Cough-induced chylothorax in a two-year-old boy - case report and review of the literature

BACKGROUND

Chylothorax is a very rare form of pleural effusion in children, especially after the neonatal period, and predominantly occurs secondary to cardiothoracic surgery. It can lead to significant respiratory distress, immunodeficiency, and malnutrition. Effective treatment strategies are therefore required to reduce morbidity.

CASE PRESENTATION

A previously healthy two-year old boy was admitted with history of heavy coughing followed by progressive dyspnea. The chest X-ray showed an extensive opacification of the right lung. Ultrasound studies revealed a large pleural effusion of the right hemithorax. Pleural fluid analysis delivered the unusual diagnosis of chylothorax, most likely induced by preceded excessive coughing. After an unsuccessful treatment attempt with a fat-free diet and continuous pleural drainage for two weeks, therapy with octreotide was initiated. This led to complete and permanent resolution of his pleural effusion within 15 days, without any side effects.

CONCLUSIONS

Severe cough may be a rare cause of chylothorax in young children. Octreotide seems to be an effective and safe treatment of spontaneous or traumatic chylothorax in children. There is, however, a lack of comprehensive studies for chylothorax in children and many issues concerning diagnostic strategies and treatment algorithms remain.

Consensus protocols for the diagnosis and management of the hereditary autoinflammatory syndromes CAPS, TRAPS and MKD/HIDS: a German PRO-KIND initiative

BACKGROUND

Rare autoinflammatory diseases (AIDs) including Cryopyrin-Associated Periodic Syndrome (CAPS), Tumor Necrosis Receptor-Associated Periodic Syndrome (TRAPS) and Mevalonate Kinase Deficiency Syndrome (MKD)/ Hyper-IgD Syndrome (HIDS) are genetically defined and characterized by recurrent fever episodes and inflammatory organ manifestations. Early diagnosis and early start of effective therapies control the inflammation and prevent organ damage. The PRO-KIND initiative of the German Society of Pediatric Rheumatology (GKJR) aims to harmonize the diagnosis and management of children with rheumatic diseases nationally. The task of the PRO-KIND CAPS/TRAPS/MKD/HIDS working group was to develop evidence-based, consensus diagnosis and management protocols including the first AID treat-to-target strategies.

METHODS

The national CAPS/TRAPS/MKD/HIDS expert working group was established, defined its aims and conducted a comprehensive literature review synthesising the recent (2013 to 2018) published evidence including all available recommendations for diagnosis and management. General and disease-specific statements were anchored in the 2015 SHARE recommendations. An iterative expert review process discussed, adapted and refined these statements. Ultimately the GKJR membership vetted the proposed consensus statements, agreement of 80% was mandatory for inclusion. The approved statements were integrated into three disease specific consensus treatment plans (CTPs). These were developed to enable the implementation of evidence-based, standardized care into clinical practice.

RESULTS

The CAPS/TRAPS/MKD/HIDS expert working group of 12 German and Austrian paediatric rheumatologists completed the evidence synthesis and modified a total of 38 statements based on the SHARE recommendation framework. In iterative reviews 36 reached the mandatory agreement threshold of 80% in the final GKJR member survey. These included 9 overarching principles and 27 disease-specific statements (7 for CAPS, 11 TRAPS, 9 MKD/HIDS). A diagnostic algorithm was established based on the synthesized evidence. Statements were integrated into diagnosis- and disease activity specific treat-to-target CTPs for CAPS, TRAPS and MKD/HIDS.

CONCLUSIONS

The PRO-KIND CAPS/TRAPS/MKD/HIDS working group established the first evidence-based, actionable treat-to-target consensus treatment plans for three rare hereditary autoinflammatory diseases. These provide a path to a rapid evaluation, effective control of disease activity and tailored adjustment of therapies. Their implementation will decrease variation in care and optimize health outcomes for children with AID.

Human monocytic myeloid-derived suppressor cells impair B-cell phenotype and function in vitro

Myeloid-derived suppressor cells (MDSCs) are key regulators of immunity that initially have been defined by their ability to potently suppress T-cell responses. Recent studies collectively demonstrate that the suppressive activity of MDSCs is not limited to T cells, but rather affects a broad range of immune cell subsets. However, relatively few studies have assessed the impact of MDSCs on B cells, particularly in the human context. Here, we report that human monocytic MDSCs (M-MDSCs) significantly interfere with human B-cell proliferation and function in vitro. We further show that the inhibition occurs independent of direct cell-contact and involves the expression of suppressive mediators such as indoleamine 2, 3-dioxygenase (IDO), arginase-1 (Arg1), and nitric oxide (NO). In addition, our studies demonstrate that the suppression of B cells by M-MDSCs is paralleled by a skewing in B-cell phenotype and gene expression signatures. M-MDSCs induced the downregulation of key surface markers on activated B cells, including IgM, HLA-DR, CD80, CD86, TACI, and CD95. Concurrently, M-MDSCs but not conventional monocytes elicited alterations in the transcription of genes involved in apoptosis induction, class-switch regulation, and B-cell differentiation and function. In summary, this study expands our understanding of the regulatory role of M-MDSCs for human B-cell responses.

The German National Registry of Primary Immunodeficiencies (2012-2017)

Introduction: The German PID-NET registry was founded in 2009, serving as the first national registry of patients with primary immunodeficiencies (PID) in Germany. It is part of the European Society for Immunodeficiencies (ESID) registry. The primary purpose of the registry is to gather data on the epidemiology, diagnostic delay, diagnosis, and treatment of PIDs. Methods: Clinical and laboratory data was collected from 2,453 patients from 36 German PID centres in an online registry. Data was analysed with the software Stata® and Excel. Results: The minimum prevalence of PID in Germany is 2.72 per 100,000 inhabitants. Among patients aged 1-25, there was a clear predominance of males. The median age of living patients ranged between 7 and 40 years, depending on the respective PID. Predominantly antibody disorders were the most prevalent group with 57% of all 2,453 PID patients (including 728 CVID patients). A gene defect was identified in 36% of patients. Familial cases were observed in 21% of patients. The age of onset for presenting symptoms ranged from birth to late adulthood (range 0-88 years). Presenting symptoms comprised infections (74%) and immune dysregulation (22%). Ninety-three patients were diagnosed without prior clinical symptoms. Regarding the general and clinical diagnostic delay, no PID had undergone a slight decrease within the last decade. However, both, SCID and hyper IgE- syndrome showed a substantial improvement in shortening the time between onset of symptoms and genetic diagnosis. Regarding treatment, 49% of all patients received immunoglobulin G (IgG) substitution (70%-subcutaneous; 29%-intravenous; 1%-unknown). Three-hundred patients underwent at least one hematopoietic stem cell transplantation (HSCT). Five patients had gene therapy. Conclusion: The German PID-NET registry is a precious tool for physicians, researchers, the pharmaceutical industry, politicians, and ultimately the patients, for whom the outcomes will eventually lead to a more timely diagnosis and better treatment.

Improvement of Guideline Adherence After the Implementation of an Antibiotic Stewardship Program in a Secondary Care Pediatric Hospital

Introduction: The accelerating threat of multidrug-resistant bacteria (MRB) forces health care providers to use antibiotics more rationally. Antibiotic stewardship programs (ASP) are a proven and safe way to achieve that goal. They have been comprehensively studied in adults but data from secondary care pediatric hospitals are lacking. Material and Methods: In our study an ASP with standard operating procedures (SOPs), audits, a weekly ward round with experts in pediatric infectious diseases and an antibiotic pocket-card for selected infectious diseases was established in July 2017 in a Munich municipal secondary care children's hospital. All antibiotic prescriptions on general pediatric wards were reviewed each in the first quarter of 2017 and 2018. The primary outcome was adherence to treatment guidelines. Secondary outcomes were substance consumption, duration of therapy and death. Results: After the ASP was implemented guideline adherence increased significantly from 33 to 63%. The consumption of cephalosporins decreased significantly (-60%), whereas aminopenicillin use increased accordingly (+120%). Neither in the pre- nor in the post-intervention group deaths occurred. Discussion: Data on ASP in pediatric secondary care hospitals are scarce. Most previous studies have been performed at tertiary care/university children's hospitals. We demonstrate a significant improvement in guideline adherence regarding antibiotic treatments after the implementation of an ASP. Cephalosporin consumption decreased which might be relevant for the selection of MRB (e.g., vancomycin-resistant enterococci). Results are limited by the single-center design and the short observation period. The study encourages the implementation of ASPs in secondary care children's hospitals.

Staphylococcal Enterotoxins Dose-Dependently Modulate the Generation of Myeloid-Derived Suppressor Cells

Staphylococcus aureus is one of the major human bacterial pathogens causing a broad spectrum of serious infections. Myeloid-derived suppressor cells (MDSC) represent an innate immune cell subset capable of regulating host-pathogen interactions, yet their role in the pathogenesis of S. aureus infections remains incompletely defined. The aim of this study was to determine the influence of different S. aureus strains and associated virulence factors on human MDSC generation. Using an in vitro MDSC generation assay we demonstrate that low concentrations of supernatants of different S. aureus strains led to an induction of functional MDSC, whereas increased concentrations, conversely, reduced MDSC numbers. The concentration-dependent reduction of MDSC correlated with T cell proliferation and cytotoxicity. Several findings supported a role for staphylococcal enterotoxins in modulating MDSC generation. Staphylococcal enterotoxins recapitulated concentration-dependent MDSC induction and inhibition, T cell proliferation and cytotoxicity, while an enterotoxin-deficient S. aureus strain largely failed to alter MDSC. Taken together, we identified staphylococcal enterotoxins as main modulators of MDSC generation. The inhibition of MDSC generation by staphylococcal enterotoxins might represent a novel therapeutic target in S. aureus infections and beyond in non-infectious conditions, such as cancer.

Human T cells modulate myeloid-derived suppressor cells through a TNF-α-mediated mechanism

Myeloid-derived suppressor cells (MDSC) represent an innate immune cell subset capable of suppressing T-cell responses in cancer and chronic inflammation. While the effect of MDSC on T cells has been defined thoroughly, the reciprocal impact of T cells on MDSC homeostasis remains poorly understood. Therefore, we comprehensively analyzed the effect of different T-cell subsets on the generation and survival of human MDSC. Using an in vitro MDSC generation assay, we demonstrate that unstimulated CD4⁺, but not CD8⁺ T cells, induce polymorphonuclear MDSC (PMN-MDSC) from CD33⁺ myeloid cells. This effect was dependent on direct cell-cell contact and required TNF-α signaling. Soluble TNF-α was dispensable for PMN-MDSC generation, suggesting that transmembrane TNF-α is involved in that trans-cellular process. Stimulated human CD3⁺ T cells delayed the apoptosis of PMN-MDSC, which was independent of TNF-α signaling or direct cell-cell contact, but was recapitulated by IL-2. Taken together, our study shows that human T cells modulate MDSC generation and survival through two distinct mechanisms and thereby fine-tune the homeostasis of human MDSC in a regulated manner.

Practice and consensus-based strategies in diagnosing and managing systemic juvenile idiopathic arthritis in Germany

BACKGROUND

Systemic juvenile idiopathic arthritis (SJIA) is an autoinflammatory disease associated with chronic arthritis. Early diagnosis and effective therapy of SJIA is desirable, so that complications are avoided. The PRO-KIND initiative of the German Society for Pediatric Rheumatology (GKJR) aims to define consensus-based strategies to harmonize diagnostic and therapeutic approaches in Germany.

METHODS

We analyzed data on patients diagnosed with SJIA from 3 national registries in Germany. Subsequently, via online surveys and teleconferences among pediatric rheumatologists with a special expertise in the treatment of SJIA, we identified current diagnostic and treatment approaches in Germany. Those were harmonized via the formulation of statements and, supported by findings from a literature search. Finally, an in-person consensus conference using nominal group technique was held to further modify and consent the statements.

RESULTS

Up to 50% of patients diagnosed with SJIA in Germany do not fulfill the International League of Associations for Rheumatology (ILAR) classification criteria, mostly due to the absence of chronic arthritis. Our findings suggest that chronic arthritis is not obligatory for the diagnosis and treatment of SJIA, allowing a diagnosis of probable SJIA. Malignant, infectious and hereditary autoinflammatory diseases should be considered before rendering a diagnosis of probable SJIA. There is substantial variability in the initial treatment of SJIA. Based on registry data, most patients initially receive systemic glucocorticoids, however, increasingly substituted or accompanied by biological agents, i.e. interleukin (IL)-1 and IL-6 blockade (up to 27.2% of patients). We identified preferred initial therapies for probable and definitive SJIA, including step-up patterns and treatment targets for the short-term (resolution of fever, decrease in C-reactive protein by 50% within 7 days), the mid-term (improvement in physician global and active joint count by at least 50% or a JADAS-10 score of maximally 5.4 within 4 weeks) and the long-term (glucocorticoid-free clinically inactive disease within 6 to 12 months), and an explicit treat-to-target strategy.

CONCLUSIONS

We developed consensus-based strategies regarding the diagnosis and treatment of probable or definitive SJIA in Germany.

Expression of checkpoint molecules on myeloid-derived suppressor cells

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous cell population expanded in cancer, infection and autoimmunity capable of suppressing T-cell functions. Checkpoint inhibitors have emerged as a key therapeutic strategy in immune-oncology. While checkpoint molecules were initially associated with T cell functions, recent evidence suggests a broader expression and function in innate myeloid cells. Previous studies provided first evidence for a potential role for checkpoints on MDSCs, yet the human relevance remained poorly understood. Therefore, we investigated the expression and functional relevance of checkpoint molecules in human MDSC-T-cell interactions. Our studies demonstrate that programmed death-ligand 1 (PD-L1) is expressed on granulocytic MDSCs upon co-culture with T cells. Transwell experiments showed that cell-to-cell contact was required for MDSC-T-cell interactions and antibody blocking studies showed that targeting PD-L1 partially impaired MDSC-mediated T-cell suppression. Collectively, these studies suggest a role for PD-L1 in human MDSC function and thereby expand the functionality of this checkpoint beyond T cells, which could pave the way for further understanding and therapeutic targeting of PD-1/PD-L1 in innate immune-mediated diseases.

Human NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) inflammasome activity is regulated by and potentially targetable through Bruton tyrosine kinase

BACKGROUND

The Nod-like receptor NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) and Bruton tyrosine kinase (BTK) are protagonists in innate and adaptive immunity, respectively. NLRP3 senses exogenous and endogenous insults, leading to inflammasome activation, which occurs spontaneously in patients with Muckle-Wells syndrome; BTK mutations cause the genetic immunodeficiency X-linked agammaglobulinemia (XLA). However, to date, few proteins that regulate NLRP3 inflammasome activity in human primary immune cells have been identified, and clinically promising pharmacologic targeting strategies remain elusive.

OBJECTIVE

We sought to identify novel regulators of the NLRP3 inflammasome in human cells with a view to exploring interference with inflammasome activity at the level of such regulators.

METHODS

After proteome-wide phosphoproteomics, the identified novel regulator BTK was studied in human and murine cells by using pharmacologic and genetic BTK ablation.

RESULTS

Here we show that BTK is a critical regulator of NLRP3 inflammasome activation: pharmacologic (using the US Food and Drug Administration-approved inhibitor ibrutinib) and genetic (in patients with XLA and Btk knockout mice) BTK ablation in primary immune cells led to reduced IL-1β processing and secretion in response to nigericin and the Staphylococcus aureus toxin leukocidin AB (LukAB). BTK affected apoptosis-associated speck-like protein containing a CARD (ASC) speck formation and caspase-1 cleavage and interacted with NLRP3 and ASC. S aureus infection control in vivo and IL-1β release from cells of patients with Muckle-Wells syndrome were impaired by ibrutinib. Notably, IL-1β processing and release from immune cells isolated from patients with cancer receiving ibrutinib therapy were reduced.

CONCLUSION

Our data suggest that XLA might result in part from genetic inflammasome deficiency and that NLRP3 inflammasome-linked inflammation could potentially be targeted pharmacologically through BTK.

Pseudomonas aeruginosa Airway Infection Recruits and Modulates Neutrophilic Myeloid-Derived Suppressor Cells

Pseudomonas aeruginosa is an opportunistic pathogen that causes infections mainly in patients with cystic fibrosis (CF) lung disease. Despite innate and adaptive immune responses upon infection, P. aeruginosa is capable of efficiently escaping host defenses, but the underlying immune mechanisms remain poorly understood. Myeloid-derived suppressor cells (MDSCs) are innate immune cells that are functionally characterized by their potential to suppress T- and natural killer (NK)-cell responses. Here we demonstrate, using an airway in vivo infection model, that P. aeruginosa recruits and activates neutrophilic MDSCs, which functionally suppress T-cell responses. We further show that the CF gene defect (CF transmembrane conductance regulator, CFTR) modulates the functionality, but not the recruitment or generation of neutrophilic MDSCs. Collectively, we define a mechanism by which P. aeruginosa airway infection undermines host immunity by modulating neutrophilic MDSCs in vivo.

Extrapulmonary Aspergillus infection in patients with CARD9 deficiency

Invasive pulmonary aspergillosis is a life-threatening mycosis that only affects patients with immunosuppression, chemotherapy-induced neutropenia, transplantation, or congenital immunodeficiency. We studied the clinical, genetic, histological, and immunological features of 2 unrelated patients without known immunodeficiency who developed extrapulmonary invasive aspergillosis at the ages of 8 and 18. One patient died at age 12 with progressive intra-abdominal aspergillosis. The other patient had presented with intra-abdominal candidiasis at age 9, and developed central nervous system aspergillosis at age 18 and intra-abdominal aspergillosis at age 25. Neither patient developed Aspergillus infection of the lungs. One patient had homozygous M1I CARD9 (caspase recruitment domain family member 9) mutation, while the other had homozygous Q295X CARD9 mutation; both patients lacked CARD9 protein expression. The patients had normal monocyte and Th17 cell numbers in peripheral blood, but their mononuclear cells exhibited impaired production of proinflammatory cytokines upon fungus-specific stimulation. Neutrophil phagocytosis, killing, and oxidative burst against Aspergillus fumigatus were intact, but neither patient accumulated neutrophils in infected tissue despite normal neutrophil numbers in peripheral blood. The neutrophil tissue accumulation defect was not caused by defective neutrophil-intrinsic chemotaxis, indicating that production of neutrophil chemoattractants in extrapulmonary tissue is impaired in CARD9 deficiency. Taken together, our results show that CARD9 deficiency is the first known inherited or acquired condition that predisposes to extrapulmonary Aspergillus infection with sparing of the lungs, associated with impaired neutrophil recruitment to the site of infection.

Differential Regulation of Myeloid-Derived Suppressor Cells by Candida Species

Myeloid-derived suppressor cells (MDSCs) are innate immune cells characterized by their ability to suppress T-cell responses. Recently, we demonstrated that the human-pathogenic fungi Candida albicans and Aspergillus fumigatus induced a distinct subset of neutrophilic MDSCs. To dissect Candida-mediated MDSC induction in more depth, we studied the relative efficacy of different pathogenic non-albicans Candida species to induce and functionally modulate neutrophilic MDSCs, including C. glabrata, C. parapsilosis, C. dubliniensis, and C. krusei. Our data demonstrate that the extent of MDSC generation is largely dependent on the Candida species with MDSCs induced by C. krusei and C. glabrata showing a higher suppressive activity compared to MDSCs induced by C. albicans. In summary, these studies show that fungal MDSC induction is differentially regulated at the species level and differentially affects effector T-cell responses.

A prospective study on the natural history of patients with profound combined immunodeficiency: An interim analysis

BACKGROUND

Absent T-cell immunity resulting in life-threatening infections provides a clear rationale for hematopoetic stem cell transplantation (HSCT) in patients with severe combined immunodeficiency (SCID). Combined immunodeficiencies (CIDs) and "atypical" SCID show reduced, not absent T-cell immunity. If associated with infections or autoimmunity, they represent profound combined immunodeficiency (P-CID), for which outcome data are insufficient for unambiguous early transplant decisions.

OBJECTIVES

We sought to compare natural histories of severity-matched patients with/without subsequent transplantation and to determine whether immunologic and/or clinical parameters may be predictive for outcome.

METHODS

In this prospective and retrospective observational study, we recruited nontransplanted patients with P-CID aged 1 to 16 years to compare natural histories of severity-matched patients with/without subsequent transplantation and to determine whether immunologic and/or clinical parameters may be predictive for outcome.

RESULTS

A total of 51 patients were recruited (median age, 9.6 years). Thirteen of 51 had a genetic diagnosis of "atypical" SCID and 14 of 51 of CID. About half of the patients had less than 10% naive T cells, reduced/absent T-cell proliferation, and at least 1 significant clinical event/year, demonstrating their profound immunodeficiency. Nineteen patients (37%) underwent transplantation within 1 year of enrolment, and 5 of 51 patients died. Analysis of the HSCT decisions revealed the anticipated heterogeneity, favoring an ongoing prospective matched-pair analysis of patients with similar disease severity with or without transplantation. Importantly, so far neither the genetic diagnosis nor basic measurements of T-cell immunity were good predictors of disease evolution.

CONCLUSIONS

The P-CID study for the first time characterizes a group of patients with nontypical SCID T-cell deficiencies from a therapeutic perspective. Because genetic and basic T-cell parameters provide limited guidance, prospective data from this study will be a helpful resource for guiding the difficult HSCT decisions in patients with P-CID.

Induction of Myeloid-Derived Suppressor Cells in Cryopyrin-Associated Periodic Syndromes

Cryopyrin-associated periodic syndromes (CAPS) are caused by mutations in the NLRP3 gene leading to overproduction of IL-1β and other NLRP3 inflammasome products. Myeloid-derived suppressor cells (MDSCs) represent a novel innate immune cell subset capable of suppressing T-cell responses. As inflammasome products were previously found to induce MDSCs, we hypothesized that NLRP3 inflammasome-dependent factors induce the generation of MDSCs in CAPS. We studied neutrophilic MDSCs, their clinical relevance, and MDSC-inducing factors in a unique cohort of CAPS patients under anti-IL-1 therapy. Despite anti-IL-1 therapy and low clinical disease activity, CAPS patients showed significantly elevated MDSCs compared to healthy controls. MDSCs were functionally competent, as they suppressed polyclonal T-cell proliferation, as well as Th1 and Th17 responses. In addition, MDSCs decreased monocytic IL-1β secretion. Multiplex assays revealed a distinct pattern of MDSC-inducing cytokines, chemokines, and growth factors. Experimental analyses demonstrated that IL-1 cytokine family members and autoinflammation-associated alarmins differentially induced human MDSCs. Increased MDSCs might represent a novel autologous anti-inflammatory mechanism in autoinflammatory conditions and may serve as a future therapeutic target.

Myeloid-Derived Suppressor Cells in Bacterial Infections

Myeloid-derived suppressor cells (MDSCs) comprise monocytic and granulocytic innate immune cells with the capability of suppressing T- and NK-cell responses. While the role of MDSCs has been studied in depth in malignant diseases, the understanding of their regulation and function in infectious disease conditions has just begun to evolve. Here we summarize and discuss the current view how MDSCs participate in bacterial infections and how this knowledge could be exploited for potential future therapeutics.

The emerging role of myeloid-derived suppressor cells in lung diseases

Myeloid-derived suppressor cells (MDSCs) are innate immune cells characterised by their potential to control T-cell responses and to dampen inflammation. While the role of MDSCs in cancer has been studied in depth, our understanding of their relevance for infectious and inflammatory disease conditions has just begun to evolve. Recent studies highlight an emerging and complex role for MDSCs in pulmonary diseases. In this review, we discuss the potential contribution of MDSCs as biomarkers and therapeutic targets in lung diseases, particularly lung cancer, tuberculosis, chronic obstructive pulmonary disease, asthma and cystic fibrosis.

Regulatory T-cell impairment in cystic fibrosis patients with chronic pseudomonas infection

RATIONALE

Patients with cystic fibrosis (CF) lung disease have chronic airway inflammation driven by disrupted balance of T-cell (Th17 and Th2) responses. Regulatory T cells (Tregs) dampen T-cell activation, but their role in CF is incompletely understood.

OBJECTIVES

To characterize numbers, function, and clinical impact of Tregs in CF lung disease.

METHODS

Tregs were quantified in peripheral blood and airway samples from patients with CF and from lung disease control patients without CF and healthy control subjects. The role of Pseudomonas aeruginosa and CF transmembrane conductance regulator (CFTR) in Treg regulation was analyzed by using in vitro and murine in vivo models.

MEASUREMENTS AND MAIN RESULTS

Tregs were decreased in peripheral blood and airways of patients with CF compared with healthy controls or lung disease patients without CF and correlated positively with lung function parameters. Patients with CF with chronic P. aeruginosa infection had lower Tregs compared with patients with CF without P. aeruginosa infection. Genetic knockout, pharmacological inhibition, and P. aeruginosa infection studies showed that both P. aeruginosa and CFTR contributed to Treg dysregulation in CF. Functionally, Tregs from patients with CF or from Cftr(-/-) mice were impaired in suppressing conventional T cells, an effect that was enhanced by P. aeruginosa infection. The loss of Tregs in CF affected memory, but not naive Tregs, and manifested gradually with disease progression.

CONCLUSIONS

Patients with CF who have chronic P. aeruginosa infection show an age-dependent, quantitative, and qualitative impairment of Tregs. Modulation of Tregs represents a novel strategy to rebalance T-cell responses, dampen inflammation, and ultimately improve outcomes for patients with infective CF lung disease.

CXCR4+ granulocytes reflect fungal cystic fibrosis lung disease

Cystic fibrosis airways are frequently colonised with fungi. However, the interaction of these fungi with immune cells and the clinical relevance in cystic fibrosis lung disease are incompletely understood.We characterised granulocytes in airway fluids and peripheral blood from cystic fibrosis patients with and without fungal colonisation, non-cystic fibrosis disease controls and healthy control subjects cross-sectionally and longitudinally and correlated these findings with lung function parameters.Cystic fibrosis patients with chronic fungal colonisation by Aspergillus fumigatus were characterised by an accumulation of a distinct granulocyte subset, expressing the HIV coreceptor CXCR4. Percentages of airway CXCR4(+) granulocytes correlated with lung disease severity in patients with cystic fibrosis.These studies demonstrate that chronic fungal colonisation with A. fumigatus in cystic fibrosis patients is associated with CXCR4(+) airway granulocytes, which may serve as a potential biomarker and therapeutic target in fungal cystic fibrosis lung disease.

Pathogenic fungi regulate immunity by inducing neutrophilic myeloid-derived suppressor cells

Despite continuous contact with fungi, immunocompetent individuals rarely develop pro-inflammatory antifungal immune responses. The underlying tolerogenic mechanisms are incompletely understood. Using both mouse models and human patients, we show that infection with the human pathogenic fungi Aspergillus fumigatus and Candida albicans induces a distinct subset of neutrophilic myeloid-derived suppressor cells (MDSCs), which functionally suppress T and NK cell responses. Mechanistically, pathogenic fungi induce neutrophilic MDSCs through the pattern recognition receptor Dectin-1 and its downstream adaptor protein CARD9. Fungal MDSC induction is further dependent on pathways downstream of Dectin-1 signaling, notably reactive oxygen species (ROS) generation as well as caspase-8 activity and interleukin-1 (IL-1) production. Additionally, exogenous IL-1β induces MDSCs to comparable levels observed during C. albicans infection. Adoptive transfer and survival experiments show that MDSCs are protective during invasive C. albicans infection, but not A. fumigatus infection. These studies define an innate immune mechanism by which pathogenic fungi regulate host defense.

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Pathogenic fungi induce myeloid-derived suppressor cells (MDSCs)

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MDSC induction involves Dectin-1/CARD9, ROS, caspase-8, and IL-1

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MDSCs dampen T and NK cell immune responses

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Adoptive transfer of MDSCs improves survival in Candida infection in vivo

A functional inflammasome activation assay differentiates patients with pathogenic NLRP3 mutations and symptomatic patients with low penetrance variants

Cryopyrin-associated periodic syndromes (CAPS) are characterized by recurrent episodes of systemic inflammation caused by mutations in the NLRP3 gene. Besides confirmed pathogenic NLRP3 mutations, patients with CAPS-like symptoms frequently show low penetrance variants in NLRP3. The disease relevance of these variants is inconsistent. In this study, we investigated if an inflammasome activation assay differentiates between patients with confirmed pathogenic CAPS mutations, patients with low penetrance NLRP3 variants (V198M and Q703K) and healthy controls. The release of mature IL-1β, IL-18, and caspase-1 into cell culture supernatants after 4h of inflammasome stimulation was significantly increased in patients with confirmed pathogenic CAPS mutations compared to low penetrance NLRP3 variants and controls. IL-1β secretion in CAPS patients correlated with disease severity. This inflammasome activation assay differentiates between autoinflammation patients with confirmed pathogenic CAPS mutations and patients with low penetrance NLRP3 variants, and points towards alternative pathophysiological mechanisms in low penetrance NLRP3 variants.

The chemokine CCL18 characterises Pseudomonas infections in cystic fibrosis lung disease

Cystic fibrosis (CF) lung disease is characterised by chronic Pseudomonas aeruginosa infection and leukocyte infiltration. Chemokines recruit leukocytes to sites of infection. Gene expression analysis identified the chemokine CCL18 as upregulated in CF leukocytes. We hypothesised that CCL18 characterises infection and inflammation in patients with CF lung disease. Therefore, we quantified CCL18 protein levels in the serum and airway fluids of CF patients and healthy controls, and studied CCL18 protein production by airway cells ex vivo. These studies demonstrated that CCL18 levels were increased in the serum and airway fluids from CF patients compared with healthy controls. Within CF patients, CCL18 levels were increased in P. aeruginosa-infected CF patients. CCL18 levels in the airways, but not in serum, correlated with severity of pulmonary obstruction in CF. Airway cells isolated from P. aeruginosa-infected CF patients produced significantly higher amounts of CCL18 protein compared with airway cells from CF patients without P. aeruginosa infection or healthy controls. Collectively, these studies show that CCL18 levels characterise chronic P. aeruginosa infection and pulmonary obstruction in patients with CF. CCL18 may, thus, serve as a potential biomarker and therapeutic target in CF lung disease.

Granulocytic myeloid derived suppressor cells expand in human pregnancy and modulate T-cell responses

Immune tolerance toward the semiallogeneic fetus plays a crucial role in the maintenance of pregnancy. Myeloid-derived suppressor cells (MDSCs) are innate immune cells characterized by their ability to modulate T-cell responses. Recently, we showed that MDSCs accumulate in cord blood of healthy newborns, yet their role in materno-fetal tolerance remained elusive. In the present study, we demonstrate that MDSCs with a granulocytic phenotype (GR-MDSCs) are highly increased in the peripheral blood of healthy pregnant women during all stages of pregnancy compared with nonpregnant controls, whereas numbers of monocytic MDSCs were unchanged. GR-MDSCs expressed the effector enzymes arginase-I and iNOS, produced high amounts of ROS and efficiently suppressed T-cell proliferation. After parturition, GR-MDSCs decreased within a few days. In combination, our results show that GR-MDSCs expand in normal human pregnancy and may indicate a role for MDSCs in materno-fetal tolerance.

Current concepts of immune dysregulation in cystic fibrosis

Cystic fibrosis (CF) lung disease is caused by mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene and is characterized by a perpetuated feedback loop of bacterial infection and inflammation. Both intrinsic (CFTR-dependent) and extrinsic (CFTR-independent) mechanisms contribute to the inflammatory phenotype of CF lung disease. Innate immune cells, initially recruited to combat bacterial pathogens, are acting in a dysregulated and non-resolving fashion in CF airways and cause harm to the host by releasing proteases and oxidants. Targeting harmful immune pathways, while preserving protective ones, remains the challenge for the future. This review highlights current concepts of innate immune dysregulation in CF lung disease.

Localization and functionality of the inflammasome in neutrophils

Neutrophils represent the major fraction of circulating immune cells and are rapidly recruited to sites of infection and inflammation. The inflammasome is a multiprotein complex that regulates the generation of IL-1 family proteins. The precise subcellular localization and functionality of the inflammasome in human neutrophils are poorly defined. Here we demonstrate that highly purified human neutrophils express key components of the NOD-like receptor family, pyrin domain containing 3 (NLRP3), and absent in melanoma 2 (AIM2) inflammasomes, particularly apoptosis-associated speck-like protein containing a CARD (ASC), AIM2, and caspase-1. Subcellular fractionation and microscopic analyses further showed that inflammasome components were localized in the cytoplasm and also noncanonically in secretory vesicle and tertiary granule compartments. Whereas IL-1β and IL-18 were expressed at the mRNA level and released as protein, highly purified neutrophils neither expressed nor released IL-1α at baseline or upon stimulation. Upon inflammasome activation, highly purified neutrophils released substantially lower levels of IL-1β protein compared with partially purified neutrophils. Serine proteases and caspases were differentially involved in IL-1β release, depending on the stimulus. Spontaneous activation of the NLRP3 inflammasome in neutrophils in vivo affected IL-1β, but not IL-18 release. In summary, these studies show that human neutrophils express key components of the inflammasome machinery in distinct intracellular compartments and release IL-1β and IL-18, but not IL-1α or IL-33 protein. Targeting the neutrophil inflammasome may represent a future therapeutic strategy to modulate neutrophilic inflammatory diseases, such as cystic fibrosis, rheumatoid arthritis, or sepsis.

Neutrophilic myeloid-derived suppressor cells in cord blood modulate innate and adaptive immune responses

Neonates show an impaired anti-microbial host defence, but the underlying immune mechanisms are not understood fully. Myeloid-derived suppressor cells (MDSCs) represent an innate immune cell subset characterized by their capacity to suppress T cell immunity. In this study we demonstrate that a distinct MDSC subset with a neutrophilic/granulocytic phenotype (Gr-MDSCs) is highly increased in cord blood compared to peripheral blood of children and adults. Functionally, cord blood isolated Gr-MDSCs suppressed T cell proliferation efficiently as well as T helper type 1 (Th1), Th2 and Th17 cytokine secretion. Beyond T cells, cord blood Gr-MDSCs controlled natural killer (NK) cell cytotoxicity in a cell contact-dependent manner. These studies establish neutrophilic Gr-MDSCs as a novel immunosuppressive cell subset that controls innate (NK) and adaptive (T cell) immune responses in neonates. Increased MDSC activity in cord blood might serve as key fetomaternal immunosuppressive mechanism impairing neonatal host defence. Gr-MDSCs in cord blood might therefore represent a therapeutic target in neonatal infections.

Modified Foxp3 mRNA protects against asthma through an IL-10-dependent mechanism

Chemically modified mRNA is capable of inducing therapeutic levels of protein expression while circumventing the threat of genomic integration often associated with viral vectors. We utilized this novel therapeutic tool to express the regulatory T cell transcription factor, FOXP3, in a time- and site-specific fashion in murine lung, in order to prevent allergic asthma in vivo. We show that modified Foxp3 mRNA rebalanced pulmonary T helper cell responses and protected from allergen-induced tissue inflammation, airway hyperresponsiveness, and goblet cell metaplasia in 2 asthma models. This protection was conferred following delivery of modified mRNA either before or after the onset of allergen challenge, demonstrating its potential as both a preventive and a therapeutic agent. Mechanistically, FOXP3 induction controlled Th2 and Th17 inflammation by regulating innate immune cell recruitment through an IL-10-dependent pathway. The protective effects of FOXP3 could be reversed by depletion of IL-10 or administration of recombinant IL-17A or IL-23. Delivery of Foxp3 mRNA to sites of inflammation may offer a novel, safe therapeutic tool for the treatment of allergic asthma and other diseases driven by an imbalance in helper T cell responses.

Differences of IgG antibody avidity after an acellular pertussis (aP) booster in adolescents after a whole cell (wcP) or aP primary vaccination

Compared to whole cell pertussis (wcP) vaccines, acellular pertussis vaccines (aP) have a better safety profile with lower reactogenicity, although their short and long-term efficacy was found to be slightly lower. Up to now, no established serological parameter to predict long-term protection exists. IgG-anti-pertussis avidity possibly determines the effect of different pertussis vaccines and boosting intervals on long-term immunity. Thus, the avidity of a tetanus-diphtheria-aP booster at 10-14 years was tested in three groups of adolescents who had been previously immunized with either five doses of aP (5aP) at 2, 4, 6, 15-18 months and 5-6 years of age, four doses of aP (4aP) or four doses of wcP (4wcP) at 2, 4, 6 and 15-18 months of age. Relative avidity index (RAI) of IgG-anti-pertussis toxin (PT) and IgG-anti-filamentous-hemagglutinin (FHA) was assessed by an adapted ELISA. RAI of IgG-anti-PT and of IgG-anti-FHA correlated positively with antibody concentrations in the pre-vaccination and in the post-vaccination analysis and significantly increased after adolescent booster with aP in all groups. Pre- and post-vaccination, the proportion of participants with IgG-anti-PT RAI>40% (moderate to high avidity) was significantly lower in the 4wcP group (52.9% and 88.9%) compared to the 5aP group (89.5% and 100.0%). In conclusion, TdaP in adolescence induces an increase of antibody avidity and, thus, is able to enhance the binding-quality of antibodies against pertussis. The study suggests including antibody avidity into serological studies on the humoral response to provide information about the long-term efficacy of the vaccine.

Neutrophils express distinct RNA receptors in a non-canonical way

RNAs are capable of modulating immune responses by binding to specific receptors. Neutrophils represent the major fraction of circulating immune cells, but receptors and mechanisms by which neutrophils sense RNA are poorly defined. Here, we analyzed the mRNA and protein expression patterns and the subcellular localization of the RNA receptors RIG-I, MDA-5, TLR3, TLR7, and TLR8 in primary neutrophils and immortalized neutrophil-like differentiated HL-60 cells. Our results demonstrate that both neutrophils and differentiated HL-60 cells express RIG-I, MDA-5, and TLR8 at the mRNA and protein levels, whereas TLR3 and TLR7 are not expressed at the protein level. Subcellular fractionation, flow cytometry, confocal laser scanning microscopy, and immuno-transmission electron microscopy provided evidence that, besides the cytoplasm, RIG-I and MDA-5 are stored in secretory vesicles of neutrophils and showed that RIG-I and its ligand, 3p-RNA, co-localize at the cell surface without triggering neutrophil activation. In summary, this study demonstrates that neutrophils express a distinct pattern of RNA recognition receptors in a non-canonical way, which could have essential implications for future RNA-based therapeutics.

[Psychotherapy and obesity: strategies, challenges and possibilities]

One fifth of the German population is obese with increasing prevalence. Psychotherapy plays an important role in weight loss programmes. Cognitive behaviour therapy, targeting lifestyle changes, including exercise and eating behaviour, is the evidence-based treatment of choice. Especially the lack of motivation or absence of weight loss, further weight gain or psychosocial burden makes psychotherapy essential. The treatment of a comorbid binge eating disorder should be initiated prior to focusing on weight loss. Remarkably difficult stages in the treatment of obesity are the initiation of changes as well as the maintenance of the achieved weight loss. Internet-based attempts will become increasingly important.

CXCR1 and CXCR2 haplotypes synergistically modulate cystic fibrosis lung disease

Cystic fibrosis (CF) lung disease severity is largely independent on the CF transmembrane conductance regulator (CFTR) genotype, indicating the contribution of genetic modifiers. The chemokine receptors CXCR1 and CXCR2 have been found to play essential roles in the pathogenesis of CF lung disease. Here, we determine whether genetic variation of CXCR1 and CXCR2 influences CF lung disease severity. Genomic DNA of CF patients in Germany (n = 442) was analysed for common variations in CXCR1 and CXCR2 using a single-nucleotide polymorphism (SNP) tagging approach. Associations of CXCR1 and CXCR2 SNPs and haplotypes with CF lung disease severity, CXCR1 and CXCR2 expression, and neutrophil effector functions were assessed. Four SNPs in CXCR1 and three in CXCR2 strongly correlated with age-adjusted lung function in CF patients. SNPs comprising haplotypes CXCR1_Ha and CXCR2_Ha were in high linkage disequilibrium and patients heterozygous for the CXCR1-2 haplotype cluster (CXCR1-2_Ha) had lower lung function compared with patients with homozygous wild-type alleles (forced expiratory volume in 1 s ≤ 70% predicted, OR 7.24; p = 2.30 × 10(-5)). CF patients carrying CXCR1-2_Ha showed decreased CXCR1 combined with increased CXCR2 mRNA and protein expression, and displayed disturbed antibacterial effector functions. CXCR1 and CXCR2 genotypes modulate lung function and antibacterial host defence in CF lung disease.

The chitinase-like protein YKL-40 modulates cystic fibrosis lung disease

The chitinase-like protein YKL-40 was found to be increased in patients with severe asthma and chronic obstructive pulmonary disease (COPD), two disease conditions featuring neutrophilic infiltrates. Based on these studies and a previous report indicating that neutrophils secrete YKL-40, we hypothesized that YKL-40 plays a key role in cystic fibrosis (CF) lung disease, a prototypic neutrophilic disease. The aim of this study was (i) to analyze YKL-40 levels in human and murine CF lung disease and (ii) to investigate whether YKL-40 single-nucleotide polymorphisms (SNPs) modulate CF lung disease severity. YKL-40 protein levels were quantified in serum and sputum supernatants from CF patients and control individuals. Levels of the murine homologue BRP-39 were analyzed in airway fluids from CF-like βENaC-Tg mice. YKL-40SNPs were analyzed in CF patients. YKL-40 levels were increased in sputum supernatants and in serum from CF patients compared to healthy control individuals. Within CF patients, YKL-40 levels were higher in sputum than in serum. BRP-39 levels were increased in airways fluids from βENaC-Tg mice compared to wild-type littermates. In both CF patients and βENaC-Tg mice, YKL-40/BRP-39 airway levels correlated with the severity of pulmonary obstruction. Two YKL-40 SNPs (rs871799 and rs880633) were found to modulate age-adjusted lung function in CF patients. YKL-40/BRP-39 levelsare increased in human and murine CF airway fluids, correlate with pulmonary function and modulate CF lung disease severity genetically. These findings suggest YKL-40 as a potential biomarker in CF lung disease.

Impaired cellular immune response to diphtheria and tetanus vaccines in children after thoracic transplantation

Safety and immunogenicity of diphtheria and tetanus booster vaccination were evaluated in 28 children after thoracic transplantation. Adverse events were documented in a patient diary. Blood was collected prior to and four wk after vaccination. Specific antibody concentrations were measured by ELISA. Lymphocytes were investigated for expression of activation markers (CD25, HLA-DR) by flow cytometry and proliferation assays with and without stimulation. Post-vaccination antibody titers were higher than prevaccination (p < 0.001), with more patients having protective antibody levels against diphtheria (p < 0.02) and tetanus (p < 0.001). There was no increased proliferation in non-stimulated or stimulated cultures after vaccination. The number of T-lymphocytes activated by the vaccination antigens was similar pre- and post-vaccination, whereas HLA-DR-expression on stimulated and non-stimulated CD4(+) T-cells increased significantly. Increase in antibodies was negatively correlated with tacrolimus dose, and impaired cellular immunity was associated with higher tacrolimus dose and steroid use. Adverse events were similar to the general population; serious adverse events and rejection did not occur. Vaccination with inactivated vaccines can be performed safely in immunosuppressed children after thoracic transplantation and induces protective antibody levels in the majority of patients. Impaired induction of specific cellular immunity is correlated with intensity of immunosuppression and may explain reduced sustainability of antibodies.

Acellular pertussis booster in adolescents induces Th1 and memory CD8+ T cell immune response

In a number of countries, whole cell pertussis vaccines (wcP) were replaced by acellular vaccines (aP) due to an improved reactogenicity profile. Pertussis immunization leads to specific antibody production with the help of CD4(+) T cells. In earlier studies in infants and young children, wcP vaccines selectively induced a Th1 dominated immune response, whereas aP vaccines led to a Th2 biased response. To obtain data on Th1 or Th2 dominance of the immune response in adolescents receiving an aP booster immunization after a wcP or aP primary immunization, we analyzed the concentration of Th1 (IL-2, TNF-α, INF-γ) and Th2 (IL-4, IL-5, IL-10) cytokines in supernatants of lymphocyte cultures specifically stimulated with pertussis antigens. We also investigated the presence of cytotoxic T cell responses against the facultative intracellular bacterium Bordetella pertussis by quantifying pertussis-specific CD8(+) T cell activation following the aP booster immunization. Here we show that the adolescent aP booster vaccination predominantly leads to a Th1 immune response based on IFNgamma secretion upon stimulation with pertussis antigen, irrespective of a prior whole cell or acellular primary vaccination. The vaccination also induces an increase in peripheral CD8(+)CD69(+) activated pertussis-specific memory T cells four weeks after vaccination. The Th1 bias of this immune response could play a role for the decreased local reactogenicity of this adolescent aP booster immunization when compared to the preceding childhood acellular pertussis booster. Pertussis-specific CD8(+) memory T cells may contribute to protection against clinical pertussis.

Diagnostic approach to the hyper-IgE syndromes: immunologic and clinical key findings to differentiate hyper-IgE syndromes from atopic dermatitis

BACKGROUND

Hyper-IgE syndromes (HIES) are primary immunodeficiency disorders characterized by Staphylococcus aureus abscesses, recurrent pneumonia, increased serum IgE levels, and eczema. The association of heterozygous signal transducer and activator of transcription 3 (STAT3) mutations with autosomal dominant (AD)-HIES allows the differentiation of AD-HIES from disorders associated with eczema and increased serum IgE levels, such as other primary immunodeficiencies and atopic dermatitis.

OBJECTIVE

To facilitate early diagnosis of AD-HIES to initiate appropriate therapy.

METHODS

The clinical phenotype (suggested by a National Institutes of Health [NIH] score of >or=40 points), STAT3 genotype, and T(H)17 cell counts were compared in a cohort of 78 patients suspected of having HIES.

RESULTS

Heterozygous STAT3 missense mutations and in-frame deletions were identified in 48 patients, all but 2 with an NIH score >or=40 points. Patients with STAT3 mutations with HIES showed significantly lower T(H)17 cell counts compared with patients with wild-type STAT3 and control subjects. Only 1 patient with wild-type STAT3 had both an NIH score >or=40 points and abnormal T(H)17 cell counts (<or=0.2% of CD4(+) cells), with this exception being identified with a homozygous dedicator of cytogenesis 8 protein (DOCK8) mutation. Pathologic shedding of primary teeth was present in 3 patients with wild-type STAT3 and 33 patients with STAT3 mutations. Internal abscesses and severe infections were exclusively seen in patients with STAT3 mutations, who also had increased pneumatocele formation and skeletal or connective tissue manifestations compared with patients with wild-type STAT3.

CONCLUSION

We expanded the number of STAT3 mutations and validated that the NIH score sensitively identifies patients with HIES. Based on our patient cohort, we propose key findings that, when combined with T(H)17 cell numbers, predict patients with AD-HIES with STAT3 mutations, supporting early diagnosis of AD-HIES.

CXCR2 mediates NADPH oxidase-independent neutrophil extracellular trap formation in cystic fibrosis airway inflammation

Upon activation, neutrophils release DNA fibers decorated with antimicrobial proteins, forming neutrophil extracellular traps (NETs). Although NETs are bactericidal and contribute to innate host defense, excessive NET formation has been linked to the pathogenesis of autoinflammatory diseases. However, the mechanisms regulating NET formation, particularly during chronic inflammation, are poorly understood. Here we show that the G protein-coupled receptor (GPCR) CXCR2 mediates NET formation. Downstream analyses showed that CXCR2-mediated NET formation was independent of NADPH oxidase and involved Src family kinases. We show the pathophysiological relevance of this mechanism in cystic fibrosis lung disease, characterized by chronic neutrophilic inflammation. We found abundant NETs in airway fluids of individuals with cystic fibrosis and mouse cystic fibrosis lung disease, and NET amounts correlated with impaired obstructive lung function. Pulmonary blockade of CXCR2 by intra-airway delivery of small-molecule antagonists inhibited NET formation and improved lung function in vivo without affecting neutrophil recruitment, proteolytic activity or antibacterial host defense. These studies establish CXCR2 as a receptor mediating NADPH oxidase-independent NET formation and provide evidence that this GPCR pathway is operative and druggable in cystic fibrosis lung disease.

Acute tryptophan depletion increases experimental nausea but also induces hunger in healthy female subjects

BACKGROUND

Acute tryptophan depletion (ATD) is an experimental model to reduce central serotonin levels.

METHODS

Thirty-eight healthy female subjects were randomly assigned to two groups (ATD and control) in a randomized, double-blinded parallel-group design. Following a standardized and balanced amino acid diet (including 1.21 g tryptophan) on the first day, they received either a protein drink without tryptophan (but substituted by other amino acids) (ATD condition) or the balanced protein drink with tryptophan (control condition) 24 h later. Four hours after its consumption, they were exposed to a standard rotation procedure. Symptom ratings (SR), ratings of hunger and mood scores were taken prior to rotation, at each break, and 15 and 30 min thereafter, together with saliva cortisol samples.

KEY RESULTS

Five subjects could not tolerate the entire rotation procedure and were excluded from analysis. For the remaining n = 33, SR and hunger ratings were higher during ATD than during control conditions, but mood was unaffected. Cortisol levels rose significantly with rotation but were unaffected by ATD. High baseline cortisol levels were associated with lower SR during rotation. The protective effects of morning cortisol were pronounced during the menstrual and follicular phase of the cycle and not present during ovulation and the luteal phase.

CONCLUSIONS & INFERENCES

Acute tryptophan depletion is associated with increased symptoms of nausea in healthy female subjects when exposed to body rotation. Acute tryptophan depletion also increases hunger rating. These opposite effects may indicate independent actions of the serotonin on central and peripheral functions.