Atopy, anergic status, and cytokine expression in HIV-infected subjects

Airway hyperresponsiveness and inflammation in Japanese patients with human immunodeficiency virus 1 infection

INTRODUCTION

Despite the growing population of long-term survivors with human immunodeficiency virus 1 (HIV) exhibiting asthma-like features worldwide, the pathogenesis underlying airway hyperresponsiveness (AHR) and airway inflammation remains unclear. We aimed to investigate AHR and airway inflammation in an HIV-infected Japanese population.

METHODS

Of 94 Japanese participants, 10 HIV-infected participants with asthma were excluded from the study. We compared the characteristics of HIV-infected (n = 34) and non-HIV-infected participants (n = 50). Eosinophilic, neutrophilic, mixed (eosinophilic and neutrophilic), and paucigranulocytic airway inflammatory phenotypes were classified based on induced sputum characteristics.

RESULTS

The prevalence of AHR in HIV-infected participants (32.4%) was significantly higher than that in their non-HIV-infected counterparts (10.0%) (P = 0.0213). The multivariate nominal logistic regression analysis revealed HIV as an independent risk factor for AHR. HIV-infected participants were significantly more likely to have a neutrophilic airway inflammatory phenotype than non-HIV-infected participants (P = 0.0358). Furthermore, HIV-infected participants with AHR demonstrated a significant correlation between AHR levels and the percentage of sputum neutrophils (r = -0.65, P = 0.0316). The percentage of sputum neutrophils was negatively associated with the blood CD4 cell count (r = -0.66, P = 0.0266).

CONCLUSIONS

We observed the high prevalence of AHR and neutrophilic airway inflammatory phenotype in Japanese participants with stable HIV infection. Our findings provide insight into the mechanisms of AHR and may facilitate the development of novel treatment for individuals with AHR and HIV infection.

Eosinophils: changing perspectives in health and disease

Eosinophils have been traditionally perceived as terminally differentiated cytotoxic effector cells. Recent studies have profoundly altered this simplistic view of eosinophils and their function. New insights into the molecular pathways that control the development, trafficking and degranulation of eosinophils have improved our understanding of the immunomodulatory functions of these cells and their roles in promoting homeostasis. Likewise, recent developments have generated a more sophisticated view of how eosinophils contribute to the pathogenesis of different diseases, including asthma and primary hypereosinophilic syndromes, and have also provided us with a more complete appreciation of the activities of these cells during parasitic infection.

Eosinophils: changing perspectives in health and disease

Eosinophils have been traditionally perceived as terminally differentiated cytotoxic effector cells. Recent studies have profoundly altered this simplistic view of eosinophils and their function. New insights into the molecular pathways that control the development, trafficking and degranulation of eosinophils have improved our understanding of the immunomodulatory functions of these cells and their roles in promoting homeostasis. Likewise, recent developments have generated a more sophisticated view of how eosinophils contribute to the pathogenesis of different diseases, including asthma and primary hypereosinophilic syndromes, and have also provided us with a more complete appreciation of the activities of these cells during parasitic infection.

HIV and asthma, is there an association?

OBJECTIVE

To evaluate whether asthma and airway hyper-responsiveness are associated with HIV infection.

METHODS

We reviewed the literature on HIV-associated pulmonary diseases, pulmonary symptoms, and immune changes which may play a role in asthma. The information was analyzed comparing the pre-HAART era to the post-HAART era data.

RESULTS

HIV-seropositive individuals commonly experience respiratory complaints yet it is unclear if the frequency of these complaints have changed with the initiation of HAART. Changes in pulmonary function testing and serum IgE are seen with HIV infection even in the post-HAART era. An increased prevalence of asthma among HIV-seropositive children treated with HAART has been reported.

CONCLUSION

The spectrum of HIV-associated pulmonary disease has changed with the introduction of HAART. Current data is limited to determine if asthma and airway hyper-responsiveness are more common among HIV-seropositive individuals treated with HAART.

HIV: practical implications for the practicing allergist-immunologist

OBJECTIVES

To review the effects of human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) on allergic diseases and discuss the clinical, pathophysiologic, diagnostic, and therapeutic challenges unique to HIV-infected patients receiving highly active antiretroviral therapy (HAART).

DATA SOURCES

The MEDLINE and OVID databases were searched to identify pertinent articles using the following keywords: HIV, AIDS, IgE, allergic rhinitis, adverse drug reaction, asthma, chronic obstructive pulmonary disease, food allergy, and immunization. References from the chosen articles were also examined.

STUDY SELECTION

Articles were selected based on their relevance to the subject matter and currency.

RESULTS

Human immunodeficiency virus infection causes immunologic alterations that ultimately lead to cell-mediated immune deficiency. In addition, the immune dysfunction caused by HIV also increases the likelihood of developing allergic and other immune-mediated diseases in many patients. HAART is associated with reconstitution of immune system function. While offering protection against infection, immune reconstitution also can provoke immunopathologic conditions. Patients infected with HIV show an increased prevalence of allergic rhinitis, adverse drug reactions, and noninfectious pulmonary complications. The pathophysiology of HIV infection is associated with unique clinical, diagnostic, and therapeutic considerations when treating allergic diseases in HIV-infected patients.

CONCLUSIONS

With the use of HAART and the subsequent decrease in infectious complications, HIV-infected patients now live longer and experience common chronic diseases. Evaluation of HIV-infected patients with rhinitis, asthma, and adverse drug reactions may become more frequent as HAART continues to extend the life expectancy of patients living with HIV. Understanding the interactions between HIV and these conditions can facilitate a knowledgeable approach to treating an HIV-infected patient.

Alterations in mast cell function and survival following in vitro infection with human immunodeficiency viruses-1 through CXCR4

HIV-1 infection leads to a disease that attacks the central regulatory mechanisms of the immune response. As mucosal tissue is one of the primary sites infected with HIV in vivo, we examined the effects of HIV exposure on human mast cells, important components of mucosal defense. Using the human mast cell line, HMC-1, which expresses CXCR4 but not CCR5 on the cell surface, we found that several HIV-1 X4 tropic lab (IIIB, RF) and primary isolates but not R5 (BAL, ADA) isolates productively infected these cells. Furthermore, stem cell factor-dependent mast cells derived from primary fetal liver or cord blood cultures were also productively infected with both X4 and R5 HIV-1 strains. Infection was blocked at the level of viral entry using monoclonal antibodies to CXCR4 and CD4. Treatment of HMC-1 with TNF-alpha and TGF-beta stimulated cell surface expression of CCR5 and up-regulated expression of both CCR5 and CXCR4 on primary mast cells, leading to increased susceptibility to both X4 and R5 viral isolates. HIV-1 infection also resulted in histamine release from these mast cells, most due in part to HIV-mediated cell death. These results demonstrate that X4 viruses can use CD4 and the CXCR4 receptor to infect mast cells, suggesting that mast cell-T cell interactions may contribute to HIV mediated immune dysfunction in the mucosa.

Serum immunoglobulin E levels in human immunodeficiency virus-infected children with pneumonia

Elevated serum immunoglobulin E (IgE) levels have been reported in association with human immunodeficiency virus (HIV) infection in adults, but there is little information in children. The aim of the present study was to compare serum IgE levels in HIV-positive and -negative children hospitalized with pneumonia in South Africa and to investigate whether IgE may be useful as a marker of specific infections or prognosis in HIV-infected children. History, examination, blood tests, and induced sputum or bronchoalveolar lavage were carried out. Of 122 children [45% female, median age 8 months (3-20 months)], 81 were infected with HIV. A history of allergy or asthma was present in three children (two of whom were HIV positive). Serum IgE was higher in HIV-infected children [83 (33-147) vs. 29 (6-113) IU/l; p = 0.011] as was immunoglobulin G (IgG) [49 (37-63) vs. 27.5 (23-34) g/l; p < 0.001]. CD4 lymphocytes [600 (330-1,210) vs. 1,900 (1,500-3,030) cells/ micro l], percentage CD4 cells [13.6 (9.4-20.3) vs. 40.1 (31.1-44.9)] and CD4 : CD8 ratio [0.3 (0.2-0.4) vs. 2 (1.4-2.8)] were lower in HIV-positive children (p < 0.001 for all). Bacteremia occurred in 12 (10%) children; other specific pathogens identified included Mycobacterium tuberculosis in eight (7%) and Pneumocystis carinii in nine (7%). There was no correlation with CD4 count, CD4 : CD8 ratio, or the presence of specific pathogens, and IgE level. In-hospital mortality (11%) did not correlate with IgE levels. HIV-infected children with pneumonia have higher serum IgE compared with seronegative patients. In HIV-positive children, IgE levels did not correlate with the degree of immunosuppression or with outcome.

Goals and milestones during treatment of HIV-1 infection with antiretroviral therapy: a pathogenesis-based perspective

Highly active antiretroviral therapy (HAART) has reduced the morbidity and mortality related to infection with the human immunodeficiency virus-1 (HIV-1) through its ability to suppress viral replication and preserve and reconstitute specific immune responses in many infected individuals. However, the complete eradication of HIV-1 with current HAART regimens is not considered possible by most experts. Moreover, many current antivirals have metabolic complications and limiting side effects. Consequently, the treatment paradigm has shifted from 'hit hard and early' to delaying the initiation of therapy until later in the course of HIV-1-related disease, with corresponding modifications of consensus treatment guidelines. Factors that need to be considered in deciding when to initiate therapy and with what regimen include the patient's risk of disease progression, the possible adverse drug effects, the patient's ability to adhere to the prescribed therapy, and the need to preserve future therapeutic options. In this article, we discuss the issues surrounding the initiation of HAART, and describe the virologic and immunologic milestones that may be achieved with effective antiretroviral therapy.

The relationship between HIV infection and atopic dermatitis

Patients with HIV infection exhibit a wide range of skin pathology, including bacterial, fungal, and viral infections, skin tumors, inflammatory and eczematous eruptions, and drug rashes. HIV-infected adults commonly develop a condition that strongly resembles atopic dermatitis and is sometimes called "atopic-like dermatitis"; moreover, atopic dermatitis and other atopic disorders have been described as common manifestations of pediatric HIV infection. Conditions such as sinusitis, asthma, and hyper-IgE syndrome, and laboratory abnormalities, eg, elevated IgE levels, eosinophilia, and possible Th1-Th2 imbalances, suggest a predilection for atopic disorders in these patients. It is of interest to examine the immune perturbations intrinsic to HIV infection, and their possible role in triggering atopic dermatitis, and to consider whether other abnormalities, such as xerosis, bacterial or viral superantigens, or epidermal barrier disruption with altered presentation of cutaneous aeroallergens, might play a significant role.

CTLA-4 upregulation during HIV infection: association with anergy and possible target for therapeutic intervention

OBJECTIVE

To study the role of cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) during HIV infection.

METHODS

Intracellular CTLA-4 expression, determined by flow-cytometry, and proliferative responses to HIV antigens, were studied in peripheral blood mononuclear cells (PBMC) from 93 HIV-1-infected [HIV(+)] patients and 40 HIV-1 seronegative controls.

RESULTS

The proportions of CTLA-4 expressing CD4+ T cells were: (1) significantly higher in HIV(+) patients, 10.95 +/- 0.66%, than in controls, 6 +/- 0.45% (P < 0.0001); (2) inversely correlated to CD4+ counts (r = -0.67, P < 0.005, n = 16, drug-naive patients; r = -0.57, P < 0.0001, n = 77, HAART-treated patients); and (3) positively correlated to proportion of activated (HLA-DR+CD3+) (r = 0.53, P < 0.0001) and memory (CD45RO+CD4+) T cells (r = 0.46, P < 0.001). CD28 median fluorescence intensity in CTLA-4- cells was twice that in CTLA-4+ cells (140 +/- 5.3 versus 70 +/- 2.28, P < 0.00001), whereas cells low in CD28 and CD4, expressed more CTLA-4 (P < 0.0001). Higher proportion of CTLA-4+CD4+ cells expressed CCR5 and Ki-67, in comparison with CTLA-4-CD4+ cells, (65 +/- 11.9 and 25 +/- 7.5% versus 27 +/- 8.9 and 3.7 +/- 2%, P < 0.0001 and P < 0.01, respectively). Among HAART-treated patients, with viral load below detectable levels, CD4+ cells increase was inversely correlated to %CTLA-4+CD4+ cells (r = -0.5, P = 0.003, n = 39). Proliferation of PBMC to anti-CD3, gp-120 depleted HIV-1 antigen or HIV-1 p24 stimulation was inversely correlated with CTLA-4 levels (r = -0.68, P = 0.0035; r = -0.38,P = 0.04; and r = -0.43, P = 0.028, respectively).

CONCLUSIONS

(1) CTLA-4 is upregulated during HIV infection and may therefore account for CD4 T-cell decline and anergy in HIV-1 infection. (2) Increased levels of CTLA-4 may undermine immune responses and in the HAART-treated patient-immune reconstitution. (3) Blocking of CTLA-4 may offer a novel approach for immune-based therapy in HIV infection.

Comparison of the quantitative competitive and semiquantitative RT-PCR methods for the determination of interferon-gamma mRNA levels in AIDS-free HIV-infected individuals

IFN-gamma mRNA expression was evaluated in nonstimulated peripheral blood mononuclear cells (PBMC) of HIV-infected and seronegative individuals using quantitative competitive and semiquantitative RT-PCR and the sensitivity of these methods was compared. A significant correlation was found between quantitative competitive and semiquantitative RT-PCR in samples of both HIV-seronegative (P = 0.004) and HIV-infected individuals (P = 0.0004). PBMC from HIV-infected individuals presented a remarkable increase of IFN-gamma mRNA expression, as determined by both types of RT-PCR methods. Semiquantitative RT-PCR even without an internal standard is also acceptable for measuring cytokine mRNA expression, but less reliable if small amounts are quantified. Moreover, we found that increased IFN-gamma mRNA expression is independent of CD4+ cell count in AIDS-free HIV-infected patients.

Prevalence of bronchial hyperresponsiveness among HIV-infected men

HIV infection is associated with immune dysregulation primarily affecting T-cell function, whereas asthma is related to excessive T-cell activity. We compared the prevalence of asthma and related conditions among adult seropositive men with the prevalence among men of similar age drawn from the general population. Seropositive men had a significantly more frequent occurrence of wheezing (54.4 versus 21.2%), bronchial hyperresponsiveness (BHR) to methacholine (26.2 versus 14.4%), and an elevated total serum IgE (37.8 versus 25.7%). Differences in BHR were significant only among smokers. Among the seropositive men, FEV(1)/FVC and an elevated IgE were the principal determinants of BHR. Our results suggest that the frequency of asthma may be underestimated in HIV disease. Furthermore, the frequent occurrence of BHR in HIV-infected men who smoke (30.1%) suggests this group may be especially susceptible to the adverse effects of cigarette smoke.