TCR usage and cytokine expression in peripheral blood and BAL T cells

T cells are thought to play an important regulatory role in atopic asthma. We hypothesized that human blood and BAL T cell subsets bearing various TCR-Vbeta genes might show selective differences in their cytokine profile. Peripheral blood (PB) and bronchoalveolar lavage (BAL) T cells from seven atopic asthmatic and six non-atopic non-asthmatic subjects were stimulated with PMA and ionomycin in the presence of monensin and analysed for TCR-Vbeta expression and production of cytokines at the single cell level. The percentage of IFN-gamma- and IL-2-producing BAL T cells was elevated compared with PB T cells from both the asthmatic subjects and the non-atopic, non-asthmatic controls. A small percentage of PB and BAL T cells produced IL-4 and IL-5, in asthmatic and normal subjects. In peripheral blood, the percentage of T cells expressing each cytokine was similar in the various TCR-Vbeta subsets and in total CD3+ T cells in all normal and six of seven asthmatic subjects. However, there was a substantial degree of heterogeneity in the cytokine profile of BAL TCR-Vbeta subsets compared with the total CD3+ T cells. This was more obvious in the asthmatic subjects with a reduction in the percentage of IFN-gamma- and IL-2-expressing T cells (five of seven asthmatic subjects) and an increase in the percentage of IL-4- and IL-5-expressing T cells (two of seven asthmatic subjects). These data confirm previous findings of an elevated proportion of IFN-gamma- and IL-2-producing BAL T cells while only a small proportion of PB and BAL T cells produce IL-4 and IL-5. Moreover, subsets of BAL T cells, defined by their TCR-Vbeta usage, may differ in their cytokine profile compared with the total CD3+ T cells, implying that T cells expressing different Vbeta elements may play different roles in regulating the airway inflammation in asthma.     

Differential role of CD80 and CD86 on alveolar macrophages in the presentation of allergen to T lymphocytes in asthma

In the asthmatic lung the altered expression of costimulatory molecules (CD80, CD86) by alveolar macrophages contributes to T lymphocyte activation and expansion. We hypothesized that CD80 and CD86 on alveolar macrophages could differentially support allergic inflammation in adult asthma. Here we studied 11 subjects with mild allergic asthma and 11 atopic non-asthmatics as controls. Dermatophagoides-specific T cell lines were derived from peripheral blood from each subject. Bronchoalveolar lavage with evaluation of lung inflammatory cells was performed in all individuals at baseline and 24 h after allergen challenge. The expression of CD80 and CD86 costimulatory molecules by alveolar macrophages was studied and, in parallel, the efficiency of antigen presentation was measured in terms of IL-4 and IL-5 production by allergen-stimulated autologous T cells. We found that in asthmatic subjects (i) the percent of CD80+, but not CD86+ alveolar macrophages was increased at baseline and did not change following allergen challenge; (ii) CD86, but not CD80, membrane expression was up-regulated following allergen challenge; (iii) both CD80 and CD86 were required to support Th2 cytokine production by allergen-specific T cells, with a prevalent role of CD86 after allergen challenge. Our data indicate that alveolar macrophages deliver costimulatory signals via CD80 and CD86, which support the production of Th2 cytokines by allergen-specific T cells. They also indicate that CD86 in vivo is up-regulated in the 24 h following allergen exposure and that this modulation is functionally relevant.     

Increased expression of IL-16 immunoreactivity in bronchial mucosa after segmental allergen challenge in patients with asthma

BACKGROUND: We have previously shown increased expression of the CD4(+) cell chemoattractant IL-16 in bronchial mucosa of patients with asthma. We investigated the effects of allergen challenge on airway IL-16 expression. METHODS: We investigated the expression of IL-16 immunoreactivity in bronchial biopsy samples obtained from atopic asthmatic subjects (n = 19) and normal subjects (n = 6) 24 hours after segmental allergen challenge. Control biopsy samples were obtained either at baseline or after diluent challenge. IL-16 expression was correlated to numbers of CD4(+) cells, CD25(+) cells, and activated eosinophils. IL-16 bioactivity was assessed in bronchoalveolar fluid obtained from patients with asthma. RESULTS: IL-16 expression was higher in control biopsy specimens obtained from subjects with asthma compared with normal subjects (P<.05). In patients with asthma, numbers of IL-16 immunoreactive cells were significantly higher in biopsy specimens obtained after allergen challenge compared with control biopsy specimens (P<.001). Allergen provocation was associated with release of IL-16 in bronchoalveolar fluid in patients with asthma. In normal subjects, there was no difference in the number of IL-16-immunoreactive cells in biopsy specimens obtained after allergen challenge compared with biopsy specimens obtained after diluent challenge. Allergen challenge was associated with an increase in the numbers of EG2(+) eosinophils in patients with asthma but not in normal subjects. IL-16 expression correlated with the numbers of CD4(+) cells and CD25(+) cells after allergen challenge in asthmatic subjects with a provocative concentration required to decrease the FEV(1) by 20% of its baseline value (PC(20)FEV(1)) < 4 mg/mL. IL-16-immunoreactive cells were identified mainly as T cells and eosinophils in asthmatic subjects after allergen challenge. CONCLUSION: Endobronchial allergen provocation in atopic asthmatic patients resulted in increased airway expression of IL-16 and release of bioactive IL-16 in airways. IL-16 may contribute to the immunoregulation of the inflammatory infiltrate in the airways in response to antigen.     

Regulation of human CD4(+) alphabeta T-cell-receptor-positive (TCR(+)) and gammadelta TCR(+) T-cell responses to Mycobacterium tuberculosis by interleukin-10 and transforming growth factor beta

Mycobacterium tuberculosis is the etiologic agent of human tuberculosis and is estimated to infect one-third of the world's population. Control of M. tuberculosis requires T cells and macrophages. T-cell function is modulated by the cytokine environment, which in mycobacterial infection is a balance of proinflammatory (interleukin-1 [IL-1], IL-6, IL-8, IL-12, and tumor necrosis factor alpha) and inhibitory (IL-10 and transforming growth factor beta [TGF-beta]) cytokines. IL-10 and TGF-beta are produced by M. tuberculosis-infected macrophages. The effect of IL-10 and TGF-beta on M. tuberculosis-reactive human CD4(+) and gammadelta T cells, the two major human T-cell subsets activated by M. tuberculosis, was investigated. Both IL-10 and TGF-beta inhibited proliferation and gamma interferon production by CD4(+) and gammadelta T cells. IL-10 was a more potent inhibitor than TGF-beta for both T-cell subsets. Combinations of IL-10 and TGF-beta did not result in additive or synergistic inhibition. IL-10 inhibited gammadelta and CD4(+) T cells directly and inhibited monocyte antigen-presenting cell (APC) function for CD4(+) T cells and, to a lesser extent, for gammadelta T cells. TGF-beta inhibited both CD4(+) and gammadelta T cells directly and had little effect on APC function for gammadelta and CD4(+) T cells. IL-10 down-regulated major histocompatibility complex (MHC) class I, MHC class II, CD40, B7-1, and B7-2 expression on M. tuberculosis-infected monocytes to a greater extent than TGF-beta. Neither cytokine affected the uptake of M. tuberculosis by monocytes. Thus, IL-10 and TGF-beta both inhibited CD4(+) and gammadelta T cells but differed in the mechanism used to inhibit T-cell responses to M. tuberculosis.     

Distribution and cytokine production of CD4 and CD8 T-lymphocyte subsets in patients with acute asthma attacks.

BACKGROUND: The activation of T cells and the elevation of Th2-type cytokines have been observed in asthmatic patients, but the relative role of CD4 and CD8 T cell is still unclear. OBJECTIVE: To investigate the role of T cell subset in patients with acute asthma attacks, we analyzed the distribution, activation status, and cytokine production of CD4 and CD8 cells. METHODS: The percentages of the CD4 and CD8 cell in peripheral blood (PB) and bronchoalveolar lavage (BAL) fluid were analyzed by flow cytometry. The cytokines (IL-4, IL-5, and IFN-gamma) and soluble IL-2 receptor (sIL-2R) were measured by ELISA in culture supernatants of CD4 and CD8 cells purified from PB. RESULTS: The CD4/CD8 ratio in PB of asthmatic patients was significantly higher than that of controls, which was significantly reduced after treatment. In contrast, there was a tendency to high percentage of CD8 cells in asthmatic patients as compared with controls in BAL, which resulted in a decreased CD4/CD8 ratio. Comparing the T cell subsets in BAL with paired PB in asthma, the CD4 cells were higher in PB, but CD8 cells were higher in BAL. The IL-4, IL-5, and sIL-2R produced by CD4 cells were significantly higher than those produced by CD8 cells in asthmatic patients. CONCLUSIONS: Our results provide evidence that activated CD4 T cells increase and produce type 2 cytokines in PB, but CD8 T cell are more sequestrated than CD4 T cells in the airway during an acute asthma attack.     

Peripheral blood CD4+ and CD8+ T cell type 1 and type 2 cytokine production in atopic asthmatic and normal subjects

BACKGROUND: Increased production of IL-4 and IL-5 and decreased production of IFN-gamma by CD4+ T cells has been implicated in asthma pathogenesis. However, CD8+ T cells also produce type 1 and type 2 cytokines and the relative roles of CD4+ and CD8+ T cell cytokine production in asthma have not been previously studied. OBJECTIVE: To determine the production of the type 1 and type 2 cytokines by CD4+ and CD8+ T cell subsets in asthmatic and normal subjects. METHODS: Intracellular cytokine staining for IL-4, -5, -10, -13 and IFN-gamma was analysed in peripheral blood CD4+ and CD8+ T cells from 24 atopic asthmatic and 20 normal subjects. RESULTS: Both subsets of T cells produced all cytokines studied and there were no significant differences between CD4+ and CD8+ T cells in their capacity to produce either type 1 or type 2 cytokines. There were significantly increased frequencies of IFN-gamma-positive CD4+ (13.1 +/- 2.4%, vs. 7.3 +/- 1.4%) and CD8+ (20.0 +/- 2.9%, vs. 9.6 +/- 2.1%) T cells in asthmatic subjects compared with normal subjects (P < 0.05), but not in frequencies of CD4+ or CD8+ T cells staining positively for IL-4, -5, -10 or -13. CONCLUSION: The frequencies of peripheral blood CD8+ T cells producing type 1 and type 2 cytokines are comparable with the frequencies of CD4+ T cells. There was an increased frequency of IFN-gamma producing CD4+ and CD8+ T cells in asthmatic compared with normal subjects. Further studies investigating T cells derived from the airways and investigating various stages within the disease process are required to further elucidate the importance of type 2 and type 1 T cell cytokine production in the pathogenesis of human allergic disease.     

IL-10 production in circulating T cells differs between allergen-induced isolated early and dual asthmatic responders

BACKGROUND: IL-10 is an anti-inflammatory cytokine released from various cells, including T cells. The role of IL-10 in asthma pathogenesis remains uncertain. Allergen inhalation by atopic asthmatic subjects results in 2 bronchoconstrictor phenotypes: isolated early response and dual response. Persistence of allergen-induced airway inflammation is a feature of dual responders. OBJECTIVES: The kinetics of IL-10 production in circulating T cells were investigated to examine a potential role of IL-10 in allergen-induced responses and airway inflammation. METHODS: Fourteen subjects with mild asthma (7 isolated early and 7 dual responders) were challenged with allergen. PBMCs taken before and 24 hours after allergen challenge were processed for intracellular IL-10 staining with fluorescent-conjugated anti-IL-10 antibody. The frequency of IL-10-producing cells was assessed for CD4(+) and CD8(+) T-cell subsets by using flow cytometry. RESULTS: Before allergen administration, the frequency of IL-10-producing CD4(+) cells was significantly higher in dual than in isolated early responders. IL-10-producing CD4(+) cells significantly increased after allergen in early responders, whereas IL-10-producing CD4(+) cells significantly decreased in dual responders. Simultaneous assessments of IL-5-producing T cells did not show any differences between each group before or after allergen administration. CONCLUSIONS: These results suggest that the contrasting profiles of IL-10 production may be associated with the different time course of allergen-induced airway inflammation between allergen-induced early and dual responders.     

CD4(+) T cell clones producing both interferon-gamma and interleukin-10 predominate in bronchoalveolar lavages of active pulmonary tuberculosis patients.

The pattern of cytokine production in T cell clones derived from bronchoalveolar lavages (BAL) of active pulmonary tuberculosis (TB) patients was analyzed in clones obtained by limiting dilution procedures which expand with high efficiency either total T lymphocytes, independently of their antigen-recognition specificity, or Mycobacterium tuberculosis-specific T cells. BAL-derived clones, representative of CD4(+) cells from five patients with active TB, produced significantly higher amounts of IFN-gamma than BAL-derived CD4(+) clones from three inactive TB donors or four controls (with unrelated, noninfectious pathology). Average IL-4 and IL-10 production did not differ significantly in the three groups. Although these data suggest a predominant Th1 response to M. tuberculosis infection in the lungs, the majority of BAL-derived CD4(+) clones produced both IFN-gamma and IL-10 and the percentage of clones with this pattern of cytokine production was significantly higher in clones derived from BAL of active TB patients than from controls. Only rare clones derived from peripheral blood (PB)-derived CD45RO(+) CD4(+) T cells of both patients (nine cases) and controls (four cases) produced both IFN-gamma and IL-10; instead, the IL-10-producing clones derived from PB T cells most often also produced IL-4, displaying a typical Th2 phenotype. Higher average amounts of IFN-gamma and IL-10 were produced by BAL-derived CD8(+) clones of four active TB patients than of four controls, although the frequency of CD8(+) clones producing both IFN-gamma and IL-10 was lower than that of CD4(+) clones. The M. tuberculosis-specific BAL-derived T cell clones from three active TB patients were almost exclusively CD4(+) and produced consistently high levels of IFN-gamma often in association with IL-10, but very rarely with IL-4. Unlike the BAL-derived clones, the M. tuberculosis-specific clones derived from PB CD45RO(+) CD4(+) T cells of three different active TB patients and two healthy donors showed large individual variability in cytokine production as well as in the proportion of CD4(+), CD8(+), or TCR gamma/delta(+) clones. These results indicate the predominance of CD4(+) T cells producing both the proinflammatory cytokine IFN-gamma and the anti-inflammatory cytokine IL-10 in BAL of patients with active TB.     

Phase I clinical trial of costimulated, IL-4 polarized donor CD4+ T cells as augmentation of allogeneic hematopoietic cell transplantation.

The primary objective of this clinical trial was to evaluate the safety, feasibility, and biologic effects of administering costimulated, interleukin (IL)-4 polarized donor CD4(+) T cells in the setting of HLA-matched sibling, T cell-replete allogeneic hematopoietic cell transplantation (HCT). Forty-seven subjects with hematologic malignancy received granulocyte colony-stimulating factor-mobilized allogeneic hematopoietic cell transplants and cyclosporine graft-versus-host disease (GVHD) prophylaxis after reduced intensity conditioning. Initial subjects received no additional cells (n = 19); subsequent subjects received additional donor CD4(+) T cells generated ex vivo by CD3/CD28 costimulation in medium containing IL-4 and IL-2 (administered day 1 after HCT at 5, 25, or 125 x 10(6) cells/kg). Studies after HCT included measurement of monocyte IL-1alpha and tumor necrosis factor alpha, detection of T cells with antitumor specificity, and characterization of T cell cytokine phenotype. The culture method generated donor CD4(+) T cells that secreted increased T helper 2 (Th2) cytokines and decreased T helper 1 (Th1) cytokines. Such Th2-like cells were administered without infusional or dose-limiting toxicity. The Th2 cohort had accelerated lymphocyte reconstitution; both cohorts had rapid hematopoietic recovery and alloengraftment. Acute GVHD and overall survival were similar in the Th2 and non-Th2 cohorts. Th2 cell recipients tended to have increased monocyte IL-1alpha and had increased tumor necrosis factor alpha secretion. CD8(+) T cells with antitumor specificity were observed in Th2 and non-Th2 cohorts. Post-transplantation T cells from Th2 cell recipients secreted IL-4 and IL-10 (Th2 cytokines) and IL-2 and interferon gamma (Th1 cytokines). Allograft augmentation with costimulated, IL-4-polarized donor CD4(+) T cells resulted in activated Th1, Th2, and inflammatory cytokine pathways without an apparent increase in GVHD.     

CD8+ T cell contributions to allergen induced pulmonary inflammation and airway hyperreactivity

The pathogenesis of asthma has been linked to the production of type 2 cytokines, which can be expressed by several cell types in the lung. These studies investigated CD8(+) T cell responses in a murine cockroach antigen (CRA) model of asthma. The results from these present studies show that depletion of CD8(+) T cells after allergen sensitization to CRA significantly reduces airway hyperreactivity, airway eosinophilia and pulmonary type 2 cytokine levels. The data demonstrate that CD8(+) T cells from CRA-sensitized mice can produce type 2 cytokines IL-4, IL-5 and IL-13 upon antigen challenge, and that the transfer of these cells into naive mice will cause airway hyperreactivity when exposed to CRA. We found that the transferred airway response is dependent on both IL-4 and IL-13 from CD8(+) T cells using cytokine knockout mice. Compared to CD4(+) T cells, CD8(+) T cells were not as numerous in the lungs of sensitized and challenged mice, but were as efficacious in the transfer of airway disease. The most severe airway response was observed when both CD4(+) and CD8(+) T cells were transferred at the same time. Altogether, these studies highlight a role for CD8(+) T lymphocytes in the development of allergen-induced airway responses.     

The effects of CD8+gammadelta T cells on late allergic airway responses and airway inflammation in rats

BACKGROUND: Gamma-delta (gammadelta) T cells regulate immune responses to foreign protein at mucosal surfaces. Whether they can modify allergen-induced early (EAR) and late airway responses (LAR) is unknown. OBJECTIVE: We have tested the hypothesis that the CD8+ subtype of gammadelta T cells decreases allergen-induced LAR and airway eosinophilia in the rat. METHODS: Brown Norway rats were administered, intraperitoneally, 3.5 x 10(4) lymph node CD8+gammadelta T cells from naive or sensitized rats. The recipients were sensitized to ovalbumin (OVA) in Al(OH)(3) 3 days after cell transfer and challenged with aerosolized OVA 14 days later. Serum IgE was measured before allergen challenge. After challenge, lung resistance was monitored for 8 hours and then bronchoalveolar lavage (BAL) was analyzed for eosinophil major basic protein (MBP), IL-4, IL-5, IL-13, and IFN-gamma messenger RNA-expressing cells. RESULTS: gammadelta T cells from naive donors significantly decreased LAR in OVA-challenged sensitized rats, whereas MBP(+) eosinophils were decreased by both gammadelta T cells from naive and sensitized donors. EAR and serum IgE levels were unchanged. The expression of IL-4, IL-5, and IL-13 by BAL cells of gammadelta T cell recipients was attenuated compared with OVA-challenged controls. This was accompanied by an increase in the expression of IFN-gamma. CONCLUSIONS: Our results are consistent with a suppressive role of CD8+gammadelta T cells on allergic airway responses. However, only gammadelta T cells from naive donors inhibit LAR.     

Cytokine profile of t lymphocytes from peripheral blood and bronchoalveolar lavage fluid in patients with active pulmonary tuberculosis

The possible immunological relationship between the pattern of Th1/Th2 cytokine production and tuberculin reactivity was assessed in patients with active Mycobacterium tuberculosis infection. The production of the intracellular cytokines interferon (IFN)-gamma and interleukin-4 (IL-4) was measured in CD4(+) and CD8(+) T cells obtained from peripheral blood and bronchoalveolar lavage fluid (BALF) of 20 tuberculin skin-positive patients and compared with the findings recorded in nine tuberculin skin-negative patients with active pulmonary tuberculosis. Upon stimulation with phorbol 12-myristate acetate/ionomycin for 6 h, tuberculin-negative patients had a significantly higher proportion of IFN-gamma-producing CD4(+) T lymphocytes in BALF than in peripheral blood, while both CD4(+) and CD8(+) T-lymphocyte subsets in BALF of tuberculin-positive patients secreted more IFN-gamma than their peripheral blood counterparts. Tuberculin-negative patients had a significantly higher proportion of IFN-gamma-producing CD4(+) T lymphocytes in peripheral blood than tuberculin-positive patients. There was no significant difference in the production of IFN-gamma by BALF CD4(+) T lymphocytes, or by either peripheral blood or BALF CD8(+) T lymphocytes. In two tuberculin-negative patients, peripheral blood CD4(+) T lymphocytes produced IL-4. Study results suggested a higher immune activity in the blood of tuberculin-negative patients, with an increased lymphocyte activity in BALF versus peripheral blood in both patient groups.     

Cytokine profiles of BAL T cells and T-cell clones obtained from human asthmatic airways after local allergen challenge.

BACKGROUND: This study assessed the heterogeneity of cytokine expression in asthma before and after local allergen challenge. METHODS: BAL T cells were obtained 10 min or 24 h after local endobronchial allergen challenge in atopic asthmatic subjects. T cells were cloned by direct limiting dilution. mRNA expression was assessed by RT-PCR, and cytokine protein production by ELISA. RESULTS: Unstimulated baseline BAL T cells expressed mRNA for IFN-gamma, IL-13, and TNF-alpha. A minority of samples expressed IL-4 and IL-5, but no IL-3 mRNA was detected. PHA stimulation increased expression of IL-3, IL-4, and IL-5 mRNA in 4/6 samples. IL-13 and GM-CSF mRNA were found in BAL cells after allergen challenge, but expression of IFN-gamma was reduced. Both IL-4 and IL-3 were strongly upregulated after PHA stimulation, while the expression of TNF-alpha and IFN-gamma was reduced, compared to equivalent baseline samples. Seventeen panels of BAL T-cell clones were derived (average cloning efficiency 1/40 T cells). Seven panels survived to 8 weeks for analysis. Clones derived 4 h after saline challenge showed strong mRNA signals for IL-13, IL-4, and IFN-gamma, whereas clones derived 24 h after allergen challenge expressed IL-13, GM-CSF, IL-3, IL-4, and often IL-5 (i.e., closer to the Th2 profile). There was considerable heterogeneity in the patterns of cytokine mRNA and protein production by different clones. CONCLUSIONS: T cells from asthmatic airways produce IL-13, IFN-gamma, and TNF-alpha, but after allergen challenge, type 2 cytokines are upregulated. mRNA and protein analysis provide complementary information on airways T-cell cytokine profiles.     

Differential capacity of CD8α+ or CD8α− dendritic cell subsets to prime for eosinophilic airway inflammation in the T-helper type 2-prone milieu of the lung

BACKGROUND: Different subsets of dendritic cells (DCs), identified in mouse spleen by their differential expression of CD8 alpha, can induce different T-helper (Th) responses after systemic administration. CD8 alpha(-) DCs have been shown to preferentially induce Th type 2 (Th2) responses whereas CD8 alpha(+) DCs induce Th1 responses. OBJECTIVE: To study if these DC subsets can still induce different Th responses in the Th2-prone milieu of the lung and differentially prime for eosinophilic airway inflammation, typical of asthma. METHODS: Donor mice first received daily Flt3L injections to expand DC numbers. Purified CD8 alpha(+) or CD8 alpha(-) splenic DCs were pulsed with ovalbumin (OVA) or phosphate-buffered saline and injected intratracheally into recipient mice in which carboxyfluorescein diacetate succinimidyl ester-labelled OVA-specific T cell receptor transgenic T cells had been injected intravenously 2 days earlier. T cell proliferation and cytokine production of Ag-specific T cells were evaluated in the mediastinal lymph nodes (MLNs) 4 days later. The capacity of both subsets of DCs, to prime for eosinophilic airway inflammation was determined by challenging the mice with OVA aerosol 10 days later. RESULTS: CD8 alpha(-) DCs migrated to the MLN and induced a vigorous proliferative T cell response accompanied by high-level production of IL-4, IL-5, IL-10 and also IFN-gamma during the primary response and during challenge with aerosol, leading to eosinophilic airway inflammation. In the absence of migration to the MLN, CD8 alpha(+) DCs still induced a proliferative response with identical levels of IFN-gamma but reduced Th2 cytokines compared with CD8 alpha(-) DCs, which led to weak eosinophilic airway inflammation upon OVA aerosol challenge. Unpulsed DCs did not induce proliferation or cytokine production in Ag-specific T cells. CONCLUSION: CD8 alpha(-) DCs are superior compared with CD8 alpha(+) DCs in inducing Th2 responses and eosinophilic airway inflammation in the Th2-prone environment of the lung.     

CD8+ T lymphocytes and leukotriene B4: novel interactions in the persistence and progression of asthma

The contribution of CD8+ T cells to the development of airway hyperresponsiveness and airway inflammation has received increased attention recently. CD8+ T cells, which are capable of secreting TH2 cytokines, including IL-4, IL-5, and IL-13, have been described in asthmatic subjects and in animals sensitized and challenged with allergen. A subset of these IL-13-producing CD8+ T cells, effector memory CD8+ T cells in the mouse, express a high-affinity receptor for leukotriene B4 (BLT1), and expression of this receptor is essential for their accumulation in the lung and development of airway hyperresponsiveness and airway inflammation. A similar subset of CD8+/BLT1+/IL-13+ T cells has also been identified in the bronchoalveolar lavage fluid of asthmatic subjects, suggesting a pathogenic role for this unique subset of CD8+ T cells in asthma.     

Human miscarriage is associated with increased number of CD26 decidual lymphocytes

Dipeptidyl peptidase-IV (DPP-IV, CD26), a serine protease with broad distribution in mammalian tissues and known activity in serum, participates in T-cell activation and promotes a Th1-like cytokine response. Previous data on murine abortion indicate that DPP-IV may play a critical role in pregnancy failure by inducing a Th1 local response. Here, we investigated the possible participation of DPP-IV in the onset of human spontaneous abortion (SA). The systemic (peripheral blood) and local (decidua) percentages of CD4(+), CD8(+), CD26(+) and CD56(+) cells as well as the number of Th1 lymphocytes (CCR5(+) cells) were assessed in samples from women after SAs (n = 20) and from women with normally progressing pregnancies (NPs) (n = 27) using flow cytometry and immunohistochemistry. We further measured the DPP-IV activity and concentrations of Th1 (interferon-gamma and tumour necrosis factor-alpha), Th2 [interleukin-4 (IL-4), IL-10] and Th3 (transforming growth factor-beta2) cytokines in serum samples. We could not find any difference in the number of CD4(+), CD8(+), CD26(+), CD26(+)/CD4(+) or CD8(+)/CD26(+) blood cells between NP and SA patients. No differences in the Th1, Th2 or Th3 cytokine levels could be observed between both groups. However, the percentages of decidual CD26(+) lymphocytes as well as the number of decidual Th1 cells were significantly higher in SA samples compared to samples from patients with NP. Our data support the hypothesis that CD26(+) decidual lymphocytes with DPP-IV activity may play a critical role in SAs, as previously suggested in an abortion mice model. This abortive effect may be mediated by enhancing the levels of Th1 abortogenic cytokines only locally.     

Late asthmatic reactions provoked by intradermal injection of T-cell peptide epitopes are not associated with bronchial mucosal infiltration of eosinophils or T(H)2-type cells or with elevated concentrations of histamine or eicosanoids in bronchoalveolar fluid.

BACKGROUND: Isolated late asthmatic reactions can be provoked by intradermal challenge of allergen-derived T-cell peptide epitopes. OBJECTIVE: The purpose of this study was to determine whether the isolated LAR is associated with the local accumulation of inflammatory cells, the expression of T(H)2 cytokines, and the production of pharmacologic mediators. METHODS: A randomized, placebo-controlled, crossover study design was used. The investigation involved bronchial and skin biopsies and bronchoalveolar lavage (BAL) fluids from 8 cat-allergic subjects who developed significant late asthmatic reactions 6 hours after intradermal injection of Fel d 1 chain 1-derived peptides (FC1Ps). RESULTS: Immunostaining of bronchial biopsy specimens showed no changes in the numbers of eosinophils, neutrophils, basophils, mast cells, CD3(+), CD4(+) or CD8(+) T cells, CD25(+) cells or macrophages, or cells mRNA(+) for IL-4, IL-5, or IL-13 when the FC1P day was compared with the diluent control day. There were also no significant differences in eosinophil numbers, either in BAL fluids or in peripheral blood after FC1P challenge. Furthermore, there were no significant alterations in the concentrations of histamine, histamine-releasing factors, or eicosanoids (LTC(4)/D(4)/E(4), PGD(2), PGE(2), TXB(2), PGF(2alpha)) in BAL fluids. FC1Ps induced a significant (P <.05) elevation in CD8(+) cells in the skin and an unexpected decrease in IL-5 in BAL fluids (P =.043). CONCLUSION: Part of the asthma process might involve T cell-dependent airway narrowing with no requirement for IgE, mast cells, or infiltrating inflammatory cells.     

Reversal of established CD4+ type 2 T helper-mediated allergic airway inflammation and eosinophilia by therapeutic treatment with DNA vaccines limits progression towards chronic inflammation and remodelling

Immunostimulatory DNA-based vaccines can prevent the induction of CD4(+) type 2 T helper (Th2) cell-mediated airway inflammation in experimental models, when administered before or at the time of allergen exposure. Here we demonstrate their efficacy in limiting the progression of an established response to chronic pulmonary inflammation and airway remodelling on subsequent allergen challenge. Mice exhibiting Th2-mediated airway inflammation induced following sensitization and challenge with group 1 allergen derived from Dermatophagoides pteronyssinus group species (Der p 1), a major allergen of house dust mite, were treated with pDNA vaccines. Their airways were rechallenged and the extent of inflammation assessed. In plasma DNA (pDNA)-vaccinated mice, infiltration of inflammatory cells, goblet cell hyperplasia and mucus production were reduced and subepithelial fibrosis attenuated. The reduction in eosinophil numbers correlated with a fall in levels of the profibrotic mediator transforming growth factor (TGF)-beta1 in bronchoalveolar lavage (BAL) and lung tissue. In addition to lung epithelial cells and resident alveolar macrophages, infiltrating eosinophils, the principle inflammatory cells recruited following allergen exposure, were a major source of TGF-beta1. Protection, conferred irrespective of the specificity of the pDNA construct, did not correlate with a sustained increase in systemic interferon (IFN)-gamma production but in a reduction in levels of the Th2 pro-inflammatory cytokines. Notably, there was a reduction in levels of interleukin (IL)-5 and IL-13 produced by systemic Der p 1 reactive CD4(+) Th2 cells on in vitro stimulation as well as in IL-4 and IL-5 levels in BAL fluid. These data suggest that suppression of CD4(+) Th2-mediated inflammation and eosinophilia were sufficient to attenuate progression towards airway remodelling. Immunostimulatory DNA may therefore have a therapeutic application in treatment of established allergic asthma in patients.