Correlation between plasma levels of cytokines and HIV-1 RNA copy number in HIV-infected patients

The CD8+ T Cell Noncytotoxic Antiviral Responses

The CD8+ T cell noncytotoxic antiviral response (CNAR) was discovered during studies of asymptomatic HIV-infected subjects more than 30 years ago. In contrast to CD8+ T cell cytotoxic lymphocyte (CTL) activity, CNAR suppresses HIV replication without target cell killing. This activity has characteristics of innate immunity: it acts on all retroviruses and thus is neither epitope specific nor HLA restricted. The HIV-associated CNAR does not affect other virus families. It is mediated, at least in part, by a CD8+ T cell antiviral factor (CAF) that blocks HIV transcription. A variety of assays used to measure CNAR/CAF and the effects on other retrovirus infections are described. Notably, CD8+ T cell noncytotoxic antiviral responses have now been observed with other virus families but are mediated by different cytokines. Characterizing the protein structure of CAF has been challenging despite many biologic, immunologic, and molecular studies. It represents a low-abundance protein that may be identified by future next-generation sequencing approaches. Since CNAR/CAF is a natural noncytotoxic activity, it could provide promising strategies for HIV/AIDS therapy, cure, and prevention.

Pattern recognition receptor mRNA expression and cytokine and granzyme levels in HIV infected individuals with neurotuberculosis

Neurotuberculosis is one of the commonest HIV-associated opportunistic infections (OI) of the CNS. Cross-talk between HIV, Mycobacterium tuberculosis and host immune responses may alter expression of pattern recognition receptors (PRRs), thereby affecting cytokine profiles and functional responses. We examined PRR mRNA expression and cytokine and granzyme levels in HIV infected individuals with neurotuberculosis and found significant downregulation of TLR9 and increased MDA5 expression compared to healthy subjects. Significantly higher Granzyme A and IFN-γ levels were also observed in the CSF of this group compared to CSF from non-infectious controls. These alterations may lead to inappropriate recruitment of immune cells to the CNS, leading to disease severity.

Bone mineral density in people living with HIV: a narrative review of the literature

Bone health status is largely absent in South Africa, the main reasons being the absence and cost-effectiveness of specific screening equipment for assessing bone mineral density (BMD). Various risk factors seem to play a role, some of which can be modified to change bone health status. Urbanisation is also a public health concern. Changing nutritional, as well as social behaviour, play integral roles in the prevalence and incidence of decreased BMD. Furthermore, human immunodeficiency virus (HIV) specifically, has a negative impact on BMD and although highly active antiretroviral therapy increases the prognosis for HIV-infected individuals, BMD still seem to decrease further. Dual energy X-ray absorptiometry is considered the gold standard for BMD assessment; however, recent developments have provided more cost-effective screening methods, among which heel quantitative ultrasound appears to be the most widely used in resource limited countries such as South Africa.

Factors Associated With the Control of Viral Replication and Virologic Breakthrough in a Recently Infected HIV-1 Controller

HIV-1 controllers are patients who control HIV-1 viral replication without antiretroviral therapy. Control is achieved very early in the course of infection, but the mechanisms through which viral replication is restricted are not fully understood. We describe a patient who presented with acute HIV-1 infection and was found to have an HIV-1 RNA level of < 100 copies/mL. She did not have any known protective HLA alleles, but significant immune activation of CD8 + T cells and natural killer (NK) cells was present, and both cell types inhibited viral replication. Virus cultured from this patient replicated as well in vitro as virus isolated from her partner, a patient with AIDS who was the source of transmission. Virologic breakthrough occurred 9 months after her initial presentation and was associated with an increase in CD4 + T cell activation levels and a significant decrease in NK cell inhibitory capacity. Remarkably, CD8 + T cell inhibitory capacity was preserved and there were no new escape mutations in targeted Gag epitopes. These findings suggest that fully replication-competent virus can be controlled in acute HIV-1 infection in some patients without protective HLA alleles and that NK cell responses may contribute to this early control of viral replication.

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We show that an HIV-1 controller was infected with pathogenic virus yet maintained low viral loads during primary infection.

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She had activated NK cells and CD8+ T cells and both cell types suppressed HIV-1 replication shortly after infection.

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She eventually lost control of viral replication, and this was associated with a reduction in NK cell suppressive activity.

HIV-1 controllers are patients who control the virus without HIV-1 medications. These patients may teach us how to design a vaccine against HIV-1. Little is known about how the virus is controlled in the early phase of infection in these patients. Here we show that a recently infected HIV-1 controller had a strong natural killer cell response to the virus. Interestingly, she lost control of the virus 9 months later and her natural killer cell response to the virus was diminished. Our work suggests that natural killer cells may have contributed to viral control in the early phase of infection.

Bone and vitamin D metabolism in HIV

Human immunodeficiency virus (HIV) infection has progressed to a chronic disease and HIV positive individuals are living longer lives. This has lead to an increase in morbidity and mortality due to secondary issues, one being HIV bone disease. HIV infected pediatric and adult populations have a greater incidence in reduction of BMD as compared to the controls. Osteoporosis has been reported to be present in up to 15 % of HIV positive patients. We are starting to understand the mechanism behind the changes in HIV bone disease. Viral proteins interfere with osteoblastic activity either by direct interaction or by the inflammatory process that they induce. Anti-viral management, including highly active antiretroviral therapy (HAART), protease inhibitors, and nucleoside/nucleotide reverse transcriptase inhibitors (NRTI) also are involved in disrupting proper bone metabolism. Vitamin D levels have strong correlation with bone disease in HIV patients, and are dependent not only to chronic disease state, but interaction of pharmacologic management and inflammatory process as well. Work up of the secondary causes of osteopenia and osteoporosis should be undertaken in all patients. DEXA scan is recommended in all post-menopausal women with HIV, all HIV infected men 50 years of age or older and in those with a history of fragility fractures regardless of age or gender. Preventive measures include adequate nutrition, calcium and Vitamin D intake daily, muscle strengthening and balance exercises to increase BMD and reduce fractures. Bisphosphonates are considered to be the first line for the treatment of HIV associated bone disease. This review will describe how the balanced mechanism of bone metabolism is interrupted by the HIV infection itself, the complications that arise from HIV/AIDS, and its treatment options.

Lipopolysaccharide-enhanced transcellular transport of HIV-1 across the blood-brain barrier is mediated by luminal microvessel IL-6 and GM-CSF

Elevated levels of cytokines/chemokines contribute to increased neuroinvasion of human immunodeficiency virus type 1 (HIV-1). Previous work showed that lipopolysaccharide (LPS), which is present in the plasma of patients with HIV-1, enhanced transcellular transport of HIV-1 across the blood-brain barrier (BBB) through the activation of p38 mitogen-activated protein kinase (MAPK) signaling in brain microvascular endothelial cells (BMECs). Here, we found that LPS (100 μg/mL, 4 hr) selectively increased interleukin (IL)-6 and granulocyte-macrophage colony-stimulating factor (GM-CSF) release from BMECs. The enhancement of HIV-1 transport induced by luminal LPS was neutralized by treatment with luminal, but not with abluminal, antibodies to IL-6 and GM-CSF without affecting paracellular permeability as measured by transendothelial electrical resistance (TEER). Luminal, but not abluminal, IL-6 or GM-CSF also increased HIV-1 transport. U0126 (MAPK kinase (MEK)1/2 inhibitor) and SB203580 (p38 MAPK inhibitor) decreased the LPS-enhanced release of IL-6 and GM-CSF. These results show that p44/42 and p38 MAPK signaling pathways mediate the LPS-enhanced release of IL-6 and GM-CSF. These cytokines, in turn, act at the luminal surface of the BMEC to enhance the transcellular transport of HIV-1 independently of actions on paracellular permeability.

Multisite comparison of high-sensitivity multiplex cytokine assays

The concentrations of cytokines in human serum and plasma can provide valuable information about in vivo immune status, but low concentrations often require high-sensitivity assays to permit detection. The recent development of multiplex assays, which can measure multiple cytokines in one small sample, holds great promise, especially for studies in which limited volumes of stored serum or plasma are available. Four high-sensitivity cytokine multiplex assays on a Luminex (Bio-Rad, BioSource, Linco) or electrochemiluminescence (Meso Scale Discovery) platform were evaluated for their ability to detect circulating concentrations of 13 cytokines, as well as for laboratory and lot variability. Assays were performed in six different laboratories utilizing archived serum from HIV-uninfected and -infected subjects from the Multicenter AIDS Cohort Study (MACS) and the Women's Interagency HIV Study (WIHS) and commercial plasma samples spanning initial HIV viremia. In a majority of serum samples, interleukin-6 (IL-6), IL-8, IL-10, and tumor necrosis factor alpha were detectable with at least three kits, while IL-1β was clearly detected with only one kit. No single multiplex panel detected all cytokines, and there were highly significant differences (P < 0.001) between laboratories and/or lots with all kits. Nevertheless, the kits generally detected similar patterns of cytokine perturbation during primary HIV viremia. This multisite comparison suggests that current multiplex assays vary in their ability to measure serum and/or plasma concentrations of cytokines and may not be sufficiently reproducible for repeated determinations over a long-term study or in multiple laboratories but may be useful for longitudinal studies in which relative, rather than absolute, changes in cytokines are important.

CD4 and Chemokine Receptors on Human Brain Microvascular Endothelial Cells, Implications for Human Immunodeficiency Virus Type 1 Pathogenesis

Central nervous system (CNS) dysfunction is commonly observed in children with human immunodeficiency virus type 1 (HIV-1) infection, but the mechanism(s) whereby HIV-1 causes encephalopathy remains incompletely understood. Human brain microvascular endothelial cells (HBMECs), which constitute the blood-brain barrier, are likely to contribute to HIV-1 encephalopathy, but it is unclear whether HIV-1 receptors (CD4, chemokine receptors) are present on HBMECs. In the present study, the presence of CD4 in six different children was demonstrated. Moreover, the presence of CD4 in situ on brain sections was shown. Distribution of CD4 expression was heterogeneous among microvessels; staining for CD4 was strong in some vessels and absent in other adjacent vessels. CD4 and chemokine coreceptors were found to be functional as intercellular adhesion molecule (ICAM)-1 expression increased upon incubation of HBMECs with activating anti-CD4 and anti-chemokine receptor antibodies. The presence of CD4 and chemokine receptors in human brain endothelium of children may have implications for the pathogenesis of HIV-1 encephalopathy and explain the higher incidence of CNS involvement in HIV-1-infected children as compared to adults.

[Bone mineral loss in patients with human immunodeficiency virus infection]

Life expectancy and quality of life among patients infected with human immunodeficiency virus (HIV) has dramatically improved with the advent of highly active antiretroviral therapy. Nonetheless, with the transformation of HIV infection into a chronic disease, a series of long-term consequences have been observed, among them osteoporosis. The prevalence of this condition is increasing among individuals with HIV infection. Although an epidemic of fragility fractures has not been described in these patients, an increase in the incidence of such fractures is anticipated as the HIV population ages, and this will undoubtedly have an impact on their quality of life. The numerous factors that favor the development of osteoporosis in these patients are related to the infection, itself, and the treatment received.

Lipopolysaccharide-enhanced transcellular transport of HIV-1 across the blood-brain barrier is mediated by the p38 mitogen-activated protein kinase pathway

Chronic systemic inflammation in the late stage of human immunodeficiency virus type-1 (HIV-1) infection could increase neuroinvasion of infected monocytes and cell-free virus, causing an aggravation of neurological disorders in AIDS patients. We previously showed that the peripheral administration of lipopolysaccharide (LPS) enhanced the uptake across the blood-brain barrier (BBB) of the HIV-1 viral protein gp120. Brain microvessel endothelial cells are targets of LPS. Here, we investigated whether the direct interaction between LPS and the BBB also affected HIV-1 transport using primary mouse brain microvessel endothelial cells (BMECs). LPS produced a dose (1-100 microg/mL)- and time (0.5-4 h)-dependent increase in HIV-1 transport and a decrease in transendothelial electrical resistance (TEER). Whereas indomethacin (cyclooxygenase inhibitor) and L-NAME (NO synthase inhibitor) did not affect the LPS-induced changes in HIV-1 transport or TEER, pentoxifylline (TNF-alpha inhibitor) attenuated the decrease in TEER induced by LPS, but not the LPS-induced increase in HIV-1 transport. LPS also increased the phosphorylation of p44/42 MAPK and p38 MAPK but not that of JNK. U0126 (p44/42 MAPK inhibitor) and SP600125 (JNK inhibitor) did not inhibit the LPS-induced increase in HIV-1 transport although U0126 attenuated the reduction in TEER. SB203580 (p38 MAPK inhibitor) inhibited the LPS-induced increase in HIV-1 transport without affecting TEER. Thus, LPS-enhanced HIV-1 transport is independent of changes in TEER and so is attributed to increased transcellular trafficking of HIV-1 across the BBB. These results show that LPS increases HIV-1 transcellular transport across the BBB by a pathway that is mediated by p38 MAPK phosphorylation in BMECs.

Bone disease and HIV infection

The high prevalence of bone demineralization among human immunodeficiency virus (HIV)-infected patients in the current therapeutic era has been described in multiple studies, sounding the alarm that we may expect an epidemic of fragility fractures in the future. However, despite noting high overall prevalences of osteopenia and osteoporosis, recent longitudinal studies that we review here have generally not observed accelerated bone loss during antiretroviral therapy beyond the initial period after treatment initiation. We discuss the continued progress toward understanding the mechanisms of HIV-associated bone loss, particularly the effects of HIV infection, antiretroviral therapy, and host immune factors on bone turnover. We summarize results of clinical trials published in the past year that studied the safety and efficacy of treatment of bone loss in HIV-infected patients and provide provisional opinions about who should be considered for bone disease screening and treatment.

The Nef-mediated AIDS-like disease of CD4C/human immunodeficiency virus transgenic mice is associated with increased Fas/FasL expression on T cells and T-cell death but is not prevented in Fas-, FasL-, tumor necrosis factor receptor 1-, or interleukin-1beta-converting enzyme-deficient or Bcl2-expressing transgenic mice

CD4(+)- and CD8(+)-T-cell death is a frequent immunological dysfunction associated with the development of human AIDS. We studied a murine model of AIDS, the CD4C/HIV transgenic (Tg) mouse model, to assess the importance of the apoptotic pathway in human immunodeficiency virus type 1 (HIV-1) pathogenesis. In these Tg mice, Nef is the major determinant of the disease and is expressed in immature and mature CD4(+) T cells and in cells of the macrophage/myeloid lineage. We report here a novel AIDS-like phenotype: enhanced death, most likely by apoptosis (as assessed by 7-aminoactinomycin D and annexin V/propidium iodide staining), of Tg thymic and peripheral CD4(+) and CD8(+) T cells. The Tg CD4(+) and CD8(+) T cells were also more susceptible to cell death after activation in vitro in mixed lymph node (LN) cultures. However, activation-induced cell death was not higher in Tg than in non-Tg-purified CD4(+) T cells. In addition, expression of Fas and FasL, assessed by flow cytometry, was increased in CD4(+) and CD8(+) T cells from Tg mice compared to that of non-Tg littermates. Despite the enhanced expression of Fas and FasL on Tg CD4(+) and CD8(+) T cells, Fas (lpr/lpr) and FasL (gld/gld) mutant CD4C/HIV Tg mice developed an AIDS-like disease indistinguishable from lpr/+ and gld/+ CD4C/HIV Tg mice, including loss of CD4(+) T cells. Similarly, CD4C/HIV Tg mice homozygous for mutations of two other genes implicated in cell death (interleukin-1beta-converting enzyme [ICE], tumor necrosis factor receptor 1 [TNFR-1]) developed similar AIDS-like disease as their respective heterozygous controls. Moreover, the double-Tg mice from a cross between the Bcl2/Wehi25 and CD4C/HIV Tg mice showed no major protection against disease. These results represent genetic evidence for the dispensable role of Fas, FasL, ICE, and TNFR-1 on the development of both T-cell loss and organ disease of these Tg mice. They also provide compelling evidence on the lack of protection by Bcl2 against Tg CD4(+)-T-cell death. In view of the high resemblance between numerous phenotypes observed in the CD4C/HIV Tg mice and in human AIDS, our findings are likely to be relevant for the human disease.

Permeability of the blood–brain barrier to HIV-1 Tat

Infection with human immunodeficiency virus-1 (HIV-1) is associated with dysfunctions of the central nervous system (CNS). HIV-1 induces its effects on the CNS by a variety of mechanisms, including by shedding the neurotoxic viral proteins such as gp120 and Tat. Both HIV-1 and gp120 have been shown to cross the blood-brain barrier (BBB). It is has not been determined, however, whether blood-borne Tat can cross the BBB. Here, we found that Tat crosses the BBB by a nonsaturable mechanism with a unidirectional influx rate of about 0.490 microl/g/min. About 0.126% of an intravenous dose of Tat enters each g of brain. Radioactively labeled albumin injected simultaneously did not cross the BBB. The hypothalamus, occipital cortex, and hippocampus were the regions of the brain most permeable to Tat. Nonsaturable brain-to-blood efflux also occurred, most likely with reabsorption into the blood of the cerebrospinal fluid. In conclusion, we found that Tat crossed the BBB bidirectionally. Such permeability could provide a mechanism by which Tat produced on one side of the BBB could affect neural or immune function on the other side.

The use of growth factors and cytokines to treat opportunistic infections in HIV-1 disease

The success of highly active antiretroviral therapy (HAART) in reducing AIDS-related mortality means that in regions where HAART is available, HIV infection may now be regarded as a chronic disease. However the inability of HAART to eliminate HIV-1 from various anatomical and cellular reservoirs within the body means that HIV-infected individuals require life-long treatment with therapy that can have significant side effects. Management of HIV disease is therefore increasingly focused on drug-related toxicities and the improvement of current HAART regimens. Here we review the potential use of immunomodulatory cytokines to directly or indirectly stimulate the mononuclear phagocyte system as adjuncts to current HIV treatment as well as their use in the management of opportunistic infections in individuals who develop immunodeficiency. We argue that cytokines, which stimulate mononuclear phagocyte activity against opportunistic pathogens, may be useful for the treatment of individuals who develop recurrent opportunistic infections. Cytokines may act synergistically with antimicrobial agents to improve outcomes, which is of particular importance since recurrent infections frequently result in resistance to standard antimicrobial treatments. Before their use can be advocated however, given their toxicity and significant cost, the potential benefits of cytokines must be demonstrated in larger clinical trials.

Decreases in plasma TNF-alpha level and IFN-gamma mRNA level in peripheral blood mononuclear cells (PBMC) and an increase in IL-2 mRNA level in PBMC are associated with effective highly active antiretroviral therapy in HIV-infected patients

In this study, we investigated the cytokine profiles of 14 treatment-naive HIV-infected patients on the initiation of highly active antiretroviral therapy (HAART). At baseline, plasma levels of TNF-alpha and its mRNA in peripheral blood mononuclear cells (PBMC) were highest in the most severely immunocompromised patients (<200 CD4+ cells/mm3). After 12 months of HAART, the virus was undetectable in the plasma of all patients (<200 copies/ml), and median CD4 T cell counts had increased (+164 cells/mm3). We also observed a gradual decrease in the number of proviral DNA copies in PBMC and in immune activation, with lower levels of IFN-gamma mRNA in PBMC associated with weaker activation of CD8+ T cells and lower levels of plasma TNF-alpha. IL-2 mRNA levels in PBMC were found to increase in parallel. The decrease in TNF-alpha and IFN-gamma levels and the increase in IL-2 production appear to be correlated with the efficacy of HAART in naive immunocompromised HIV-infected individuals.

Elevated levels of tumor necrosis factor alpha (TNF-alpha) in human immunodeficiency virus type 1-transgenic mice: prevention of death by antibody to TNF-alpha

Homozygous human immunodeficiency virus type 1 (HIV-1)-transgenic mice (Tg26) appear normal at birth but die within 3 to 4 weeks. The skin of these animals shows diffuse scaling and high-level expression of both HIV-1 mRNA and gp120. Previous experiments showed that treatment with human chorionic gonadatropin (hCG) prevented death and the expression of HIV-1 mRNA and gp120. The present experiments were initiated to study the role of tumor necrosis factor alpha (TNF-alpha) in HIV-1-induced pathology. Examination of the sera of Tg26 mice revealed a 50-fold increase in TNF-alpha levels compared to those in nontransgenic mice. Treatment with antibody to TNF-alpha prevented death, resulted in near normal growth, and produced a marked decrease in skin lesions and a profound reduction in the expression of HIV-1 mRNA and gp120. Both TNF-alpha antibody and hCG reduced TNF-alpha levels in sera by approximately 75%. We conclude that TNF-alpha contributes in a major way to HIV-1-induced pathology in transgenic mice and that both hCG and antibody to TNF-alpha prevent the development of pathology by suppressing the level of TNF-alpha.

Gp120 activates children's brain endothelial cells via CD4

Encephalopathy represents a common and serious manifestation of HIV-1 infection in children, but its pathogenesis is unclear. We demonstrated that gp120 activated human brain microvascular endothelial cells (HBMEC) derived from children in up-regulating ICAM-1 and VCAM-1 expression, IL-6 secretion and increased monocyte transmigration across monolayers. Another novel observation was our demonstration of CD4 in isolated HBMEC and on microvessels of children's brain cryosections. Gp120-induced monocyte migration was inhibited by anti-gp120 and anti-CD4 antibodies. This is the first demonstration that gp120 activates HBMEC via CD4, which may contribute to the development of HIV-1 encephalopathy in children.

T(H)1 to T(H)2 shift of cytokines in peripheral blood of HIV-infected patients is detectable by reverse transcriptase polymerase chain reaction but not by enzyme-linked immunosorbent assay under nonstimulated conditions

BACKGROUND

Dysregulation of cytokines has been implicated in the pathogenesis of HIV infection. Therefore, we determined tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-4, IL-10, and interferon-gamma (IFN-gamma) mRNA and serum levels in HIV-infected patients under nonstimulated conditions.

MATERIAL AND METHODS

Blood samples of 32 HIV-infected patients and 10 healthy HIV-negative controls were analyzed. Cytokine serum levels were quantified by enzyme-linked immunosorbent assay (ELISA). Cytokine mRNA levels were determined semiquantitatively by competitive reverse transcriptase polymerase chain reaction (RT-PCR) and expressed as ratios relative to those of beta-actin.

RESULTS

Competitive RT-PCR was shown to be more sensitive than protein ELISA in analyzing cytokine production. We found a significant correlation between steady-state mRNA ratios and serum protein levels for TNF-alpha. Significantly higher cytokine mRNA ratios were found in those patients with IL-10 and IFN-gamma levels detectable by ELISA. Steady-state mRNA ratios of TNF-alpha, IL-4, and IL-10 were significantly increased in patients with highly replicative HIV-infection. Furthermore, elevated IL-4:IFN-gamma ratios were related to both high viral load and loss of CD4 cells.

DISCUSSION

Determination of steady-state mRNA ratios by semiquantitative RT-PCR represents a sensitive method to analyze cytokines in peripheral blood of HIV-infected patients under nonstimulated conditions. The data obtained with this technique provide further evidence for a T(H)1 to T(H)2 cytokine shift with progressive HIV disease.

Soluble tumor necrosis factor alpha receptors (sTNF-Rs) in HIV-1-infected intravenous drug users: change in circulating sTNF-R type II level and survival for AIDS patients

This study in intravenous drug users (IVDUs) investigated differences in serum soluble tumor necrosis factor types I and II (sTNFR-I and II) concentrations in HIV-1-infected IVDUs and controls. This study also investigated whether changes of sTNFRs concentration affect the risk of death among patients with AIDS. A cross-sectional study of 54 subjects with AIDS, 47 HIV-seropositive IVDUs, 47 HIV-seronegative IVDUs, and 21 healthy subjects showed that sTNFRs concentration increases from healthy controls to AIDS patients through HIV-seronegative and HIV-seropositive subjects (p < 0.01). sTNFR-I concentration, however, was shown to be similar in HIV-seronegative IVDUs and healthy controls. In the longitudinal study, serum concentration of sTNFRs was determined near AIDS diagnosis in 21 IVDUs and 1 year later (start for the survival study). Cox proportional hazards regression was performed to assess the prognostic value of percent change of sTNFR level alone and in combination with T lymphocyte subsets, HIV-p24 antigenemia and opportunistic infections for death within 240 days. Uni- and multivariate Cox modelling for dichotomised variables according to its median showed an increase of sTNFR-II by at least 30% to be single significant predictor of death: crude relative risk 3.69, p = 0.03; adjusted relative risk 5.67, p = 0.02. Mean survival was 126 days in 11 patients whose sTNFR-II level increased by at least 30%, and 176 days in 10 patients with less change in sTNFR-II (p = 0.02).

CONCLUSIONS

sTNFRs concentration is higher in IVDUs than in healthy controls and is highest in AIDS patients. Survival of patients with AIDS is associated with variation in the concentration of sTNFR-II.

Impact of early HIV-1 RNA and T-lymphocyte dynamics during primary HIV-1 infection on the subsequent course of HIV-1 RNA levels and CD4+ T-lymphocyte counts in the first year of HIV-1 infection. Sydney Primary HIV Infection Study Group

Plasma HIV-1 RNA and CD4+ T-cell counts after HIV-1 seroconversion are important independent markers that predict the clinical course of HIV-1 infection. The prognostic significance of these parameters during primary HIV-1 infection, however, remains largely unknown. In a cohort of 53 male study subjects (age, 33 +/- 7 years), who consecutively presented with primary HIV-1 infection, we analyzed the relationship between early plasma HIV-1 RNA, CD4+ and CD8+ T-cell counts, beta2-microglobulin, and p24-antigen levels determined in the first 3 months and subsequent plasma HIV-1 RNA levels and CD4+ T-cell counts 6 to 12 months after onset of primary symptoms. Peak, nadir, and median HIV-1 RNA levels in the first 30 days were already significantly associated with HIV-1 RNA levels at 6 to 12 months (p = .02, p < .0001, and p = .01, respectively). Similarly, early nadir and median CD4+ T-lymphocyte counts in the first 30 days showed a significant relationship with CD4+ T-cell counts at 6 to 12 months (p = .009 and p = .0008, respectively). Study subjects with an early decline of CD4+ counts to <500 cells/microl had an eightfold higher risk that CD4+ counts were <500 cells/microl at 1 year. Of all evaluated virologic parameters, only nadir HIV-1 RNA at 76 days predicted CD4+ counts at 6 to 12 months (p = .006). Early HIV-1 RNA levels and CD4+ counts are already associated with the time course of those parameters 6 to 12 months after onset of symptoms. Nadir viral load was the strongest predictor of HIV-1 RNA levels as well as of CD4+ counts at 6 to 12 months. An early decline of CD4+ T lymphocytes may be a useful clinical prognostic marker for rapid disease progression.

Granulocyte-Macrophage Colony-Stimulating Factor Upregulates Reduced 5-Lipoxygenase Metabolism in Peripheral Blood Monocytes and Neutrophils in Acquired Immunodeficiency Syndrome

Leukotrienes (LT) are mediators derived from the 5-lipoxygenase (5-LO) pathway, which play a role in host defense, and are synthesized by both monocytes (peripheral blood monocyte [PBM]) and neutrophils (PMN). Because 5-LO metabolism is reduced in alveolar macrophages and PMN from acquired immunodeficiency syndrome (AIDS) subjects, we investigated the synthesis of LT by PBM and PMN from these subjects. There was a reduction (74.2% ± 8.8% of control) in LT synthesis in PBM from human immunodeficiency virus (HIV)-infected compared with normal subjects. Expression of 5-LO (51.2% ± 8.8% of control), and 5-LO activating protein (FLAP) (48.5% ± 8.0% of control) was reduced in parallel. We hypothesized that this reduction in LT synthetic capacity in PBM and PMN was due to reduced cytokine production by CD4 T cells, such as granulocyte-macrophage colony-stimulating factor (GM-CSF). We treated 10 AIDS subjects with GM-CSF for 5 days. PBM 5-LO metabolism ex vivo was selectively increased after GM-CSF therapy and was associated with increased 5-LO and FLAP expression. PMN leukotriene B4(LTB4) synthesis was also augmented and associated with increased 5-LO, FLAP, and cytosolic phospholipase A2 expression. In conclusion, as previously demonstrated for PMN, PBM from AIDS subjects also demonstrate reduced 5-LO metabolism. GM-CSF therapy reversed this defect in both PBM and PMN. In view of the role of LT in antimicrobial function, cytokine administration in AIDS may play a role as adjunct therapy for infections.

Granulocyte-Macrophage Colony-Stimulating Factor Upregulates Reduced 5-Lipoxygenase Metabolism in Peripheral Blood Monocytes and Neutrophils in Acquired Immunodeficiency Syndrome

Leukotrienes (LT) are mediators derived from the 5-lipoxygenase (5-LO) pathway, which play a role in host defense, and are synthesized by both monocytes (peripheral blood monocyte [PBM]) and neutrophils (PMN). Because 5-LO metabolism is reduced in alveolar macrophages and PMN from acquired immunodeficiency syndrome (AIDS) subjects, we investigated the synthesis of LT by PBM and PMN from these subjects. There was a reduction (74.2% ± 8.8% of control) in LT synthesis in PBM from human immunodeficiency virus (HIV)-infected compared with normal subjects. Expression of 5-LO (51.2% ± 8.8% of control), and 5-LO activating protein (FLAP) (48.5% ± 8.0% of control) was reduced in parallel. We hypothesized that this reduction in LT synthetic capacity in PBM and PMN was due to reduced cytokine production by CD4 T cells, such as granulocyte-macrophage colony-stimulating factor (GM-CSF). We treated 10 AIDS subjects with GM-CSF for 5 days. PBM 5-LO metabolism ex vivo was selectively increased after GM-CSF therapy and was associated with increased 5-LO and FLAP expression. PMN leukotriene B4(LTB4) synthesis was also augmented and associated with increased 5-LO, FLAP, and cytosolic phospholipase A2 expression. In conclusion, as previously demonstrated for PMN, PBM from AIDS subjects also demonstrate reduced 5-LO metabolism. GM-CSF therapy reversed this defect in both PBM and PMN. In view of the role of LT in antimicrobial function, cytokine administration in AIDS may play a role as adjunct therapy for infections.

Spontaneous and antigen-induced production of HIV-inhibitory beta-chemokines are associated with AIDS-free status

The beta-chemokines RANTES, macrophage inflammatory protein (MIP)-1alpha, and MIP-1beta suppress infection by macrophage-tropic strains of HIV and simian immunodeficiency virus (SIV) by binding and down-regulating the viral coreceptor, CCR5. Accordingly, we have examined whether higher levels of CCR5 ligands are associated with a more favorable clinical status in AIDS. A cross-sectional study of 100 subjects enrolled in the Multicenter AIDS Cohort Study at the Baltimore site was conducted to measure chemokine production and lymphocyte proliferation by peripheral blood mononuclear cells (PBMC). Statistical analyses of the data revealed that the production of HIV-suppressive beta-chemokines by HIV antigen-stimulated PBMC was significantly higher in HIV-positive subjects without AIDS compared with subjects with clinical AIDS. Increased chemokine production was also correlated with higher proliferative responses to HIV antigens. Both parameters were significantly lower in the AIDS versus non-AIDS group. Notably, significantly higher levels of MIP-1alpha were also observed with unstimulated PBMC from seronegative subjects at risk for HIV infection released as compared with seropositive and non-Multicenter AIDS Cohort Study seronegative subjects. The association of chemokine production with antigen-induced proliferative responses, more favorable clinical status in HIV infection, as well as with an uninfected status in subjects at risk for infection suggests a positive role for these molecules in controlling the natural course of HIV infection.

HIV infection and pathogenesis: what about chemokines?

Several chemotactic cytokines, or chemokines. inhibit HIV replication by blocking or down regulating chemokine receptors that serve as entry cofactors for the virus. Although the role of chemokine receptors in HIV pathogenesis has been the subject of intense interest, chemokines are comparatively less seriously considered as potential correlates of protection from HIV infection and disease progression. However, a critical analysis of newly available data reveals substantial evidence to support a beneficial role for chemokines in HIV infection and disease. In this review we summarize the results of such studies and their promising implications for HIV infection.

Kinetics of β-Chemokine Levels during Anti-HIV Therapy

Chemokines are pro-inflammatory cytokines that inhibit human immunodeficiency virus type 1 (HIV-1) replication in vitro. We studied the kinetics of the β-chemokines, macrophage inhibitory protein (MIP)-1α, MIP-1β, RANTES, and monocyte chemotactic protein (MCP)-1 in plasma during 12 months of antiretroviral therapy in 26 HIV-1-infected patients and in 11 untreated subjects. Eleven patients with moderate immunodeficiency had HIV-1 RNA levels <50 copies/ml after 1 year, whereas 12 out of 15 patients with severe immunodeficiency had detectable virus. At baseline, MCP-1 levels correlated positively with HIV-1 RNA and DNA levels and inversely with CD4 cell counts. A reverse pattern was seen for the MIP-1β levels. No correlation was seen between MIP-1α or RANTES and any of the parameters. Also, there was a dichotomy between the different β-chemokines in response to therapy. Decreases of MCP-1 and RANTES levels were found, but no durable changes of MIP-1α and MIP-1β. The MCP-1 levels rebounded back to baseline after 1 year in the patients who responded virologically, which could possibly reflect an increased immune activation. The biological consequences of the changes in β-chemokines levels during antiretroviral treatment are still unknown and deserve further studies.