Type 1 and type 2 cytokines in HIV infection -- a possible role in apoptosis and disease progression

Lymphopenia an important immunological abnormality in patients with COVID-19: Possible mechanisms

The lymphopenia as a major immunological abnormality occurs in the majority of severe COVID-19 patients, which is strongly associated with mortality rate. A low proportion of lymphocytes may express the main receptor for SARS-CoV-2, called angiotensin-converting enzyme 2 (ACE2). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can also use ACE2-independent pathways to enter lymphocytes. Both SARS-CoV-2- and immune-mediated mechanisms may contribute to the occurrence of lymphopenia through influencing the lymphocyte production, survival or tissue re-distribution. The metabolic and biochemical changes can also affect the production and survival of lymphocytes in COVID-19 patients. Lymphopenia can cause general immunosuppression and promote cytokine storm, both of them play an important role in the viral persistence, viral replication, multi-organ failure and eventually death. Here, a comprehensive view concerning the possible mechanisms that may lead to the lymphocyte reduction in COVID-19 patients is provided, while highlighting the potential intervention approaches to prevent lymphopenia.

Correlation of High Interleukin 17A and Interleukin 6 Levels with High Virus Load Among Subtype C HIV-infected, Antiretroviral Therapy-naive Zimbabwean Patients: A Cross-sectional Study

Introduction:

In response to the human immunodeficiency virus (HIV) infection, activated immune cells produce several cytokines that alter the immune response and HIV disease progression. We quantified Th1/Th2/Th17 cytokines in an antiretroviral therapy naïve (ART) cohort to investigate their correlation with traditional markers of HIV disease progression; CD4+ T-lymphocytes and virus load (VL).

Methods:

We enrolled 247 HIV-infected ART-naïve participants into the study. CD4+ T- and CD8+ T-lymphocytes were enumerated using flow cytometry. VL was quantified using the Cavidi ExaVirTM Load assay. IL-2, IL-4, IL-6, IL-10, IL-17A, TNF-α, and IFN-γ levels were quantified using the BD Cytometric Bead Array Human Th1/Th2/Th17 cytokine assay. The Kendall’s rank correlation coefficient was used to determine the correlation between log10 transformed data for cytokine levels and CD4+ T- and CD8+ T-lymphocytes, CD4/CD8 ratio, and VL.

Results:

The median CD4+ T- and CD8+ T-lymphocyte counts were 458 cells/µL (IQR:405-556) and 776 cells/µL (IQR:581-1064), respectively. The median CD4/CD8 ratio was 0.6 (IQR: 0.45-0.86). The median VL was log103.3.copies/mL (IQR:2.74-3.93). Low CD4+ T-lymphocyte counts (p=0.010) and CD4/CD8 ratio (p=0.044) were significantly correlated with high VL. There was no significant correlation of cytokine levels with CD4+ T-, CD8+ T-lymphocyte counts and CD4/CD8 ratio. However, high levels of IL-17A (p=0.012) and IL-6 (p=0.034) were significantly correlated with high VL.

Conclusion:

Our study contributes to the little knowledge available on the role of cytokine profiles in the immune response to subtype C HIV infection.

Vernal keratoconjunctivitis in human immunodeficiency virus - The possible role of T-helper 1-T-helper 2 shift

Human immunodeficiency virus infection (HIV) is associated with a reduced T-helper (Th) 1 response, and vernal keratoconjunctivitis (VKC) occurs secondary to a heightened Th2 response. VKC has been reported to occur in patients with HIV. In all probability, a Th1–Th2 shift occurs in the immune response in progressive HIV patients with a decreasing CD4 count. This shift could be the probable cause for the initiation and gradual worsening of the VKC in our patient that corresponded to the dropping CD4 counts. VKC resolved only after a change in antiretroviral therapy for HIV that caused a demonstrable increase in the CD4 counts possibly by reversing the shift.

Interleukin-10 production at the early stage of infection with foot-and-mouth disease virus related to the likelihood of persistent infection in cattle

The factors leading to persistent infection of foot-and-mouth disease (FMD) virus in ruminants are not well defined. This paper provides evidence of the presence of interleukin-10 (IL-10) early in the course of infection (1–4 days) as a factor in the development of persistence of FMD virus in cattle. Results showed that serum IL-10 in carrier cattle infected with FMD virus type O (n = 4) was detected and peaked at 1 or 2 days post infection and rapidly declined thereafter. In contract, serum IL-10 levels in non-carrier cattle (n = 21) were very low or undetectable during the same period.

Immunoendocrine interactions during HIV-TB coinfection: implications for the design of new adjuvant therapies

Worldwide, around 14 million individuals are coinfected with both tuberculosis (TB) and human immunodeficiency virus (HIV). In coinfected individuals, both pathogens weaken immunological system synergistically through mechanisms that are not fully understood. During both HIV and TB infections, there is a chronic state of inflammation associated to dramatic changes in immune cytokine and endocrine hormone levels. Despite this, the relevance of immunoendocrine interaction on both the orchestration of an effective immune response against both pathogens and the control of the chronic inflammation induced during HIV, TB, or both infections is still controversial. The present study reviews immunoendocrine interactions occurring during HIV and TB infections. We also expose our own findings on immunoendocrine cross talk in HIV-TB coinfection. Finally, we evaluate the use of adrenal hormones and their derivatives in immune-therapy and discuss the use of some of these compounds like the adjuvant for the prevention and treatment of TB in HIV patients.

Hypothalamic-pituitary-adrenal axis in HIV infection and disease

HIV infection induces hypothalamic-pituitary-adrenal (HPA) axis derangements. Partial glucocorticoid resistance has been observed in a subset of AIDS patients, possibly owing to HIV-induced altered cytokine secretion and action. Because glucocorticoids have immunomodulatory effects, the severity of the HPA axis disorder could play a central role in disease progression. The characteristic phenotype of AIDS patients (visceral obesity, lipodystrophy) may be owing to effects of HIV proteins on the HPA axis, including changes in glucocorticoid and insulin sensitivity of target tissues, as well as altered cytokine production and interaction with the HPA axis, genetic causes, comorbidities, and, possibly, use of antiretroviral agents.

Human immune deficiency virus (HIV) infection and the hypothalamic pituitary adrenal axis

The hypothalamic pituitary adrenal (HPA) axis is the most common of the endocrine lines/axis' to be affected by HIV infection. There are multiple factors that contribute to this HPA axis dysregulation. Direct invasion of the various organs in the axis can be either by opportunistic infections or infiltrative diseases. The soluble factors or cytokines released during viral infection and the chronic inflammatory state that follows, also contribute to these alterations. The actions of these cytokines released by the immune response can both activate the HPA axis and cause a glucocorticoid resistant state. Further, many of the anti-retroviral and other medications used to treat HIV infection can contribute to HPA axis dysfunction. While the diagnosis and treatment of endocrine dysfunction is the same as in any other patient, management pathways may be quite different. While some may be adaptive responses, life threatening adrenal insufficiency can also be present. It is important the latter be picked up expeditiously and treated promptly to avoid mortality.

The influence of depression on the progression of HIV: direct and indirect effects

The authors suggest a theoretical model of pathways of HIV progression, with a focus on the contributions of depression-as well as secondary, behavioral and emotional variables. Literature was reviewed regarding (a) comorbid depression and the direct physiological effects on HIV progression and (b) intermediary factors between HIV and disease progression. Intermediary factors included (a) substance use, (b) social support, (c) hopelessness, (d) medication nonadherence, and (e) risky sexual behavior and the contraction of secondary infections. The authors suggest direct physiological pathways from depression to HIV progression and indirect pathways (e.g., behavioral, social, and psychological). In addition to depression, substance use, poor social support, hopelessness, medication nonadherence, and risky sexual behavior seem to be integral in HIV progression. Based on the individual relationships of these variables to depression and HIV progression, a comprehensive multipath model, incorporating all factors, serves to explain how severe emotional distress may lead to accelerated progression to AIDS.

Laboratorial atopy markers in children with human immunodeficiency virus

Changes in immune system functions are one of the most important consequences of human immunodeficiency virus (HIV) infection. Studies have reported a higher prevalence of disease mediated by immunological hypersensitivity mechanisms in HIV-positive patients. This study aims to observe how immunological changes in HIV-infected children interfere in atopy determinants. Fifty-seven HIV-positive children were studied between June 2004-August 2005 to evaluate the possible modifications in atopy diagnosis from prick test environmental allergen reactivity. Patients were subjected to two evaluations: on both occasions, atopic and non-atopic groups were correlated with immunological (CD4+ and CD8+ lymphocyte concentrations and serum levels of IgA, IgM, IgG and IgE) and viral parameters (HIV viral load). The percent atopy was 20.05 in the first and 29.82 in the second evaluation and atopy was diagnosed in patients without immunosuppression or with moderate immunosuppression. Six patients changed from a negative to a positive atopy profile. One patient with a decreased CD4+ T lymphocyte concentration failed to demonstrate prick test positivity between evaluations. Multivariate analysis showed that the variables associated with atopy diagnosis included a personal history of allergic diseases as well as elevated IgE for age and elevated IgE levels. Atopy development in HIV-infected children seems to be modulated by genetic and environmental factors as well as immunological condition.

Phenotypic and Functional Effects of Heat Shock Protein 90 Inhibition on Dendritic Cell

The 90-kDa heat shock protein (Hsp90) plays an important role in conformational regulation of cellular proteins and thereby cellular signaling and function. As Hsp90 is considered a key component of immune function and its inhibition has become an important target for cancer therapy, we here evaluated the role of Hsp90 in human dendritic cell (DC) phenotype and function. Hsp90 inhibition significantly decreased cell surface expression of costimulatory (CD40, CD80, CD86), maturation (CD83), and MHC (HLA-A, B, C and HLA-DP, DQ, DR) markers in immature DC and mature DC and was associated with down-regulation of both RNA and intracellular protein expression. Importantly, Hsp90 inhibition significantly inhibited DC function. It decreased Ag uptake, processing, and presentation by immature DC, leading to reduced T cell proliferation in response to tetanus toxoid as a recall Ag. It also decreased the ability of mature DC to present Ag to T cells and secrete IL-12 as well as induce IFN-gamma secretion by allogeneic T cells. These data therefore demonstrate that Hsp90-mediated protein folding is required for DC function and, conversely, Hsp90 inhibition disrupts the DC function of significant relevance in the setting of clinical trials evaluating novel Hsp90 inhibitor therapy in cancer.

Resolution of a chronic viral infection after interleukin-10 receptor blockade

A defining characteristic of persistent viral infections is the loss and functional inactivation of antiviral effector T cells, which prevents viral clearance. Interleukin-10 (IL-10) suppresses cellular immune responses by modulating the function of T cells and antigen-presenting cells. In this paper, we report that IL-10 production is drastically increased in mice persistently infected with lymphocytic choriomeningitis virus. In vivo blockade of the IL-10 receptor (IL-10R) with a neutralizing antibody resulted in rapid resolution of the persistent infection. IL-10 secretion was diminished and interferon γ production by antiviral CD8⁺ T cells was enhanced. In persistently infected mice, CD8α⁺ dendritic cell (DC) numbers declined early after infection, whereas CD8α⁻ DC numbers were not affected. CD8α⁻ DCs supported IL-10 production and subsequent dampening of antiviral T cell responses. Therapeutic IL-10R blockade broke the cycle of IL-10–mediated immune suppression, preventing IL-10 priming by CD8α⁻ DCs and enhancing antiviral responses and thereby resolving infection without causing immunopathology.

Immune modulation of the hypothalamic-pituitary-adrenal (HPA) axis during viral infection

Compelling data has been amassed indicating that soluble factors, or cytokines, emanating from the immune system can have profound effects on the neuroendocrine system, in particular the hypothalamic- pituitary-adrenal (HPA) axis. HPA activation by cytokines (via the release of glucocorticoids), in turn, has been found to play a critical role in restraining and shaping immune responses. Thus, cytokine-HPA interactions represent a fundamental consideration regarding the maintenance of homeostasis and the development of disease during viral infection. Although reviews exist that focus on the bi-directional communication between the immune system and the HPA axis during viral infection (188,235), others have focused on the immunomodulatory effects of glucocorticoids during viral infection (14,225). This review, however, concentrates on the other side of the bi-directional loop of neuroendocrine-immune interactions, namely, the characterization of HPA axis activity during viral infection and the mechanisms employed by cytokines to stimulate glucocorticoid release.

Human immunodeficiency virus type 1 Vpr impairs dendritic cell maturation and T-cell activation: implications for viral immune escape

Antigen presentation and T-cell activation are dynamic processes involving signaling molecules present in both APCs and T cells. Effective APC function and T-cell activation can be compromised by viral immune evasion strategies, including those of human immunodeficiency virus type 1 (HIV-1). In this study, we determined the effects of HIV-1 Vpr on one of the initial target of the virus, dendritic cells (DC), by investigating DC maturation, cytokine profiling, and CD8-specific T-cell stimulation function followed by a second signal. Vpr impaired the expression of CD80, CD83, and CD86 at the transcriptional level without altering normal cellular transcription. Cytokine profiling indicated that the presence of Vpr inhibited production of interleukin 12 (IL-12) and upregulated IL-10, whereas IL-6 and IL-1beta were unaltered. Furthermore, DC infected with HIV-1 vpr+ significantly reduced the activation of antigen-specific memory and recall cytotoxic-T-lymphocyte responses. Taken together, these results indicate that HIV-1 Vpr may in part be responsible for HIV-1 immune evasion by inhibiting the maturation of costimulatory molecules and cytokines essential for immune activation.

Expression of interleukin-10 and interleukin-12 in piglets experimentally infected with porcine reproductive and respiratory syndrome virus (PRRSV)

The expression of mRNA encoding interleukin-10 (IL-10) and IL-12 was studied, by the reverse transcription-polymerase chain reaction and by in-situ hybridization with a non-radioactive digoxigenin-labelled cDNA probe, in formalin-fixed, paraffin wax-embedded lung tissue from piglets inoculated intranasally with a Korean isolate (North American genotype) of porcine reproductive and respiratory syndrome virus (PRRSV). IL-12p35-positive cells were detected in the lung at 1 day post-inoculation (dpi), their number increasing at 5 dpi, and rapidly decreasing thereafter. In contrast, IL-10- and IL-12p40-positive cells were detected in the lung at 1 dpi, their number increasing at 3 dpi, and rapidly decreasing thereafter. Hybridization signals for IL-10, IL-12p35 and IL-12p40 were always associated with inflammation. Expression of these cytokines was minimal in non-lesional lung of PRRSV-infected piglets and in normal lung from control piglets. In-situ hybridization in serial sections of lung tissues indicated close co-localization of PRRSV and these cytokines in interstitial pneumonia. The results suggest that the expression of IL-10 and IL-12 plays a role in pulmonary defence mechanisms against PRRSV infection.

HIV-1 protein Vpr suppresses IL-12 production from human monocytes by enhancing glucocorticoid action: potential implications of Vpr coactivator activity for the innate and cellular immunity deficits observed in HIV-1 infection

The HIV-1 protein Vpr has glucocorticoid receptor coactivator activity, potently increasing the sensitivity of glucocorticoid target tissues to cortisol. Patients with AIDS and normal cortisol secretion have manifestations compatible with glucocorticoid hypersensitivity of the immune system, such as suppression of innate and cellular immunities. The latter can be explained by glucocorticoid-induced inhibition of cytokine networks regulating innate and Th1-driven cellular immunity. We demonstrated that extracellularly administered Vpr protein dose-dependently potentiated glucocorticoid-induced suppression of both mRNA expression and secretion of IL-12 subunit p35 and IL-12 holo-protein, but not IL-12 subunit p40 or IL-10, by human monocytes/macrophages stimulated with LPS or heat-killed, formalin-fixed Staphylococcus aureus (Cowan strain 1). This effect was inhibited by the glucocorticoid receptor antagonist RU 486. Also, Vpr changed the expression of an additional five glucocorticoid-responsive genes in the same direction as dexamethasone and was active in potentiating the trans-activation, but not the trans-repression, properties of the glucocorticoid receptor on nuclear factor kappaB- or activating protein 1-regulated simple promoters. Thus, extracellular Vpr enhances the suppressive actions of the ligand-activated glucocorticoid receptor on IL-12 secretion by human monocytes/macrophages. Through this effect, Vpr may contribute to the suppression of innate and cellular immunities of HIV-1-infected individuals and AIDS patients.

Immunity to Candida

Candida species are commensal fungal organisms as well as opportunistic pathogens of mucosal tissues. From the commensal relationship, most healthy individuals have demonstrable Candida-specific immunity. In immunocompromised persons, however, fungal infections caused primarily by C. albicans often occur. In HIV disease, up to 90% of HIV+ persons will have a symptomatic episode of oropharyngeal candidiasis (OPC) sometime during progression to AIDS, many of which become recurrent. In contrast, vulvovaginal candidiasis (VVC) and systemic Candida infections (candidaemia) are much less common during HIV disease, indicating the diversity and compartmentalization of the host response to Candida. Both innate resistance and acquired immunity play some role in maintaining C. albicans in the commensal state and protecting the systemic circulation. Polymorphonuclear leukocytes (PMNL) are critical for protection against systemic infections, whereas cell-mediated immunity (CMI) by Th1-type CD4+ T-cells is important for protection against mucosal infections. However, there is a discordant role for CMI at the vaginal versus oral mucosa, whereas little to no role for local or systemic CMI is evident at the vaginal mucosa. In contrast, there is a strong correlation between reduced blood CD4+ cells and the incidence of OPC, but it remains unclear whether systemic or local CMI is more important. Evaluation of systemic CMI in a cohort of HIV+ individuals with and without mucosal candidiasis revealed that Candida-specific CMI is not different between HIV+ persons with OPC or VVC and HIV- persons. Thus, the correlation of reduced CD4+ cell numbers to OPC may be explained by the requirement for a threshold number of systemic CD4+ cells to protect the oral mucosa together with the status of local immunity. Indeed, HIV+ persons with and without OPC had a Th2-type salivary cytokine profile suggestive of susceptibility to Candida infection compared with a protective Th0/Th1-type profile in HIV- persons. Candida-specific antibodies, although present, are controversial relative to a role in protection or eradication of infection. While studies of mucosal innate resistance are limited, we recently found that epithelial cells from saliva and vaginal lavages of healthy individuals inhibit the growth of Candida in vitro. This epithelial cell anti-Candida activity requires cell contact by viable cells with no role for soluble factors, including saliva. Interestingly, oral epithelial cells from HIV+ persons with OPC had significantly reduced activity, indicating some protective role for the epithelial cells. Taken together, these data suggest that immunity to Candida is site-specific, compartmentalized and involves innate and/or acquired mechanisms from systemic and/or local sources.

Differences between T cell epitopes recognized after immunization and after infection

Evidence suggests that cellular immune responses play a crucial role in the control of HIV and SIV replication in infected individuals. Several vaccine strategies have therefore targeted these CD8(+) and CD4(+) responses. Whether vaccination induces the same repertoire of responses seen after infection is, however, a key unanswered question in HIV vaccine development. We therefore compared the epitope specificity induced by vaccination to that present postchallenge in the peripheral blood. Intracellular cytokine staining of PBMC stimulated with overlapping 15/20-mer peptides spanning the proteins of SIV were measured after DNA/modified vaccinia Ankara vaccination of eight rhesus macaques. Lymphocytes from 8 animals recognized a total of 39 CD8 epitopes and 41 CD4 epitopes encoded by the vaccine. T cell responses were again monitored after challenge with SIVmac239 to investigate the evolution of these responses. Only 57% of all CD8(+) T cell responses and 19% of all CD4(+) T cell responses present after vaccination were recalled after infection as measured in the peripheral blood. Interestingly, 29 new CD8 epitopes and 5 new CD4 epitopes were recognized by PBMC in the acute phase. These new epitopes were not detected after vaccination, and only some of them were maintained in the chronic phase (33% of CD8 and no CD4 responses). Additionally, 24 new CD8 epitopes and 7 new CD4 epitopes were recognized by PBMC in the chronic phase of infection. The repertoire of the immune response detected in the peripheral blood after immunization substantially differed from the immune response detected in the peripheral blood after infection.

Cytokine and chemokine dysregulation in hyper-IgE syndrome

Hyper-IgE syndrome is characterized by severe recurrent staphylococcal infections, eczema, bone abnormalities, and markedly elevated levels of immunoglobulin E (IgE). The genetic basis is not known and the central immunologic defect is largely undefined. Reduced neutrophil chemotaxis is often described, and variable T cell defects have been demonstrated in some patients. It has been hypothesized that hyper-IgE is associated with a Th1/Th2 imbalance. We wished to characterize cytokine and chemokine imbalances that might reflect the underlying disease process or reflect ongoing pathologic processes. Nine patients with hyper-IgE syndrome and six controls were studied. Radioimmunoassays, flow cytometry, and gene array analyses were performed to characterize cytokine and chemokine production. Hyper-IgE patients express more IL-12, while ENA-78, MCP-3, and eotaxin are markedly underexpressed. Underexpression of a set of chemokines could explain a number of features of hyper-IgE syndrome and may offer a new paradigm for the understanding of this disorder.

Macaques with rapid disease progression and simian immunodeficiency virus encephalitis have a unique cytokine profile in peripheral lymphoid tissues

The influence of host cytokine response on viral load, disease progression, and neurologic lesions was investigated in the simian immunodeficiency virus (SIV)-infected macaque model of AIDS. Cytokine gene expression (interleukin-1beta [IL-1beta], IL-2, IL-6, IL-10, gamma interferon [IFN-gamma], and tumor necrosis factor alpha [TNF-alpha]) and viral loads were evaluated by semiquantitative reverse transcription-PCR in lymph nodes of 5 control animals and 28 animals infected with SIVmac251 at the terminal stages of AIDS. Infected animals showed higher expression of IFN-gamma, IL-6, and IL-10 mRNAs compared with controls. Levels of all cytokines were comparable between animals with rapid (survival, <200 days) or slow/normal (survival, >200 days) disease progression. However, among rapid progressors, the eight animals with SIV encephalitis had a unique cytokine profile (increased IL-2, IL-6, and IFN-gamma) that was associated with higher viral loads. These observations provide evidence that host cytokine responses may influence SIV neuropathogenesis independent of disease progression.

IL-10 mediation of activation-induced TH1 cell apoptosis and lymphoid dysfunction in polymicrobial sepsis

Recent studies suggest that increased activation-induced lymphocyte apoptosis (AICD) is detected in mouse splenocytes during polymicrobial sepsis which may contribute to lymphocyte immune dysfunction [i.e., decreased interleukin (IL-)2 and interferon-gamma (IFN-gamma) production] leading to the associated morbidity seen in those animals. Thus, we wanted to examine the hypothesis that immune suppressive agents, such as IL-4, IL-10 or prostaglandin E2(PGE2), known to be elevated in septic animals, also contribute to this increase in AICD. Here we demonstrate that the inclusion of monoclonal antibody (mAb) to IL-10, but not anti-IL-4 or ibuprofen (IBU), blunted this sepsis induced increase in splenocyte AICD. Additionally, septic mice deficient in the IL-10 gene product (-/-) showed neither an increase in AICD nor a loss of IL-2/IFN-gamma release capacity. Interestingly, mAb to IL-10 did not altered the extent of AICD in a Th2-cell line, but exogenous IL-10 did potentiate Th1-like cell line AICD. This was consistent with the finding that the increased AICD seen in septic mouse splenocytes was restricted largely to the CD4+ cells producing IL-2 (Th1-cells) and that mAb to IL-10 treatment suppressed this change. Furthermore, IL-10 appears to mediate its AICD effect by upregulation of the Fas receptor and Fas receptor signaling protein components, but not by altered expression of Bcl/Bax/Bad family members, in septic mouse splenocytes. To the extent that these processes contribute in a pathological fashion to the animal's capacity to survive sepsis we have previously observed that in vivo post-treatment of mice with mAb IL-10 markedly attenuated septic mortality. Collectively, these data indicate that in the septic mouse the Th2 cytokine IL-10 not only serves to actively induce Th1 lymphocyte immune dysfunction but also plays a role in their apoptotic depletion. These processes in turn appear to contribute to the animal's inability to ward off lethal septic challenge.

TH2 lymphocytes from atopic patients treated with immunotherapy undergo rapid apoptosis after culture with specific allergens

BACKGROUND

In atopic patients treatment with specific immunotherapy (SIT) induced a shift in the balance of T-cell immune response away from a T(H)2-type (producing mostly IL-4) in favor of a T(H)1-type T-lymphocyte response (with the preferential production of IFN-gamma). However, the mechanisms through which SIT acts are less clear. We have recently shown that allergens may induce an activation-induced cell death process in lymphocytes from SIT-treated atopic patients.

OBJECTIVE

This study aimed to determine whether allergen-induced apoptosis can occur in a specific subset of cells.

METHODS

The study was performed in lymphocytes from normal subjects and atopic patients, some of whom were treated with SIT. Cells were cultured in the presence of gramineous pollen (Lolium perenne) allergenic extracts. Cell phenotype and intracellular cytokine expression were measured by means of fluorescent mAbs. Apoptosis was measured by using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling. Fluorescence was analyzed in a FACScan flow cytometer, and the data were evaluated with Consort 30 software.

RESULTS

Our results showed that allergens induce apoptosis of lymphocytes in SIT-treated atopic patients. Apoptosis occurs mainly in T(H)2 lymphocytes with the IL-4+/CD4+ phenotype and subsequently increases the percentage of IFN-gamma(+) cells in the culture.

CONCLUSION

These results suggest that the shift from T(H)2 to T(H)1 induced by SIT in atopic patients may be mediated, at least in part, by the induction of an activation-induced cell death process in allergen-responder T(H)2 cells.

Opposite effects of IL-10 on the ability of dendritic cells and macrophages to replicate primary CXCR4-dependent HIV-1 strains

We investigated the effect of IL-10 on replication of primary CXCR4-dependent (X4) HIV-1 strains by monocyte-derived dendritic cells (DCs) and macrophages (M Phis). M Phis efficiently replicated CXCR4-dependent HIV-1 (X4 HIV-1) strains NDK and VN44, whereas low levels of p24 were detected in supernatants of infected DCs. IL-10 significantly increased X4 HIV-1 replication by DCs but blocked viral production by M Phis as determined by p24 levels and semiquantitative nested PCR. IL-10 up-regulated CXCR4 mRNA and protein expression on DCs and M Phis, suggesting that IL-10 enhances virus entry in DCs but blocks an entry and/or postentry step in M Phis. The effect of IL-10 on the ability of DCs and M Phis to transmit virus to autologous CD4(+) T lymphocytes was investigated in coculture experiments. DCs exhibited a greater ability than did M Phis to transmit a vigorous infection to CD4(+) T cells despite their very low replication capacity. IL-10 had no effect on HIV-1 replication in DC:T cell cocultures but markedly decreased viral production in M Phi:T cell cocultures. These results demonstrate that IL-10 has opposite effects on the replication of primary X4 HIV-1 strains by DCs and M Phis. IL-10 increases X4-HIV-1 replication in DCs but does not alter their capacity to transmit virus to CD4(+) T lymphocytes. These findings suggest that increased levels of IL-10 observed in HIV-1-infected patients with disease progression may favor the replication of X4 HIV-1 strains in vivo.

Regulation of interleukin 12 and interleukin 10 expression in vaccinia virus-infected human monocytes and U-937 cell line

Regulation of IL-12 and IL-10 production in normal human monocytes infected with vaccinia virus (VV) was analysed. IL-12 and IL-10 mRNAs were measured by reverse transcriptase-polymerase chain reaction (RT-PCR) and IL-12 and IL-10 protein by ELISA. RT-PCR analysis revealed a marked-up regulation of IL-12 (p40) and IL-10 expression in virally infected cells compared with that from control (non-infected) cells at 24 h post-infection (p.i.). IL-12 transcripts occurred earlier (at 4 h p.i.) than IL-10 mRNA. A significant increase in IL-12 and IL-10 secretion into the medium was caused by the virus, and even a much more pronounced increase in both interleukins expression (mRNAs and proteins) followed LPS or Staphylococcus aureus treatment. Vaccinia virus infection did not alter IL-10 secretion and IL-10 mRNA content (or even cause a decrease) in a human monocytic cell line U937. Undetectable levels of IL-12 protein were found in the cell line although the transcripts were present in the cells at first hours p.i. It appears now that vaccinia virus transiently and sequentially induces IL-12 and IL-10 in human monocytes.

Predictors of atopy in HIV-infected patients

BACKGROUND

Some studies have reported an increase of atopy in HIV-infected (HIV+) patients, but the cause still remains unclear.

OBJECTIVE

To determine the prevalence of atopy in HIV+ patients and to investigate its predictors.

METHODS

Seventy-four HIV+ hospitalized patients (46 of them with AIDS) were studied prospectively for the presence of atopy, based on immediate hypersensitivity to common allergens by prick test. Serum immunoglobulins, specific IgE, lymphocyte subsets, and the expression of low affinity IgE receptor (CD23) on B cells were determined.

RESULTS

Thirty-one percent of patients presented IgE values greater than 150 ku/L (39% of patients without AIDS and 26% of AIDS patients; P = .23) and 47% showed an increase (> or = 2%) in the percentage of CD23+ B cells. Non-AIDS patients had higher IgE values than AIDS patients (346 +/- 605 versus 175 +/- 276; P = .16). Atopy prevalence was higher in non-AIDS than in AIDS patients (28% versus 11%; P = .06). Specific IgE agreed with positive prick test in 58% of cases. Multivariate analysis showed that a personal history suggestive of allergic disease and IgE > 150 ku/L were predictors of atopy, while gender, risk group, CD4+ T cells, CD23 expression on B cells, and AIDS were not associated.

CONCLUSIONS

HIV+ patients present a higher prevalence of atopy in early stages of HIV infection than general population. Since allergic reactions could accelerate HIV-infection by increasing type 2 cytokines, it is important to evaluate the atopic state in HIV+ patients with IgE > 150 ku/L or with suggestive allergic history in order to prevent it.

[Role of cytokines and chemokines in the non-progression of HIV infection in vertically infected children]

BACKGROUND

To study the cytokine production in vertically HIV-1-infected children with more of 7 years of HIV infection and different pattern of progression.

PATIENTS AND METHODS

We study 32 HIV-1-infected children: 8 NA children (age > 7 years, asymptomatic or with light symptoms, without antiretroviral treatment and TCD4+ > 25%); 10 NE1 children (> 6 years, symptomatic, with antiretroviral treatment and TCD4+ > 25%); 14 NE2-3 children (> 6 years, symptomatic, with antiretroviral treatment and TCD4+ < 25%) and 16 (C) controls, children non-VIH+. The peripheral mononuclear cells of HIV-infected children (PBLs) were cultivated and cytokine production was quantified in the supernatant.

RESULTS

The non-stimulated PBMC from HIV-infected children produced more TNF-alpha and less IL-2 that C-group. The production of IFN-gamma was lower in the groups NE1 and NE2-3 than in C-group. The production of IFN-gamma was higher in group NA than in NE2-3. In the phytohaemagglutinin (PHA) stimulated PBLs, the production of TNF-alpha was higher in NA and NE1 than in controls. The production of IL-2 was similar in NA and NE1 than in controls. The production of IL-2 was similar in NA and NE1 than in control group, but the groups NE2-3 produced less IL-2 than control and NE1 groups. The production of IFN-gamma and RANTES were significantly higher in NA than in controls. The groups NE1 and NE2-3 produced lower levels of IL-5 than control and NA groups. The groups NE2-3 produced lower levels of IL-10 than control group. The ratio IFN-gamma/IL-5 and IFN-gamma/IL-10 were higher in group NA than in control and NE1.

CONCLUSIONS

In non-progressors HIV-infected children the immune response is conserved and we have observed an increased Th1 response, while in progressors HIV-infected children receiving antiretroviral treatment we could observe a diminished Th2 response. Moreover, our data clearly indicate that the decrease of IL-2 is an early marker of HIV-infection.

Epinephrine-induced mobilization of natural killer (NK) cells and NK-like T cells in HIV-infected patients

HIV infection is known to cause changes in phenotype and function of natural killer (NK) cells. The aim of this study was to characterize the NK cells mobilized from peripheral reservoirs in human immunodeficiency virus (HIV)-infected patients and controls. Seventeen HIV-infected patients and eight age- and sex-matched controls received a 1-h epinephrine infusion. Epinephrine induced mobilization of high numbers of NK-like T cells with no difference between HIV-infected patients and controls. Interestingly, all subjects mobilized NK cells containing increased proportions of perforin, in particular the CD3(-)CD16(+)CD56(+) NK cell subset. The HIV-infected patients mobilized CD3(-)CD16(-)CD56(+) and CD3(-)CD16(+)CD56(+) NK cells to a lesser extent than did controls. In contrast, the HIV-infected patients mobilized relatively more CD3(-)CD16(+)CD56(-) NK cells independent of antiretroviral treatment. It is suggested that these cells represent an immature NK cell subpopulation possibly resulting from an impaired cytokine tissue environment in HIV-infected patients.

Reduction in T cell apoptosis in patients with HIV disease following antiretroviral therapy

Patients with HIV infection manifest increased T lymphocyte apoptosis. This study investigated the influence of antiretroviral therapy (ART) upon lymphocyte apoptosis in 23 HIV-infected adults naive to protease inhibitors. Patients were enrolled in a treatment trial consisting of Nelfinavir (NFV), d4T, or NFV + d4T for 24 weeks, followed by triple therapy (NFV + reverse transcriptase inhibitors) for an additional 24 weeks. Spontaneous T cell apoptosis in cultured PBMC decreased by 23.67 +/- 18.2% (P < 0.006) at 48 weeks and plasma HIV RNA decreased by 1.79 +/- 0.59 log(10) RNA copies/ml (P < 0.001). The absolute decrease and slope of T cell apoptosis correlated with plasma virus load and with activated CD8 T cells and was inversely correlated with CD4 T cells. We conclude that reduction in chronic antigenic stimulation and the absence of cellular signals elicited by viral products contribute to the rescue of T lymphocytes from apoptosis, which facilitates immunologic recovery in ART-treated patients.

Antigen-specific cytokine response to hepatitis C virus core epitopes in HIV/hepatitis C virus-coinfected patients

OBJECTIVE

Epidemiological data indicate that hepatitis C virus (HCV) infection runs a more rapid and severe course of disease in HIV-coinfected patients, probably because of an altered immune response.

DESIGN

We investigated whether HCV-specific cytokine responses are affected by HIV coinfection.

METHODS

Using triple colour flow cytometry on peripheral blood lymphocytes after stimulation with the four major immunodominant HCV core T cell epitopes, CT1-CT4, we determined intracytoplasmic production of IFN-gamma, IL-2, IL-4, IL-10 and CD30 expression, a putative surrogate marker of type 2 cells. Fifteen patients with asymptomatic HIV/HCV coinfection (group A), 15 patients with chronic HCV infection (group B) and 10 HIV-infected patients without hepatitis C (group C) were included in the study.

RESULTS

In group A, HCV antigens induced significantly higher IL-2 and IFN-gamma production than groups B and C (P < 0.05). Groups A and B showed a similar induction of CD30, which was significantly higher than in group C (P < 0.001). Remarkably, in group A HCV antigens induced IL-4 production in addition to IL-10 and IFN-gamma in the CD30 subset, whereas in groups B and C no IL-4 induction was observed in this T cell subset (P < 0.002).

CONCLUSION

Our data suggest that asymptomatic HIV coinfection importantly alters the HCV-specific cytokine response towards a greater production of proinflammatory type 1 cytokines. Moreover, the antiviral activity of type 1 cytokines may be modified by an increased production of type 2 cytokines in the CD30 subset. The altered cytokine pattern may contribute to the adverse natural course of hepatitis C in HIV coinfection.

Retrovirally induced switch from production of IL-12 to IL-4 in dendritic cells

Dendritic cells (DC) in HIV-1 infection show a reduced capacity to stimulate primary T cell proliferation. Exposure of bone marrow-derived DC to Rauscher leukemia virus (RLV) provides a mouse model for studying retrovirally induced reduction in stimulatory capacity for T cells. Treatment with IL-12, a cytokine that promotes the development of Th1 cells, has been postulated as a treatment for AIDS and is effective at restoring cell-mediated immunity in mice infected with mouse AIDS virus or with RLV (see Knight, S. C. and Patterson, S., Annu. Rev. Immunol. 1994. 15: 593-615 for references). Here we studied the direct effect of RLV and of IL-12 on bone marrow-derived DC. Normal DC produced IL-12 and IL-10 and stimulated primary allogeneic T cell proliferation. Exposure of DC to RLV caused reduced production of IL-12, production of IL-4 was seen in DC for the first time and T cell stimulation was inhibited. Addition of IL-12 reinstated and enhanced IL-12 synthesis in RLV-treated DC, abrogated production of IL-10 and IL-4 and restored stimulatory activity. Manipulation of cytokine production in DC could be a stratagem that has evolved in the retrovirus to avoid stimulation of cellular responses.

Th1/Th2 cytokine expression in saliva of HIV-positive and HIV-negative individuals: a pilot study in HIV-positive individuals with oropharyngeal candidiasis

Current data suggest that T-helper (Th)2-type cytokine responses are often associated with progression to AIDS in HIV-positive individuals. Similarly, Th2-type cytokines are associated with susceptibility to mucosal candidiasis, of which oropharyngeal candidiasis (OPC) is one of the most common opportunistic infections in HIV-positive individuals. Although little information is available on host defense mechanisms at the level of the oral mucosa, recent studies suggest that local cell-mediated immunity (CMI) is equally or more important than that in the periphery for host defense against mucosal Candida albicans infections. This study investigated the potential presence of oral-associated CMI through the expression of Th1/Th2-type cytokines in saliva of immunocompetent and immunocompromised individuals with and without OPC. Results showed a constitutive mixed Th1/Th2 cytokine expression (Th0) in whole saliva of healthy HIV-negative individuals. In contrast, HIV-positive individuals had a dominant Th2-type salivary cytokine profile (interleukin-4 [IL-4], IL-10) (IL-2, interferon-y [IFN-gamma], IL-12) that seemingly resulted from a lack of Th1-type cytokines rather than enhanced Th2-type cytokines. Moreover, pilot analyses of those with OPC showed evidence for a more profound salivary Th2-type profile. Both HIV-positive and HIV-negative patients, irrespective of CD4 counts, had some level of positive in vitro systemic lymphocyte proliferative responses to C albicans antigens. These results suggest that the Th1/Th2 cytokine dichotomy in HIV disease is detectable in situ in oral secretions and may be a useful indicator of oral-associated CMI to better understand resistance/susceptibility of HIV-positive individuals to oral opportunistic infections, including OPC.