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Fever is common among individuals seeking healthcare after traveling to tropical regions. Despite the association with potentially severe disease, the etiology is often not determined. Plasma protein patterns can be informative to understand the host response to infection and can potentially indicate the pathogen causing the disease. In this study, we measured 49 proteins in the plasma of 124 patients with fever after travel to tropical or subtropical regions. The patients had confirmed diagnoses of either malaria, dengue fever, influenza, bacterial respiratory tract infection, or bacterial gastroenteritis, representing the most common etiologies. We used multivariate and machine learning methods to identify combinations of proteins that contributed to distinguishing infected patients from healthy controls, and each other. Malaria displayed the most unique protein signature, indicating a strong immunoregulatory response with high levels of IL10, sTNFRI and II, and sCD25 but low levels of sCD40L. In contrast, bacterial gastroenteritis had high levels of sCD40L, APRIL, and IFN‐γ, while dengue was the only infection with elevated IFN‐α2. These results suggest that characterization of the inflammatory profile of individuals with fever can help to identify disease‐specific host responses, which in turn can be used to guide future research on diagnostic strategies and therapeutic interventions. [ABSTRACT FROM AUTHOR]

Objective: The lung is implicated as a site for breach of tolerance prior to onset of seropositive rheumatoid arthritis (RA). To substantiate this, we investigated lung‐resident B cells in bronchoalveolar lavage (BAL) samples from untreated early RA patients and anti–citrullinated protein antibody (ACPA)–positive individuals at risk for developing RA. Methods: Single B cells (n = 7,680) were phenotyped and isolated from BAL samples from individuals at risk of RA (n = 3) and at RA diagnosis (n = 9). The immunoglobulin variable region transcripts were sequenced and selected for expression as monoclonal antibodies (n = 141). Monoclonal ACPAs were tested for reactivity patterns and binding to neutrophils. Results: Using our single‐cell approach, we found significantly increased proportions of B lymphocytes in ACPA+ compared to ACPA– individuals. Memory and double‐negative B cells were prominent in all subgroups. Upon antibody re‐expression, 7 highly mutated citrulline‐autoreactive clones originating from different memory B cell subsets were identified, both in individuals at risk of RA and early RA patients. Lung IgG variable gene transcripts from ACPA+ individuals carried frequent mutation‐induced N‐linked Fab glycosylation sites (P < 0.001), often in the framework 3 of the variable region. Two of the lung ACPAs bound to activated neutrophils, 1 from an individual at risk of RA and 1 from an early RA patient. Conclusion: T cell–driven B cell differentiation resulting in local class switching and somatic hypermutation are evident in lungs before as well as in early stages of ACPA+ RA. Our findings add to the notion of lung mucosa being a site for initiation of citrulline autoimmunity preceding seropositive RA. [ABSTRACT FROM AUTHOR]

The 6‐month infection risk was 43% lower in patients with sarcoidosis who initiated methotrexate compared to those who started azathioprine. Our findings suggest that unless contraindications exist, methotrexate should be preferred over azathioprine as the primary steroid‐sparing choice in individuals with sarcoidosis. Background and objective: No clinical trial has examined the risk of infection associated methotrexate and azathioprine, two advocated treatments for sarcoidosis. We aimed to compare the 6‐month risk of infection after the initiation of methotrexate or azathioprine. Methods: We conducted a retrospective target trial emulation using Swedish pre‐existing data. We searched for eligible participants who were dispensed methotrexate or azathioprine in the Prescribed Drug Register (PDR) every day between January 2007 and June 2013. Adults were eligible if they had ≥2 ICD‐coded visits for sarcoidosis in the National Patient Register (NPR) and were dispensed ≥1 systemic corticosteroid but no methotrexate or azathioprine in the past 6 months (PDR). Within 6 months of methotrexate or azathioprine initiation, diagnosis of infectious disease was identified (visit in the NPR where infectious disease was the primary diagnosis). We estimated RR and risk differences comparing methotrexate (n = 667) to azathioprine initiations (n = 259) using targeted maximum likelihood estimation (TMLE) adjusting for demographic factors, comorbidity and sarcoidosis severity proxies. Results: There were 43 infections in the methotrexate group (adjusted 6‐month risk 6.8%) and 29 infections in the azathioprine group (12.0%). The RR for infectious disease at 6 months associated with methotrexate compared to azathioprine initiation was 0.57 (95% CI: 0.39, 0.82) and the risk difference was −5.2% (95% CI: −8.5%, −1.8%). The RR at 9 months was attenuated to 0.77 (95% CI: 0.52, 1.14). Conclusion: Methotrexate appears to be associated with a lower risk of infection in sarcoidosis than azathioprine, but randomized trials should confirm this finding. [ABSTRACT FROM AUTHOR]

Objective: Autoantibodies targeting histidyl–transfer RNA synthetase (HisRS; anti–Jo‐1) are common in the idiopathic inflammatory myopathies (IIMs) and antisynthetase syndrome. This study was undertaken to investigate immunity against HisRS in the blood and lungs of patients with IIM/antisynthetase syndrome. Methods: Bronchoalveolar lavage (BAL) fluid, BAL fluid cells, and peripheral blood mononuclear cells (PBMCs) from patients with IIM/antisynthetase syndrome (n = 24) were stimulated with full‐length HisRS protein or a HisRS‐derived peptide (HisRS11–23). BAL fluid and PBMCs from patients with sarcoidosis (n = 7) and healthy subjects (n = 12) were included as controls. The CD4+ T cell response was determined according to levels of CD40L up‐regulation and cytokine expression using flow cytometry. Anti–Jo‐1 autoantibody responses in the serum and BAL fluid were assessed by enzyme‐linked immunosorbent assay. Lung biopsy samples from patients with IIM/antisynthetase syndrome (n = 14) were investigated by immunohistochemistry. Results: In BAL fluid, CD4+ T cells from 3 of 4 patients with IIM/antisynthetase syndrome responded to stimulation with HisRS protein, as measured by the median fold change in CD40L expresssion in stimulated cells compared to unstimulated cells (median fold change 3.6, interquartile range [IQR] 2.7–14.7), and 2 of 3 patients with IIM/antisynthetase syndrome had the highest responses to HisRS11–23 (median fold change 88, IQR 27–149). In PBMCs, CD4+ T cells from 14 of 18 patients with IIM/antisynthetase syndrome responded to HisRS protein (median fold change 7.38, IQR 2.69–31.86; P < 0.001), whereas a HisRS11–23 response was present in 11 of 14 patients with IIM/antisynthetase syndrome (median fold change 3.4, IQR 1.87–10.9; P < 0.001). In the control group, there was a HisRS11–23 response in 3 of 7 patients with sarcoidosis (median fold change 2.09, IQR 1.45–3.29) and in 5 of 12 healthy controls (median fold change 2, IQR 1.89–2.42). CD4+ T cells from patients with IIM/antisynthetase syndrome displayed a pronounced Th1 phenotype in the BAL fluid when compared to the PBMCs (P < 0.001), producing high amounts of interferon‐γ and interleukin‐2 following stimulation. Anti–Jo‐1 autoantibodies were detected in BAL fluid and germinal center (GC)–like structures were seen in the lung biopsy samples from patients with IIM/antisynthetase syndrome. Conclusion: The results of this study demonstrate a pronounced presence of HisRS‐reactive CD4+ T cells in PBMCs and BAL fluid cells from patients with IIM/antisynthetase syndrome as compared to patients with sarcoidosis and healthy controls. These findings, combined with the presence of anti–Jo‐1 autoantibodies in BAL fluid and GC‐like structures in the lungs, suggest that immune activation against HisRS might take place within the lungs of patients with IIM/antisynthetase syndrome. [ABSTRACT FROM AUTHOR]

This study describes for the first time the expression levels of genes encoding membrane transporters and drug-metabolizing enzymes in the lungs of ex-smoking patients with chronic obstructive pulmonary disease (COPD). Membrane transporters and drug-metabolizing enzymes are key determinants of drug uptake, metabolism, and elimination for systemically administered as well as inhaled drugs, with consequent influence on clinical efficacy and patient safety. In this study, while no difference in gene expression was found between healthy and COPD subjects, we identified a significant regional difference in mRNA expression of both membrane transporters and drug-metabolizing enzymes between central and peripheral tissue in both healthy and COPD subjects. The majority of the differentially expressed genes were higher expressed in the central airways such as the transporters SLC2A1 (GLUT1), SLC28A3 (CNT3), and SLC22A4 (OCTN1) and the drug-metabolizing enzymes GSTZ1, GSTO2, and CYP2F1. Together, this increased knowledge of local pharmacokinetics in diseased and normal lung may improve modeling of clinical outcomes of new chemical entities intended for inhalation therapy delivered to COPD patients. In addition, based on the similarities between COPD and healthy subjects regarding gene expression of membrane transporters and drug-metabolizing enzymes, our results suggest that clinical pharmacological studies in healthy volunteers could be a valid model of COPD patients regarding drug disposition of inhaled drugs in terms of drug metabolism and drug transporters. [ABSTRACT FROM AUTHOR]

Objective It has been suggested that immunologic events in the lungs may be involved in triggering immunity, in particular production of anti-citrullinated protein antibodies (ACPAs) during early phases of rheumatoid arthritis (RA). The aim of this study was to investigate the structural and immunologic features of the lungs in incident cases of early RA in relation to ACPA presence and smoking status. Methods High-resolution computed tomography (HRCT) was used to examine the lungs of 105 patients with early, untreated RA (70 with ACPA-positive RA and 35 with ACPA-negative RA) and 43 healthy individuals. Bronchoscopy with collection of bronchoalveolar lavage (BAL) fluid and mucosal bronchial biopsy specimens was performed in 23 RA patients. The presence of citrullinated proteins in the bronchial tissue was detected by immunohistochemical staining. ACPAs (detected with an anti-cyclic citrullinated peptide 2 test) and total Ig levels were determined in the sera and BAL fluid of RA patients. Results HRCT imaging revealed that 63% of ACPA-positive RA patients had parenchymal lung abnormalities, compared with only 37% of ACPA-negative RA patients and 30% of healthy controls (each P < 0.05). These significant differences remained after adjustment for smoking status. Airway changes detected by HRCT were more frequent in RA patients than in healthy controls (66% versus 42%; P < 0.05), but there was no difference between ACPA-positive and ACPA-negative RA patients. Immunohistochemical studies of the bronchial tissue showed increased staining for citrullinated proteins in ACPA-positive RA patients compared with ACPA-negative RA patients ( P < 0.05). ACPA levels were relatively higher in the BAL fluid as compared with the sera of ACPA-positive RA patients, suggesting that there is local production of ACPAs in the lungs of these patients. Conclusion The presence of ACPAs is associated with parenchymal lung abnormalities, site-specific citrullination, and antibody enrichment in the lungs early in the development of ACPA-positive RA. [ABSTRACT FROM AUTHOR]

Introduction: Sarcoidosis is a granulomatous disorder of unknown aetiology, affecting young adults and frequently involving the lungs. Objective: The aim of the present review was to give an overview of the clinical aspects in sarcoidosis. Results: The majority of patients recover, but some develop a chronic disease that may result in fibrosis and respiratory failure. Besides the lungs, peripheral lymph nodes, the skin, the liver and the eyes are commonly affected as well. The genetic background, as well as environmental factors, is of importance for developing sarcoidosis. The incidence varies in different populations, in the Nordic countries approximately with 20/100 000 new patients yearly. Sarcoidosis is diagnosed when clinical and radiological findings are supported by histological evidence in the form of non-caseating epithelioid cell granulomas, and when other causes of these features are excluded. Patients in need of treatment are usually treated with corticosteroids, topically or as oral steroids. A clinical effect of immunomodulatory drugs blocking tumour necrosis factor (TNF)α has been suggested from several case reports, while two controlled studies showed only minor effects; however, with a tendency to a more pronounced effect on patients with a more severe disease. The immune response in sarcoidosis, with a typical accumulation of CD4+ T-cells to the lungs, indicate the existence of specific antigens in this disease. Recently, antigens derived from infectious agents such as Mycobacteria and Proprionibacterium acnes have come into focus. Lymphocyte populations with immunoregulatory functions have recently been investigated and seem to be dysfunctional in sarcoidosis, opening the possibility of developing new treatment strategies in this disease. Conclusion: Recent technical developments have provided better tools, enabling detailed and more thorough analyses of the inflammatory process in sarcoidosis. Please cite this paper as: Grunewald J. Clinical aspects and immune reactions in sarcoidosis. The Clinical Respiratory Journal 2007; 1:64–73. [ABSTRACT FROM AUTHOR]

Kawasaki disease (KD) is a paediatric multisystem necrotizing vasculitis constituting the most frequent cause of acquired heart disease in childhood. Conflicting data have been reported regarding expanded T-cell populations using particular T-cell receptor (TCR) β-chain variable (BV) gene segments, suggesting either a superantigen- or a conventional antigen-mediated immune response in this disease. In order to further investigate the role of T lymphocytes, cells were stained with an extensive panel of 21 different TCRBV specific monoclonal antibobies (MoAbs) covering almost 70% of all T-cells. Flow cytometry was employed to analyse the expression of the TCRBV repertoire in the CD4+ and CD8+ subsets separately, and of activation markers, in freshly isolated peripheral blood lymphocytes of 25 Kawasaki disease patients during the acute and convalescent phases of the disease. No abnormal usage of any TCRBV family was found, neither acutely nor during convalescence, compared with a control group of healthy children. However, a significant increase in interleukin-2 receptor (IL-2R)-expressing T lymphocytes restricted to the CD4+ subset was observed in KD patients. Our data confirm a strong immune activation in KD that might be of importance in the pathogenesis of the disease. [ABSTRACT FROM AUTHOR]

An abstract of the article "Carbon monoxide levels in exhaled breath as a measure of recent smoking status," by AnnSofi Sandberg and colleagues is presented.

Objective: To investigate T cell receptor (TCR) expression in 3 different compartments that could be involved in patients with myositis: muscle, lung, and peripheral blood., Methods: Nine patients with polymyositis (PM), dermatomyositis, or inclusion body myositis underwent bronchoscopy and bronchoalveolar lavage (BAL) as well as muscle biopsy and blood sampling. A panel of 19 monoclonal antibodies specific for TCR V(beta) (BV) and V(alpha) (AV) were used to characterize the TCR profile in CD4(+) and CD8(+) T cell populations in BAL fluid and peripheral blood by flow cytometry. Muscle biopsy tissues were analyzed by immunohistochemistry. Patients were also typed for HLA-DRB1 and DRB3 alleles., Results: A total of 17 T cell expansions were detected in BAL fluid, 6 in the CD4(+) T cell population and 11 in the CD8(+) T cell population. Four T cell expansions were detected in peripheral blood. A selective TCR V usage was found in muscle. Two PM patients, both of whom had BAL fluid BV3(+) T cell expansions in the CD4 population and in whom BV3 was also a prominent TCR V segment in muscle tissue, shared the HLA-DRB1*03 allele. These 2 patients were the only ones who were positive for anti-Jo-1 antibody., Conclusion: We found a restricted accumulation of T lymphocytes expressing selected TCR V-gene segments in the target organ compartments (i.e., lung and muscle). The occurrence of shared TCR gene segment usage in muscle and lungs could suggest common target antigens in these organs.

Objective: To investigate whether smoking and HLA-DR shared epitope (SE) genes may interact in triggering immune reactions to citrulline-modified proteins., Methods: In a case-control study involving patients with recent-onset rheumatoid arthritis (RA), we studied interactions between a major environmental risk factor (smoking), major susceptibility genes included in the SE of HLA-DR, and the presence of the most specific autoimmunity known for RA (i.e., antibodies to proteins modified by citrullination). Immunostaining for citrullinated proteins in cells from bronchoalveolar lavage fluid was used to investigate whether smoking is associated with citrullination in the lungs., Results: Previous smoking was dose-dependently associated with occurrence of anticitrulline antibodies in RA patients. The presence of SE genes was a risk factor only for anticitrulline-positive RA, and not for anticitrulline-negative RA. A major gene-environment interaction between smoking and HLA-DR SE genes was evident for anticitrulline-positive RA, but not for anticitrulline-negative RA, and the combination of smoking history and the presence of double copies of HLA-DR SE genes increased the risk for RA 21-fold compared with the risk among nonsmokers carrying no SE genes. Positive immunostaining for citrullinated proteins was recorded in bronchoalveolar lavage cells from smokers but not in those from nonsmokers., Conclusion: We identified an environmental factor, smoking, that in the context of HLA-DR SE genes may trigger RA-specific immune reactions to citrullinated proteins. These data thus suggest an etiology involving a specific genotype, an environmental provocation, and the induction of specific autoimmunity, all restricted to a distinct subset of RA.

Background: Flour dust in bakeries is known to cause allergic as well as nonallergic respiratory symptoms. Fungal alpha-amylase is a commonly used baking additive that has been shown to have allergenic properties. The aim of this study was to investigate any effects on bronchoalveolar lavage (BAL) cells and peripheral blood lymphocytes (PBL) of healthy individuals exposed to airborne wheat flour dust with or without fungal alpha-amylase added., Methods: Fifteen subjects were exposed during 1 hr in an exposure chamber, ten individuals to wheat flour alone and five with alpha-amylase added. BAL was performed 2-6 weeks before and 1 day after the exposure. BAL cells were differentially counted and flowcytometric analysis of the expression of activation, adhesion, and subset markers on alveolar macrophages (AM) and T cells in BAL fluid and peripheral blood were carried out., Results: Exposure to wheat flour dust increased the total number of cells in BAL fluid from 75.4 (i.q. range 70.4-104.1) to 127.4 (92.1-187.4) cells x 10(6)/L, P < 0.01. There was a significant difference in the change of total BAL cell concentration between the study group exposed to wheat flour only (n = 10; increase with 91.9 x 10(6)/L) and the group exposed to wheat flour with the baking additive fungal alpha-amylase (n = 5; decrease with 5.4 x 10(6)/L). The exposure level of respirable dust was lower in the group that received alpha-amylase and the increase in BAL cell concentration showed a positive correlation with the concentration of respirable dust in the exposure chamber (r = 0.80, P < 0.001). The phenotypic analysis of AM indicated an influx of monocytic cells., Conclusions: The results indicate that the concentration of respirable dust, but not alpha-amylase, is of importance for the recruitment of inflammatory cells to the peripheral airways in healthy individuals exposed to wheat flour dust., (Copyright 2003 Wiley-Liss, Inc.)