Aberrant Expression of Novel Cytokine IL-38 and Regulatory T Lymphocytes in Childhood Asthma.

We investigated the expression of novel anti-inflammatory interleukin (IL)-38 and regulatory T (Treg) lymphocytes in childhood asthma patients. The protein and mRNA expression level of IL-38, periostin, peripheral CD4⁺CD25⁺CD134⁺ T lymphocytes as well as CD4⁺CD25(high)FoxP3⁺ and CD4⁺CD25(high)CD127(-) Treg lymphocytes from 40 asthmatic patients and 20 normal control (NC) subjects were studied using ELISA, qPCR and flow cytometry. Serum and supernatant cytokines/chemokines were determined by multiplex assay. Serum IL-38, IL-5, IL-17, IL-6, interferon-γ, periostin, IL-1ß and IL-13 concentrations were significantly higher in asthmatic patients with or without steroid treatment than those in controls (all p < 0.05). The percentages of both CD4⁺CD25(high)FoxP3⁺ and CD4⁺CD25(high)CD127(-) Treg lymphocytes were markedly decreased in asthmatic patients with and without steroid treatment than those in controls (all p < 0.05). The elevated IL-38 concentration negatively correlated with the percentage of Treg lymphocytes in asthmatic patients with high level (>40 ng/mL) of periostin (p < 0.05). Although the comparable mRNA levels of IL-38 and its receptor IL-36R were found between patients and controls, the mRNA level of IL-38 positively correlated with IL-36R and negatively correlated with IL-10 in all asthmatic patients (both p < 0.05). The percentage of CD4⁺CD25⁺CD134⁺ activated T lymphocytes was also significantly higher in asthmatic patients with steroid treatment than those in controls (p < 0.05). This cross-sectional study demonstrated that the overexpression of circulating IL-38 may play a role in the immunopathogenesis in asthma.

Profiles of cytokine and chemokine gene expression in human pulmonary epithelial cells induced by human and avian influenza viruses.

Influenza pandemic remains a serious threat to human health. In this study, the repertoire of host cellular cytokine and chemokine responses to infections with highly pathogenic avian influenza H5N1, low pathogenicity avian influenza H9N2 and seasonal human influenza H1N1 were compared using an in vitro system based on human pulmonary epithelial cells. The results showed that H5N1 was more potent than H9N2 and H1N1 in inducing CXCL-10/IP-10, TNF-alpha and CCL-5/RANTES. The cytokine/chemokine profiles for H9N2, in general, resembled those of H1N1. Of interest, only H1N1, but none of the avian subtypes examined could induce a persistent elevation of the immune-regulatory cytokine - TGF-ß2. The differential expression of cytokines/chemokines following infection with different influenza viruses could be a key determinant for clinical outcome. The potential of using these cytokines/chemokines as prognostic markers or targets of therapy is worth exploring.

Survey for the presence of BK, JC, KI, WU and Merkel cell polyomaviruses in human brain tissues.

BACKGROUND: Recently three previously unknown polyomaviruses (KI, WU and Merkel cell polyomaviruses) have been identified from human specimens. The spectrum of clinical manifestations and their tissue tropism are currently unknown. Since a member of this virus family, JC virus, is well-known for its capacity to establish latency in human brain tissue where reactivation in immunocompromised individuals can result in fatal progressive multifocal leukoencephalopathy, we sought to examine for the presence of all the five known human polyomaviruses in a series of human brain tissues. OBJECTIVES: To investigate the possibility of neuropersistence of the newly identified human polyomaviruses. STUDY DESIGN: Autopsy brain tissues were collected from 10 different brain regions of 30 individuals who died from diseases unrelated to viral infections. Nested PCR was used to assess the presence or absence of viral DNA. RESULTS: Ten samples collected from five individuals were found to harbour JCV DNA. In contrast, none of the 300 brain tissues examined showed positive results for BK, KI, WU or Merkel cell polyomavirus. CONCLUSION: The newly identified KI, WU and Merkel cell polyomaviruses either do not, or have a much lower neuropersistent potential compared to JCV.

Seasonal influenza activity in Hong Kong and its association with meteorological variations.

Influenza seasons appear consistently in the temperate regions, but are more variable in tropical/subtropical regions. The determinant for such variation remains poorly understood. This study documented the activity of influenza over a 10-year period in Hong Kong; examining its association with changes in temperature and relative humidity. The two types of influenza exhibited different correlations with meteorological variations. Influenza A showed two seasonal peaks occurring respectively in winter/spring and summer months in most years. Influenza B showed a clear winter/spring peak, but its activity during summer months was more variable. Cold and humid conditions were associated with a higher activity of both influenza A and B. In contrast, hot and humid conditions were associated with a higher activity of influenza A, but were associated with only a moderate, less consistent increase in the activity of influenza B. A trend of increase in the magnitude of summer peaks of influenza A, but not influenza B, was observed. A hypothetical 2 degrees C rise in temperature would decrease the proportion of favorable days for influenza A in December-April from 78% to 57%, but an increase from 58% to 71% in May-November; with a similar effect (from 83% to 62%) for influenza B during December-April, but a modest change (from 17% to 18%) during May-November. The presence of two seasonal peaks of influenza annually emphasizes the need to evaluate the duration of protective immunity offered by vaccination. Further study on the effects of climate change and global warming on the activity of influenza is warranted.

Viral loads and duration of viral shedding in adult patients hospitalized with influenza.

BACKGROUND: The goal of this study was to characterize viral loads and factors affecting viral clearance in persons with severe influenza. METHODS: This was a 1-year prospective, observational study involving consecutive adults hospitalized with influenza. Nasal and throat swabs were collected at presentation, then daily until 1 week after symptom onset. Real-time reverse-transcriptase polymerase chain reaction to determine viral RNA concentration and virus isolation were performed. Viral RNA concentration was analyzed using multiple linear or logistic regressions or mixed-effect models. RESULTS: One hundred forty-seven inpatients with influenza A (H3N2) infection were studied (mean age+/-standard deviation, 72+/-16 years). Viral RNA concentration at presentation positively correlated with symptom scores and was significantly higher than that among time-matched outpatients (control subjects). Patients with major comorbidities had high viral RNA concentration even when presenting>2 days after symptom onset (mean+/-standard deviation, 5.06+/-1.85 vs 3.62+/-2.13 log10 copies/mL; P=.005; beta, +0.86 [95% confidence interval, +0.03 to +1.68]). Viral RNA concentration demonstrated a nonlinear decrease with time; 26% of oseltamivir-treated and 57% of untreated patients had RNA detected at 1 week after symptom onset. Oseltamivir started on or before symptom day 4 was independently associated with an accelerated decrease in viral RNA concentration (mean beta [standard error], -1.19 [0.43] and -0.68 [0.33] log10 copies/mL for patients treated on day 1 and days 2-3, respectively; P<.05) and viral RNA clearance at 1 week (odds ratio, 0.10 [95% confidence interval, 0.03-0.35] and 0.30 [0.10-0.90] for patients treated on day 1-2 and day 3-4, respectively). Conversely, major comorbidities and systemic corticosteroid use for asthma or chronic obstructive pulmonary disease exacerbations were associated with slower viral clearance. Viral RNA clearance was associated with a shorter hospital stay (7.0 vs 13.5 days; P=.001). CONCLUSION: Patients hospitalized with severe influenza have more active and prolonged viral replication. Weakened host defenses slow viral clearance, whereas antivirals started within the first 4 days of illness enhance viral clearance.

Clearance of dengue virus in the plasma-derived therapeutic proteins.

BACKGROUND: Viral safety is of paramount importance for human plasma-derived therapeutic proteins. Recent reports of blood-associated transmission and continuous regional outbreaks of dengue fever have prompted a validation of clearance of dengue virus in the manufacture processes of the plasma-derived products. STUDY DESIGN AND METHODS: A high titer of cultured dengue virus serotype 2 was spiked into process samples before individual steps of albumin and immunoglobulin manufacture processes, including cold ethanol precipitation, cation-exchange chromatography, pasteurization, solvent/detergent treatment, and virus filtration. Clearance of dengue virus was quantified with TCID(50) assays in the culture of Vero E6 cells and, when appropriate, real-time polymerase chain reaction (RT-PCR) assays. RESULTS: The individual process steps were all effective in the inactivation and/or removal of dengue virus, and the data obtained clearly demonstrate that the risk of dengue virus transmission was reduced cumulatively by at least 10.12 and at least 14.24 log in the albumin and immunoglobulin manufacture processes, respectively. CONCLUSION: The dedicated viral inactivation and/or removal approaches currently implemented in the manufacture of plasma-derived products provide a good safety margin with regard to the transmission of dengue virus.

Evaluation of Epstein-Barr virus antigen-based immunoassays for serological diagnosis of nasopharyngeal carcinoma.

BACKGROUND: Immunofluorescence (IF) assays based on Epstein-Barr virus (EBV)-encoded antigens have traditionally been the preferred approach for serological screening of nasopharyngeal carcinoma (NPC). OBJECTIVES: To compare the performance of two new commercial assays (indicated by COMM) using, respectively, the IF and enzyme-linked immunosorbent assay (ELISA) formats with an in-house IF assay (IFA). STUDY DESIGN: Sera from 163 patients with histologically confirmed NPC, and 98 healthy controls were tested with each of these assays and their results compared. RESULTS: The sensitivity, specificity, positive and negative predictive values, respectively, for the COMM VCA IgA ELISA were 92.6%, 94.9%, 96.8%, 88.6%; for the COMM VCA IgA IFA were 96.9%, 41.8%, 73.5%, 89.1%; for the in-house VCA IgA IFA were 98.2%, 72.4%, 85.6%, 95.9%; for the COMM EA IgA ELISA were 46.6%, 100%, 100%, 53.0%; for the COMM EA IgA IFA were 77.3%, 100%, 100%, 72.6%; and for the in-house EA IgA IFA were 77.9%, 99.0%, 99.2%, 72.9%. CONCLUSIONS: The receiver operating characteristic curves comparison showed a marginal superior accuracy for the COMM VCA IgA ELISA, suggesting this to be used as a high-throughput serological screening assay, with the more specific COMM EA IgA IFA as a follow-up confirmatory assay in this NPC-endemic area.

Characterizing 56 complete SARS-CoV S-gene sequences from Hong Kong.

BACKGROUND: The spike glycoprotein (S) gene of the severe acute respiratory syndrome-associated coronavirus (SARS-CoV) has been useful in analyzing the molecular epidemiology of the 2003 SARS outbreaks. OBJECTIVES: To characterize complete SARS-CoV S-gene sequences from Hong Kong. STUDY DESIGN: Fifty-six SARS-CoV S-gene sequences, obtained from patients who presented with SARS to the Prince of Wales Hospital during March-May 2003, were analysed using a maximum likelihood (ML) approach, together with 138 other (both human and animal) S-gene sequences downloaded from GenBank. RESULTS: The maximum-likelihood (ML) trees showed little evolution occurring within these 56 sequences. Analysis with the other sequences, showed three distinct SARS clusters, closely correlated to previously defined early, middle and late phases of the 2003 international SARS outbreaks. In addition, two new single nucleotide variations (SNVs), T21615A and T21901A, were discovered, not previously reported elsewhere. CONCLUSIONS: The ML approach to the reconstruction of tree phylogenies is known to be superior to the more popular, less computationally and time-demanding neighbour-joining (NJ) approach. The ML analysis in this study confirms the previously reported SARS epidemiology analysed mostly using the NJ approach. The two new SNVs reported here are most likely due to the tissue-culture passaging of the clinical samples.

The large 386-nt deletion in SARS-associated coronavirus: evidence for quasispecies?

The severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is reported to have deletions of various sizes. Recently, the large 386-nucleotide deletion (L386del) comprising nucleotide positions 27719-28104 and spanning open reading frames 9-11 has been reported in the genomes of some human isolates from Hong Kong. In this study, archived specimens from 71 patients with SARS who were admitted to the New Territory East Cluster Hospitals in Hong Kong were analyzed to determine whether the L386del variant of SARS-CoV was present. There was no clear relationship between the presence of the L386del variant and SARS clinical severity as defined either by the need for intensive-care therapy and/or ventilation or by death. One patient had evidence of both the L386del variant and the wild-type variant in the same clinical specimen, supporting the idea that SARS-CoV exists as a quasispecies in some patients, although the clinical significance of these quasispecies remains unclear.

Hepatitis C virus genotype distribution among intravenous drug user and the general population in Hong Kong.

This study describes the distribution of hepatitis C genotypes among 106 intravenous drug users and 949 non-drug users in Hong Kong. Genotypes were identified by multiplex RT-PCR targeting the core region of viral genome. The accuracy of this typing system in identifying genotypes 1b and 6a was assessed by phylogenetic analysis. The distribution of hepatitis C virus (HCV) genotypes amongst non-drug users was 63.6% for genotype 1b, 23.6% for 6a, 4.5% for 1a, 3.9% for 3a, and 3.1% for 2a; whereas amongst the intravenous drug users, it was 58.5% for genotype 6a, 33.0% for 1b, 5.7% for 3a, 0.9% for 1a, and 0.9% for 2a. The proportion of genotype 6a was significantly higher (P < 0.001), whereas that for genotype 1b was significantly lower (P = 0.001) for the intravenous drug user group. Multivariate analysis revealed significant independent associations for the distribution of HCV genotypes 1b and 6a with age, sex, and intravenous drug user status. The co-circulation of a common (1b) and a rare (6a) HCV genotype in Hong Kong provides a unique opportunity for future studies to compare their transmission efficiency, clinical course, and response to treatment.