TH1 and TH2 cytokine mRNA and protein levels in human immunodeficiency virus (HIV)-seropositive and HIV-seronegative youths

An Outlook on the Etiopathogenesis of Pulmonary Hypertension in HIV

Although overall survival rates of patients infected with human immunodeficiency virus (HIV) have been significantly improved by antiretroviral therapy (ART), chronic comorbidities associated with HIV result in a worsening quality of life. Pulmonary arterial hypertension (PAH) is the most prevalent comorbidity associated with HIV infection. Despite low viremia and a non-replicative state maintained by ART, few people develop PAH. Previous data from animal models and human pulmonary microvascular endothelial cells (HPMVECs) suggests a constellation of events occurring during the propagation of HIV-associated PAH (HIV-PAH). However, these studies have not successfully isolated HIV virions, HIV-DNA, protein 24 antigen (p24), or HIV-RNA from the pulmonary endothelial cells (ECs). It provides an insight into an ongoing inflammatory process that could be attributed to viral proteins. Several studies have demonstrated the role of viral proteins on vascular remodeling. A composite of chronic inflammatory changes mediated by cytokines and growth factors along with several inciting risk factors such as Hepatitis C virus (HCV) co-infection, genetic factors, male predominance, illegal drug usage, and duration of HIV infection have led to molecular changes that result in an initial phase of apoptosis followed by the formation of apoptotic resistant hyperproliferative ECs with altered phenotype. This study aims to identify the risk factors and mechanisms behind HIV-PAH pathobiology at the host-pathogen interface at the intracellular level.

Treatment with Tumor Necrosis Factor-α Inhibitors, History of Allergy, and Hypercalcemia Are Risk Factors of Immune Reconstitution Inflammatory Syndrome in HIV-Negative Pulmonary Tuberculosis Patients

Immune reconstitution inflammatory syndrome (IRIS) is an immune reaction that occurs along with the recovery of the patient’s immunity. Tuberculosis-related IRIS (TB-IRIS) upon tumor necrosis factor (TNF)-α inhibitor treatment has been reported in non-human immunodeficiency virus (HIV) patients. However, the importance of biological treatment, as a risk factor of IRIS, has not yet been established. In this study, we examined TB-IRIS in non-HIV patients to explore the role of TNF-α inhibitor treatment. Out of 188 patients with pulmonary TB, seven patients had IRIS. We examined univariate logistic and multivariate analysis to elucidate risk factors of TB-IRIS. Univariate analysis indicated that usage of immunosuppressive drugs, TNF-α inhibitors, and history of food or drug allergy were significantly related with TB-IRIS. On initial treatment, the values of serological markers such as serum albumin and serum calcium were significantly related with TB-IRIS. There was a higher mortality rate in patients with TB-IRIS. Furthermore, multivariate analysis revealed that usage of TNF-α inhibitors, history of allergy, and serum hypercalcemia were related to TB-IRIS. Usage of TNF-α inhibitors, history of allergy, and serum hypercalcemia may be independent predictors of TB-IRIS in non-HIV patients. Since higher mortality has been reported for TB-IRIS, we should pay attention to TB patients with these risk factors.

Rapid and Slow Progressors Show Increased IL-6 and IL-10 Levels in the Pre-AIDS Stage of HIV Infection

Cytokines are intrinsically related to disease progression in HIV infection. We evaluated the plasma levels of Th1/Th2/Th17 cytokines in extreme progressors, including slow (SPs) and rapid (RPs) progressors, who were thus classified based on clinical and laboratory follow-up covering a period of time before the initiation of HAART, ranging from 93–136.5 months for SPs and 7.5–16.5 months for RPs. Analyses were also performed based on the different stages of HIV infection (chronic, pre-HAART individuals—subjects sampled before initiating HAART but who initiated therapy from 12 to 24 months—and those receiving HAART). The plasma cytokine levels of 16 HIV-infected rapid progressors and 25 slow progressors were measured using a Human Th1/Th2/Th17 CBA kit. The IL-6 and IL-10 plasma levels differed significantly between the stages of HIV infection. The IL-6 levels were higher in slow progressors pre-HAART than in chronically infected SPs and HIV-seronegative individuals. The IL-10 levels were higher in slow progressors pre-HAART than in slow progressors receiving HAART and HIV-seronegative controls, and in rapid progressors, the IL-10 levels were higher in pre-HAART subjects than in HIV-seronegative controls. The results reflect the changes in the cytokine profile occurring during different clinical stages in HIV+ subjects. Our results suggest an association between increased IL-6 and IL-10 levels and pre-HAART stages independent of the slow or rapid progression status of the subjects. Thus, increased IL-6 and IL-10 levels could indicate a global inflammatory status and could be used as markers of the disease course in HIV-infected individuals.

Comparison of the specificities of IgG, IgG-subclass, IgA and IgM reactivities in African and European HIV-infected individuals with an HIV-1 clade C proteome-based array

A comprehensive set of recombinant proteins and peptides of the proteome of HIV-1 clade C was prepared and purified and used to measure IgG, IgG-subclass, IgA and IgM responses in HIV-infected patients from Sub-Saharan Africa, where clade C is predominant. As a comparison group, HIV-infected patients from Europe were tested. African and European patients showed an almost identical antibody reactivity profile in terms of epitope specificity and involvement of IgG, IgG subclass, IgA and IgM responses. A V3-peptide of gp120 was identified as major epitope recognized by IgG₁>IgG₂ = IgG₄>IgG₃, IgA>IgM antibodies and a C-terminal peptide represented another major peptide epitope for the four IgG subclasses. By contrast, gp41-derived-peptides were mainly recognized by IgG₁ but not by the other IgG subclasses, IgA or IgM. Among the non-surface proteins, protease, reverse transcriptase+RNAseH, integrase, as well as the capsid and matrix proteins were the most frequently and strongly recognized antigens which showed broad IgG subclass and IgA reactivity. Specificities and magnitudes of antibody responses in African patients were stable during disease and antiretroviral treatment, and persisted despite severe T cell loss. Using a comprehensive panel of gp120, gp41 peptides and recombinant non-surface proteins of HIV-1 clade C we found an almost identical antibody recognition profile in African and European patients regarding epitopes and involved IgG-sublass, IgA- and IgM-responses. Immune recognition of gp120 peptides and non-surface proteins involved all four IgG subclasses and was indicative of a mixed Th1/Th2 immune response. The HIV-1 clade C proteome-based test allowed diagnosis and monitoring of antibody responses in the course of HIV-infections and assessment of isotype and subclass responses.

The activation and dynamics of cytokine expression by CD4+ T cells and AIDS progression in HIV-1-infected Chinese individuals

CD4(+) T cells are the main targets of HIV-1 and play a central role during the progression of AIDS, but the mechanism has not been clearly elucidated. In the present study, blood samples were collected from HIV-1-infected Chinese individuals, including typical progressors (TPs) and long-term nonprogressors (LTNPs). More HIV-1 productively infected CD4(+) T cells were obtained through co-cultures and the infected CD4(+) T cells were discriminated from bystander cells by intracellular p24 staining. The activation level and dynamics of cytokine expression of CD4(+) T cells were analyzed. After stimulating the freshly isolated PBMCs with PHA, the frequencies of CD69(+)CD4(+) T cells/CD25(+)CD4(+) T cells were higher in TP than in LTNP group and were positively correlated with viral load and negatively correlated with CD4(+) T cell counts. The activation level of CD4(+) T cells in the co-cultured PBMCs was higher in TP than in LTNP group, and HIV-1 productively infected CD4(+) T cells were more activated than bystander CD4(+) T cells. The expression of Th1 cytokines (IL-2 and IFN-γ) and the frequency of Th1 cells in co-cultured PBMCs were lower in TP than in LTNP group. HIV-1 productively infected CD4(+) T cells expressed higher level of Th1/Th2 cytokines than bystander cells. More productive HIV-1 infection occurred in Th1 than in Th2 cells, followed by Th0 cells. The present results suggest that the excessive activation level of CD4(+) T cells and the preferential replication of HIV-1 in Th1 cells that lead to the shift of Th1 to Th2 are likely crucial to AIDS progression in HIV-1-infected Chinese individuals.

Programmed death 1 receptor changes ex vivo in HIV-infected adults following initiation of highly active antiretroviral therapy

This study investigates the short-term effects of highly active antiretroviral therapy (HAART) on programmed death 1 receptor (PD-1) expression and lymphocyte function. We compared lymphocytes from human immunodeficiency virus (HIV)-infected adults prior to the initiation of HAART with lymphocytes from the same subjects following 2 months of treatment. Short-term HAART resulted in a moderate increase in the expression of PD-1 on both CD4(+) and CD8(+) T cells; yet, there was still a significant reduction in viral load and recovery of CD4(+) T cells. After 2 months of HAART, lymphocytes from the subjects had a reduction in lymphoproliferative responses to phytohemagglutinin (PHA) and an increased response to the Candida recall antigen and the HIV antigen p24 compared to pretreatment lymphocytes. PHA-stimulated peripheral blood mononuclear cells (PBMCs) from samples obtained 2 months after HAART produced higher levels of Th-1 cytokines (gamma interferon [IFN-γ] and tumor necrosis factor alpha[TNF-α]) than the levels observed for samples taken before treatment was initiated. There were no significant changes in the proinflammatory cytokine interleukin-2 (IL-2) or Th-2 cytokines (IL-4, IL-5, and IL-10) in the corresponding samples. Ex vivo PD-1 blockade significantly augmented PHA-induced lymphoproliferation as well as the levels of Th-1 cytokines and to a lesser extent the levels of Th-2 cytokines in PBMC cultures. The ability to downregulate PD-1 expression may be important in enhancing immune recovery in HIV infection.

Expression of γ-chain cytokine receptors on CD8+ T cells in HIV infection with a focus on IL-7Rα (CD127)

When interleukin-2 (IL-2) receptor γ-chain (γ(C))-sharing cytokine receptors on T cells bind their specific ligands (IL-2, -4, -7, -9, -15 or -21), they initiate a variety of cell signals that promote survival, differentiation or antiviral or antitumor cytolytic functions. Although expression of the γ(C) is constitutive across T-cell subsets, the varying expression of other receptor complex components can regulate cytokine signalling and function. Impaired γ(C) cytokine activity in HIV infection, and the role of γ(C) cytokines in CD8(+) T-cell function and homeostasis, implicates these molecules among potential contributors to the observed decline of cytolytic activity (CTL) in HIV disease. In particular, this review will be highlighting information about the IL-7 receptor (IL-7R) complex, which is composed of the γ(C) and the IL-7Rα (CD127) chains. There has been an abundance of HIV-related CD127 research and its important role in CD8(+) T-cell survival and function. The expression of CD127 undergoes dramatic changes throughout the course of T-cell responses in HIV infection. The expression of CD127 is significantly decreased in progressive HIV disease, whereas effective antiretroviral therapy results in its recovery. Observations of impaired IL-7 activity in HIV(+) individuals have suggested that CD127 has an important role in HIV immunopathogenesis. In addition, a soluble form of CD127 (sCD127) is upregulated in the plasma of HIV(+) individuals. Hence, CD127 is being increasingly considered as a marker of disease prognosis, and related information may provide insight into understanding the expression and role of other γ(C) receptors in HIV disease and contribute to the development of novel cytokine-based therapeutics.

Identification of three immunologic correlates for HIV type 1 pathogenesis in youth

To evaluate the stability and heterogeneity of cytokine and chemokine profiles in 80 youth with and without HIV-1 infection, we tested plasma samples at repeated visits without antiretroviral therapy. Among nine analytes that were quantified using multiplexing assays, interleukin 10 (IL-10), IL-18, and soluble CD30 persistently showed a positive correlation with HIV-1 viral load (Spearman ρ = 0.40-0.59, p < 0.01 for all). A negative correlation with CD4(+) T cell counts (ρ = -0.40 to -0.60, p < 0.01 for all) was also persistent for the three analytes. Analyses restricted to 48 AIDS-free youth (96 visits) yielded similar findings, as did multivariable models in which race, sex, age, body mass index, and time interval between visits were treated as covariates. These relationships reflected two novel features observed for all three analytes. First, their presence in plasma was relatively stable between visits (ρ = 0.50-0.90, p < 0.03), regardless of HIV-1 infection status. Second, pairwise correlation was strong and persistent in HIV-1-seropositive youth (ρ = 0.40-0.59, p < 0.01), but not in HIV-1, seronegatives (p > 0.13). Additional analytes, especially eotaxin/CCL11 and SDF-1β/CXCL12, had no correlation with HIV-1-related outcomes despite their stability between visits. Overall, circulating IL-10, IL-18, and soluble CD30 could partially track unfavorable responses to HIV-1 infection in youth. These markers of persistent immune activation are individually and collectively indicative of HIV-1 pathogenesis.

The relevance of cytokines for development of protective immunity and rational design of vaccines

Cytokines are key regulators of the immune system that shape innate and adaptive immune responses. An adequate balance of the cytokine environment is critical to achieve protective immunity and to avoid immunopathology. Present knowledge allows a deeper understanding of the cytokine network and their sometimes conflicting roles in the development of immune responses, as well as their relevance in the establishment and maintenance of immunological memory. New insights have been gained into the role of different T cell subsets for protection against infection or tumor growth. The incorporation of cytokines as molecular adjuvants in vaccines has been attempted to strengthen vaccine-induced immune responses, and as a rational approach to modulate cytokine milieu in vivo and tailor host immunity for specific situations. These approaches have been tried in experimental models and veterinary species, and a few of them have entered into clinical trials. However, manipulating the cytokine network to modulate immune responses is not a simple task, because cytokine functions are complex and the final effects on the immune response will depend on timing and length of exposure, cell(s) targeted and other cytokines present in the same microenvironment. Here, we will review our present understanding on the role of cytokines in the development of effector and memory T cell responses. Also the potential use of cytokines as molecular adjuvant for vaccines against infectious diseases and cancer will be revised.

Hepatitis C virus genotype and HIV coinfection affect cytokine mRNA levels in unstimulated PBMC but do not shift the T1/T2 balance

Rapid progression of hepatitis C virus (HCV) disease in patients with HIV/HCV may reflect different cytokine responses and be influenced by HCV genotype. This is addressed by a study of patients with HIV/HCV coinfection and infection with HCV genotype 2 or 3 (2/3). They are compared with coinfected patients infected with genotype 1 and HCV monoinfected patients matched for HCV genotype. IFN-gamma, IL-10, IL-4 and IL-4delta2 mRNA were quantified by real-time PCR in unstimulated PBMC and after in vitro stimulation with HCV core or nonstructural 3/4A antigen. In unstimulated PBMC, levels of IFN-gamma and IL-4 mRNA were lowest in HIV/HCV genotype 1 patients, intermediate in HIV/HCV genotype 2/3 patients and highest in HCV genotype 2/3 patients. Neither HCV genotype nor HIV affected levels of IL-10 mRNA in unstimulated PBMC or IFN-gamma, IL-4 and IL-10 mRNA in PBMC stimulated with HCV antigens. Levels of IL-4 and IL-4delta2 mRNA correlated in mitogen-stimulated PBMC from all patient groups but both were low in HIV/HCV genotype 1 patients. Serum soluble CD30 levels (a putative marker of a T2 cytokine environment) did not differ between patient groups. The data do not suggest a shift in the T1/T2 balance driven by HIV coinfection or HCV genotype but either may affect IL-4 bioavailability.