Emerging roles of innate lymphoid cells in inflammatory diseases: Clinical implications

Innate lymphoid cells (ILC) represent a group of lymphocytes that lack specific antigen receptors and are relatively rare as compared to adaptive lymphocytes. ILCs play important roles in allergic and nonallergic inflammatory diseases due to their location at barrier surfaces within the airways, gut, and skin, and they respond to cytokines produced by activated cells in their local environment. Innate lymphoid cells contribute to the immune response by the release of cytokines and other mediators, forming a link between innate and adaptive immunity. In recent years, these cells have been extensively characterized and their role in animal models of disease has been investigated. Data to translate the relevance of ILCs in human pathology, and the potential role of ILCs in diagnosis, as biomarkers and/or as future treatment targets are also emerging. This review, produced by a task force of the Immunology Section of the European Academy of Allergy and Clinical Immunology (EAACI), encompassing clinicians and researchers, highlights the role of ILCs in human allergic and nonallergic diseases in the airways, gastrointestinal tract, and skin, with a focus on new insights into clinical implications, therapeutic options, and future research opportunities.

Effect of Bacillus subtilis C-3102 on loose stools in healthy volunteers

Ingestion of Bacillus subtilis C-3102 spores (C-3102) has relieved the symptoms of diarrhoea in piglets and changed the composition of gut microbiota in humans. Recently, it was suggested that the composition of the human gut microbiota affects stool consistency. In this study, a double-blind, randomised, placebo-controlled trial was conducted to assess the preventive effects of chronic diarrhoea in healthy volunteers with loose stools by ingestion of C-3102. The results showed that oral doses of C-3102 tablets significantly decreased the Bristol Stool Scale score and stool frequency, and also significantly improved abdominal sounds. With regard to gut microbiota, the relative abundance of Lachnospira, Actinomyces and SMB53 were significantly changed. This study shows that C-3102 could be effective for treating loose stools (Trial registration: UMIN000022583, http://tinyurl.com/ya4refqn ).

Characterization of Native Human Thrombopoietin in the Blood of Normal Individuals and of Patients with Haematologic Disorders

Thrombopoietin (TPO) isolated from thrombocytopenic plasma of various animal species has previously been shown to comprise only truncated forms of the molecule, presumably generated by proteolysis. Native TPO has now been partially purified from normal human plasma by immunoaffinity chromatography and was confirmed to be biologically active. Gel filtration in the presence of SDS revealed that TPO eluted in two peaks: a major peak corresponding to the elution position of fully glycosylated recombinant human TPO (rhTPO) consisting of 332 amino acid residues, and a minor peak corresponding to a smaller molecular size. Immunoblot analysis also revealed that most plasma-derived TPO migrated at the same position as fully glycosylated rhTPO, corresponding to a molecular size of ~80 to 100 kDa. Furthermore, the size distribution of circulating TPO in patients with various haematologic disorders did not differ markedly from that of plasma-derived TPO from healthy individuals. These results indicate that the truncation of circulating TPO is not related to disease pa-thophysiology, and that the predominant form of TPO in blood is a biologically active ~80- to 100-kDa species. The size distribution of TPO extracted from normal platelets was similar to that of TPO in plasma; the proportion of truncated TPO was decreased by prior incubation of platelets with hirudin, indicating that the endogenous truncated TPO, at least in platelet extract, was generated by thrombin-mediated cleavage.

Platelets Exposed to Elevated Levels of Endogenous Thrombopoietin In Vivo Have a Reduced Response to Megakaryocyte Growth and Development Factor In Vitro

Thrombopoietin (TPO), or megakaryocyte growth and development factor (MGDF), has been shown to potentiate the sensitivity of normal human platelets to various agonists in vitro. The present study investigated the functional and biochemical properties of platelets from mice rendered thrombocytopenic by sublethal irradiation with regard to the reactivity to recombinant murine MGDF (rmMGDF) in vitro. During the course of reversible thrombocytopenia following irradiation, platelets from irradiated mice which had lower platelet counts and reciprocally higher plasma TPO levels showed lower reactivity to rmMGDF in agonist-induced platelet aggregation. Intravenous injections of recombinant soluble murine c-Mpl (sMpl), which has the ability to capture TPO, after irradiation restored the reactivity of platelets at the platelet nadir to rmMGDF. On the other hand, platelets prepared from normal mice 3 h after a single intravenous injection of pegylated rmMGDF did not respond to rmMGDF. There was a marked decrease in c-Mpl and Janus kinase 2 (JAK2) in platelets from irradiated mice at the platelet nadir. Similar results were observed with platelets from mice administered pegylated rmMGDF. JAK2 was only moderately decreased, however, in platelets from mice given sMpl after irradiation. These results indicate that exposure of platelets to increased endogenous TPO levels in vivo in thrombocytopenic mice leads to a reduction in the platelet reactivity to rmMGDF in vitro. Further, these results suggest that the c-Mpl-mediated signaling pathway, which is essential for the priming effect of rmMGDF, is defective in thrombocytopenic murine platelets.

Dynamics of M1 macrophages in oral mucosal lesions during the development of acute graft-versus-host disease in rats

The role of macrophage infiltrates in oral mucosal acute graft-versus-host disease (AGVHD) remains unclear, although clinical studies suggest that macrophage infiltration correlates directly with the severity of AGVHD. In this study, we investigated the role of M1 macrophage infiltration in the oral mucosa of rats with AGVHD. Lewis rat spleen cells were injected into (Lewis × Brown Norway) F₁ rats to induce systemic GVHD. Tongue samples were evaluated using histology, immunohistochemistry, dual immunofluorescence, real-time reverse transcription-polymerase chain reaction, Transwell migration assays and Stamper-Woodruff binding assays. At the onset of oral mucosal AGVHD, dual immunofluorescence and migration assays revealed that M1 macrophages had accumulated in the basement membrane (BM) region via the laminin/CD29 β1 integrin pathway. Macrophage-secreted matrix metalloproteinase-2 was related to BM degradation. The adhesion of macrophages to the oral epithelium could be inhibited by pretreating macrophages with a CC chemokine receptor 2 (CCR2) antibody and/or pretreating lesion sections with monocyte chemoattractant protein-1 (MCP-1) antibody. Our data show that the migration and adhesion of M1 macrophages are associated with oral mucosal AGVHD, which is mediated in part by both laminin/CD29 β 1 intern and MCP-1/CCR2 pathways. Therefore, our study provides additional support for the contribution of macrophage infiltrate to the development of oral mucosal AGVHD.

Difference in clearance of exogenously administered smooth-form LPS following host responses among normal, sensitized and LPS-tolerant mice

Clearance of exogenously administered Salmonella abortus equi LPS from the circulation following induction of host responses, e.g. release of soluble CD14 (sCD14) and TNFα production, were investigated. The endotoxin unit of administered LPS in plasma was monitored by a combined method. After 1 h, more than 80% of injected LPS disappeared from the circulation of normal mice at all doses except a 100 μg dose, but sCD14 in plasma could not yet be detected by Western blotting. Release of sCD14 reached a peak 9 h after LPS injection. According to pretreatment with either Propionibacterium acnes or silver nitrate, the clearance rates of exogenously added LPS from the circulation were accelerated in comparison with the rate in normal mice, but plasma TNF levels were the opposite. In LPS-tolerant mice, LPS clearance and production of TNF and sCD14 was reduced. Pretreatment with anti-CD14 mAb reduced LPS-induced TNF production but did not influence the clearance rates. Taken together, in vivo, sCD14 may not play a critical role for early LPS clearance.

Measurement of different types of endotoxin in murine plasma by pretreatment with alkaline reagent and kinetic chromogenic Limulus test

Using a combined pretreatment methodology employing an alkaline reagent and a kinetic chromogenic Limulus test using Endospecy®, different types of endotoxins in murine plasma were able to be measured quantitatively. The detection of smooth (S)-form Salmonella abortus equi LPS (S-LPS) was approximately twice as sensitive as Helicobacter pylori LPS in aqueous solution. S-LPS added to whole mouse blood was recovered quantitatively from plasma, but the rough (R)-form S. minnesota LPS was not. The rates of clearance of S-LPS from the circulation following intravenous injection were shown to be different among BALB/c, C3H/HeN and B10Sn mice. Infection of mice with Salmonella typhimurium 3 days earlier resulted in accelerated clearance of subsequently injected LPS from the circulation. Significantly higher amounts of free non-microbe-associated LPS were detected in the blood of mice 1 h after infection with Escherichia coli O111:B4 followed by immediate treatment with ceftazidime, in comparison with non-antibiotic-treated but infected mice.

Nitric oxide confers cisplatin resistance in human lung cancer cells through upregulation of aldo-keto reductase 1B10 and proteasome

In this study, we show that exposure of human lung cancer A549 cells to cisplatin (cis-diamminedichloroplatinum, CDDP) promotes production of nitric oxide (NO) through generation of reactive oxygen species (ROS) and resulting upregulation of inducible NO synthase (iNOS). The incubation of the cells with a NO donor, diethylenetriamine NONOate, not only reduced the CDDP-induced cell death and apoptotic alterations (induction of CCAAT-enhancer-binding protein homologous protein and caspase-3 activation), but also elevated proteolytic activity of 26S proteasome, suggesting that the activation of proteasome function contributes to the reduction of CDDP sensitivity by NO. Monitoring expression levels of six aldo-keto reductases (AKRs) (1A1, 1B1, 1B10, 1C1, 1C2, and 1C3) during the treatment with the NO donor and subsequent CDDP sensitivity test using the specific inhibitors also proposed that upregulation of AKR1B10 by NO is a key process for acquiring the CDDP resistance in A549 cells. Treatment with CDDP and NO increased amounts of nitrotyrosine protein adducts, indicative of peroxynitrite formation, and promoted the induction of AKR1B10, inferring a relationship between peroxynitrite formation and the enzyme upregulation in the cells. The treatment with CDDP or a ROS-related lipid aldehyde, 4-hydroxy-2-nonenal, facilitated the iNOS upregulation, which was restored by increasing the AKR1B10 expression. In contrast, the facilitation of NO production by CDDP treatment was hardly observed in AKR1B10-overexpressing A549 cells and established CDDP-resistant cancer cells (A549, LoVo, and PC3). Collectively, these results suggest the NO functions as a key regulator controlling AKR1B10 expression and 26S proteasome function leading to gain of the CDDP resistance.

Serum glycopeptidolipid core IgA antibody levels in patients with chest computed tomography features of mycobacterium aviumintracellulare complex pulmonary disease

Measurement of serum glycopeptidolipid core IgA antibody (GPL antibody) was recently reported to show a high sensitivity and specificity for diagnosing Mycobacterium avium-intracellulare complex (MAC) pulmonary disease (MAC-PD), but its clinical value has not been confirmed. This study aims to evaluate the seropositive rate in patients with suspected MAC-PD based on chest computed tomography (CT), and to examine whether GPL antibody reflects the extent of lung involvement on CT or the number of bacteria in sputum, retrospectively. Among 66 patients with suspected MAC-PD on CT, 36 patients were negative for MAC by culture and 30 were positive. Sputum grades of MAC were evaluated by fluorochrome microscopy of sputum smears. The lungs were divided into six regions to assess the extent of disease. Serum levels of GPL antibody were measured with an enzyme immunoassay (cut-off value >0.7 U/ml). The GPL antibody positive rate was 19.4% among patients who were negative for MAC by culture versus 73.3% among culture–positive patients. The serum level of GPL antibody was significantly correlated with the sputum smear grade (r=0.43, p less than 0.05) and was also correlated with the number of lung regions showing MAC-PD features on CT (r=0.43, less than 0.05). Some MAC-PD patients may have CT features of MAC with positive level of GPL antibody, although the diagnosis cannot be confirmed by culture. GPL antibody levels reflect the pulmonary burden of MAC, as assessed from the sputum smear grade and number of involved regions on chest CT.