Personalized medicine and back-allogeneic exosomes for cancer immunotherapy

Extracellular vesicles, especially exosomes, have been explored for cancer immunotherapy. The initial studies made use of autologous B-cell or dendritic cell-derived exosomes, with the idea that MHC-peptide complexes on the exosomal surface would stimulate an MHC-restricted cancer-specific immune response. This was also verified in mouse systems, whilst the effects in human clinical systems were more modest. Several studies have explored the mechanisms for exosomal T-cell activation, and a picture emerges where the antigen-presenting cells, possibly both B cells and dendritic cells of the recipient, are needed to induce a potent T-cell response to exosomes. Therefore, the exosomes function more as an adjuvant-like delivery system of antigens, and we need to further understand the exact components that trigger the most broad and potent immune responses. Here, we describe the grounds for using allogeneic exosomes for cancer therapy, something that would greatly improve the feasibility of new exosome-based immunotherapeutic approaches to cure cancer.

Positioning Psychiatric and Mental Health Nursing as a Transformative Force in Health Care

From the perspective of psychiatric and mental health nurses in Sweden, this discussion paper aims to position psychiatric and mental health nursing as a transformative force contributing to enforcing person-centered values and practices in health care. We argue the potential impact of psychiatric and mental health nursing on service user health and recovery, nursing student education and values, and the organization and management of health care. Psychiatric and mental health nursing is discussed as a caring, reflective, and therapeutic practice that promotes recovery and health. Implications for nursing education, research, management, and practice are outlined.

Evaluating reflective practice groups in a mental health context: Swedish translation and psychometric evaluation of the clinical supervision evaluation questionnaire

BACKGROUND

Implementation of reflective practice groups in psychiatric and mental health contexts might improve the quality of care through promoting self-awareness, clinical insight, and facilitating stress management and team building. There is a need for valid and reliable instruments to test the outcomes of reflective practice groups in the mental health context. This study aimed to test the validity and reliability of the Swedish version of the Clinical Supervision Evaluation Questionnaire.

METHODS

The instrument was translated from English to Swedish using a translation and back-translation procedure. Data for the calculation of content validity was collected from an expert group. Data for the reliability analysis was collected from rehabilitation assistants and ward managers participating in reflective practice groups (n = 20). Content validity was measured by computing a content validity index. Construct validity was assessed by calculating the corrected item-total correlation statistics. Reliability was evaluated by analysing the Cronbach's alpha coefficient, the intraclass correlation coefficient and inter-item correlations.

RESULTS

The content validity index for the scale as a whole was 0.94. Item-total correlations ranged between 0.23 and 0.81, and deletion of an item did not notably improve Cronbach's alpha. Cronbach's alpha for the scale was 0.89. The intraclass correlation coefficient for single measures was 0.35. The mean inter-item correlation was .37.

CONCLUSION

The Swedish version of the Supervision Evaluation Questionnaire has a degree of reliability and validity that is comparable to the original version in English, indicating that it can be used as an assessment of reflective practice groups in the mental health context.

Differences in exosome populations in human breast milk in relation to allergic sensitization and lifestyle

BACKGROUND

Breast-feeding has many beneficial effects on the developing immune system of the newborn. Breast milk contains immunoregulatory factors, such as nano-sized vesicles named exosomes. This study aimed at characterizing breast milk exosomes from human early milk and mature milk and to investigate whether allergic sensitization and an anthroposophic lifestyle could influence the exosome profile.

METHODS

Breast milk was collected from 22 mothers at day 3-8 and from 61 mothers at 2 months postpartum, all part of the ALADDIN birth cohort. Isolated exosomes were captured on anti-MHC-class II- or anti-CD63 beads and analyzed by flow cytometry. Exosomal phenotype was related to lifestyle and allergic sensitization of the mothers, and sensitization of the child at 2 years of age.

RESULTS

We found a higher content of exosomes in early milk compared with mature milk. Early milk exosomes were enriched in HLA-DR molecules and displayed significantly lower levels of HLA-ABC compared with those in mature milk. Phenotypically different subpopulations of exosomes were found in mature milk. Significantly lower levels of MUC1 were detected on CD63-enriched exosomes from sensitized mothers compared with nonsensitized. Furthermore, women with an anthroposophic lifestyle had significantly lower MUC1 expression on their HLA-DR-enriched milk exosomes and up-regulated levels of CD63 on CD63-enriched exosomes compared with nonanthroposophic mothers. Notably, mothers whose children developed sensitization had an increased amount of HLA-ABC on their milk exosomes enriched for CD63.

CONCLUSIONS

The phenotype of exosomes in breast milk varies with maternal sensitization and lifestyle, which might influence allergy development in the child.

Bronchoalveolar lavage fluid exosomes contribute to cytokine and leukotriene production in allergic asthma

BACKGROUND

Leukotrienes (LTs) are potent pro-inflammatory mediators involved in asthma. Exosomes, nanosized vesicles released from various cells, can stimulate or down-regulate immune responses, depending on the state and nature of the originating cell. We have recently shown an altered exosome profile in bronchoalveolar lavage fluid (BALF) of patients with sarcoidosis, but their role in asthma is unknown. Our aims were to investigate whether exosomes from BALF have LT biosynthetic capacity and to explore phenotypic and functional characteristics of BALF exosomes in asthma.

METHODS

Bronchoalveolar lavage fluid exosomes were collected from healthy individuals (n = 13) and patients with mild allergic asthma to birch pollen (n = 12) before and after birch allergen provocation. Exosomes were characterized by flow cytometry and Western blot. Their capacity to induce IL-8 and LT production in the human bronchial epithelial cell (BEC) line 16HB14o- was measured by ELISA and reverse-phase HPLC, respectively.

RESULTS

Compared to BALF exosomes from healthy individuals, BALF exosomes from asthmatics displayed higher levels of exosome-associated markers, such as the tetraspanins CD63 and CD81 and the scavenger receptor CD36. No major differences were observed between BALF exosomes from before and after allergen provocation. Furthermore, we show that BALF exosomes contain enzymes for LT biosynthesis. The effect of exosomes to promote LTC(4) and IL-8 release in BEC was significantly increased for exosomes from asthmatics, and the CysLT(1) receptor antagonist Montelukast reduced exosome-induced IL-8 secretion.

CONCLUSIONS

Bronchoalveolar lavage fluid exosomes from asthmatic and healthy individuals exhibit distinct phenotypes and functions. BALF exosomes from asthmatics might contribute to subclinical inflammation by increasing cytokine and LTC(4) generation in airway epithelium.

Exosomes - nanovesicles with possible roles in allergic inflammation

Exosomes are nano-sized membrane vesicles which are released extracellularly after fusion of multivesicular endosomes with the cell membrane. Despite their characteristic composition of proteins compared to the cell membrane, no exosome-specific molecule has so far been characterized. Exosomes are found in bronchoalveolar lavage (BAL), urine, serum and breast milk, and are released from several cells implicated in allergy including mast cells, dendritic cells (DC), T cells and epithelial cells. Antigen-loaded exosomes have been shown to be highly immunogenic and we propose that exosomes could be a modulating factor in allergic responses. Allergen-presenting exosomes could transport allergen and stimulate allergen-specific T cells, and possibly also biasing T cell responses depending on the molecules present on the exosome surface. Furthermore, exosomes from mast cells, highly active in allergic reactions, have been found to induce DC maturation and also to be able to transport functional RNA to recipient cells, suggesting a new pathway for cell communication. Reversely, tolerizing exosomes e.g. tolerosomes, from gut or breast milk, could block an allergic response or prevent allergy development. A better understanding of the role of exosomes in allergies could make us understand how allergy can be prevented or lead to the development of more efficient treatments.

Malassezia sympodialis differently affects the expression of LL-37 in dendritic cells from atopic eczema patients and healthy individuals

BACKGROUND

Atopic eczema (AE) is a multifactorial disease, which has increased in prevalence. The skin-colonizing yeast Malasezzia sympodialis can induce IgE- and T-cell reactivity in patients with AE. LL-37 is an endogenous peptide antibiotic belonging to the cathelicidin family. The aim of this study was to examine whether exposure to M. sympodialis would affect the expression of LL-37 in dendritic cells.

METHODS

The presence of LL-37 was analyzed in monocyte-derived dendritic cells (MDDCs) generated from healthy individuals and patients with AE by Western blotting and the corresponding cDNA by real-time quantitative RT-PCR. Antibacterial activity was measured with an inhibition zone assay in fractions after reverse phase chromatography.

RESULTS

For the first time we here present data, showing that LL-37 is produced by MDDCs. Notably, the secretion of LL-37 was substantially enhanced in M. sympodialis-exposed MDDCs generated from patients with a high degree of eczema, as measured by SCORAD, compared to healthy controls and patients with a low SCORAD. The relative expression of LL-37 transcript in MDDCs generated from patients was up-regulated after 1 h of exposure to M. sympodialis and declined gradually at the time points analyzed, whereas the transcription was unaffected in the MDDCs of healthy controls.

CONCLUSIONS

Our results suggest that M. sympodialis can trigger the innate immune response differently in patients with AE and healthy individuals. The enhanced LL-37 secretion from the MDDCs in the patients with AE may reflect the severity of their inflammatory response to M. sympodialis.

Low numbers of interleukin-12-producing cord blood mononuclear cells and immunoglobulin E sensitization in early childhood

BACKGROUND

Successful pregnancies are associated with skewing towards a Th2 cytokine profile. Cytokine responses to allergens can be detected in cord blood mononuclear cells (CBMC), suggesting allergen priming already in utero.

OBJECTIVE

To investigate the cytokine profile in CBMC after in vitro stimulation with allergens and to relate the responses to the outcome in terms of allergic disease at 2 years of age.

METHODS

CBMC were isolated from 82 children. The responses to ovalbumin (OVA), birch, cat and phytohaemagglutinin (PHA) were investigated by the ELISpot technique. The numbers of IFN-gamma-, IL-4- and IL-12-producing CBMC were counted for each stimulation. The children were followed prospectively; skin prick test (SPT) and RAST towards food and inhalant allergens were assessed at 24 months of age.

RESULTS

Sixteen (19.5%) children were classified as IgE sensitized (positive SPT; > or =3 mm and/or RAST; > or =0.35 kUA/L). The numbers of IL-12-producing CBMC after stimulation with birch, OVA and cat were lower among IgE-sensitized children, statistically significant for cat. IFN-gamma-producing cells, did not differ in numbers between the sensitized and non-sensitized children. Children who had atopic eczema/dermatitis syndrome (AEDS) during the observation (n=53) had significantly lower numbers of IFN-gamma-producing CBMC after stimulation with OVA and cat than their non-AEDS counterparts.

CONCLUSIONS

Although the numbers of infants in our study are limited our data suggest that a low number of IL-12-producing CBMC is associated with IgE sensitization during early childhood and that a reduced number of IFN-gamma-producing CBMC promotes the development of AEDS during the first 2 years of life.

Exosomes with major histocompatibility complex class II and co-stimulatory molecules are present in human BAL fluid

Exosomes are 30-100 nm diameter vesicles formed by inward budding of endosomal compartments and are produced by several cell types, including T-cells, B-cells and dendritic cells (DC)s. Exosomes from DCs express major histocompatibility complexes (MHC) class I and II, and co-stimulatory molecules on their surface, and can induce antigen-specific activation of T-cells. The aims of the present study were to investigate for the presence of exosomes in bronchoalveolar lavage fluid (BALF) from healthy individuals, and to establish if these exosomes bear MHC and co-stimulatory molecules. The authors analysed BALF taken from seven healthy volunteers and used exosomes from monocyte-derived DC (MDDC) cultures as a reference. After ultracentrifugation, exosomes were bound to anti-MHC class II coated magnetic beads and analysed by flow cytometry and electron microscopy. The authors report for the first time that exosomes are present in BALF. These exosomes are similar to MDDC derived exosomes as they express MHC class I and II, CD54, CD63 and the co-stimulatory molecule CD86. The results demonstrate that exosomes are present in the lung, and since they contain both major histocompatibility complex and co-stimulatory molecules it is likely that they are derived from antigen presenting cells and might have a regulatory role in local immune defence.

Influence of atopic heredity on IL-4-, IL-12- and IFN-gamma-producing cells in in vitro activated cord blood mononuclear cells

Several reports have claimed that there is a greater risk for a child with an atopic mother to develop allergy as compared to a child with an atopic father. This suggests that the fetal environment during pregnancy might be of importance for the development of atopic disease. Both proliferative and cytokine responses have been detected in cord blood mononuclear cells (CBMC) after stimulation with allergens, suggesting allergen priming already in utero. The aim of this study was to investigate whether the atopic status of the mother influences cytokine production by CBMC. We compared interleukin (IL)-4, IL-12 and interferon (IFN)-gamma-producing CBMC from children with double atopic heredity (dh), maternal atopic heredity only (mh) or no atopic heredity (nh). CBMC were stimulated in vitro with allergens (birch, ovalbumin and cat), phytohaemagglutinin (PHA) or purified protein derivative (PPD) and cytokine-producing cells were measured by the enzyme-linked immunospot assay. In response to PHA, the frequency of IL-4-producing cells, as well as the ratio of IL-4/IFN-gamma-producing cells, were significantly higher in the dh group compared to the nh group. High numbers of IL-12-producing cells in response to allergens were detected, significantly highest in the nh group, followed by the dh and mh groups. Our results suggest that there is a stronger Th2 bias after in vitro stimulation of CBMC from children with atopic heredity, as reflected by higher IL-4/IFN-gamma ratios in response to PHA, and lower numbers of IL-12-producing cells after allergen stimulation. Whether these differences influence later allergy development will be evaluated when the atopic status of the children is assessed at 2 years of age.

Specific immunotherapy prevents increased levels of allergen-specific IL-4- and IL-13-producing cells during pollen season

BACKGROUND

Specific allergen immunotherapy (SIT) is effective for treatment of IgE-mediated diseases: however, the mechanisms of action still remain unclear. Earlier, we showed that IL-4 and IL-13 are produced in response to specific allergens. The aim of this study was to investigate whether these cytokine responses were affected by allergen SIT, and, furthermore, to evaluate the effect of SIT on allergen-specific IgE and IgG4 levels.

METHODS

Blood samples from pollen-sensitized individuals were collected before the pollen season (before treatment) and during the pollen season (after SIT or placebo treatment). Peripheral blood mononuclear cells were activated in vitro with allergens and the numbers of IL-4-, IL-13-, IL-10-, and IFN-gamma-producing cells were determined by ELISPOT. Serum levels of allergen-specific IgE and IgG4 were measured by RAST and ELISA, respectively.

RESULTS

The numbers of IL-4- and IL-13-producing cells were shown to be increased in the placebo group during the pollen season, an increment which was absent in patients receiving allergen SIT. We found an increase in allergen-specific IgG4 in the SIT-treated individuals, but not in the placebo group. Both groups displayed elevated specific IgE levels during the pollen season.

CONCLUSIONS

Taken together, our data show a downregulation of IL-4- and IL-13-producing cells in peripheral blood after SIT, suggesting induction of nonresponsiveness/tolerance or a redistribution of these cells. Furthermore, we demonstrate that SIT acts on antibody production by increasing the specific IgG4 levels.

Increased frequencies of allergen-induced interleukin-13-producing cells in atopic individuals during the pollen season

We have reported previously that allergen-specific serum IgE levels were correlated with allergen-induced interleukin (IL)-4 in type I allergic individuals. Here, we wanted to investigate whether IL-13, another switch factor for IgE, was induced by allergen in vitro and if so, whether this was correlated with the elevated serum IgE-levels seen in atopic individuals, and whether the cytokine profile changed during pollen season. Peripheral blood mononuclear cells from 14 atopic and 14 healthy individuals collected out of the pollen season were incubated in vitro with allergens (birch or timothy) and the number of IL-4, IL-13, IL-10 and IFN-gamma producing cells was determined by ELISPOT. In response to the specific allergen, IL-13-producing cells were seen in allergic but not in healthy individuals. The number of IL-13-producing cells was significantly correlated with the allergen-specific serum IgE levels. When the allergic individuals were tested during the pollen season, the number of allergen-specific IL-4- and IL-13-producing cells, as well as serum levels of specific IgE, increased. The IL-13 increase seen in ELISPOT was confirmed by a RT-PCR assay. No seasonal changes were seen in response to purified protein derivative (PPD) or the mitogen PHA. During the pollen season, the IL-4 and IL-13 responses were highly correlated. Taken together, our results support the roles of both IL-13 and IL-4 in the regulation of allergen-specific IgE levels in atopic individuals.

Increased allergen-specific Th2 responses in vitro in atopic subjects receiving subclinical allergen challenge

The study aimed to determine whether inhalation of subclinical allergen doses-leads to a shift in the balance between T helper (Th) 1 and Th2 cells in asthmatic patients. Elevated IgE requires allergen-specific T cells producing cytokines such as interleukin (IL)-4 or IL-13. Interferon-gamma (IFN-gamma) produced by Th1 cells counteracts the effects of IL-4. In nature, allergic persons are often exposed to low levels of allergen, leading to hyperreactivity, but not to acute allergic reactions. In this study, nine allergic persons inhaled low doses of allergen or placebo in a double-blind manner over seven consecutive weekdays. During the study, the bronchial responsiveness to histamine challenge increased, but no subject exhibited asthmatic symptoms. Blood was drawn on days 0, 1, 4, and 9, and the number of IL-4- and IFN-gamma-producing cells was measured by enzyme-linked immunospot (ELISPOT) assay after in vitro stimulation with a low-dose phytohemagglutinin (PHA) mixed with the relevant allergen or with PHA alone. In three of the four subjects receiving allergen, the IL-4/IFN-gamma ratio increased during the time of the study. No increase was seen in the placebo group. No increase was seen in serum IgE levels in any of the groups. We conclude that a shift in the balance between Th1 and Th2 cells can be detected in subjects exposed to subclinical allergen doses.

Specific induction of interleukin-4-producing cells in response to in vitro allergen stimulation in atopic individuals

BACKGROUND AND OBJECTIVE

CD4+ T cells can be divided into two major subsets, T helper (TH)1 and TH2 cells. Interleukin-4 (IL-4) is produced by TH2 cells and induces switching of immunoglobulin (Ig) M/IgG to IgE. Interferon-gamma (IFNgamma) produced by TH1 cells counteracts the IgE-promoting effects of IL-4. In this study we wanted to investigate whether the number of IL-4-producing cells could be a direct measurement of allergen exposure in vitro, and whether this was correlated to the elevated serum IgE-levels seen in atopic persons.

METHODS

We compared the number of IL-4- and IFNgamma-producing cells using an enzyme-linked immunospot assay (ELISPOT) in response to allergens from birch and cat in peripheral mononuclear cells from atopic and healthy individuals.

RESULTS

In the two sensitized groups there was an increase in the number of IL-4-producing cells in response to the specific allergen which was not seen in the healthy group (1/20000 cells and 1/200000 cells, respectively, P < 0.001 for birch). In criss-cross experiments where birch-sensitized individuals were stimulated with cat allergen, no IL-4-producing cells were seen, indicating a high degree of specificity. In individual subjects, the elevated numbers of IL-4-producing cells were significantly correlated with their allergen-specific serum IgE levels. When allergen was combined with a suboptimal dose of PHA, there was a synergistic increase in the number of allergen-induced IL-4-producing cells (1/4000 cells) in the atopic donors, which was not seen with the number of IFNgamma-producing cells.

CONCLUSIONS

Allergen-specific IL-4 producing cells in a peripheral blood mononuclear cell (PBMC) culture can be detected by ELISPOT and the response can synergistically be enhanced by suboptimal concentrations of PHA.

Allergen induced cytokine profiles in type I allergic individuals before and after immunotherapy

Allergen immunotherapy (IT) involves subcutaneous injections of increasing doses of specific allergen over a period of time. It is recognised as highly effective in the treatment of patients with allergic rhinitis. However, the specific immunological mechanisms by which IT achieves its effect have not been fully elucidated. Recent studies, have shown that the clinical effects following IT of allergic individuals is concomitant with a reduced production of IL-4 by allergen specific CD4+ T-cells. The aim of the present study was to gain better knowledge about the immunological mechanisms by which IT exerts its beneficial effects. For this purpose, peripheral blood mononuclear cells (PBMC) from ten individuals receiving birch allergen or placebo in an IT-study performed in a double-blind manner, were analysed for IL-4, IFN-gamma, IL-5 and IL-10 mRNA expression at the onset of the study and during the pollen season, during treatment. Both spontaneous and in vitro allergen-induced cytokine mRNA expression was analysed using reverse transcriptase-polymerase chain reaction (RT-PCR). Spontaneous expression of IL-4 mRNA could be detected in most of the allergic patients, but not in healthy donors. The IT-treated patients showed a decrease in the spontaneous expression of IL-4 mRNA during the pollen season as compared to at the onset of the study, while in patients receiving placebo the IL-4 mRNA expression increased or remained unchanged. Similar results were obtained after in vitro stimulation with allergen. This was in contrast to the results for IFN-gamma, which was readily detected in both patient groups with no significant differences between the groups at either timepoint. IL-5 was shown to be increased during the pollen season in both groups and thereby presumably not affected by allergen IT. Taken together, these observations suggest that the cytokine profiles in circulating T lymphocytes change as a consequence of allergen IT.