Driving CARs to new places: locally produced BCMA CAR T cells to treat multiple myeloma

Not available.

The bromodomain protein TRIM28 controls the balance between growth and invasiveness in melanoma

Melanoma tumors are highly metastatic partly due to the ability of melanoma cells to transition between invasive and proliferative states. However, the mechanisms underlying this plasticity are still not fully understood. To identify new epigenetic regulators of melanoma plasticity, we combined data mining, tumor models, proximity proteomics, and CUT&RUN sequencing. We focus on the druggable family of bromodomain epigenetic readers and identify TRIM28 as a new regulator of melanoma plasticity. We find that TRIM28 promotes the expression of pro-invasive genes and that TRIM28 controls the balance between invasiveness and growth of melanoma cells. We demonstrate that TRIM28 acts via the transcription factor JUNB that directly regulates the expression of pro-invasive and pro-growth genes. Mechanistically, TRIM28 controls the expression of JUNB by negatively regulating its transcriptional elongation by RNA polymerase II. In conclusion, our results demonstrate that a TRIM28-JUNB axis controls the balance between invasiveness and growth in melanoma tumors and suggest that the bromodomain protein TRIM28 could be targeted to reduce tumor spread.

HLA-independent T cell receptors for targeting tumors with low antigen density

Chimeric antigen receptors (CARs) are receptors for antigen that direct potent immune responses. Tumor escape associated with low target antigen expression is emerging as one potential limitation of their efficacy. Here we edit the TRAC locus in human peripheral blood T cells to engage cell-surface targets through their T cell receptor-CD3 complex reconfigured to utilize the same immunoglobulin heavy and light chains as a matched CAR. We demonstrate that these HLA-independent T cell receptors (HIT receptors) consistently afford high antigen sensitivity and mediate tumor recognition beyond what CD28-based CARs, the most sensitive design to date, can provide. We demonstrate that the functional persistence of HIT T cells can be augmented by constitutive coexpression of CD80 and 4-1BBL. Finally, we validate the increased antigen sensitivity afforded by HIT receptors in xenograft mouse models of B cell leukemia and acute myeloid leukemia, targeting CD19 and CD70, respectively. Overall, HIT receptors are well suited for targeting cell surface antigens of low abundance.

Combining a CAR and a chimeric costimulatory receptor enhances T cell sensitivity to low antigen density and promotes persistence

Despite the high remission rates achieved using T cells bearing a chimeric antigen receptor (CAR) against hematogical malignancies, there is still a considerable proportion of patients who eventually experience tumor relapse. Clinical studies have established that mechanisms of treatment failure include the down-regulation of target antigen expression and the limited persistence of effective CAR T cells. We hypothesized that dual targeting mediated by a CAR and a chimeric costimulatory receptor (CCR) could simultaneously enhance T cell cytotoxicity and improve durability. Concomitant high-affinity engagement of a CD38-binding CCR enhanced the cytotoxicity of BCMA-CAR and CD19-CAR T cells by increasing their functional binding avidity. In comparison to second-generation BCMA-CAR or CD19-CAR T cells, double-targeted CAR + CD38-CCR T cells exhibited increased sensitivity to recognize and lyse tumor variants of multiple myeloma and acute lymphoblastic leukemia with low antigen density in vitro. In addition, complimentary costimulation by 4-1BB and CD28 endodomains provided by the CAR and CCR combination conferred increased cytokine secretion and expansion and improved persistence in vivo. The cumulatively improved properties of CAR + CCR T cells enabled the in vivo eradication of antigen-low tumor clones, which were otherwise resistant to treatment with conventional CAR T cells. Therefore, multiplexing targeting and costimulation through the combination of a CAR and a CCR is a powerful strategy to improve the clinical outcomes of CAR T cells by enhancing cytotoxic efficacy and persistence, thus preventing relapses of tumor clones with low target antigen density.

132 HLA-independent T cell receptors effectively target low abundance antigens

Background

Chimeric antigen receptors (CARs) engage antigen independently of HLA and enable sustained T cell proliferation when they are endowed with both activating and costimulatory functions. While remission rates have been noticeably elevated in numerous clinical trials targeting CD19, CD22 or BCMA, relapses are common. One of the several underlying relapse mechanisms is antigen escape, which refers to a relapsing tumor that is either negative for the targeted antigen or expresses the latter at a low level. Failure to eliminate antigen-low tumors raises questions about the sensitivity of CARs and the minimum antigen density that is required for effective tumor eradication. Unlike CARs, TCRs engage antigen in an HLA-dependent manner, and they do so with high sensitivity. We hypothesized that a TCR/CD3 complex containing the same heavy and light immunoglobulin chains as a CAR will display increased sensitivity to the target antigen.

Methods

We edited the TRAC locus in human primary T cells to establish a novel antigen receptor structure, termed HLA-independent TCR or HIT receptor, by incorporating into the TCR/CD3 complex the same heavy and light chains as those of a corresponding CAR. We assessed their antigen sensitivity against a panel of cell lines expressing different antigen levels, analyzing their cytotoxicity, cytokine secretion, signaling response and degranulation activity. HIT and CAR T cells were further evaluated for their anti-tumor response using established ALL and AML mouse models.

Results

CD19-TRAC-HIT and CD19-TRAC-CAR T cells lysed wild-type NALM6 (~27,000 CD19 molecules) and NALM6 variants with 100-fold less CD19. As CD19 levels decreased further, CAR T cells no longer killed their target, in contrast to HIT T cells. HIT T cells showed increased expression of IFN-gamma, IL-2 and TNF-alpha upon exposure to NALM6 cells expressing ~20 CD19 molecules per cell, compared to CAR T cells. This increased sensitivity of HIT receptors correlated to their greater signaling response, upon exposure to the low-antigen-density NALM6. Phospho-proteomic analyses further confirmed this increased response of HIT T cells to low antigen levels. Altogether, these results confirm that HIT receptors endow T cells with greater antigen sensitivity than canonical CARs. We further showed that HIT T cells have higher in vivo anti-tumor activity compared to CAR T cells in mice bearing low-antigen-density ALL or AML.

Conclusions

HIT receptors consistently afford high antigen sensitivity and mediate tumor recognition beyond what current CARs can provide. HIT receptors open new prospects for targeting cell surface antigens of low abundance.

Ethics Approval

Eight- to 12-week-old NOD/SCID/IL-2Rgamma-null (NSG) male mice (Jackson Laboratory) were used under a protocol approved by the MSKCC Institutional Animal Care and Use Committee.

TRIM21 controls Toll-like receptor 2 responses in bone-marrow-derived macrophages

TRIM21 is an interferon‐stimulated E3 ligase that controls the activity of pattern‐recognition signaling via ubiquitination of interferon regulatory factors and DDX41. Previous studies on the role of TRIM21 in innate immune responses have yielded contradictory results, suggesting that the role of TRIM21 is cell specific. Here, we report that bone‐marrow‐derived macrophages (BMDMs) generated from Trim21^−/− mice have reduced expression of mature macrophage markers. Reflecting their reduced differentiation in response to macrophage colony‐stimulating factor (M‐CSF), Trim21^−/− BMDMs had decreased expression of M‐CSF signature genes. Although Trim21^−/− BMDMs responded normally to Toll‐like receptor 9 (TLR9) activation, they produced lower levels of pro‐inflammatory cytokines in response to the TLR2 agonist PAM3CSK4. In line with this, the response to infection with the Bacillus Calmette–Guérin strain of Mycobacterium bovis was also diminished in Trim21^−/− BMDMs. Our results indicate that TRIM21 controls responses to TLR2 agonists.

miR-31 regulates energy metabolism and is suppressed in T cells from patients with Sjögren's syndrome

Systemic autoimmune diseases are characterized by the overexpression of type I IFN stimulated genes, and accumulating evidence indicate a role for type I IFNs in these diseases. However, the underlying mechanisms for this are still poorly understood. To explore the role of type I IFN regulated miRNAs in systemic autoimmune disease, we characterized cellular expression of miRNAs during both acute and chronic type I IFN responses. We identified a T cell-specific reduction of miR-31-5p levels, both after intramuscular injection of IFNβ and in patients with Sjögren's syndrome (SjS). To interrogate the role of miR-31-51p in T cells we transfected human CD4⁺ T cells with a miR-31-5p inhibitor and performed metabolic measurements. This identified an increase in basal levels of glucose metabolism after inhibition of miR-31-5p. Furthermore, treatment with IFN-α also increased the basal levels of human CD4⁺ T-cell metabolism. In all, our results suggest that reduced levels of miR-31-5p in T cells of SjS patients support autoimmune T-cell responses during chronic type I IFN exposure.

The Expression of BAFF Is Controlled by IRF Transcription Factors

Patients with systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (pSS) are typically characterized by the presence of autoantibodies and an IFN-signature. The strength of the IFN-signature positively correlates with disease severity, suggesting that type I IFNs are active players in these diseases. BAFF is a cytokine critical for development and proper selection of B cells, and the targeting of BAFF has emerged as a successful treatment strategy of SLE. Previous reports have suggested that BAFF expression is directly induced by type I IFNs, but the precise mechanism for this remains unknown. In this article, we demonstrate that BAFF is a bona fide ISG and that IFN regulatory factors (IRFs) control the expression of BAFF. We identify IRF1 and IRF2 as positive regulators of BAFF transcription and IRF4 and IRF8 as potent repressors; in addition, we have mapped the precise binding site for these factors in the BAFF promoter. IFN-β injections induced BAFF expression mainly in neutrophils and monocytes, and BAFF expression in neutrophils from pSS patients strongly correlated with the strength of the IFN-signature. In summary, we show that BAFF expression is directly induced by type I IFNs via IRF1 and IRF2, whereas IRF4 and IRF8 are negative regulators of BAFF expression. These data suggest that type I IFN blockade in SLE and pSS patients will lead to downregulation of BAFF and a consequential reduction of autoreactive B cell clones and autoantibodies.

Continuous inhibition of 11β-hydroxysteroid dehydrogenase type I in adipose tissue leads to tachyphylaxis in humans and rats but not in mice

BACKGROUND AND PURPOSE

11β-hydroxysteroid dehydrogenase type I (11β-HSD1), a target for Type 2 diabetes mellitus, converts inactive glucocorticoids into bioactive forms, increasing tissue concentrations. We have compared the pharmacokinetic-pharmacodynamic (PK/PD) relationship of target inhibition after acute and repeat administration of inhibitors of 11β-HSD1 activity in human, rat and mouse adipose tissue (AT).

EXPERIMENTAL APPROACH

Studies included abdominally obese human volunteers, rats and mice. Two specific 11β-HSD1 inhibitors (AZD8329 and COMPOUND-20) were administered as single oral doses or repeat daily doses for 7-9 days. 11β-HSD1 activity in AT was measured ex vivo by conversion of (3) H-cortisone to (3) H-cortisol.

KEY RESULTS

In human and rat AT, inhibition of 11β-HSD1 activity was lost after repeat dosing of AZD8329, compared with acute administration. Similarly, in rat AT, there was loss of inhibition of 11β-HSD1 activity after repeat dosing with COMPOUND-20 with continuous drug cover, but effects were substantially reduced if a 'drug holiday' period was maintained daily. Inhibition of 11β-HSD1 activity was not lost in mouse AT after continuous cover with COMPOUND-20 for 7 days.

CONCLUSIONS AND IMPLICATIONS

Human and rat AT, but not mouse AT, exhibited tachyphylaxis for inhibition of 11β-HSD1 activity after repeat dosing. Translation of observed efficacy in murine disease models to human for 11β-HSD1 inhibitors may be misleading. Investigators of the effects of 11β-HSD1 inhibitors should confirm that desired levels of enzyme inhibition in AT can be maintained over time after repeat dosing and not rely on results following a single dose.

Interferon beta treatment of multiple sclerosis increases serum interleukin-7

BACKGROUND

Interleukin-7 (IL-7) is a non-redundant cytokine for T-cell development and survival. The IL-7 signaling pathway has been genetically and functionally associated with several autoimmune diseases including multiple sclerosis (MS).

OBJECTIVE

The objective of this paper is to elucidate the effect of the widely used immunomodulatory MS therapy interferon beta (IFNβ) on IL-7 homeostasis.

METHODS

Swedish MS patients were screened for IL-7 concentration in serum and blood cell counts. IL-7 receptor alpha chain (IL-7Rα) expression was determined by semi-quantitative real-time polymerase chain reaction (PCR) and flow cytometry.

RESULTS

IFNβ treatment led to significantly increased serum IL-7 levels (mean: 17 pg/ml) compared with healthy controls (mean: 7.6 pg/ml) and natalizumab-treated patients (mean: 5.3 pg/ml). In vitro and in vivo, peripheral blood leukocytes showed decreased IL-7Rα expression and IL-7 consumption upon IFNβ exposure, suggesting that their IL-7 responsiveness is impaired during treatment.

CONCLUSIONS

MS patients undergoing IFNβ treatment have increased serum IL-7 levels and decreased IL-7 consumption. Given IL-7's important role in T-cell immunity, this relationship may be highly relevant for IFNβ's treatment efficacy.

Assessment of beta-cell function in young patients with type 2 diabetes: arginine-stimulated insulin secretion may reflect beta-cell reserve

OBJECTIVE

Simple methods for the evaluation of dynamic b-cell function in epidemiological and clinical studies of patients with type 2 diabetes (T2D) are needed. The aim of this study was to evaluate the dynamic beta-cell function in young patients with T2D with different disease durations and treatments.

METHODS

Overall, 54 subjects with T2D from the Diabetes Incidence Study in Sweden (DISS) and 23 healthy control participants were included in this cross-sectional study. Beta-cell function was assessed by intravenous (i.v.) administration of arginine followed by i.v. glucose. The acute insulin and C-peptide responses to arginine (AIRarg and Ac-pepRarg, respectively) and to glucose (AIRglu and Ac-pepRglu, respectively)were estimated.Homeostasis model assessment of b-cell function(HOMA-b) andCpeptide assessments were also used for comparisons between patients with T2D and control participants.

RESULTS

AIRarg and Ac-pepRarg, but not AIRglu and Ac-pepRglu, could differentiate between patients with different disease durations. AIRglu values were 89% (P < 0.001) lower and AIRarg values were 29% (P < 0.01) lower in patients with T2D compared with control participants. HOMA-b and fasting plasma C-peptide levels did not differ between the T2D and control groups.

CONCLUSION

In young patients with T2D, the insulin secretory response to i.v. glucose is markedly attenuated, whereas i.v. arginine-stimulated insulin release is better preserved and can distinguish between patients with different disease duration and antidiabetic therapies. This suggests that the i.v. arginine stimulation test may provide an estimate of functional beta-cell reserve.

Pharmacodynamic effects of the oral glucokinase activator AZD6370 after single doses in healthy volunteers assessed with euglycaemic clamp

AIMS

This study evaluated the safety, tolerability, pharmacokinetics and pharmacodynamic effects of the glucokinase activator (GKA) AZD6370 in non-diabetic subjects, using the euglycaemic clamp to avoid the risk of hypoglycaemia.

METHODS

Oral single ascending doses of AZD6370 10-650 mg or subcutaneous short-acting insulin 4 or 12 U were given to healthy fasting subjects. AZD6370 safety, tolerability and pharmacokinetics were assessed. Pharmacodynamic effects on serum (S)-insulin and glucose infusion rate (GIR) were investigated with euglycaemic clamp. AZD6370 10-20 mg was also assessed when taken with food without euglycaemic clamp.

RESULTS

AZD6370 was well tolerated and no safety concerns were raised. AZD6370 was rapidly absorbed and eliminated, and plasma concentration was proportional to dose. Both S-insulin and GIR increased following AZD6370 administration. The observed increase in GIR correlated with increasing AZD6370 area under the plasma concentration vs. time curve, demonstrating a dose-concentration-dependent pharmacodynamic effect. AZD6370 at doses of 50 and 80 mg had similar effects to short-acting insulin 4 U on peripheral S-insulin levels but greater effects on GIR, suggesting an effect beyond the increase of peripheral S-insulin levels at lower doses. In the food interaction part of the study, performed without euglycaemic clamp, dose escalation was stopped at a low dose (20 mg) because of hypoglycaemia.

CONCLUSION

The euglycaemic clamp was successfully used to avoid hypoglycaemia and to demonstrate pharmacodynamic effects, that is, markedly increased insulin secretion and glucose utilisation, following administration of AZD6370 in healthy fasting subjects. In addition to the effect on pancreatic insulin secretion, the data support an extra-pancreatic (hepatic) component of GKA action.

Inhalation toxicity of (1-->3)-beta-D glucan: recent advances

To investigate the effects of (1→3)-β-D-glucan after inhalation, animals were exposed to different forms of glucan and the number of lung lavage cells was determined 24 h after exposure. None of the different forms assayed caused any increase in cell numbers. In animals exposed to endotoxin, all types of cells were increased after 24 h. A simultaneous exposure to curdlan reduced this increase in a dose-related fashion. The results suggest that (1→3)-β-D-glucan-related acute injury to the lung is induced by mechanisms other than those induced by inflammagenic agents such as endotoxin.

Atropine improves insulin sensitivity in both lean and abdominally obese subjects

BACKGROUND

Dysregulated autonomic nerve activity may contribute to the development of type 2 diabetes. The aim of this study was to assess the effects of an anticholinergic agent, atropine, and a cholinergic agent, physostigmine, on insulin sensitivity in lean and abdominally obese subjects.

SUBJECTS AND METHODS

In a single-blinded three-way crossover study, six lean and six abdominally obese nondiabetic subjects [three males and three females in each group; age, 43.8 ± 14.8 vs. 46.8 ± 4.8 yr (mean ± sd); body mass index, 22.6 ± 1.7 vs. 28.8 ± 1.3 kg/m(2); and waist circumference, 85 ± 2 vs. 99 ± 6 cm, respectively] were given iv infusions with atropine (15 μg/kg bolus, 4 μg/kg · h infusion), physostigmine (0.12 μg/kg · min) or saline (0.9% NaCl) in a randomized treatment order. Infusions were started 30 min before and continued throughout a 120-min euglycemic (5.6 mm) hyperinsulinemic (40 mU/m(2) · min) clamp.

RESULTS

Insulin sensitivity (M-value, i.e. glucose infusion rate divided by lean body mass) during the last 60 min of the clamp was higher during infusion with atropine than saline (9.2 ± 1.0 vs. 7.6 ± 1.0 mg/kg lean body mass · min, mean ± sem; P = 0.015) in all subjects. Physostigmine did not differ significantly from saline (8.2 ± 1.0). M-values were significantly higher in lean vs. obese [atropine, 11.6 ± 1.4 vs. 7.6 ± 1.3; physostigmine, 10.8 ± 1.3 vs. 6.3 ± 1.3; and saline, 9.1 ± 1.4 vs. 6.4 ± 1.3, respectively (all P < 0.05)], but the incremental effect of atropine vs. saline did not differ consistently between groups.

CONCLUSION

Insulin sensitivity was higher during a short-term atropine infusion compared with saline in both lean and abdominally obese subjects. This insulin-sensitizing effect of cholinergic blockade is unexpected, and the underlying mechanisms should be further investigated.

Interleukin-17-producing T-helper cells and related cytokines in human airways exposed to endotoxin

Previous studies on mouse models have indicated that interleukin (IL)-17 and IL-17-producing T-helper (Th) cells are important for pulmonary host defence against Gram-negative bacteria. Human correlates to these findings have not yet been demonstrated. The aim of the present study was to determine whether or not IL-17-producing Th cells are present and whether IL-17 and other Th17-associated cytokines are involved in the immunological response to endotoxin in human airways. Segmental exposure to endotoxin and contralateral exposure to vehicle were performed in the lungs of healthy volunteers, with subsequent bronchoalveolar lavage 12 or 24 h after exposure to study local changes in cytokines and inflammatory cells. Endotoxin exposure increased concentrations of IL-17, IL-22 and their downstream effector molecules, human β-defensin-2 and IL-8/CXC chemokine ligand 8, in bronchoalveolar lavage fluid. Th cells with the capacity to produce IL-17 were found among the bronchoalveolar lavage cells, and expression of IL-17 mRNA correlated with expression of the transcription factor, retinoic-acid-receptor-related orphan receptor C variant 2. Moreover, endotoxin increased the numbers of neutrophils, macrophages and IL-17-producing T-cells, as well as the concentration of the Th17-regulating cytokines, IL-21 and IL-23. In conclusion, IL-17-producing Th cells are present, and IL-17, as well as other Th17-associated cytokines, is involved in the immunological response to endotoxin in human airways.

Tadalafil increases muscle capillary recruitment and forearm glucose uptake in women with type 2 diabetes

AIMS/HYPOTHESIS

Recent evidence suggests that reduced synthesis of nitric oxide in endothelial cells, i.e. endothelial dysfunction, contributes to the impaired action of insulin in the vasculature of patients with type 2 diabetes. We investigated whether selective inhibition of phosphodiesterase-5 by tadalafil has beneficial effects on peripheral microcirculation and glucose uptake in these patients.

METHODS

We enrolled seven postmenopausal women with type 2 diabetes and ten age-matched healthy women as controls in a placebo-controlled study to evaluate the acute metabolic effects of tadalafil. We performed microdialysis and blood flow measurements in muscle, and sampled arterial and deep venous blood before and after a single dose of tadalafil 20 mg or placebo. Circulating glucose and insulin levels, muscle capillary recruitment as reflected by permeability surface area for glucose (PS(glu)) and forearm glucose uptake were measured.

RESULTS

In women with type 2 diabetes, but not in the control group, tadalafil induced increases in the incremental AUC for PS(glu) (tadalafil vs placebo 41 +/- 11 vs 4 +/- 2 ml [100 g](-1) min(-1), p < 0.05) and forearm glucose uptake (46 +/- 9 vs 8 +/- 4 micromol [100 g](-1) min(-1), p < 0.05). The variable that best predicted forearm glucose uptake was PS(glu), which explained 70% of its variance. However, fasting glucose and insulin concentrations were similar following treatment with placebo or tadalafil in the two groups.

CONCLUSIONS/INTERPRETATION

This study suggests that tadalafil evokes positive metabolic effects in insulin-resistant women with type 2 diabetes.

Repeated measurements of 11β-HSD-1 activity in subcutaneous adipose tissue from lean, abdominally obese, and type 2 diabetes subjects--no change following a mixed meal

The aim of this study was to measure 11β-HSD-1 activity in subcutaneous adipose tissue by an ex vivo method in three subgroups; lean, obese, and type 2 diabetes subjects, both in the fasting state and after a mixed meal and to determine the variability and reproducibility of this method. Eighteen subjects were investigated; 6 lean, 6 abdominally obese, and 6 type 2 diabetes subjects (BMI 22 ± 1, 30 ± 3 and 31 ± 3 kg/m², respectively). Needle biopsies were taken repeatedly and an index of 11β-HSD-1 activity was measured as percent conversion of (3)H-cortisone to (3)H-cortisol/100 mg tissue. For two separate biopsies taken in the fasting state on the same day, the within subjects CV was 16% and the between CV was 36% for 11β-HSD-1 activity for all subjects. For two biopsies taken in the fasting state at two different days, the total within subjects CV was 38% and the between subjects CV was 46%. Lean subjects had lower 11β-HSD-1 activity (4.8 ± 1.5% conversion of ³H-cortisone to ³H-cortisol/100 mg tissue) than both obese (14.4 ± 1.6% conversion, p<0.01) and type 2 diabetes subjects (11.7 ± 1.9% conversion, p<0.05) in the fasting state. There was no effect of a meal on 11β-HSD-1 activity in any of the three groups. The conclusions from this study are: 1) the variation coefficient for the ex vivo adipose tissue 11β-HSD-1 activity method was ∼25% for repeat measures within subjects; 2) food intake had no major impact on enzyme activity; and 3) 11β-HSD-1 activity in subcutaneous adipose tissue was significantly increased in obese subjects with or without T2DM compared to lean subjects without diabetes.

IL-5 expression and release from human CD34 cells in vitro; ex vivo evidence from cases of asthma and Churg-Strauss syndrome

BACKGROUND

Eosinophils develop from hematopoietic CD34(+) progenitor cells in the bone marrow (BM) under the influence of Interleukin-5 (IL-5). The primary source of IL-5 is T-lymphocytes, although other sources may exist. The aims of this study were to determine whether CD34(+) cells from human peripheral blood (PB) and BM have the capacity to produce IL-5 when stimulated in vitro, and secondly, whether an elevated number of IL-5-producing CD34(+) cells can be found in situ in ongoing eosinophilic disease.

METHODS

CD34(+) cells from PB and BM were stimulated in vitro, and IL-5 production and release was assessed by ELISA, ELISPOT, flow cytometry and immunocytochemistry. Blood and BM from a patient with Churg-Strauss syndrome were analyzed by flow cytometry for CD34(+)/IL-5(+) cells, and immunohistochemical staining of CD34(+)/IL-5(+) cells in bronchial biopsies from an asthmatic patient was performed.

RESULTS

Both PB and BM CD34(+) cells can produce and release IL-5 when stimulated in vitro. In the Churg-Strauss patient, IL-5-producing CD34(+) cells were found in PB and BM. Oral glucocorticoid treatment markedly decreased the number of IL-5-positive CD34 cells in the BM. CD34(+)/IL-5(+) cells were present in a patient with asthma.

CONCLUSION

CD34(+) cells in blood and BM are capable of producing IL-5 both in vitro and in vivo in humans, arguing that these cells may have the capacity to contribute to eosinophilic inflammation. Consequently, targeting CD34(+) progenitor cells that produce and release IL-5 may be effective in reducing the mobilization of eosinophil lineage-committed cells in eosinophilic-driven diseases.

New production of eosinophils and the corresponding TH1/TH2 balance in the lungs after allergen exposure in BALB/c and C57BL/6 mice

Allergic asthma is associated with eosinophilic inflammation in the airways. Animal models commonly used to elucidate allergic inflammation mechanisms include BALB/c and C57BL/6 mice. Our aim was to evaluate lung eosinophilia and the corresponding Th1/Th2 balance in the two strains after allergen exposure. BALB/c and C57BL/6 mice were subjected to ovalbumin-induced allergic airway inflammation using BrdU to label newly produced cells. The numbers of new eosinophils were evaluated by differential cell count and immunocytochemistry (MBP+BrdU+). Proliferation rate of lung eosinophils was measured by analysis of CD45+CCR3+BrdU+ cells by FACS. Distribution of newly produced eosinophils in the lung and the Th1/Th2 (CD4+T-bet+/CD4+GATA-3+) balance was evaluated by immunohistochemistry. Allergen challenge with ovalbumin induced comparable eosinophilia in bone marrow (BM), blood and lung tissue in both strains of mice compared to phosphate-buffered saline controls, which was confirmed by immunocytochemistry. There was a small increase in the number of lung MBP+BrdU(-) eosinophils in C57BL/6 mice compared to BALB/c mice, which suggests a basal increase in this strain following sensitization. While there was no difference in eosinophilic proliferation in the lung, the distribution of the newly produced eosinophils differs between the two strains. BALB/c mice showed staining primarily around vessels and airways, whereas C57BL/6 mice showed a more even distribution in the lung tissue. No difference in the Th1/Th2 balance was observed between two strains. This study shows that there is a difference in the distribution of eosinophils in the lung between the C57BL/6 and BALB/c mice, but no difference in eosinophil production or Th1/Th2 balance.

Loss of the lupus autoantigen Ro52/Trim21 induces tissue inflammation and systemic autoimmunity by disregulating the IL-23-Th17 pathway

Ro52/Trim21 is targeted as an autoantigen in systemic lupus erythematosus and Sjögren's syndrome. Polymorphisms in the Ro52 gene have been linked to these autoimmune conditions, but the molecular mechanism by which Ro52 may promote development of systemic autoimmune diseases has not been explored. To address this issue, we generated Ro52-null mice (Ro52^−/−), which appear phenotypically normal if left unmanipulated. However, Ro52^−/− mice develop severe dermatitis extending from the site of tissue injury induced by ear tags. The affected mice further develop several signs of systemic lupus with hypergammaglobulinemia, autoantibodies to DNA, proteinuria, and kidney pathology. Ro52, which was recently identified as an E3 ligase, mediates ubiquitination of several members of the interferon regulatory factor (IRF) family, and the Ro52-deficient mice have an enhanced production of proinflammatory cytokines that are regulated by the IRF transcription factors, including cytokines involved in the Th17 pathway (interleukin [IL] 6, IL-12/IL-23p40, and IL-17). Loss of IL-23/IL-17 by genetic deletion of IL-23/p19 in the Ro52^−/− mice conferred protection from skin disease and systemic autoimmunity. These data reveal that the lupus-associated Ro52 protein is an important negative regulator of proinflammatory cytokine production, and they provide a mechanism by which a defective Ro52 function can lead to tissue inflammation and systemic autoimmunity through the IL-23–Th17 pathway.

Prolonged eosinophil production after allergen exposure in IFN-gammaR KO mice is IL-5 dependent

Asthma is a T helper 2 (Th2)-driven inflammatory process characterized by eosinophilia. Prolonged airway eosinophilia is commonly observed in asthma exacerbations. Our aim was to evaluate whether eosinophilia in prolonged allergic inflammation is associated with a continuous supply of new eosinophils to the airways, and how this is regulated. Ovalbumin (OVA)-sensitized interferon-gamma receptor knockout mice (IFN-gammaR KO), known to maintain a long-lasting eosinophilia after allergen exposure, were compared to wild type (wt) controls. Animals were exposed to OVA or phosphate-buffered saline on three consecutive days, and bone marrow (BM), blood and bronchoalveolar lavage (BAL) samples were collected 24 h, 7 and 21 days later. Newly produced cells were labelled using bromodeoxyuridine (BrdU). Serum IL-5 was measured and its role was investigated by administration of a neutralizing anti-IL-5 antibody. In-vitro eosinophilopoiesis was examined in both groups by a colony-forming assay. Allergen challenge increased eosinophils in BM, blood and BAL, in both IFN-gammaR KO and wt mice, both 24 h and 7 days after the last allergen exposure. At 21 days after the last exposure, only IFN-gammaR KO mice maintained significantly increased eosinophil numbers. Approximately 50% of BAL granulocytes in IFN-gammaR KO were produced during the last 6 days. Interleukin (IL)-5 concentration was increased in IFN-gammaR KO mice, and anti-IL-5 reduced eosinophil numbers in all compartments. Increased numbers of eosinophil colonies were observed in IFN-gammaR KO mice after allergen exposure versus controls. In this model of a Th2-driven prolonged allergic eosinophilia, new eosinophils contribute to the extended inflammation in the airways by enhanced BM eosinophilopoiesis in an IL-5-dependent manner.

Regulation of allergen-induced bone marrow eosinophilopoiesis: role of CD4+ and CD8+ T cells

BACKGROUND

The mechanisms of the distant stimulation of the bone marrow (BM) after airway allergen exposure remain largely obscure. T cells have been implicated in allergic airway inflammation but their role in allergen-induced BM eosinophilopoiesis is poorly understood. The aim of this study was to determine the role of CD4(+) and CD8(+) T cells in allergen-induced BM eosinophilopoiesis.

METHODS

Ovalbumin (OVA)-sensitized wild type (WT), CD4 knockout (CD4-/-) and CD8 knockout (CD8-/-) mice were exposed intranasally to OVA or saline. Bromo-deoxyuridine (BrdU) was used to label newly produced cells. Bone marrow, blood and bronchoalveolar lavage (BAL) were sampled 24 h after the final exposure. Immunostaining for newly produced eosinophils (i.e. BrdU(+)/MBP(+)) and BM eosinophil progenitor [CD34(+)/CD45(+)/interleukin-5 (IL-5)Ralpha(+)] cells was performed.

RESULTS

The number of newly produced BM eosinophils (BrdU(+)/MBP(+) cells) was significantly reduced in allergen exposed CD4-/- or CD8-/- mice compared with allergen exposed WT mice, which was followed by a subsequent decrease in newly produced blood and airway eosinophils. Furthermore, BM eosinophil progenitors were significantly reduced in allergen exposed CD4-/- and CD8-/- mice compared with WT mice. Finally, serum IL-5 and Bronchoalveolar lavage fluid eotaxin-2 levels were abolished in allergen exposed CD4-/- mice to levels seen in saline exposed WT mice.

CONCLUSIONS

These data suggests that both CD4(+) and CD8(+) T cells have a regulatory role in allergen-induced BM eosinophilopoiesis, whereas CD4(+) T cells are obligatory for allergen-induced airway eosinophilia. The subsequent traffic of eosinophils to the airways is likely to be at least partly regulated by a CD4(+) T-cell-dependent local airway eotaxin-2 production.

Differential effects of fluticasone and montelukast on allergen-induced asthma

Early asthmatic responses (EAR) and late asthmatic responses (LAR) to allergen are induced by the local release of a series of bronchoconstrictor mediators, including leukotrienes and histamine. Both anti-leukotrienes and other anti-asthma drugs, such as inhaled glucocorticoids, have been shown to reduce both EAR and LAR. The aim of the present study was to directly compare the effects of regular treatment with an oral anti-leukotriene, montelukast (Mont; 10 mg once daily, for 8 days), and an inhaled glucocorticoid [fluticasone propionate (FP) 250 microg twice daily for 8 days] on the EAR and LAR to an inhaled allergen challenge. Patients with a documented EAR and LAR at a screening visit were randomized to these treatments, or placebo, in a double-blind, double-dummy, crossover fashion. Allergen challenge at a dose causing both an EAR and LAR was given on the eighth day of treatment. The maximum fall in FEV1 during the EAR was 17.8% during placebo treatment, 8.3% during Mont and 16.3% during FP (P <0.05 for Mont vs placebo). The maximum fall during the EAR was 13.8% during placebo treatment, 11.8% during Mont and 2% during FP treatment (P <0.05 for FP vs placebo and FP vs Mont). PC20 methacholine was significantly higher 24 h after allergen challenge during FP-treatment compared with Mont (P <0.05). Both montelukast and fluticasone reduced the relative amount of sputum eosinophils after allergen compared with placebo treatment. This study shows that anti-leukotrienes are effective to attenuate the EAR, whereas inhaled glucocorticoids are more effective than anti-leukotrienes in attenuating the EARs and improves bronchial hyperresponsiveness to a greater extent. In conclusion, inhaled glucocorticoids have overall greater efficacy than oral anti-leukotrienes to attenuate allergen-induced airway responses in mild asthmatic patients.

Allergen stimulates bone marrow CD34(+) cells to release IL-5 in vitro; a mechanism involved in eosinophilic inflammation?

The specific mechanisms that alter bone marrow (BM) eosinophilopoiesis in allergen-induced inflammation are poorly understood. The aims of this study were to evaluate (a) whether the number of BM CD34(+) cells is altered due to allergen sensitization and exposure in vivo and (b) whether BM CD34(+) cells produce and release interleukin (IL)-5, IL-3 and granulocyte macrophage-colony stimulating factor (GM-CSF) after stimulation in vitro. A mouse model of ovalbumin (OVA)-induced airway inflammation was used. Bone marrow CD34(+) cells were cultured in vitro and the cytokine release was measured by enzyme-linked immunosorbent assay. The IL-5-production from CD34(+) cells was confirmed by immunocytochemistry. Airway allergen exposure increased the number of BM CD34(+) cells (P = 0.01). Bone marrow CD34(+) cells produced IL-5 when stimulated with the allergen OVA in vitro, but not IL-3 or GM-CSF. Nonspecific stimulus with calcium ionophore and phorbol-myristate-acetate of BM CD34(+) cells caused release of IL-5, IL-3 and GM-CSF. The induced release of IL-5 was increased in alum-injected vs naive mice (P = 0.02), but was not affected by allergen sensitization and exposure. The release of IL-3 and GM-CSF was increased after allergen sensitization and exposure (P < 0.02). In conclusion, allergen can stimulate BM CD34(+) cells to produce IL-5 protein. It is likely that the CD34(+) cells have autocrine functions and thereby regulate the early stages of BM eosinophilopoiesis induced by airway allergen exposure. Alum, a commonly used adjuvant, enhances the release of IL-5 and may thereby enhance eosinophilopoiesis.

Regulation and counterregulation of lipolysis in vivo: different roles of sympathetic activation and insulin

To obtain further information on the regulation of lipolysis in vivo, the effect of increasing sympathetic nerve activity via lower body negative pressure (LBNP, -20 mm Hg) was studied in 11 healthy human subjects. Subcutaneous and muscle microdialysis as well as blood flow measurements were performed in the postabsorptive state and during an euglycemic hyperinsulinemic clamp. LBNP for 30 min in the postabsorptive phase resulted in an approximately 50% increase (P < 0.005) in the interstitial-arterial concentration difference for glycerol in adipose tissue, whereas no such effect was registered in muscle. Blood flow in adipose tissue and the forearm remained unaltered. During euglycemic hyperinsulinemic conditions (p-insulin 645 +/- 62 pmol/liter), both interstitial adipose tissue and arterial concentrations of glycerol were reduced. LBNP resulted in an increase in interstitial-arterial concentration difference in glycerol similar to that seen in the postabsorptive state (approximately 50%, P < 0.05). Muscle glycerol was not changed by either insulin or LBNP. Glucose infusion rate during the clamp was significantly decreased during LBNP (7.82 +/- 0.88 vs. 8.67 +/- 1.1 ml/kg.min, P < 0.05). We conclude that the sympathetic nervous activation by LBNP results in an increased lipolysis rate in adipose tissue both in the postabsorptive phase and during insulin infusion. On the other hand, muscle glycerol output was not affected by either LBNP or insulin. The data suggest that 1) lipolysis is regulated differently in muscle and adipose tissue, 2) postabsorptive lipolysis is mainly regulated by insulin, and 3) sympathetic nervous activation effectively inhibits the antilipolytic action of insulin by inducing insulin resistance.

A role of GM-CSF in the accumulation of neutrophils in the airways caused by IL-17 and TNF-alpha

The T-cell cytokine interleukin (IL)-17 selectively accumulates neutrophils in murine airways in vivo and may thus constitute a link between activation of T-lymphocytes and accumulation of neutrophils. In this study, the authors evaluated the role of granulocyte macrophage-colony stimulating factor (GM-CSF) in accumulation of neutrophils in the airways caused by IL-17 and tumour necrosis factor (TNF)-alpha. In vitro, human (h) IL-17 concentration-dependently stimulated the release of GM-CSF protein (enzyme-linked immunosorbent assay) in human bronchial epithelial cells (16HBE). IL-17 also time-dependently stimulated the release of GM-CSF protein in venous endothelial (human umbilical vein endothelial cells) cells in vitro. Co-stimulation with IL-17 plus the pro-inflammatory cytokine TNF-alpha potentiated the release of GM-CSF protein in 16HBE cells. hIL-17 also enhanced the expression of GM-CSF messenger ribonucleic acid in 16HBE cells (reverse transcriptase polymerase chain reaction), with a similar order of magnitude as TNF-alpha. Conditioned cell medium from bronchial epithelial cells co-stimulated with hIL-17 plus TNF-alpha prolonged survival (trypan blue exclusion) of human neutrophils in vitro and this effect was blocked by an anti-GM-CSF antibody. In vivo, local co-stimulation with mouse IL-17 plus TNF-alpha caused an additive potentiation of the accumulation of neutrophils in bronchoalveolar lavage fluid from mouse airways and this effect was blocked by an anti-GM-CSF antibody given systemically. In conclusion, granulocyte macrophage-colony stimulating factor is involved in the accumulation of neutrophils in the airways caused by interleukin-17 and tumour necrosis factor-alpha, probably via effects on both recruitment and survival of neutrophils.

Reduced late asthmatic response by repeated low-dose allergen exposure

Allergic asthmatic individuals are often exposed to low-doses of allergen in their everyday life. Extended exposure to allergen has lead to down-regulation of the allergic process in cell systems and in animal models. The aim of this study was to evaluate whether any such inhibitory mechanism of allergic responses can be seen in man in vivo. Patients with mild asthma were repeatedly and double-blindly exposed to 25% of the individual dose of allergen that caused an early (EAR) and late asthmatic reaction (LAR). One day after the low-dose allergen or placebo exposure periods, the same individual was given a high-dose allergen challenge. Sputum and blood were collected for the evaluation of eosinophils. Exposure to repeated low doses of allergen induced increased bronchial methacholine responsiveness 6 h after the final allergen exposure (p=0.018), and an increase in the number of eosinophils in sputum. By contrast, the late asthmatic response after challenge with a high dose of allergen was significantly attenuated by approximately 30% at 24 h after the final low-dose allergen exposure (p = 0.03). In summary, repeated low doses of allergen given directly to the airways, attenuate the high-dose allergen-induced late response, despite enhanced bronchial hyperresponsiveness to methacholine and elevated sputum eosinophils prior to allergen challenge.

Estimations of muscle interstitial insulin, glucose, and lactate in type 2 diabetic subjects

Previous measurement of insulin in human muscle has shown that interstitial muscle insulin and glucose concentrations are approximately 30-50% lower than in plasma during hyperinsulinemia in normal subjects. The aims of this study were to measure interstitial muscle insulin and glucose in patients with type 2 diabetes to evaluate whether transcapillary transport is part of the peripheral insulin resistance. Ten patients with type 2 diabetes and ten healthy controls matched for sex, age, and body mass index were investigated. Plasma and interstitial insulin, glucose, and lactate (measured by intramuscular in situ-calibrated microdialysis) in the medial quadriceps femoris muscle were analyzed during a hyperinsulinemic euglycemic clamp. Blood flow in the contralateral calf was measured by vein plethysmography. At steady-state clamping, at 60-120 min, the interstitial insulin concentration was significantly lower than arterial insulin in both groups (409 +/- 86 vs. 1,071 +/- 99 pmol/l, P < 0.05, in controls and 584 +/- 165 vs. 1, 253 +/- 82 pmol/l, P < 0.05, in diabetic subjects, respectively). Interstitial insulin concentrations did not differ significantly between diabetic subjects and controls. Leg blood flow was significantly higher in controls (8.1 +/- 1.2 vs. 4.4 +/- 0.7 ml. 100 g(-1).min(-1) in diabetics, P < 0.05). Calculated glucose uptake was less in diabetic patients compared with controls (7.0 +/- 1.2 vs. 10.8 +/- 1.2 micromol. 100 g(-1).min(-1), P < 0.05, respectively). Arterial and interstitial lactate concentrations were both higher in the control group (1.7 +/- 0.1 vs. 1.2 +/- 0.1, P < 0. 01, and 1.8 +/- 0.1 vs. 1.2 +/- 0.2 mmol/l, P < 0.05, in controls and diabetics, respectively). We conclude that, during hyperinsulinemia, muscle interstitial insulin and glucose concentrations did not differ between patients with type 2 diabetes and healthy controls despite a significantly lower leg blood flow in diabetic subjects. It is suggested that decreased glucose uptake in type 2 diabetes is caused by insulin resistance at the cellular level rather than by a deficient access of insulin and glucose surrounding the muscle cell.

Eosinophilopoiesis in a murine model of allergic airway eosinophilia: involvement of bone marrow IL-5 and IL-5 receptor alpha

The airway inflammation in asthma is dominated by eosinophils. The aim of this study was to elucidate the contribution of newly produced eosinophils in airway allergic inflammation and to determine mechanisms of any enhanced eosinophilopoiesis. OVA-sensitized BALB/c mice were repeatedly exposed to allergen via airway route. Newly produced cells were identified using a thymidine analog, 5-bromo-2'-deoxyuridine, which is incorporated into DNA during mitosis. Identification of IL-5-producing cells in the bone marrow was performed using FACS. Bone marrow CD3+ cells were enriched to evaluate IL-5-protein release in vitro. Anti-IL-5-treatment (TRFK-5) was given either systemically or directly to the airways. IL-5R-bearing cells were localized by immunocytochemistry. Repeated airway allergen exposure caused prominent airway eosinophilia after three to five exposures, and increased the number of immature eosinophils in the bone marrow. Up to 78% of bronchoalveolar lavage (BAL) granulocytes were 5-bromo-2'-deoxyuridine positive. After three allergen exposures, both CD3+ and non-CD3 cells acquired from the bone marrow expressed and released IL-5-protein. Anti-IL-5 given i.p. inhibited both bone marrow and airway eosinophilia. Intranasal administration of anti-IL-5 also reduced BAL eosinophilia, partly via local effects in the airways. Bone marrow cells, but not BAL eosinophils, displayed stainable amounts of the IL-5R alpha-chain. We conclude that the bone marrow is activated by airway allergen exposure, and that newly produced eosinophils contribute to a substantial degree to the airway eosinophilia induced by allergen. Airway allergen exposure increases the number of cells expressing IL-5-protein in the bone marrow. The bone marrow, as well as the lung, are possible targets for anti-IL-5-treatment.

IL-12 regulates bone marrow eosinophilia and airway eotaxin levels induced by airway allergen exposure

BACKGROUND

Airway allergen exposure causes local eosinophilic cell infiltration. This cellular inflammatory response is likely to involve the release of eosinophils from peripheral storage pools, and possibly also regeneration of eosinophils in the bone marrow. IL-12 is an inhibitory cytokine in allergic inflammation, shown to reduce eosinophilic cell infiltration. The aim of the present study was to determine whether airway allergen exposure increases bone marrow eosinophil production, and, if so, whether IL-12 modulates this effect.

METHODS

Ovalbumin-sensitized C57BL/6 mice and IL-12 knockout (KO) mice were exposed to allergen via the airway route, and the inflammatory cell response was evaluated in bronchoalveolar lavage fluid, blood, and bone marrow.

RESULTS

Allergen instillation intranasally produced a dose-dependent inflammatory response in the lower airways of sensitized mice. This inflammatory response was dominated by eosinophils, but there were also increases of both lymphocytes and neutrophils. Sensitization and airway allergen exposure also increased the IL-5-dependent growth of bone marrow cells in vitro. The enhanced bone marrow responsiveness in vitro was paralleled by an increased number of bone marrow eosinophils in vivo. After sensitization and repeated allergen exposure, IL-12 KO mice showed higher eosinophil levels in both BAL and bone marrow than parallel wild-type control mice. Furthermore, BAL-eotaxin levels were increased in IL-12 KO mice as opposed to parallel wild-type controls after allergen exposure.

CONCLUSIONS

Airway allergen exposure induced systemic immunologic responses, including increased eosinophil numbers in both airways and bone marrow, and also enhanced IL-5 responsiveness in bone marrow cells. IL-12 may regulate airway eosinophilia at both the level of eosinophilopoiesis and the level of local recruitment of eosinophils into the airways.

Muscle glucose uptake is effectively activated by ischemia in type 2 diabetic subjects

It has previously been shown that Wortmannin, a phosphatidylinositol 3-kinase inhibitor, inhibits glucose transport activated by insulin but not by ischemia, suggesting the importance of an activating mechanism that bypasses the insulin signal. To evaluate the relevance of this insulin-independent pathway in insulin-resistant subjects, the ability of ischemia to stimulate glucose uptake was investigated in 9 patients with type 2 diabetes and in 9 healthy control subjects (fasting glucose level 9.4 +/- 0.8 vs. 5.1 +/- 0.1 mmol/l, P < 0.001, in type 2 diabetic patients and control subjects, respectively; fasting insulin level insulin 8.1 +/- 2.6 vs. 4.5 +/-0.7 mU/l, P < 0.05, respectively) matched for sex, age, and BMI. Arterial plasma and interstitial concentrations of glucose and lactate (measured by subcutaneous and muscle microdialysis) were recorded in the forearm before, during, and after ischemia induced locally for 20 min. During ischemia, the muscle interstitial glucose concentration decreased significantly from 7.7 +/- 0.6 to 5.4 +/- 0.4 mmol/l (P < 0.01) and from 4.4 +/- 0.3 to 3.6 +/- 0.3 mmol/l (P < 0.05) in type 2 diabetic patients and control subjects, respectively. The arterial-interstitial (A-I) glucose concentration difference was 1.7 +/- 0.6 and 0.7 +/- 0.3 mmol/ at basal, and it increased significantly to 3.5 +/- 0.7 (P < 0.01) and 1.4 +/-0.3 mmol/l (P < 0.05) during ischemia in each group, respectively. Interstitial lactate increased significantly during ischemia from 0.8 +/- 0.1 to 1.1 +/- 0.1 mmol/l (P < 0.05) and from 0.5 +/- 0.1 to 0.9 +/- 0.2 mmol/l (P < 0.05), respectively. The A-I glucose concentration difference was abolished immediately postischemia and regained after approximately 15 min, whereas high interstitial lactate levels remained elevated throughout the study. Subcutaneous interstitial glucose concentrations remained unchanged during ischemia and postischemia in both groups, whereas the interstitial lactate concentration in adipose tissue increased during ischemia from 1.4 +/- 0.2 to 2.0 +/- 0.2 mmol/l (P < 0.05) and from 1.1 +/- 0.1 to 1.8 +/- 0.3 mmol/l (P < 0.05) in type 2 diabetic patients and control subjects, respectively. Plasma glucose and lactate levels were unchanged in both groups during the study period. The results show that in muscle, but not in adipose tissue, glucose uptake is efficiently activated by ischemia in insulin-resistant type 2 diabetic subjects, suggesting the activation of a putative alternative pathway to the insulin signal in muscle cells.

Increased elastase and myeloperoxidase activity associated with neutrophil recruitment by IL-17 in airways in vivo

BACKGROUND

A recent study demonstrated that intratracheal administration of the T-lymphocyte cytokine IL-17 recruits neutrophils into airways in vivo by C-X-C chemokine release. It is not known whether IL-17 may also activate airway neutrophils.

OBJECTIVE

Our purpose was to evaluate whether IL-17 activates neutrophils in airways in vivo and, if so, whether the proinflammatory cytokine IL-1beta modulates this action of IL-17.

METHODS

Intratracheal administration of human (h) IL-17 or rat (r) IL-1beta or hIL-17 plus rIL-1beta in anesthetized, spontaneously breathing rats was followed by bronchoalveolar lavage (BAL) 6 hours later. The BAL fluid was characterized in terms of neutrophil count, of the activity for myeloperoxidase (MPO), and in some cases of the activity for elastase (ELA). Isolated rat neutrophils were stimulated with hIL-17 in vitro, followed by characterization of MPO activity in the cell medium.

RESULTS

hIL-17 (1 microg) increased the ELA and the MPO activity, as well as the neutrophil count in BAL fluid, whereas the proinflammatory cytokine rIL-1beta (2.5 ng) did not. Pretreatment with rIL-1beta enhanced IL-17induced ELA and MPO activity, without increasing the neutrophil count. The BAL ELA activity was inhibited by a specific inhibitor of neutrophil serine proteases. Stimulation with hIL-17 in vitro did not increase MPO activity in isolated neutrophils.

CONCLUSION

IL-17 can activate neutrophils in association with their recruitment into the airways in vivo and this effect is probably achieved through induced release of mediators from other airway cells.

Neutrophil recruitment by human IL-17 via C-X-C chemokine release in the airways

IL-17 is a recently discovered cytokine that can be released from activated human CD4+ T lymphocytes. This study assessed the proinflammatory effects of human (h) IL-17 in the airways. In vitro, hIL-17 increased the release of IL-8 in human bronchial epithelial and venous endothelial cells, in a time- and concentration-dependent fashion. This effect of hIL-17 was inhibited by cotreatment with an anti-hIL-17 Ab and was potentiated by hTNF-alpha. In addition, hIL-17 increased the expression of hIL-8 mRNA in bronchial epithelial cells. Conditioned medium from hIL-17-treated bronchial epithelial cells increased human neutrophil migration in vitro. This effect was blocked by an anti-hIL-8 Ab. In vivo, intratracheal instillation of hIL-17 selectively recruited neutrophils into rat airways. This recruitment of neutrophils into the airways was inhibited by an anti-hIL-17 Ab and accompanied by increased levels of rat macrophage inflammatory protein-2 (rMIP-2) in bronchoalveolar lavage (BAL) fluid. The BAL neutrophilia was also blocked by an anti-rMIP-2 Ab. The effect of hIL-17 on the release of hIL-8 and rMIP-2 was also inhibited by glucocorticoids, in vitro and in vivo, respectively. These data demonstrate that hIL-17 can specifically and selectively recruit neutrophils into the airways via the release of C-X-C chemokines from bronchial epithelial cells and suggest a novel mechanism linking the activation of T-lymphocytes to recruitment of neutrophils into the airways.

Measurement of interstitial insulin in human muscle

Previous measurements in lymph and adipose tissue have indicated that interstitial insulin concentrations are approximately 40% lower than in plasma. Measurements of insulin in human muscle interstitial fluid have not been performed yet. We developed a new external reference technique for calibration of microdialysis catheters in situ. This technique allows correct assessments of interstitial peptide concentrations and was employed to estimate the insulin concentration in medial quadriceps femoris muscle in 11 individuals (age: 37 +/- 3 yr; body mass index: 25.2 +/- 1.2 kg/m2) during a two-step euglycemic hyperinsulinemic clamp. At steady-state insulin and glucose infusion, plasma glucose was 5.9 +/- 0.2 mmol/l, plasma insulin was 155 +/- 17 mU/l, and interstitial muscle insulin was 67 +/- 19 mU/l (n = 9; P < 0.01). At a higher insulin infusion rate, the steady-state plasma insulin concentration was 379 +/- 58 mU/l, and interstitial insulin concentration was 180 +/- 40 mU/l (P < 0.01). The data show for the first time that high physiological and supraphysiological plasma insulin levels give 30-50% lower interstitial concentrations of insulin in the muscle. The importance of capillary delivery as a rate-limiting step for the insulin effect is suggested.

Mild experimental exacerbation of asthma induced by individualised low-dose repeated allergen exposure. A double-blind evaluation

Low doses of environmental allergens have been proposed to increase bronchial hyperreactivity in sensitised individuals, without causing immediate asthmatic reactions. The primary aim of the present study was to evaluate whether repeated low doses of allergen, that do not cause overt bronchoconstriction, cause augmented non-specific bronchial reactivity. A secondary aim was to evaluate whether any changes in reactivity are associated with increased variability of lung function, and whether signs of inflammatory activity could be found. To do this, mild asthmatic patients without regular symptoms, but with both immediate and late reactions in response to a high dose of inhaled cat allergen extract, were included in a double blind, placebo controlled, cross-over study in which a low dose of allergen was administered on four consecutive days (Monday to Thursday). The dose of allergen was individualised for each patient, and was calculated to be 25% of the total dose given to produce an immediate and late response at screening. Repeated low dose allergen exposure produced a significant increase in methacholine reactivity compared to placebo, whereas FEV1 in the morning did not significantly change during the allergen week. Each low dose allergen exposure caused small changes in FEV1 (approximately 7% drop), which was significant vs. placebo only on day 2 (Tuesday). During the allergen week, six of eight patients reported asthma symptoms on at least one occasion, and variability in lung function, measured with a portable spirometer, was increased. Repeated low doses of allergen also produced a significant increase of P-ECP vs. placebo, without a significant rise in circulating eosinophils. However, no significant changes in circulating CD3, CD4, CD8, CD19, or CD25 cells were found, evaluated by FACS analysis. We conclude that low doses of allergen produce signs of a mild exacerbation of asthma, including increased bronchial reactivity to methacholine. This clinical model may be useful to evaluate both the pathophysiological mechanisms of asthma, and the effects of novel anti-asthma drugs.

An intranasal glucocorticoid inhibits the increase of specific IgE initiated during birch pollen season

BACKGROUND

Recent in vitro findings show that glucocorticoids in combination with IL-4 can induce the synthesis of IgE, indicating that glucocorticoids may promote allergy.

OBJECTIVE

A double-blind, placebo-controlled study was performed to evaluate the effect of an intranasal glucocorticoid on the levels of birch pollen-specific IgE antibodies in serum from patients with allergic rhinitis.

METHODS

Eighteen patients with allergic rhinitis received treatment with an intranasal glucocorticoid (beclomethasone dipropionate, 400 microg/day) or placebo for 5 weeks, starting from the beginning of the birch pollen season. Blood samples for anti-birch IgE evaluation were taken before treatment was initiated and at 2 and 5 weeks after the beginning of the study.

RESULTS

The beclomethasone group (n = 9) had significantly lower symptom scores when compared with the placebo group (n = 9) (0.86 +/- 0.26 vs 2.79 +/- 0.76, p value = 0.01). Both the treatment group and the placebo group showed a trend of an increase in anti-birch IgE levels 2 weeks after the beginning of the treatment (from 33.1 +/- 13.1 kU/L to 44.9 +/- 20.9 kU/L in the beclomethasone group and from 53.2 +/- 18.9 kU/L to 64.1 +/- 22.1 kU/L in the placebo group). Treatment with beclomethasone returned anti-birch IgE levels to baseline by the end of the study, whereas in the placebo group the anti-birch IgE levels continued to increase (final values, 33.1 +/- 11.9 kU/L vs 72.6 +/- 23.2 kU/L, respectively). The change in IgE antibody levels in the placebo group was significantly higher than that in the beclomethasone group. No statistically significant changes in total IgE or soluble CD23 levels were detected.

CONCLUSION

We conclude that treatment with an intranasal glucocorticoid initiated at the beginning of the pollen season inhibits the induced increase in specific IgE.

Bronchial hyperresponsiveness, epithelial damage, and airway eosinophilia after single and repeated allergen exposure in a rat model of anhydride-induced asthma

Bronchial hyperresponsiveness (BHR) and damage of the epithelium, as well as eosinophilia in the airway wall, induced by trimellitic anhydride (TMA) in sensitized brown Norway rats were studied. Rats were challenged once or seven times with aerosol of TMA conjugated to rat serum albumin (TMA-RSA) 3 weeks after intradermal TMA sensitization. Airway responsiveness (-log PC300 of acetylcholine i.v.) was measured 24 h after allergen challenge. Epithelial lesion and eosinophil infiltration in the airway walls were quantified under light microscopy, and TMA-specific IgE and IgG in serum were evaluated with ELISA. High levels of TMA-specific IgE and IgG were found in all rats in the sensitized groups compared to nonsensitized groups (P < 0.001). Repeated allergen challenges of 0.03% TMA-RSA for 7 consecutive days enhanced the level of TMA-specific IgG, compared to single challenge (P < or = 0.05). Single allergen challenge of 0.3% TMA-RSA had a nonsignificant tendency to produce BHR in sensitized rats compared to nonsensitized rats (P = 0.06). However, repeated allergen challenges (0.003% and 0.03% TMA-RSA for 7 consecutive days) produced significant BHR in sensitized rats (P < 0.05). Furthermore, repeated low-dose (0.003%) TMA-RSA challenge produced more BHR than a 10 times higher single dose (0.03%) (P < 0.05). Slight damage of the airway epithelium was seen in sensitized and repeat-challenged groups. However, bronchial eosinophilia was found in the sensitized and single-challenged groups, but not in nonsensitized nonchallenged, and sensitized repeat-challenged groups (P < 0.005). We conclude that the brown Norway rat can be sensitized with TMA, and that repeated low-dose allergen challenges produce slight epithelial damage and BHR which is independent of ongoing eosinophilia in the airway wall.

Pulmonary cell infiltration after chronic exposure to (1-->3)-beta-D-glucan and cigarette smoke

OBJECTIVE AND DESIGN

To evaluate the effect of a microbial cell wall component--(1-->3)-beta-D-glucan--on the inflammatory effect induced by cigarette smoke in a subchronic exposure situation.

MATERIAL

Groups of guinea-pigs were exposed 5 days/week to cigarette smoke, an aerosol of (1-->3)-beta-D-glucan, or to both.

METHODS

The numbers of different inflammatory cells were studied in histological sections, enzyme digested lung tissue and in lung lavage. Cell enzyme production was measured.

RESULTS

Exposure to (1-->3)-beta-D-glucan or cigarette smoke caused only minor alterations in inflammatory cells. Given together they caused an increase in cellularity in the tissue with significantly increased numbers of macrophages, lymphocytes, neutrophils and eosinophils. There was also an increase in subepithelial eosinophils. Lung lavage cell enzyme production was slightly lower in the combined exposure group.

CONCLUSION

The results demonstrate that (1-->3)-beta-D-glucan synergistically increases the inflammation induced by cigarette smoke. The mechanism may be a downregulation of the macrophage control of inflammatory cell migration into the lung tissue.

Socio-economic client characteristics and consequences of abortion in Nairobi

In Nairobi, 281 women presenting with alleged miscarriage were subdivided in the following subgroups, 91 spontaneous abortions (group 1), 152 suspected induced abortions (group 2) and 38 admittedly induced abortions (group 3). In the statistical analysis women in group 1 were compared with women from groups 2 and 3 combined (here referred to as group 4). Group 4 differed significantly from group 1 in the following respects: they were younger (p = 0.03) although they had previously born more babies (p = 0.008), lived more often together with their parents (p = 0.024), were less often married (p = 0.000012), worked more often as housewives (p = 0.00079), and lived in bigger households (p = 0.000015). No significant differences were encountered regarding religious beliefs. Group 4 women were more informed about contraceptives than group 1 (p = 0.04), particularly regarding injectables (p = 0.000096) and oral contraceptives (p = 0.0013) but also intra uterine devices (p = 0.024). Almost 90% of group 4 women indicated post abortion contraceptive interest, while only 1/3 of group 1 women did so. Group 3 women needed extensive parenteral treatment with a total hospital treatment cost amounting to 300 times that of group 1. The total cost of intravenous infusions was almost 10 times as high in group 3 as in group 1. The total number of days in hospital was significantly higher in group 4 than in group 1 (p = 0.0098).(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary inflammation induced by repeated inhalations of beta(1,3)-D-glucan and endotoxin

In an animal model of hypersensitivity pneumonitis (HP) guinea-pigs were exposed for 5 weeks to an aerosol of bacterial endotoxin, beta(1,3)-D-glucan (curdlan) or a combination. Exposure to endotoxin or curdlan showed only small changes in inflammatory cells in airways or the lung wall, histologically or in terms of enzyme secretion from alveolar macrophages. When the two agents were given together, a histology resembling HP was seen with alveolar infiltrates and early granulomas. Inflammatory cells in airways were increased and enzyme production of macrophages was changed, suggesting an effect of curdlan on the inflammatory regulating capacity of airway macrophages. The results suggest that interference with macrophage function and inflammation are important components in the development of HP.