Extending the role of tryptase in perioperative anaphylaxis: Predicting positive results in basophil activation tests.

Background: Basophil activation tests (BATs) are useful in identifying culprits of perioperative anaphylaxis (PA), but their utility remains limited due to technical limitations, cost, and availability. Being able to prioritize patients with likely higher yields for BAT would be useful in reducing costs and manpower. Objective: We sought to investigate whether tryptase levels and clinical parameters may be useful for selecting patients for BATs. Methods: We performed a 10-year retrospective study in Hong Kong to investigate the performance of BATs associated with tryptase levels (taking during PA) and other clinical parameters. Results: Of 90 patients, 70 (77.8%) showed significant tryptase level elevation and 37 (41.1%) had a positive BAT result. BAT-positive patients presented with significantly higher absolute levels (15.9 µg/L vs 9.1 µg/L; P = .018), absolute elevation (12.8 µg/L vs 7.1 µg/L; P = .012), and fold elevation (5.6- vs 4.1-fold; P = .014) of acute tryptase than did BAT-negative patients. Among patients with positive BAT result, 94.6% (35 of 37) demonstrated elevated acute tryptase, significantly more than the BAT-negative group (66.0%; P < .001). In regression analysis, tryptase elevation was the sole significant factor correlated to BAT positivity (odds ratio, 10.14; 95% CI, 2.15-47.85; P = .003). Overall, elevated acute tryptase demonstrated a sensitivity of 94.7% and a negative predictive value of 90.0% in predicting positive results with BATs. Conclusions: We observed that tryptase elevation is a very sensitive predictor of BAT positivity among patients with identified culprits of PA. Acute elevation of tryptase would not only aid in confirming anaphylaxis but may also help guide the decision toward selecting labor-intensive and costly in vitro tests such as BATs.

Detection of antinuclear antibodies: recommendations from EFLM, EASI and ICAP.

OBJECTIVES: Antinuclear antibodies (ANA) are important for the diagnosis of various autoimmune diseases. ANA are usually detected by indirect immunofluorescence assay (IFA) using HEp-2 cells (HEp-2 IFA). There are many variables influencing HEp-2 IFA results, such as subjective visual reading, serum screening dilution, substrate manufacturing, microscope components and conjugate. Newer developments on ANA testing that offer novel features adopted by some clinical laboratories include automated computer-assisted diagnosis (CAD) systems and solid phase assays (SPA). METHODS: A group of experts reviewed current literature and established recommendations on methodological aspects of ANA testing. This process was supported by a two round Delphi exercise. International expert groups that participated in this initiative included (i) the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group "Autoimmunity Testing"; (ii) the European Autoimmune Standardization Initiative (EASI); and (iii) the International Consensus on ANA Patterns (ICAP). RESULTS: In total, 35 recommendations/statements related to (i) ANA testing and reporting by HEp-2 IFA; (ii) HEp-2 IFA methodological aspects including substrate/conjugate selection and the application of CAD systems; (iii) quality assurance; (iv) HEp-2 IFA validation/verification approaches and (v) SPA were formulated. Globally, 95% of all submitted scores in the final Delphi round were above 6 (moderately agree, agree or strongly agree) and 85% above 7 (agree and strongly agree), indicating strong international support for the proposed recommendations. CONCLUSIONS: These recommendations are an important step to achieve high quality ANA testing.

Ten-year outcomes of Perioperative Anaphylaxis Workup Study in Hong Kong (PAWS-HK): Performance of diagnostic modalities.

BACKGROUND: Studies on perioperative anaphylaxis (PA) in Asia are lacking. Furthermore, allergy workup for PA has largely been limited to the "silver standard" of skin tests (ST). Using in vitro tests as an adjunct to ST may improve and overcome these diagnostic challenges. OBJECTIVE: To evaluate the clinical characteristics and diagnostic tests of patients with suspected PA through the Perioperative Anaphylaxis Workup Study in Hong Kong cohort. METHODS: Patients with a diagnosis of PA over a 10-year period were recruited into the Perioperative Anaphylaxis Workup Study in Hong Kong. We reviewed the medical records, tryptase elevation, and diagnostic tests including ST, specific immunoglobulin E, and basophil activation tests (BAT). RESULTS: In 151 patients with PA, diagnosis was reached in three-fourths of the cases (113/151, 74.8%). The most common culprits identified were neuromuscular blocking agents (25.8%), ß lactams (17.2%) and chlorhexidine (13.9%). Severe anaphylaxis was associated with female sex, older age, elevated acute tryptase levels, and more cardiovascular manifestations during induction. Skin tests remained the most sensitive diagnostic modality overall (66.2%). BAT showed better performance for chlorhexidine and gelofusine anaphylaxis, with sensitivity of 80.0% and 79.6%, respectively. Specific Immunoglobulin E indicated even higher sensitivity (95.2%) than did ST (85.0%) and BAT (80.0%) for chlorhexidine anaphylaxis but performed poorly for other drugs. CONCLUSION: Neuromuscular blocking agents remain the most common culprit in PA. There was a higher prevalence of gelofusine anaphylaxis in our cohort than was seen in the literature. Skin tests remain the most sensitive testing modality. In vitro tests for chlorhexidine and gelofusine showed promising results, but more studies to further elucidate its use are warranted.

Synchronized abdominal compression as a novel treatment of life-threatening preschool asthma.

Introduction: In severe asthma, management of life-threatening air trapping that persists despite initiation of standard asthma treatment is difficult in the absence of extracorporeal membranous oxygenation.Case study: Three children with life-threatening asthma could not be adequately ventilated despite maximum conventional treatment because of severe air trapping. A novel method of active expiration by abdominal compression with a standard ventilator was adopted with immediate effect with significant improvement in ventilation.Conclusion: Synchronized abdominal compression is a novel and simple method that allows an effective treatment of severe air trapping in an intubated paralyzed asthma child.

Optic neuritis in Hong Kong: a 1-year follow-up study.

To investigate the etiology and prevalence of optic neuritis in a Chinese population. This was a single centre prospective cohort study. Consecutive patients with either a first or recurrent attack of optic neuritis from November 2010 to December 2011 were recruited from a district hospital in Hong Kong Special Administrative Region, China. All patients underwent serology testing for NMO (neuromyelitis optica) IgG; oligoclonal bands from lumbar puncture; computer tomography and contrast magnetic resonance imaging (MRI) of the brain and orbit as well as visual field; and optical coherence tomography testing. Patients were followed up for 1 year after the initial attack. 30 optic neuritis subjects were recruited. 73.3 % (22/30) remain as clinical isolated syndrome (CIS) after 1-year follow-up. 10 % (3/30) patients developed multiple sclerosis. 10 % (3/30) were diagnosed with NMO and 6.7 % (2/30) with NMO-spectrum disorder. The majority of acute unilateral optic neuritis in Chinese was CIS in origin although a fraction does progress to develop MS or NMO-related disorders. Clinicians should be aware of the associations and offer appropriate systemic workups.

A proteomic glimpse into the initial global epigenetic changes during HIV infection.

HIV-1 replication requires the insertion of viral DNA into the host genome, which is catalyzed by HIV-1 integrase. This integration event can lead to vast changes in the chromatin landscape and gene transcription. In this study, we sought to correlate the extensive changes of histone PTM abundances with the equally dynamic shifts in host transcriptional activity. To fully capture the changes that were occurring during the course of HIV-infection, we performed time-courses in which we extracted both histones and mRNA from HIV-infected, UV-inactivated HIV-infected and mock-infected SUP-T1 cells. We then analyzed the alterations to histone PTM profiles using nano-LC-MS/MS, as well as the expression of chromatin-associated enzymes, such as histone deacetylases, acetyltransferases, demethylases, methyltransferases, and histone chaperone proteins. As expected, we observed major changes in histone PTM abundances, which we linked to massive fluctuations in mRNA expression of associated chromatin enzymes. However, we find few differences between HIV and HIVUV (UV-inactivated) infection, which suggests that initial histone PTM changes during HIV infection are from the host in response to the infection, and not due to the HIV virus manipulating the transcriptional machinery. We believe that these preliminary experiments can provide a basis for future forays into targeted manipulations of histone PTM-regulated aspects of HIV progression through its replication cycle.

Identification of EZH2 and EZH1 small molecule inhibitors with selective impact on diffuse large B cell lymphoma cell growth.

The histone methyltransferase enhancer of Zeste homolog 2 (EZH2) is a candidate oncogene due to its prevalent overexpression in malignant diseases, including late stage prostate and breast cancers. The dependency of cancer cells on EZH2 activity is also predicated by recurrent missense mutations residing in the catalytic domain of EZH2 that have been identified in subtypes of diffuse large B cell lymphoma, follicular lymphoma and melanoma. Herein, we report the identification of a highly selective small molecule inhibitor series of EZH2 and EZH1. These compounds inhibit wild-type and mutant versions of EZH2 with nanomolar potency, suppress global histone H3-lysine 27 methylation, affect gene expression, and cause selective proliferation defects. These compounds represent a structurally distinct EZH2 inhibitor chemotype for the exploration of the role of Polycomb Repressive Complex 2-mediated H3K27 methylation in various biological contexts.

A quantitative atlas of histone modification signatures from human cancer cells.

BACKGROUND: An integral component of cancer biology is the understanding of molecular properties uniquely distinguishing one cancer type from another. One class of such properties is histone post-translational modifications (PTMs). Many histone PTMs are linked to the same diverse nuclear functions implicated in cancer development, including transcriptional activation and epigenetic regulation, which are often indirectly assayed with standard genomic technologies. Thus, there is a need for a comprehensive and quantitative profiling of cancer lines focused on their chromatin modification states. RESULTS: To complement genomic expression profiles of cancer lines, we report the proteomic classification of 24 different lines, the majority of which are cancer cells, by quantifying the abundances of a large panel of single and combinatorial histone H3 and H4 PTMs, and histone variants. Concurrent to the proteomic analysis, we performed transcriptomic analysis on histone modifying enzyme abundances as a proxy for quantifying their activity levels. While the transcriptomic and proteomic results were generally consistent in terms of predicting histone PTM abundance from enzyme abundances, several PTMs were regulated independently of the modifying enzyme expression. In addition, combinatorial PTMs containing H3K27 methylation were especially enriched in breast cell lines. Knockdown of the predominant H3K27 methyltransferase, enhancer of zeste 2 (EZH2), in a mouse mammary xenograft model significantly reduced tumor burden in these animals and demonstrated the predictive utility of proteomic techniques. CONCLUSIONS: Our proteomic and genomic characterizations of the histone modification states provide a resource for future investigations of the epigenetic and non-epigenetic determinants for classifying and analyzing cancer cells.

H5N1 virus causes significant perturbations in host proteome very early in influenza virus-infected primary human monocyte-derived macrophages.

H5N1 influenza viruses, which cause disease in humans, have unusually high pathogenicity. The temporal response of primary human monocyte-derived macrophages infected with highly pathogenic H5N1 and seasonal H1N1 influenza viruses was evaluated using mass spectrometry-based quantitative proteomic profiling. This was done in order to demonstrate significant perturbation of the host proteome upon viral infection, as early as 1 hour after infection. This early host response distinguished H5N1 infection from H1N1 infection, the latter inducing less of a response. The most pronounced effect was observed on the translational machinery, suggesting that H5N1 might gain advantage in replication by using the cell protein synthesis machinery early in the infection.

Morphine produces immunosuppressive effects in nonhuman primates at the proteomic and cellular levels.

Morphine has long been known to have immunosuppressive properties in vivo, but the molecular and immunologic changes induced by it are incompletely understood. To explore how these changes interact with lentiviral infections in vivo, animals from two nonhuman primate species (African green monkeys and pigtailed macaques) were provided morphine and studied using a systems biology approach. Biological specimens were obtained from multiple sources (e.g. lymph node, colon, cerebrospinal fluid, and peripheral blood) before and after the administration of morphine (titrated up to a maximum dose of 5 mg/kg over a period of 20 days). Cellular immune, plasma cytokine, and proteome changes were measured and morphine-induced changes in these parameters were assessed on an interorgan, interindividual, and interspecies basis. In both species, morphine was associated with decreased levels of Ki-67(+) T-cell activation but with only minimal changes in overall T-cell counts, neutrophil counts, and NK cell counts. Although changes in T-cell maturation were observed, these varied across the various tissue/fluid compartments studied. Proteomic analysis revealed a morphine-induced suppressive effect in lymph nodes, with decreased abundance of protein mediators involved in the functional categories of energy metabolism, signaling, and maintenance of cell structure. These findings have direct relevance for understanding the impact of heroin addiction and the opioids used to treat addiction as well as on the potential interplay between opioid abuse and the immunological response to an infective agent.

Anti-ganglioside antibodies were not detected in human subjects infected with or vaccinated against 2009 pandemic influenza A (H1N1) virus.

Recipients of influenza A (H1N1) vaccine in 1976 had an increased risk for the neurologic disorder Guillain-Barré syndrome (GBS). Anti-ganglioside antibodies, which might be associated with the development of GBS, were previously reported to be induced in mice immunized with an H1N1 vaccine of 1976 or another influenza vaccine. In this study we analyzed anti-ganglioside antibodies in human subjects infected with or vaccinated against 2009 pandemic H1N1, including eight patients diagnosed to have post-vaccination GBS. Antibodies against GM1 or another ganglioside were not detected in any subject or in vaccinated mice. Our results did not support the induction of anti-ganglioside antibodies by influenza viruses or vaccines.

A synopsis of current haemophilia care in Hong Kong.

OBJECTIVE: To provide a synopsis of current haemophilia care in Hong Kong. DESIGN: Retrospective survey. SETTING: All haematology units of the Hospital Authority in Hong Kong. PATIENTS: All patients with haemophilia A and haemophilia B. RESULTS: To date, there were 222 mild-to-severe haemophilia patients (192 type A, 30 type B) under regular public care in Hong Kong (43% were considered severe, 33% moderate, and 24% mild), which gave a crude prevalence of 6.8/100 000 male inhabitants. A total of 12.8 million units of Factor VIII and 3 million units of Factor IX were prescribed annually. This amounts to 1.83 units of FVIII per capita of the population, which is comparable to that of other developed countries. Leading causes of mortality were human immunodeficiency virus-related complications (10 cases) and cerebral bleeding (2 cases). The life expectancy of patients with severe haemophilia in Hong Kong is improving; currently the oldest patient is 60 years old. Such improved survival may be due to enhanced factor availability, prompt treatment of bleeding episodes at home, safer factor products, and better antiviral treatment. Primary prophylaxis is the accepted standard of care for severe and moderate cases, and "Factor First" has become hospital policy. However, 12 patients continue to present treatment challenges, due to the documented presence of factor inhibitors. In all, 28, 100, and 14 cases respectively were positive for human immunodeficiency virus, hepatitis C virus, and hepatitis B virus; the youngest patients with the corresponding infections being 28, 13, and 22 years old. Comprehensive care with dedicated physiotherapy, surgical support, and radionucleotide synovectomy may reduce morbidity further. CONCLUSION: A multidisciplinary approach can further improve the future care for haemophilia patients in Hong Kong.

MicroRNA expression and virulence in pandemic influenza virus-infected mice.

The worst known H1N1 influenza pandemic in history resulted in more than 20 million deaths in 1918 and 1919. Although the underlying mechanism causing the extreme virulence of the 1918 influenza virus is still obscure, our previous functional genomics analyses revealed a correlation between the lethality of the reconstructed 1918 influenza virus (r1918) in mice and a unique gene expression pattern associated with severe immune responses in the lungs. Lately, microRNAs have emerged as a class of crucial regulators for gene expression. To determine whether differential expression of cellular microRNAs plays a role in the host response to r1918 infection, we compared the lung cellular "microRNAome" of mice infected by r1918 virus with that of mice infected by a nonlethal seasonal influenza virus, A/Texas/36/91. We found that a group of microRNAs, including miR-200a and miR-223, were differentially expressed in response to influenza virus infection and that r1918 and A/Texas/36/91 infection induced distinct microRNA expression profiles. Moreover, we observed significant enrichment in the number of predicted cellular target mRNAs whose expression was inversely correlated with the expression of these microRNAs. Intriguingly, gene ontology analysis revealed that many of these mRNAs play roles in immune response and cell death pathways, which are known to be associated with the extreme virulence of r1918. This is the first demonstration that cellular gene expression patterns in influenza virus-infected mice may be attributed in part to microRNA regulation and that such regulation may be a contributing factor to the extreme virulence of the r1918.

Decoding the multifaceted HIV-1 virus-host interactome.

Recently in BMC Medical Genomics, Tozeren and colleagues have uncovered virus-host interactions by searching for conserved peptide motifs in HIV and human proteins. Their computational model provides a novel perspective in the interpretation of high-throughput data on the HIV-host interactome.

Dynamic host energetics and cytoskeletal proteomes in human immunodeficiency virus type 1-infected human primary CD4 cells: analysis by multiplexed label-free mass spectrometry.

We report on a proteomic analysis of ex vivo human immunodeficiency virus (HIV) type 1 infection in human primary CD4 cells by shotgun liquid chromatography-tandem mass spectrometry analysis, revealing two distinct proteomic profiles at two phases of virus replication. Relative to mock-infected cells, 168 signature proteins exhibited abundance changes at the first sign of Gag p24 production (8 h postinfection [p.i.]) or the peak of virus replication (24 h p.i.); interestingly, most of the changes were exclusive to only one phase of virus replication. Based on characterization by functional ontology and known human-HIV protein interactions, we observed the enrichment for protein abundance increases pertaining to protein synthesis and nucleasomal reorganization amid an otherwise placid cellular proteome at the first sign of HIV replication. In contrast, we observed indications of decreased protein turnover, concomitant with heightened DNA repair activities and preludes to apoptosis, in the presence of robust virus replication. We also observed hints of disruptions in protein and small molecule trafficking. Our label-free proteomic strategy allowed us to perform multiplexed comparisons-we buttressed our detection specificity with the use of a reverse transcriptase inhibitor as a counterscreen, enabling highlighting of cellular protein abundance changes unique to robust virus replication as opposed to viral entry. In conjunction with complementary high-throughput screens for cellular partners of HIV, we put forth a model pinpointing specific rerouting of cellular biosynthetic, energetic, and trafficking pathways as HIV replication accelerates in human primary CD4 cells.

Virus-host interactions: from systems biology to translational research.

Research embracing systems biology approaches and careful analysis of the critical host response has greatly expanded our understanding of infectious diseases. First-generation studies based on genomics and proteomics have made significant progress in establishing the foundation for network-based investigations on virus-host interactions. More recently, data from complementary high-throughput technologies, such as siRNA and microRNA screens and next-generation sequencing, are augmenting systems level analyses and are providing a more detailed and insightful multidimensional view of virus-host networks. Together with advances in data integration, systems biology approaches now have the potential to provide profound impacts on translational research, leading to the more rapid development of new therapeutics and vaccines for infectious diseases. In this review, we highlight new high-throughput technologies, a new philosophy for studying virus-host interactions, and discuss the potential of systems biology to facilitate bench-to-bedside research and create novel strategies to combat disease. Can we save the world using these approaches? Read on.

Modified Epworth Sleepiness Scale in Chinese children with obstructive sleep apnea: a retrospective study.

BACKGROUND AND OBJECTIVE: The purpose of this study is to assess whether Chinese children with high apnea-hypopnea index (AHI) are sleepier by a modified Epworth Sleepiness Scale (ESS). MATERIALS AND METHODS: Records were retrospectively reviewed. We included children who were between 3 and 12 years old, admitted for overnight polysomnogram because of suspected obstructive sleep apnea syndrome (OSAS). A modified ESS was used to assess excessive daytime sleepiness (EDS) of the children. RESULTS: One hundred ninety-two Chinese children were included. Children with high AHI, defined as AHI > 5.0, were sleepier than children with AHI less than or equal to 5. After adjustment by age, gender, and obesity, children with high AHI remained significantly sleepier. Modified ESS was significantly correlated with AHI (rho = 0.124, 95% CI = 0.004-0.281). Modified ESS score of >8 was the best cutoff point with the sensitivity and specificity of 0.29 and 0.91, respectively. The odds ratio of children with modified ESS > 10 having high AHI was 4.231 (95%CI = 1.248 to 14.338) and children with modified ESS > 8 had the highest odds ratio, 4.295(95%CI = 1.66 to 11.1), of having high AHI. CONCLUSION: Chinese children with high AHI appear to be sleepier than children with low AHI. Children with suspected OSAS and high modified ESS, i.e., ESS > 8, had significantly higher odds ratio of having high AHI. Increased sleepiness is a specific but not a sensitive symptom in snoring children with high AHI. Screening for EDS in snoring children may help us identify those with high AHI and prioritize the management of those children.

Good's syndrome in a patient with cytomegalovirus retinitis.

Thymoma-related adult-onset immunodeficiency or Good's syndrome is an uncommon condition. This case, of a 50-year-old woman who was human immunodeficiency virus-negative and developed herpes zoster and severe cytomegalovirus retinitis 6 months after removal of a thymoma, is the first to be reported in Hong Kong. Immunological investigations revealed no B cells, hypogammaglobulinaemia, a low CD4 count, and a low CD4/CD8 ratio. We recommend that immunological investigations, including T-cell subsets, B cells, and quantitative immunoglobulins, should be part of the routine diagnostic evaluation of patients with thymoma and infections.

The association of RANTES polymorphism with severe acute respiratory syndrome in Hong Kong and Beijing Chinese.

BACKGROUND: Chemokines play important roles in inflammation and antiviral action. We examined whether polymorphisms of RANTES, IP-10 and Mig affect the susceptibility to and outcome of severe acute respiratory syndrome (SARS). METHODS: We tested the polymorphisms of RANTES, IP-10 and Mig for their associations with SARS in 495 Hong Kong Chinese SARS patients and 578 controls. Then we tried to confirm the results in 356 Beijing Chinese SARS patients and 367 controls. RESULTS: RANTES -28 G allele was associated with SARS susceptibility in Hong Kong Chinese (P < 0.0001, OR = 2.80, 95%CI:2.11-3.71). Individuals with RANTES -28 CG and GG genotypes had a 3.28-fold (95%CI:2.32-4.64) and 3.06-fold (95%CI:1.47-6.39) increased risk of developing SARS respectively (P < 0.0001). This -28 G allele conferred risk of death in a gene-dosage dependent manner (P = 0.014) with CG and GG individuals having a 2.12-fold (95% CI: 1.11-4.06) and 4.01-fold (95% CI: 1.30-12.4) increased risk. For the replication of RANTES data in Beijing Chinese, the -28 G allele was not associated with susceptibility to SARS. However, -28 CG (OR = 4.27, 95%CI:1.64-11.1) and GG (OR = 3.34, 95%CI:0.37-30.7) were associated with admission to intensive care units or death due to SARS (P = 0.011). CONCLUSION: RANTES -28 G allele plays a role in the pathogenesis of SARS.