronic infection. We examined the capacity of repeated structured therapeutic interruptions (STI) to restore HIV-specific CD4 and CD8 T-cell responses that controlled virus production. Eleven STI (median duration, 7 days; ranges, 4 to 24 days) were performed in three chronically HIV-infected patients with CD4 counts above 400/mm(3) and less than 200 HIV RNA copies/ml after 18 to 21 months of HAART; treatment resumed after 1 week or when virus became detectable. HIV-specific T-cell responses were analyzed by proliferation, gamma interferon (IFN-gamma) production, and enzyme-linked immunospot assays. Seven virus rebounds were observed (median, 4,712 HIV-1 RNA copies/ml) with a median of 7 days during which CD4 and CD8 counts did not significantly change. After treatment resumed, the viral load returned below 200 copies/ml within 3 weeks. Significant CD4 T-cell proliferation and IFN-gamma production against HIV p24 appeared simultaneously with or even before the virus rebounds in all patients. These CD4 responses lasted for less than 3 weeks and disappeared before therapeutic control of the virus had occurred. Increases in the numbers of HIV-specific CD8 T cells were delayed compared to changes in HIV-specific CD4 T-cell responses. No delay or increase in virus doubling time was observed after repeated STI. Iterative reexposure to HIV during short STI in chronically infected patients only transiently mobilized HIV-specific CD4 T1-helper cells, which might be rapidly altered by virus replication. Such kinetics might explain the failure at delaying subsequent virus rebounds and raises concerns about strategies based on STI to restore durable HIV-specific T-cell responses in chronic HIV infection.

CD4+Ki67+ lymphocytes in HIV-infected patients are effector T cells accumulated in the G1 phase of the cell cycle

Entry into the cell cycle represents a fundamental step before generating an effector immune response. The relationship between the cell cycle and antigen-driven T cell response remains, however, poorly understood in virus infection, including HIV. We have identified a critical fraction of CD4+CD45RO+ memory T lymphocytes that express the Ki67 antigen in chronically HIV-infected patients. A high accumulation of Ki67 protein is detected in CD4+CD45RO+Ki67+ cells that are in the G1 phase of the cell cycle (92 ¿ 5 %) but not in S and G2 + M phases, in contrast to normal individuals. Of these cells, 20 - 60 % are spontaneously producing IL-2 and IFN-, unlike CD4+CD45RO+ that do not express Ki67. In addition, HIV-p24 antigen is detectable only in a small fraction CD4+Ki67+ cells. In conclusion, CD4+Ki67+ lymphocytes are circulating effector cells accumulated in the G1 phase of the cell cycle and may be involved in the immune surveillance during HIV infection.

High levels of human herpesvirus 8 viral load, human interleukin-6, interleukin-10, and C reactive protein correlate with exacerbation of multicentric castleman disease in HIV-infected patients

Multicentric Castleman disease (MCD) is a distinct type of lymphoproliferative disorder associated with inflammatory symptoms and interleukin-6 (IL-6) dysregulation. In the context of human immunodeficiency virus (HIV) infection, MCD is associated with human herpesvirus 8 (HHV8) infection. In a prospective study of 23 HIV-infected patients with MCD, clinical symptoms of MCD were present at 45 visits, whereas patients were in chemotherapy-induced clinical remission at 50 visits. Symptoms were associated with a high level of serum C reactive protein, high HHV8 viral load in peripheral blood mononuclear cells, and high plasma human IL-6 and IL-10 levels. Strong correlations between plasma IL-6 and plasma IL-10 with the HHV8 viral load suggest that both cytokines may be involved in the pathogenesis of this virus-associated lymphoproliferative disorder.

[Antiretroviral therapy and immune reconstitution]

The course of the HIV infection has been dramatically modified since the introduction of highly active antiretroviral therapy (HAART) combining inhibitors of the HIV-1 reverse transcriptase and protease. Despite some controversies about the extent to which the immune system can normalize, it is generally admitted nowadays that a numerical and functional CD4 cell profile more akin to asymptomatic HIV-infected individuals can be restored in AIDS patients and can confer host protection against opportunistic events. The best hallmark of such immune restoration is the massive decline in the mortality and morbidity related to AIDS that have been registered in all industrialized countries. These changes involve a recirculation of mature peripheral T cells, a regeneration of naive T cells from thymic origin and a restoration of memory CD4 T cell réactivities. Although these recent advances warrant increased optimism, HAART by reducing the virus burden is unable to restore immunity against HIV itself, except when introduced at the very early stage after virus inoculation. The single condition required for immune reconstitution is an efficient and durable inhibition of virus replication. These positive effects can be obtained at late stages of the disease even when the patients have been heavily pre-treated. They also demonstrate that HIV does not definitively alter the lymphoid tissues nor the immune defenses, even aller years of infection and severe immune suppression, except for HIV-specific CD4 T helper cells.

T cell changes after combined nucleoside analogue therapy in HIV primary infection

OBJECTIVE

To characterize the immune changes after treatment of acute HIV-1 infection with triple nucleoside analogue therapy.

DESIGN

Immunological and virological parameters were monitored from day 0 to weeks 36-44 in eight patients [median CD4 cells = 451 cells/microl (range: 149-624), viral load = 4.8 log10 copies/ml (range: 6.5-3.3)] who started at time of primary HIV infection (PHI) a therapy including zidovudine (ZDV), didanosine (ddl), and lamivudine (3TC).

METHODS

Lymphoid subsets were evaluated on peripheral blood lymphocytes by four-colour flow cytometry using a panel of mAbs directed against differentiation and activation markers.

RESULTS

We observed a median -2.1 (range: -1; -3.3) log10 copies/ml viral load decrease and a median +158 cells/microl (range: +7 to +316) CD4 cell count increase at week 4 reaching normal CD4 cell count values of 761 CD4 cells/microl (range: 389-1153) at weeks 36-44. Virus undetectability was obtained at week 24 for all subjects. A rapid CD4 T cell amplification involved both memory and naive CD4 T cells. This was associated with a very rapid and significant decrease in activation markers [human leukocyte antigen-DR (HLA-DR), CD38] on both CD4 and CD8 T cell subsets together with a CD8+CD28+ cell increase as early as week 4.

CONCLUSIONS

These results show that early therapy with nucleoside analogues can correct the immunological abnormalities observed in CD4 and CD8 T cell subsets at the time of PHI. This early kinetics in T cell recovery appears to be faster than in established disease.

Determinants of paradoxical CD4 cell reconstitution after protease inhibitor-containing antiretroviral regimen

OBJECTIVES

We evaluated the parameters influencing CD4 cell reconstitution after the introduction of highly active antiretroviral therapies in real life, as well as the frequency and the determinants of the discrepancies occurring between virus and CD4 cell count evolution.

DESIGN AND METHODS

A total of 317 pre-treated patients starting a protease inhibitor (PI)-containing regimen were prospectively followed for 2 years on an intent-to-treat basis for CD4 cell counts and viral loads.

RESULTS

The CD4 cell counts rapidly increased from baseline (50/mm3) by a median of 50/mm3 at month 2 (+0.72 CD4 cells/mm3/day) and up to 137/mm3 at the last follow-up (second slope: +0.16 CD4 cells/mm3/day). Two independent major factors among five parameters tested significantly affected the first phase, which was negatively correlated to the slope of CD4 cell decline before PI initiation, and was positively correlated to baseline CD4 cell counts (P = 0.0001); the second phase was mostly affected by the mean viral load reduction over time (P = 0.0001). Paradoxical CD4 cell reconstitution (15% of cases) was defined by a rapid or slow CD4 cell increase contrasting with a minor or strong viral reduction, respectively. The role of previous CD4 cell decline and the low effect of viral load reduction during the first 2 months explain the early paradoxical CD4 cell responses. The major influence of viral load reduction on the long-term reconstitution, however, reduces such paradoxical responses at 2 years.

CONCLUSIONS

Early paradoxical CD4 cell reconstitution after the introduction of a PI are explained by the major influence of previous disease progression on the early CD4 cell increase, whereas the magnitude of viral load reduction over time reduces such paradoxical evolutions in the long term.

[Immunologic reconstruction after antiretroviral treatment]

DATA FAVORING IMMUNE RECONSTITUTION: Multiple drug therapies for HIV infection have enabled a major reduction in the viral load, higher CD4 counts, and a lower incidence of opportunistic infections and tumor formations, and subsequently lower hospitalization rates and mortality. TWO STAGES OF CD4 RECONSTITUTION: In HIV-positive patients with advanced stage disease treated with a protease inhibitor associated with 2 nucleoside analog reverse transcriptase inhibitors and followed prospectively, it has been observed that CD4 counts rise considerably, with a rapid increase during the first 2 months followed by a slower but still positive slope over a period of 18 months. Discordant results have however also been observed suggesting an ineffective anti-viral effect or a retarded immune reconstitution. SEVERAL MECHANISMS: The lymphocyte amplification observed during the early phase corresponds to re-circulation of CD4 and CD8 lymphocytes which had been sequestered in lymphoid organs; most of these CD4 lymphocytes are memory cells. A second phase corresponds to a more moderate and progressive rise in naive CD4 cells which originate from an unknown source. This biphasic reconstitution of CD4 lymphocytes is associated with a correction of the chronic lymphocyte overactivation. PARTIAL IMMUNE RECONSTITUTION: With treatment, the capacity to respond to known antigens reappears. This restored capacity is secondary to the amplification of CD4 memory cells and appears prior to the expansion phase of naive cells. The response remains moderate and is only observed against antigens from microorganisms highly prevalent during advanced stage infection.

In situ T-cell responses in a primary regressive melanoma and subsequent metastases: a comparative analysis

In an earlier study of the immune response in a patient with a cutaneous primary regressive melanoma, a T-cell-receptor diversity analysis demonstrated in situ amplification of certain lymphocytes. Two of them could be cloned and characterized as CD8+ HLA-class-l-restricted CTL with strong selective anti-tumor activity. Following a disease-free period of 3 years, the patient developed a gastric metastasis and subsequently (after an additional year) a metastasis in one axillary lymph node. Melanoma cell lines derived from the 2 secondary lesions have been established here. It was found that these metastatic cells have maintained expression of both HLA-class-I molecules and the peptidic antigen(s) recognized by the 2 clones amplified at the primary site. However, the corresponding T lymphocytes were either undetectable or poorly represented both in the gastric and in the axillary lesions. These results suggest that substantial alterations in the quality of T-cell infiltrates occurred during melanoma progression, despite an apparent stability in presentation of tumor-associated antigen(s) which initially triggered a positive rejection response.

Positive effects of combined antiretroviral therapy on CD4+ T cell homeostasis and function in advanced HIV disease

Highly active antiretroviral therapy (HAART) increases CD4(+) cell numbers, but its ability to correct the human immunodeficiency virus (HIV)-induced immune deficiency remains unknown. A three-phase T cell reconstitution was demonstrated after HAART, with: (i) an early rise of memory CD4(+) cells, (ii) a reduction in T cell activation correlated to the decreasing retroviral activity together with an improved CD4(+) T cell reactivity to recall antigens, and (iii) a late rise of "naïve" CD4(+) lymphocytes while CD8(+) T cells declined, however, without complete normalization of these parameters. Thus, decreasing the HIV load can reverse HIV-driven activation and CD4(+) T cell defects in advanced HIV-infected patients.

Diversity of the cytotoxic melanoma-specific immune response: some CTL clones recognize autologous fresh tumor cells and not tumor cell lines

In the present work, to analyze the heterogeneity of the tumor-specific cytotoxic immune response, a large number of T cell clones were generated from the infiltrate of a tumor-proximal invaded lymph node, and two kinds of melanoma-specific CD8+ CTL clones were derived. The majority of T cell clones (about a hundred) are characterized by a specific lysis of the autologous tumor cell lines. Among 34 of the latter clones, HLA-A2 molecule and MART-1(27-35) peptide have been shown to play a predominant role in tumor recognition. However, no significant amplification at the tumor site was observed for 3 of these CTL. The other kind of tumor-specific CTL (1 oligoclonal and 2 clonal cell lines) did not lyse the autologous melanoma cell lines but lysed the "fresh" autologous tumor cells in a MHC class I-dependent manner. Functional analysis of the two different CTL clones have shown that they did not lyse NK targets, autologous peripheral monocytes, activated T cells, and transformed B cells or any of the few allogeneic cultured and uncultured melanoma cells we tested. TCR repertoire analysis has shown that one of these CTL clones was significantly detectable "in situ" among tumor-infiltrating lymphocytes, while not detectable among PBMC. Such melanoma-specific lymphocytes, which could not have been picked out through conventional screening procedures using tumor cell lines, could potentially play a role in tumor rejection. These results suggest that the immune response analyzed toward melanoma cell lines does not totally reflect the in situ immune status.

Diversity of the cytotoxic melanoma-specific immune response: some CTL clones recognize autologous fresh tumor cells and not tumor cell lines

In the present work, to analyze the heterogeneity of the tumor-specific cytotoxic immune response, a large number of T cell clones were generated from the infiltrate of a tumor-proximal invaded lymph node, and two kinds of melanoma-specific CD8+ CTL clones were derived. The majority of T cell clones (about a hundred) are characterized by a specific lysis of the autologous tumor cell lines. Among 34 of the latter clones, HLA-A2 molecule and MART-1(27-35) peptide have been shown to play a predominant role in tumor recognition. However, no significant amplification at the tumor site was observed for 3 of these CTL. The other kind of tumor-specific CTL (1 oligoclonal and 2 clonal cell lines) did not lyse the autologous melanoma cell lines but lysed the "fresh" autologous tumor cells in a MHC class I-dependent manner. Functional analysis of the two different CTL clones have shown that they did not lyse NK targets, autologous peripheral monocytes, activated T cells, and transformed B cells or any of the few allogeneic cultured and uncultured melanoma cells we tested. TCR repertoire analysis has shown that one of these CTL clones was significantly detectable "in situ" among tumor-infiltrating lymphocytes, while not detectable among PBMC. Such melanoma-specific lymphocytes, which could not have been picked out through conventional screening procedures using tumor cell lines, could potentially play a role in tumor rejection. These results suggest that the immune response analyzed toward melanoma cell lines does not totally reflect the in situ immune status.

T-cell receptor repertoire in neuroblastoma patients

Spontaneous regression of widespread lesions is a characteristic feature of neuroblastoma. One may postulate that the immune response contributes to these clinical regressions. Accordingly, we studied the T-cell receptor (TCR) repertoire of tumor-infiltrating lymphocytes in eight neuroblastoma tumors. The expression of 29 V alpha and 24 V beta gene segment subfamily specificities was analyzed by PCR and compared by computerized densitometry of Southern blots to values obtained in the blood. Overall, the TCR repertoire of these eight patients was diverse, with virtually all V alpha and V beta specificities expressed. Nonetheless, four of these patients showed V beta 2 gene segment subfamily overexpression in the tumor corresponding to local expansion of polyclonal T-cell subpopulations. In one patient, this expansion could be due to local secretion of superantigenic activity, as suggested by the specific stimulation of murine T cells expressing a human V beta 2 chain by supernatant of the corresponding neuroblastoma cell line. In addition, high-resolution analysis of the TCR beta transcript complementarity-determining region 3 sizes identified three patients (of six studied) with marked clonal T-cell expansion in the tumor not seen in the blood. The specific expression of several dominant clono-types in the tumor may be related to the recognition of neuroblastoma-specific antigens in these patients. Together, these results on the TCR repertoire expressed in vivo may lead to the characterization of putative immune response mechanisms (i.e., antigen- or superantigen-driven stimulation) which participate in tumor regression.

[Comparative analysis of the immune response in a case of primary regressive melanoma followed by gastric metastasis]

The theory of immunosurveillance against cancer has been an extensively debated question over the last decades. Multiple indirect arguments have supported the view that the immune system may control, at least in certain cases, malignant cell growth while direct demonstration is still lacking in the human. In an attempt to address this issue, we have selected a study model, namely spontaneously regressive melanoma. A primary cutaneous lesion was investigated. T cell repertoire analysis showed the in situ amplification of at least two tumor infiltrating lymphocyte (TILs) expressing the V beta 13 and V beta 16 variable TCR gene segments respectively. The two clones were precisely characterized by sequence of the TCR beta chain junctional region. Further functional study demonstrated that both lymphocytes displayed a selective cytotoxic activity against autologous tumor cells. The V beta 16+ cells, predominant in vivo, were shown to be closely opposed to the melanoma cells. Together, these studies demonstrated the existence of a local adaptative immune response associated to tumor regression, thus strongly supporting the validity of the immunosurveillance concept. A gastric metastasis which occurred three years after the primary lesion has been studied here. Overexpression of the V beta 13 and V beta 16 TCR segments was no longer detected by direct PCR analysis in situ. Sequencing transcripts from V beta 13+ and V beta 16+ TILs confirmed that the two CTLs, identified in the primary lesions, were not represented with high frequency. The V beta 13+ cell was however shown to be present while the V beta 16+ CTL was not detected. Yet, characterization of a tumor cell line derived from the gastric site indicated that the peptidic antigen(s) which induced the initially successfully immune response was still expressed. The present data illustrate that it has become possible to perform very precise analysis of local immune responses during cancer development. Such an improvement together with the recently initiated molecular characterization of tumor associated peptidic antigens, should provide the basis for improved strategies of cancer immunotherapy.

Direct evidence to support the immunosurveillance concept in a human regressive melanoma

The concept of immunosurveillance against cancer has been an extensively debated question over the last decades. Multiple indirect arguments have supported the view that the immune system may control, at least in certain cases, malignant cell growth while direct demonstration is still lacking in the human. In an attempt to address this issue, we have selected a study model, namely spontaneously regressive melanoma. In previous series of experiments, the variability of T cell receptors (TCRs) in the lymphocytes infiltrating a regressive tumor lesion was investigated. Results demonstrated that clonal T cell populations, precisely defined through their V-D-J junctional sequences, were amplified in situ. One clone was predominant, expressing the V beta 16 variable gene segment. A specific anti-V beta 16 TCR mAb was generated here to purify and functionally characterize the corresponding cells. A tumor-infiltrating lymphocyte-derived V beta 16+ T cell line was developed using this reagent. These in vitro cultured cells were found to express the in vivo predominant TCR sequence exclusively and to display an HLA-B14-restricted cytotoxic activity against the autologous tumor cells. Immunohistochemical experiments, performed with the anti-V beta 16 mAb, showed that the corresponding CTLs are present in the tumor area, some of them being closely opposed to the melanoma cells. Together, these studies demonstrate the existence of a local adaptive immune response clinically associated to tumor regression, thus strongly supporting the validity of the immunosurveillance concept in certain human tumors.

Evidence for in situ amplification of cytotoxic T-lymphocytes with antitumor activity in a human regressive melanoma

We have derived from lymphocytes infiltrating a human regressive melanoma lesion a series of T-cell receptor alpha/beta-dependent, HLA-B14-restricted cytotoxic T-lymphocyte clones reactive against the autologous tumor. Analysis of the T-cell receptor gene expression revealed that all the clones represented a unique cell expressing a V beta 13.1/J beta 1.1 gene segment. T-cell receptor transcripts expressed in the cloned cells were compared to those present in the uncultured tumor tissue. This analysis demonstrated that the specific cytotoxic T-lymphocyte clones characterized in vitro was actually selected and amplified in vivo at the lesion site. These results provide strong evidence that effector T-cells have contributed to tumor regression.

Simple method for quantifying alpha-tocopherol in low-density+very-low-density lipoproteins and in high-density lipoproteins

We assessed the distribution of alpha-tocopherol in serum lipoprotein samples after separating the lipoprotein fractions by either sequential ultracentrifugation or selective precipitation with sodium phosphotungstate-magnesium chloride reagent. alpha-Tocopherol concentrations were determined by reversed-phase high-performance liquid chromatography. After ultracentrifugation, we found that in men, low- and very-low-density serum lipoproteins (LDL-VLDL) contained 53.6% of alpha-tocopherol vs 46.4% in high-density lipoproteins (HDL). In women, serum LDL-VLDL contained 45.6% alpha-tocopherol after ultracentrifugation vs 54.4% in HDL. After selective precipitation, the proportions of alpha-tocopherol in men were 56.1% in LDL-VLDL vs 43.9% in HDL, and in women, 45.4% in LDL-VLDL vs 54.6% in HDL. After selective precipitation, alpha-tocopherol recovery from whole lipoprotein fractions was 97% to 100% vs 80% after ultracentrifugation, thus allowing more accurate alpha-tocopherol quantification than after separation by ultracentrifugation.