C. W. K. Lam

Proinflammatory cytokines (IL‐17, IL‐6, IL‐18 and IL‐12) and Th cytokines (IFN‐γ, IL‐4, IL‐10 and IL‐13) in patients with allergic asthma

Allergen‐reactive T helper type‐2 (Th2) cells and proinflammatory cytokines have been suggested to play an important role in the induction and maintenance of the inflammatory cascade in allergic asthma. We compared the plasma concentrations of novel proinflammatory cytokines IL‐17 and IL‐18, other proinflammatory cytokines IL‐6 and IL‐12, Th2 cytokines IL‐10 and IL‐13, and intracellular interferon‐γ (IFN‐γ) and IL‐4 in Th cells of 41 allergic asthmatics and 30 sex‐ and age‐matched health control subjects. Plasma cytokines were measured by enzyme‐linked immunosorbent assay. Intracellular cytokines were quantified by flow cytometry. Plasma IL‐18, IL‐12, IL‐10, IL‐13 concentrations were significantly higher in allergic asthmatic patients than normal control subjects (IL‐18: median 228·35 versus 138·72u2003pg/ml, Pu2003<u20030·001; IL‐12: 0·00 versus 0·00u2003pg/ml, Pu2003=u20030·001; IL‐10: 2·51 versus 0·05u2003pg/ml, Pu2003<u20030·034; IL‐13: 119·38 versus 17·89u2003pg/ml, Pu2003<u20030·001). Allergic asthmatic patients showed higher plasma IL‐17 and IL‐6 concentrations than normal controls (22·40 versus 11·86u2003pg/ml and 3·42 versus 0·61u2003pg/ml, respectively), although the differences were not statistically significant (Pu2003=u20030·077 and 0·053, respectively). The percentage of IFN‐γ‐producing Th cells was significantly higher in normal control subjects than asthmatic patients (23·46 versus 5·72%, Pu2003<u20030·001) but the percentage of IL‐4 producing Th cells did not differ (0·72 versus 0·79%, Pu2003>u20030·05). Consequently, the Th1/Th2 cell ratio was significantly higher in normal subjects than asthmatic patients (29·6 versus 8·38%, Pu2003<u20030·001). We propose that allergic asthma is characterized by an elevation of both proinflammatory and Th2 cytokines. The significantly lower ratio of Th1/Th2 cells confirms a predominance of Th2 cells response in allergic asthma.

Plasma inflammatory cytokines and chemokines in severe acute respiratory syndrome

Severe acute respiratory syndrome (SARS) is a recently emerged infectious disease caused by a novel coronavirus, but its immunopathological mechanisms have not yet been fully elucidated. We investigated changes in plasma T helper (Th) cell cytokines, inflammatory cytokines and chemokines in 20 patients diagnosed with SARS. Cytokine profile of SARS patients showed marked elevation of Th1 cytokine interferon (IFN)‐γ, inflammatory cytokines interleukin (IL)‐1, IL‐6 and IL‐12 for at least 2 weeks after disease onset, but there was no significant elevation of inflammatory cytokine tumour necrosis factor (TNF)‐α, anti‐inflammatory cytokine IL‐10, Th1 cytokine IL‐2 and Th2 cytokine IL‐4. The chemokine profile demonstrated significant elevation of neutrophil chemokine IL‐8, monocyte chemoattractant protein‐1 (MCP‐1), and Th1 chemokine IFN‐γ‐inducible protein‐10 (IP‐10). Corticosteroid reduced significantly IL‐8, MCP‐1 and IP‐10 concentrations from 5 to 8u2003days after treatment (all Pu2003<u20030·001). Together, the elevation of Th1 cytokine IFN‐γ, inflammatory cytokines IL‐1, IL‐6 and IL‐12 and chemokines IL‐8, MCP‐1 and IP‐10 confirmed the activation of Th1 cell‐mediated immunity and hyperinnate inflammatory response in SARS through the accumulation of monocytes/macrophages and neutrophils.

Asthma and atopy are associated with chromosome 17q21 markers in Chinese children

Background:u2002 Single‐nucleotide polymorphism (SNP)‐based genome‐wide association study revealed that markers on chromosome 17q21 were linked to childhood asthma but not atopy in Caucasians, with the strongest signal being detected for the SNP rs7216389 in the ORMDL3 gene. Such association was unknown in Chinese. This study delineated the allele and genotype frequencies of 10 SNPs at chromosome 17q21, and investigated the relationship between these SNPs and asthma and plasma IgE in southern Chinese children.

Interleukin (IL)-4 and IL-13 up-regulate monocyte chemoattractant protein-1 expression in human bronchial epithelial cells: involvement of p38 mitogen-activated protein kinase, extracellular signal-regulated kinase 1/2 and Janus kinase-2 but not c-Jun NH2-terminal kinase 1/2 signalling pathways

The Th2 cytokines interleukin (IL)‐4 and IL‐13 and chemokine monocyte chemoattractant protein‐1 (MCP‐1) are significantly involved in bronchial hyperreactivity (BHR) and remodelling in allergic asthma. Although IL‐4 and IL‐13 can regulate a number of chemokines from bronchial epithelium, their regulatory effect on the expression of MCP‐1 is as yet unproved. We aim to investigate the intracellular signalling mechanisms of IL‐4 and IL‐13 regulating the expression and secretion of MCP‐1 from human bronchial epithelial cells. BEAS‐2B cells, derived from a human bronchial epithelial cell line, were activated with or without IL‐4 and/or IL‐13 for different time intervals. MCP‐1 gene expression and protein secretion were measured by reverse transcription–polymerase chain reaction and enzyme‐linked immunosorbent assay, respectively. Activation of signalling molecules p38 mitogen‐activated protein kinase (MAPK), extracellular signal‐regulated kinase (ERK), c‐Jun NH2‐terminal kinase (JNK) and Janus kinase‐2 (JAK‐2) was accessed by Western blotting. IL‐4 and IL‐13 were found to up‐regulate gene expression and significantly increase the release of MCP‐1 from BEAS‐2B cells. Both cytokines could activate p38 MAPK, ERK and JAK‐2, but not JNK activity. Inhibition of p38 MAPK, ERK and JAK‐2 activities by pretreating the cells with their corresponding inhibitors SB203580, PD98059 and AG490, respectively, significantly suppressed IL‐4‐ and IL‐13‐induced MCP‐1 production in BEAS‐2B cells. Together, the above results illustrate that the activation of p38 MAPK, ERK and JAK‐2 but not JNK is crucial for IL‐4‐ and IL‐13‐induced MCP‐1 release in human bronchial epithelial cells. Our findings may provide insight into the future development of more effective therapeutic agents for treating allergic asthma.

Elevated production of interleukin-18 is associated with renal disease in patients with systemic lupus erythematosus

Summary To investigate the production mechanism and proinflammatory role of the cytokine interleukin (IL‐18) in lupus nephritis, we investigated the plasma concentrations of IL‐18 and nitric oxide (NO) and the release of IL‐18 and NO from mitogen‐activated peripheral blood monomuclear cells (PBMC), in 35 SLE patients with renal disease (RSLE), 37 patients without renal disease (SLE) and 28 sex‐ and age‐matched healthy control subjects (NC). IL‐18 and NO concentrations were measured by ELISA and colourimetric non‐enzymatic assay, respectively. Gene expressions of IL‐18 and IL‐18 receptor were analysed by RT‐PCR. Plasma IL‐18 and NO concentrations were significantly higher in RSLE than NC (both Pu2003<u20030·01). Elevation of plasma IL‐18 in RSLE correlated positively and significantly with SLE disease activity index and plasma NO concentration (ru2003=u20030·623, Pu2003<u20030·0001 and ru2003=u20030·455, Pu2003=u20030·017, respectively), and the latter also showed a positive and significant correlation with plasma creatinine (ru2003=u20030·410, Pu2003=u20030·034) and urea (ru2003=u20030·685, Pu2003<u20030·0001). There was no significant difference in gene expressions of IL‐18 and IL‐18 receptor in PBMC among RSLE, SLE and NC. Percentage increase in culture supernatant IL‐18 concentration was significantly higher in RSLE than SLE and NC (both Pu2003<u20030·05). The basal NO release was significantly higher in RSLE than that in SLE and NC (both Pu2003<u20030·005). IL‐18 is therefore suggested to play a crucial role in the inflammatory processes of renal disease in SLE.

Hypercytokinemia and Hyperactivation of Phospho-p38 Mitogen-Activated Protein Kinase in Severe Human Influenza A Virus Infection

BACKGROUNDnWe postulate that hypercytokinemia plays a role in immunopathogenesis of severe human influenza.nnnMETHODSnWe prospectively studied 39 consecutive patients who were hospitalized with severe influenza A virus infection. On laboratory confirmation of the diagnosis, paired acute-phase (obtained at hospital admission) and convalescent-phase (obtained >10 days after hospital admission) plasma samples were collected for assay of 11 cytokines and chemokines (interleukin [IL] 1 beta; IL-6; IL-10; IL-12p70; tumor necrosis factor alpha; IL-8; monokine induced by interferon [IFN]-gamma; IFN-inducible protein 10; monocyte chemoattractant protein 1; regulated upon activation, normal T cell-expressed and secreted; and IFN-gamma) using cytometric bead-array analysis and enzyme-linked immunosorbent assay. Simultaneously, virus concentration in the acute-phase nasopharyngeal aspirate was determined using real-time quantitative reverse-transcriptase polymerase chain reaction. Intracellular signaling molecules regulating lymphocyte activation, phospho-p38 mitogen-activated protein kinase and phospho-extracellular signal-regulated protein kinase in CD4+ and CD8+ T lymphocytes were studied in the acute-phase samples using flow cytometric analysis and were compared with results for samples from healthy control subjects.nnnRESULTSnStatistically significant increases in plasma IL-6 (3.7-fold increase), IL-8 (2.6-fold increase), IFN-induced protein 10 (4.9-fold increase), and monokine induced by IFN-gamma (2.3-fold increase) concentrations were detected during acute illness (P < .01 for all, by Wilcoxon signed-rank test); the highest concentrations were observed on symptom days 3 and 4. Corresponding plasma cytokine and chemokine concentrations and nasopharyngeal viral loads showed statistically significant correlations (rho = 0.41, 0.49, 0.54, and 0.46, respectively; P < or = .01). Phospho-p38 mitogen-activated protein kinase expression in CD4+ lymphocytes was increased, correlating with cytokine concentrations (e.g., for IFN-induced protein 10, rho = 0.78; P < .01); phospho-extracellular signal-regulated protein kinase was suppressed. Advanced age and comorbidity were associated with aberrant IL-6, IL-8, and monokine induced by IFN-gamma responses (P < .05, by Mann-Whitney U test). An elevated IL-6 concentration was independently associated with prolonged hospitalization (hospitalization for >5 days; P = .02), adjusted for age, comorbidity, and virus load.nnnCONCLUSIONSnHypercytokinemia (of proinflammatory and T helper 1 cytokines) is detected in severe influenza, correlating with clinical illness and virus concentration. Hyperactivation of phospho-p38 mitogen-activated protein kinase (in T helper cells) is possibly involved. Early viral suppression may attenuate these potentially deleterious cytokine responses.

IL-25 regulates the expression of adhesion molecules on eosinophils : mechanism of eosinophilia in allergic inflammation

Background:u2002 Interleukin‐25 (IL‐25) is a novel T‐helper‐2 (Th2) cytokine of the IL‐17 family that plays a key role in allergic inflammation. Recent studies reported that over‐expression of IL‐25 in mouse induces eosinophilia. We investigated the effect of IL‐25 on the expression of several adhesion molecules on human eosinophils and the underlying intracellular mechanisms.

Role of p38 MAPK and NF-kB for chemokine release in coculture of human eosinophils and bronchial epithelial cells.

Eosinophils are principal effector cells of inflammation in allergic asthma, characterized by their accumulation and infiltration at inflammatory sites mediated by the chemokine eotaxin and their interaction with adhesion molecules expressed on bronchial epithelial cells. We investigated the modulation of nuclear factor‐κB (NF‐κB) and the mitogen‐activated protein kinase (MAPK) pathway on the in vitro release of chemokines including regulated upon activation normal T cell expressed and secreted (RANTES), monokine induced by interferon‐γ (MIG), monocyte chemoattractant protein‐1 (MCP‐1), interleukin (IL)‐8, and interferon‐inducible protein‐10 (IP‐10) upon the interaction of human bronchial epithelial BEAS‐2B cells and eosinophils. Gene expression of chemokines was evaluated by RT‐PCR and the induction amount of chemokines quantified by cytometric bead array. NF‐κB and p38 MAPK activities were assessed by electrophoretic mobility shift assay and Western blot, respectively. The interaction of eosinophils and BEAS‐2B cells was found to up‐regulate the gene expression of the chemokines IL‐8, MCP‐1, MIG, RANTES and IP‐10 expression in BEAS‐2B cells, and to significantly elevate the release of the aforementioned chemokines except RANTES in a coculture of BEAS‐2B cells and eosinophils. IκB‐α phosphorylation inhibitor, BAY 11–7082, and p38 MAPK inhibitor, SB 203580 could decrease the release of IL‐8, IP‐10 and MCP‐1 in the coculture. Together, the above results show that the induction of the release of chemokines in a coculture of epithelial cells and eosinophils are regulated by p38 MAPK and NF‐κB activities of BEAS‐2B cells, at least partly, through intercellular contact. Our findings therefore shed light on the future development of more effective agents for allergic and inflammatory diseases.

Increased expression of plasma and cell surface co‐stimulatory molecules CTLA‐4, CD28 and CD86 in adult patients with allergic asthma

The co‐stimulatory interactions of the B7 family molecules CD80 and CD86 on antigen‐presenting cells, together with their T cell counter receptors CD28 and cytotoxic T lymphocyte‐associated antigen‐4 (CTLA‐4), modulate T lymphocyte‐mediated immune responses in a reciprocal manner. To investigate whether there is altered expression and the clinical significance of soluble co‐stimulatory molecules in asthmatic patients, plasma concentrations of sCTLA‐4, sCD28, sCD80 and sCD86 in 51 adult allergic asthmatic adults with or without steroid treatment, and 35 sex‐ and age‐matched control subjects were measured by enzyme‐linked immunosorbent assay (ELISA). Cell surface expression of CTLA‐4 and CD28 on peripheral blood mononuclear cells (PBMC) were analysed by flow cytometry. Results showed that the plasma sCTLA‐4 concentration was significantly higher in all asthmatic patients while sCD28 and sCD86 concentrations were significantly higher in steroid and non‐steroid treated asthmatic patients, respectively, compared with control subjects (all Pu2003<u20030·01). Significantly increased cell surface expression of CD28 but not CTLA‐4 on PBMC was found in asthmatic patients compared with controls (Pu2003<u20030·05). The plasma concentration and cell surface expression of CTLA‐4 were found to exhibit positive and significant correlations with those of CD28 (both Pu2003<u20030·05). Serum total IgE concentration correlated positively and significantly with sCTLA‐4 and sCD28 concentrations in allergic asthmatic patients (both Pu2003<u20030·05). The increased expression of these soluble co‐stimulatory molecules may reflect the dysregulation of T cell activation, thereby contributing to the immunopathogenesis of allergic asthma.

Nitric oxide synthase polymorphisms and asthma phenotypes in Chinese children.

Background Nitric oxide (NO) is a key factor for balancing T‐helper type 1/T‐helper type 2 immunity. Single nucleotide polymorphisms (SNPs) in nitric oxide synthase (NOS) genes have been associated with atopy and exhaled NO concentrations in Caucasians. We investigated the association between asthma traits and genetic polymorphisms in neuronal NO synthase (NOS1) and endothelial NO synthase (NOS3) in Chinese children.