Genetic association of COVID-19 severe versus non-severe cases by RNA sequencing in patients hospitalised in Hong Kong

INTRODUCTION

The coronavirus disease 2019 (COVID-19) pandemic has caused extensive disruption of public health worldwide. There were reports of COVID-19 patients having multiple complications. This study investigated COVID-19 from a genetic perspective.

METHODS

We conducted RNA sequencing (RNA-Seq) analysis of respiratory tract samples from 24 patients with COVID-19. Eight patients receiving mechanical ventilation or extracorporeal membrane oxygenation were regarded as severe cases; the remaining 16 patients were regarded as non-severe cases. After quality control, statistical analyses were performed by logistic regression and the Kolmogorov-Smirnov test to identify genes associated with disease severity.

RESULTS

Six genes were associated with COVID-19 severity in both statistical tests, namely RPL15, BACE1-AS, CEPT1, EIF4G1, TMEM91, and TBCK. Among these genes, RPL15 and EIF4G1 played roles in the regulation of mRNA translation. Gene ontology analysis showed that the differentially expressed genes were mainly involved in nervous system diseases.

CONCLUSION

RNA sequencing analysis showed that severe acute respiratory syndrome coronavirus 2 infection is associated with the overexpression of genes involved in nervous system disorders.

Host inflammatory response is the major marker of severe respiratory syncytial virus infection in older adults

OBJECTIVES

We aim to study the viral kinetics and host inflammatory response of RSV infection in older adults, and their correlation with disease severity.

METHODS

We performed a prospective observational study in adults with RSV infection. We serially collected nasal-throat swabs for quantification of RSV-A and RSV-B viral load, and peripheral blood samples for measurement of cytokine/chemokine concentrations. The study endpoints were (i) requiring supplemental oxygen therapy, and (ii) non-invasive ventilation, intensive care, or died within 30 days of admission. We performed multivariable logistic regression models to identify independent variables for severe disease.

RESULTS

We enrolled 71 hospitalized patients and 10 outpatients treated for RSV infection (median age 75 years, 51% male, and 74% with comorbidities). Among hospitalized patients, 61% required supplemental oxygen therapy, and 18% had severe disease requiring non-invasive ventilation or intensive care, or died within 30 days. Inflammatory cytokine/chemokines IL-6, CXCL8/IL-8, CXCL9/MIG and CXCL10/IP-10 increased significantly during the acute phase of illness. IL-6 concentration was independently associated with severe disease after adjusting for confounding factors. RSV viral load was not associated with disease severity throughout the course of illness.

CONCLUSION

Host inflammatory response is a major marker of severe disease in older adults with RSV infection.

POS0459 UNSUPERVISED CLUSTERING IDENTIFIES UNIQUE SUBSETS OF PATIENTS IN A RACIALLY AND ETHNICALLY DIVERSE RHEUMATOID ARTHRITIS COHORT

Background:

Single biomarkers have limited utility to date in guiding RA clinical care. Machine learning algorithms may better identify and stratify RA patients with differential outcomes.

Objectives:

To determine if unsupervised machine learning methods can be employed in a racially and ethnically diverse RA cohort to identify clusters of patients with different disease activity trajectories, as measured by DAS28ESR.

Methods:

Data are derived from the longitudinal, observational University of California, San Francisco RA Cohort. Along with routine labs, medications and disease activity assessments, a multiple biomarker of disease activity (MBDA) panel was obtained at each visit. The MBDA measures 12 serum biomarkers. Four patient clusters were identified by unsupervised K-prototype clustering after collapsing all observations into a cross sectional dataset. Plots were created to display longitudinal disease activity trajectories for each cluster. Lasso regression was applied to identify biomarkers associated with DAS28ESR.

Results:

We identified 4 distinct clusters in our cohort (Table 1) with visually different disease activity trajectories (Fig. 1). Cluster 1 (n=116) was older (63.6±9.7), had the highest proportion of Asian participants (n=73, 63%) with the most study visits and longest disease duration. Cluster 2 (n=70) had the highest mean DAS28ESR (5.5±0.7), and the highest mean dose of prednisone (8.6±4.9 mg/day). Cluster 3 had the lowest number of participants (n=14), study visits and lowest biologic use (28.6%). Cluster 4 was the largest cluster (n=173) with the shortest disease duration (4.9±3.8 years) and highest biologic use (61.3%). In the Lasso regressions, leptin was found to have significant positive associations with DAS28ESR in the whole group as well as Clusters 2 and 4. EGF had negative associations with DAS28ESR in the whole group, Cluster 1 and 4. CRP had positive associations with DAS28ESR in the whole group and Cluster 1. YKL40 and VCAM1 were found to have significant associations in Clusters 1 and 3, respectively.

Conclusion:

We identified 4 unique clusters of RA patients in a racially and ethnically diverse longitudinal cohort with different disease activity trajectories and biomarkers associated with disease activity. Although additional work is needed to explore longitudinal outcomes in each cluster, the application of machine learning methods may identify unique combinations of patient and disease characteristics influencing RA clinical outcomes.

Table 1.

Demographics and clinical characteristics of the RA cohort. Biomarkers significantly associated with DAS28ESR were determined by Lasso regression Values listed are per standard deviation of each biomarker.

Overall(N=373)Cluster 1 (N=116)Cluster 2 (N=70)Cluster 3 (N=14)Cluster 4 (N=173)Demographics:Age54.8 ± 3.663.6 ± 9.750.8 ± 14.958.2 ± 15.850.3 ± 12.1Female Sex318 (85%)101 (87%)57 (81%)11 (79%)149 (86%)Race: Hispanic/Latino181 (49%)22 (19%)47 (67%)5 (36%)107 (62%) Asian123 (33%)73 (63%)8 (11%)6 (43%)36 (21%) Black35 (9%)12 (10%)8 (11%)2 (14%)13 (8%) White & Other34 (9%)9 (7%)7 (10%)1 (7%)17 (10%)Clinical Characteristics:Rheumatoid Factor315 (85%)104 (90%)56 (80%)13 (93%)142 (82%)ACPA297 (80%)98 (85%)54 (77%)12 (86%)133 (77%)Disease Duration7.8 ± 7.613.7 ± 9.75.4 ± 4.66.7 ± 5.74.9 ± 3.8csDMARD344 (92%)108 (93%)63 (90%)13 (93%)160 (93%)Biologic DMARD185 (50%)45 (39%)30 (43%)4 (29%)106 (61%)Prednisone Dose6.7 ± 3.86.0 ± 4.08.6 ± 4.95.8 ± 1.46.3 ± 2.8Body Mass Index28.2 ± 4.526.6 ± 3.828.7 ± 3.828.0 ± 6.229.1 ± 4.7DAS28ESR4.2 ± 1.14.2 ± 1.05.5 ± 0.83.9 ± 0.83.7 ± 0.9Lasso Results:EGF-0.16*-0.41***-----0.20**Leptin0.15**--0.21*--0.21**c-reactive protein0.34**0.51***------VCAM1-------0.73*--YKL40--0.26*------

-EGF: epidermal growth factor; VCAM1: Vascular cell adhesion protein 1; YKL40: Chitinase-3-like protein 1.

-*p<0.05, **p<0.01, ***p<0.001

Figure 1.

DAS28ESR trajectory plots with 95%CIs for the whole cohort and by cluster.

Acknowledgements:

This work was supported by the Rheumatology Research Foundation Scientist Development Award.

Disclosure of Interests:

None declared

Health Care Transition Perceptions Among Parents of Adolescents with Congenital Heart Defects in Georgia and New York

With increasing survival trends for children and adolescents with congenital heart defects (CHD), there is a growing need to focus on transition from pediatric to adult specialty cardiac care. To better understand parental perspectives on the transition process, a survey was distributed to 451 parents of adolescents with CHD who had recent contact with the healthcare system in Georgia (GA) and New York (NY). Among respondents, 90.7% reported excellent, very good or good health-related quality of life (HRQoL) for their adolescent. While the majority of parents (77.8%) had been told by a provider about their adolescent's need to transition to adult specialty cardiac care, most reported concerns about transitioning to adult care. Parents were most commonly concerned with replacing the strong relationship with pediatric providers (60.7%), locating an appropriate adult provider (48.7%), and accessing adult health insurance coverage (43.6%). These findings may offer insights into transition planning for adolescents with CHD.

Proximity to risk-appropriate perinatal hospitals for pregnant women with congenital heart defects in New York state

Background

Women with congenital heart defects (CHDs) experiencing pregnancies require specialized delivery care and extensive monitoring that may not be available at all birthing hospitals. In this study, we examined proximity to, and delivery at, a hospital with an appropriate level of perinatal care for pregnant women with CHDs and evaluated predictors of high travel distance to appropriate care. Appropriate care was defined as Level 3 perinatal hospitals and Regional Perinatal Centers (RPCs).

Methods

Inpatient delivery records for women with CHD in New York State (NYS) between 2008 and 2013 were obtained. Driving time and transit time were calculated between the pregnant woman’s residence and the actual delivery hospital as well as the closest Level 3 or RPC hospital using Geographic Information Systems (GIS). Linear and logistic regression models evaluated predictors of high distance to, and utilization of, appropriate delivery care respectively.

Results

From 2008 to 2013, there were 909 deliveries in a NYS hospital by women with CHDs. Approximately 75% of women delivered at a Level 3 or RPC hospital. Younger women, those who reside in rural and smaller urban areas, and those who are non-Hispanic White had a greater drive time to an appropriate care facility. After adjustment for geographic differences, racial/ethnic minorities and poor women were less likely to deliver at an appropriate delivery care center.

Conclusions

Although most women with CHDs in NYS receive appropriate delivery care, there are some geographic and socio-demographic differences that require attention to ensure equitable access.

Secondary repair of incompetent pulmonary valves after previous surgery or intervention: Patient selection and outcomes

OBJECTIVES

Pulmonary valve (PV) regurgitation (PR) is common after intervention for a hypoplastic right ventricular outflow tract. Secondary PV repair is an alternative to replacement (PVR), but selection criteria are not established. We sought to elucidate preoperative variables associated with successful PV repair and to compare outcomes between repair and PVR.

METHODS

Patients who underwent surgery for secondary PR from 2010 to 2017 by a single surgeon were studied. The PV annulus and leaflets were measured on the preoperative echocardiogram and magnetic resonance images, and the primary predictor variable was leaflet area indexed to ideal PV annulus area (iPLA) by magnetic resonance imaging. PV repair and PVR groups were compared using multivariable logistic regression, and with a conditional inference tree. Freedom from PV dysfunction and from reintervention were assessed with Kaplan-Meier survival analyses.

RESULTS

Of 85 patients, 31 (36%) underwent PV repair. By multivariable analysis, longer PV total leaflet length (cm/m²) (β = 3.00, standard error [SE] = 0.82, P < .001), larger PV z score (β = 1.34, SE = 0.39, P = .001), and larger iPLA (β = 8.13, SE = 2.62, P = .002) were associated with repair. iPLA of 0.90 or greater was 91% sensitive and 83% specific for achieving PV repair. At a median of 4.1 years follow-up, there was greater freedom from significant PR in the PV repair group (log rank P = .008).

CONCLUSIONS

Patients with an iPLA >0.9, and those with an iPLA between 0.7 and 0.9 with a PV annulus z score >0 should be considered for a native PV repair. At midterm follow-up, patients with a PV repair were not more likely to develop PR or to require reintervention when compared with patients undergoing PVR.

Population-based surveillance of congenital heart defects among adolescents and adults: surveillance methodology

BACKGROUND

Improved treatment of congenital heart defects (CHDs) has increased survival of persons with CHDs; however, no U.S. population-based systems exist to assess prevalence, healthcare utilization, or longer-term outcomes among adolescents and adults with CHDs.

METHODS

Novel approaches identified individuals aged 11-64 years who received healthcare with ICD-9-CM codes for CHDs at three sites: Emory University in Atlanta, Georgia (EU), Massachusetts Department of Public Health (MA), New York State Department of Health (NY) between January 1, 2008 (2009 for MA) and December 31, 2010. Case-finding sources included outpatient clinics; Medicaid and other claims data; and hospital inpatient, outpatient, and emergency visit data. Supplemental information came from state vital records (EU, MA), and birth defects registries (EU, NY). Demographics and diagnostic and procedural codes were linked, de-duplicated, and shared in a de-identified dataset. Cases were categorized into one of five mutually exclusive CHD severity groups; non-cardiac comorbidity codes were grouped into broad categories.

RESULTS

73,112 individuals with CHD codes in healthcare encounters were identified. Primary data source type varied: clinics (EU, NY for adolescents), claims (MA), hospital (NY for adults). There was a high rate of missing data for some variables and data varied in format and quality. Some diagnostic codes had poor specificity for CHD ascertainment.

CONCLUSIONS

To our knowledge, this is the first population-based, multi-site CHD surveillance among adolescents and adults in the U.S. Identification of people living with CHDs through healthcare encounters using multiple data sources was feasible, though data quality varied and linkage/de-duplication was labor-intensive.

Liver fibrosis and fatty liver in Asian HIV-infected patients

BACKGROUND

Little is known about the importance of liver fibrosis and fatty liver in HIV-monoinfected individuals without hepatitis virus co-infection, particularly among the Asian population.

AIM

To evaluate prevalence and risk factors for liver fibrosis and fatty liver in Asian HIV-monoinfected individuals.

METHODS

Eighty asymptomatic HIV-monoinfected individuals (tested negative for HBV/HCV) were compared with 160 matched HIV-uninfected healthy controls. Transient elastography and proton-magnetic resonance spectroscopy ((1) H-MRS) were performed to measure liver stiffness and hepatic steatosis respectively. Blood samples were analysed for metabolic profiles and markers of steatohepatitis (e.g. cytokeratin-18).

RESULTS

All HIV-infected individuals (mean ± s.d. age 54 ± 11 years, male 93%, Chinese 94%; diagnosis median duration 8 (IQR 4-13 years) were stable on anti-retrovirals (PI-based 58.7%, NNRTI-based 25.0% integrase-inhibitors 16.3%); diabetes, dyslipidaemia, and metabolic syndrome were common. Fatty liver disease was detected in 28.7%. There was significantly higher degree of liver stiffness [4.9 (IQR 4.1-6.2) kPa vs. 4.2 (IQR 3.6-5.0) kPa, P < 0.001], and greater proportions developed significant fibrosis (7.0 kPa, 14.3% vs. 3.1%, P = 0.001) and cirrhosis (10.3 kPa, 5.2% vs. 0.6%, P = 0.040) compared with controls. HIV infection was an independent risk factor for significant fibrosis (adjusted OR 4.00, 95% CI 1.29-12.41, P = 0.016). HIV-infected individuals with fatty liver had excessive liver stiffness and fibrosis. Two cases of asymptomatic hepatocellular carcinoma were detected.

CONCLUSIONS

HIV-monoinfected patients are at risk for liver fibrosis and cirrhosis. HIV-related mechanisms and fatty liver disease may play important roles. Screening and intervention to prevent severe outcomes should be considered.

Usefulness of the Seattle Heart Failure Model to identify adults with congenital heart disease at high risk of poor outcome

Our objective was to determine whether the Seattle Heart Failure Model (SHFM) differentiates patients with adult congenital heart disease (ACHD) at high versus low risk for cardiovascular outcomes and poor exercise capacity. The ACHD population is growing and presents increasingly for care in the community and at tertiary centers. Few strategies exist to identify the patients with ACHD at high risk for heart failure and mortality.We studied 153 adults with transposition of the great arteries, Ebstein anomaly, tetralogy of Fallot, double outlet right ventricle, and single ventricle from 2 ACHD centers. The primary outcome was cardiovascular death, with a secondary composite outcome of death, transplant, ventricular assist device, cardiovascular admission, and treatment for arrhythmia. We defined risk groups based on SHFM 5-year predicted survival: high (predicted survival <70%), intermediate (70% to 85%), and low risk (>85%). Ten patients had the primary outcome of death, and 46 the combined end point. The hazard of death in the SHFM high- versus the intermediate-risk group was 7.09 (95% confidence interval 1.5 to 33.4, p = 0.01; no deaths in the low-risk group) and the hazard of the composite outcome between the high- versus low-risk group was 6.64 (95% confidence interval 2.5 to 17.6, p = 0.0001). Kaplan-Meier survival analysis showed greater probability of all-cause mortality (p = 0.003) in the high-risk group. In conclusion, the SHFM can help identify subjects with ACHD at risk for adverse outcome and poor cardiopulmonary efficiency. This may add to the care of patients with ACHD in the community and streamline care at tertiary centers.

Frequent detection of plasmid-mediated quinolone resistance (qnr) genes in multidrug-resistant Enterobacteriaceae blood isolates, Hong Kong

Plasmid-mediated quinolone resistance (qnr) genes confer low-level resistance but provide background for selection of highly-resistant strains. We investigated their prevalence and significance in clinical Enterobacteriaceae bacteremic isolates in Hong Kong. A prospective, hospital-based study was conducted (January 2008 to March 2009). Consecutive, non-duplicate blood isolates of extended-spectrum-β-lactamase (ESBL) and/or plasmid-mediated AmpC (PMAmpC) β-lactamase-producing Enterobacteriaceae were collected and subjected to qnr genes detection using multiplex PCR. Direct sequencing was performed to characterize the qnr and the co-existing bla genes. Clinical and microbiological variables, including antimicrobial resistance profiles, were compared between infections by 'qnr-positive' and 'qnr-negative' Enterobacteriaceae. Altogether 199 ESBL/PMAmpC-producing Enterobacteriaceae isolates were studied. qnr genes were detected in 20 % (qnrB, n = 24; qnrS, n = 16; qnrA, n = 0), of which 85% were Klebsiella spp. There was a strong association with PMAmpC genes (qnrB and DHA-1; p < 0.001). 'qnr-positive' isolates were more commonly hospital-acquired (60.0% vs 35.8%; adjusted OR 2.68, 95%CI 1.32-5.46) and multidrug-resistant (e.g. amoxicillin-clavulanate 90-100%, piperacillin-tazobactam 40-57%, ceftazidime 53-78%; sulfamethoxazole/trimethoprim 60-70%; ciprofloxacin 53-65%, levofloxacin 35-48%). Patients with 'qnr-positive' Enterobacteriaceae bacteremia had a higher 30-day mortality (45% vs 22%, p = 0.003). High Pitt bacteremia score, development of pneumonia, and failure to receive susceptible fluoroquinolone (adjusted HR 4.27; 95%CI 1.45-12.61) or carbapenem (adjusted HR 3.04; 95%CI 1.49-6.20) treatment were independent factors associated with death. A high proportion of ESBL/PMAmpC-producing Enterobacteriaceae (typically Klebsiella) bacteremic isolates carried qnr. These strains were multidrug-resistant, which was associated with inappropriate treatment and high fatality. Further dissemination of qnr and selection of fluoroquinolone/β-lactam-resistant strains should be closely monitored and controlled.

Not all obstructive cardiac lesions are created equal: double-chamber right ventricle in pregnancy

Double-chambered right ventricle (DCRV) is a rare form of right ventricular outflow tract (RVOT) obstruction accounting for approximately 1% of patients with congenital heart disease. It consists of an anomalous muscle bundle that divides the right ventricle usually between the sinus (inlet) and the infundibulum (outlet). This division creates a proximal chamber with high pressure and a distal chamber with low pressure. The hemodynamic obstruction of the RVOT is usually an acquired phenomenon, however the substrate for the anomalous muscle bundle is likely congenital. The diagnosis of DCRV should be considered in the young patient with an elevated right ventricular systolic pressure and intracavitary gradient. Echocardiography and cardiac MRI are the principal diagnostic tools for the assessment of DCRV. This entity is often misdiagnosed as pulmonary hypertension in the young patient, and can often go overlooked and untreated for many years. Definitive therapy involves surgical resection of the muscle bundle. This can often be curative and if done in a timely fashion, may prevent right ventricular remodeling. We describe the unique diagnostic dilemma, the course and management of a young adult with DCRV during pregnancy.

Interferon gamma release assay for differentiating tuberculosis among pneumonia cases in acute healthcare setting

OBJECTIVES

Early diagnosis of smear-negative tuberculosis remains challenging. The role of an interferon-gamma release assay (IGRA) in discriminating active pulmonary tuberculosis (PTB) among cases of 'pneumonia' was investigated.

METHODS

Consecutive patients admitted to an acute hospital in Hong Kong (intermediate TB burden) during 2006-2008 because of pneumonia and suspected PTB were recruited for IGRA (Quantiferon-TB Gold, QFN-G) study. Diagnosis of tuberculosis was confirmed by mycobacterial culture or histology.

RESULTS

Altogether 179 patients were recruited (median (IQR) age 59 (44-75), 68.7% male); active PTB was confirmed in 63 (35.2%). Among the AFB-smear-negative 'pneumonias' (n = 152), age>50 (OR 0.27, 95% CI 0.09-0.84), absence of weight loss (OR 0.30, 95% CI 0.10-0.88), and negative IGRA (OR 0.08, 95% CI 0.03-0.25) were independently associated with lower risks of PTB. The overall sensitivity, specificity, positive and negative predictive values for the IGRA in diagnosing active PTB were 60%, 87%, 72% and 80% respectively. Among smear-negative 'pneumonias' (n = 152), the performance values of IGRA were 64%, 87%, 62% and 88% respectively; in the absence of characteristic clinical or radiographic features of PTB, the negative predictive value (NPV) improved to 90-95%.

CONCLUSIONS

The high NPV of QFN-G among smear-negative 'pneumonias' can be useful for risk stratification in hospitalized patients suspected of PTB. Further investigation on the role of these assays in patient management is warranted.

Prevalence of left ventricular systolic dysfunction in adults with repaired tetralogy of fallot

Left ventricular (LV) systolic dysfunction has been observed in patients with repaired tetralogy of Fallot (TOF), although its clinical associations are unknown. Adults with repaired TOF were identified from 11 adult congenital heart disease centers. Clinical history was reviewed. Patients with pulmonary atresia were excluded. Echocardiograms were reanalyzed to estimate LV ejection fraction. LV function was defined as normal (LV ejection fraction ≥ 55%) or mildly (45% to 54%), moderately (35% to 44%), or severely (< 35%) decreased. Right ventricular (RV) and LV dimensions and Doppler parameters were remeasured. Function of all valves was qualitatively scored. Of 511 patients studied, LV systolic dysfunction was present in 107 (20.9%, 95% confidence interval 17.4 to 24.5). Specifically, 74 (14.4%) had mildly decreased and 33 (6.3%) had moderately to severely decreased systolic function. Presence of moderate to severe LV dysfunction was associated with male gender, LV enlargement, duration of shunt before repair, history of arrhythmia, QRS duration, implanted cardioverter-defibrillator, and moderate to severe RV dysfunction. Severity or duration of pulmonary regurgitation was not different. In conclusion, LV systolic dysfunction was found in 21% of adult patients with TOF and was associated with shunt duration, RV dysfunction, and arrhythmia.

Arrhythmia Burden in Adults With Surgically Repaired Tetralogy of Fallot

Background— The arrhythmia burden in tetralogy of Fallot, types of arrhythmias encountered, and risk profile may change as the population ages.

Methods and Results— The Alliance for Adult Research in Congenital Cardiology (AARCC) conducted a multicenter cross-sectional study to quantify the arrhythmia burden in tetralogy of Fallot, to characterize age-related trends, and to identify associated factors. A total of 556 patients, 54.0% female, 36.8±12.0 years of age were recruited from 11 centers. Overall, 43.3% had a sustained arrhythmia or arrhythmia intervention. Prevalence of atrial tachyarrhythmias was 20.1%. Factors associated with intraatrial reentrant tachycardia in multivariable analyses were right atrial enlargement (odds ratio [OR], 6.2; 95% confidence interval [CI], 2.8 to 13.6), hypertension (OR, 2.3; 95% CI, 1.1 to 4.6), and number of cardiac surgeries (OR, 1.4; 95% CI, 1.2 to 1.6). Older age (OR, 1.09 per year; 95% CI, 1.05 to 1.12), lower left ventricular ejection fraction (OR, 0.93 per unit; 95% CI, 0.89 to 0.96), left atrial dilation (OR, 3.2; 95% CI, 1.5 to 6.8), and number of cardiac surgeries (OR, 1.5; 95% CI, 1.2 to 1.9) were jointly associated with atrial fibrillation. Ventricular arrhythmias were prevalent in 14.6% and jointly associated with number of cardiac surgeries (OR, 1.3; 95% CI, 1.1 to 1.6), QRS duration (OR, 1.02 per 1 ms; 95% CI, 1.01 to 1.03), and left ventricular diastolic dysfunction (OR, 3.3; 95% CI, 1.5 to 7.1). Prevalence of atrial fibrillation and ventricular arrhythmias markedly increased after 45 years of age.

Conclusions— The arrhythmia burden in adults with tetralogy of Fallot is considerable, with various subtypes characterized by different profiles. Atrial fibrillation and ventricular arrhythmias appear to be influenced more by left- than right-sided heart disease.

Whole lymphoma B cells allow efficient cross-presentation of antigens by dendritic cells

BACKGROUND

In order to compensate for the paucity of defined tumor antigens (Ag) in non-Hodgkin's lymphomas, a promising approach might be the use of whole tumor cells as a source of tumor Ag to pulse antigen-presenting cells (APC). However, it is not presently known how the tumor cells should be delivered to APC to optimize the cross-presentation of tumor Ag to anti-tumor CD8 T cells. We aimed to compare CD20-opsonized, apoptotic and necrotic human tumor cells for their capacity to induce endocytosis and cross-presentation of tumor-associated Ag by dendritic cells (DC) or macrophages.

METHODS

Endocytosis of human tumor-derived material by macrophages or DC was monitored by flow cytometry. We used a previously described influenza model and studied cross-presentation of viral Ag as cellular surrogate tumor-associated Ag by APC after endocytosis of lymphoma B cells treated by inactivated influenza virus.

RESULTS

Optimal endocytosis was obtained when tumor cells were opsonized by an anti-CD20 antibody and, as expected, macrophages were more phagocytic than DC. However, Ag from opsonized, apoptotic and live cells, but not from necrotic lymphoma cells, were efficiently cross-presented by DC but not by macrophages.

DISCUSSION

We have developed a new model with human primary lymphoma cells to study the cross-presentation of tumor-associated Ag by APC. The results we have obtained support the use of whole lymphoma cells from patients to pulse DC to induce an anti-tumor immune response.

Co-circulation of human metapneumovirus and SARS-associated coronavirus during a major nosocomial SARS outbreak in Hong Kong

Background

The clinico-epidemiological significance of human metapneumovirus (hMPV) detected during the SARS outbreak is unknown.

Objectives

To characterize a nosocomial hMPV outbreak during the 2003 SARS epidemic.

Study design and methods

All available nasopharyngeal aspirate (NPA) collected from confirmed patients during the first 8 weeks of the SARS outbreak in 2003 were tested for hMPV by a nested RT-PCR assay targeting the F-gene. Clinico-epidemiological information was used to analyze the relationship of hMPV co-infection to specific risk factors (demographics/symptoms/outcomes; status as health-care workers (HCWs)/patients; history of exposure/contact; ward location). Multivariate logistic regression analysis was performed to determine independent risk factors.

Results

An hMPV outbreak occurred during 6–16 March 2003 (first week of the Hong Kong SARS epidemic). hMPV RNA was detected in 31 of 155 (20%) NPAs from SARS patients. HCW status (OR 2.72, 95% CI 1.11–6.68; p = 0.029) or epidemiological linkage to the SARS outbreak ward (OR 3.59, 95% CI 1.42–9.05; p = 0.007) were independent factors associated with hMPV infection. Symptoms of cough and coryza were more common in co-infected individuals (22.6% vs. 15.9%) but this was not statistically significant. Other clinical manifestations and outcomes were not different in co-infected patients.

Conclusions

A major nosocomial hMPV outbreak involving HCWs occurred during the early SARS epidemic. Patients with dual hMPV and SARS infection were not sicker than those with SARS infection only.

Hypercytokinemia and hyperactivation of phospho-p38 mitogen-activated protein kinase in severe human influenza A virus infection

BACKGROUND

We postulate that hypercytokinemia plays a role in immunopathogenesis of severe human influenza.

METHODS

We 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.

RESULTS

Statistically 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.

CONCLUSIONS

Hypercytokinemia (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.

Role of laboratory variables in differentiating SARS-coronavirus from other causes of community-acquired pneumonia within the first 72 h of hospitalization

The Centers for Disease Control and Prevention (CDC) recommend that SARS-coronavirus (SARS-CoV) testing be considered in epidemiologically high-risk patients hospitalized with community-acquired pneumonia (CAP) if no alternative diagnosis is identified after 72 h. The aim of this study was to identify routine laboratory variables that might indicate the need for SARS-CoV testing. Routine hematological/biochemical variables in patients with laboratory-confirmed SARS (2003) were compared with those in consecutive patients hospitalized June–December 2004 with radiologically confirmed CAP. Stepwise logistic regression analyses were performed to identify discriminating variables at baseline and by day 3 of hospitalization. Nasopharyngeal aspiration and antigen detection for influenza virus and respiratory syncytial virus using an immunofluorescence assay (IFA) were routinely performed in patients with CAP. Altogether, 181 patients with CAP (who remained undiagnosed by IFA) and 303 patients with SARS were studied. The mean intervals from symptom onset to admission were 3.1 and 2.8 days, respectively (p > 0.05). The etiological agent of CAP was identified retrospectively in only 39% of cases, the majority being bacterial pathogens. At baseline, age and absolute neutrophil count (ANC) were the only independent discriminating variables (p < 0.0001). Using a value of <4.4 × 10⁹/l as the cutoff for ANC, the sensitivity and specificity of ANC for discriminating SARS were 64 and 95%, respectively (AUC 0.90). By day 3 of hospitalization, age (p < 0.0001), change in ANC (p = 0.0003), and change in bilirubin (p = 0.0065) were discriminating variables. A model combining age <65 years, a change in ANC of >−3 × 10⁹/l, and a change in bilirubin of ≥0 mmol/l had a sensitivity of 43% and a specificity of 95% for SARS (AUC 0.90). There are only a few laboratory features (including lymphopenia) that clearly discriminate SARS from other causes of CAP. Nevertheless, when evaluating epidemiologically high-risk patients with CAP and no immediate alternative diagnosis, a low ANC on presentation along with poor clinical and laboratory responses after 72 h of antibiotic treatment may raise the index of suspicion for SARS and indicate a need to perform SARS-CoV testing.

Cryptococcosis in apparently immunocompetent patients

BACKGROUND

Few reports have described the clinical and microbiological features of cryptococcosis in immunocompetent patients.

AIM

To compare clinical presentations and outcomes of cryptococcosis in immunocompetent vs. immunocompromised patients.

DESIGN

Retrospective case series.

METHODS

All culture- or histology-confirmed cases (n = 46) of cryptococcosis in two acute hospitals in Hong Kong (1995-2005) were included. Clinical presentations, rates of fungaemia, cerebrospinal fluid (CSF) parameters and clinical outcomes were recorded.

RESULTS

Twenty patients (43.5%) were apparently immunocompetent, 17 (37.0%) had predisposing factors other than HIV infection, and 9 (19.6%) were HIV-positive. Thirty-one (67.4%) presented with meningitis, four (8.7%) with pulmonary cryptococcosis, and 11 (23.9%) with extraneural, extrapulmonary cryptococcosis. Of the immunocompetent patients with retrievable isolates (n = 8), three (37.5%) were Cryptococcus gattii; all isolates (n = 6) from immunocompromised patients were Cryptococcus neoformans var. grubii. Immunocompetent patients more commonly presented with meningitis (80.0% vs. 47.1%, p = 0.03), and tended toward lower rates of fungaemia (10.0% vs. 35.3%, p = 0.06) and mortality (25.0% vs. 52.9%, p = 0.06). Death was associated with fungaemia (p = 0.01) and underlying malignancy (p < 0.01). In cryptococcal meningitis, immunocompetent patients had longer mean time from illness onset to presentation (34.4 vs. 12.6 days, p = 0.02), more intense inflammatory responses (CSF: white blood cells 108 vs. 35 x 10(9)/l, p = 0.03; protein 1.61 g/l vs. 0.79 g/l, p = 0.07), less fungaemia (0% vs. 26.7%, p = 0.04) and more satisfactory clinical outcomes (81.3% vs. 46.7%, p = 0.04).

DISCUSSION

A substantial proportion of patients with cryptococcosis are apparently immunocompetent. C. neoformans var. grubii and C. gattii are the common causes. Immunocompetent patients tend to present with localized, indolent neurological disease, with more intense inflammatory responses but better clinical outcomes.

Preparation of purified lymphoma cells suitable for therapy

BACKGROUND

Very few tumoral Ags have yet been isolated in NHL B cells. It is nevertheless possible to use whole tumor cells as a source of tumor Ags. We describe the purification of large numbers of human NHL B cells directly from lymph node or spleen biopsies, and different preparations allowing their use in a clinical setting.

METHODS

The purification procedure consists of the negative selection of tumor B cells: cells to be eliminated are opsonized by CD2 Abs, and then coupled to magnetic beads for separation by the Isolex 300 magnetic separator.

RESULTS

The mean yield of the purification was 74% for CD19+ cells, with a mean purity of 87%, dependent on the initial fraction of tumor cells in the biopsy. Using this procedure, a large number of purified tumor cells can be recovered from a biopsy in sterile conditions. We also describe treatments of B cells that can enhance their uptake by APCs, a critical step in anti-tumor immunotherapy strategies. Cells were opsonized by rituximab, or induced in apoptosis by irradiation, or necrosis by heating. Cell lysates were directly prepared from purified tumor cells.

DISCUSSION

These procedures were reproducible on every lymphoma cell, and treated cells were phagocytosed by APCs. The methodology described here allows the evaluation of the immunological potential of apoptotic, necrotic, opsonized lymphoma cells, or their lysates, in a clinical setting.

Growth and differentiation of human lens epithelial cells in vitro on matrix

PURPOSE

To characterize the growth and maturation of nonimmortalized human lens epithelial (HLE) cells grown in vitro.

METHODS

HLE cells, established from 18-week prenatal lenses, were maintained on bovine corneal endothelial (BCE) extracellular matrix (ECM) in medium supplemented with basic fibroblast growth factor (FGF-2). The identity, growth, and differentiation of the cultures were characterized by karyotyping, cell morphology, and growth kinetics studies, reverse transcription-polymerase chain reaction (RT-PCR), immunofluorescence, and Western blot analysis.

RESULTS

HLE cells had a male, human diploid (2N = 46) karyotype. The population-doubling time of exponentially growing cells was 24 hours. After 15 days in culture, cell morphology changed, and lentoid formation was evident. Reverse transcription-polymerase chain reaction (RT-PCR) indicated expression of alphaA- and betaB2-crystallin, fibroblast growth factor receptor 1 (FGFR1), and major intrinsic protein (MIP26) in exponential growth. Western analyses of protein extracts show positive expression of three immunologically distinct classes of crystallin proteins (alphaA-, alphaB-, and betaB2-crystallin) with time in culture. By Western blot analysis, expression of p57(KIP2), a known marker of terminally differentiated fiber cells, was detectable in exponential cultures, and levels increased after confluence. MIP26 and gamma-crystallin protein expression was detected in confluent cultures, by using immunofluorescence, but not in exponentially growing cells.

CONCLUSIONS

HLE cells can be maintained for up to 4 months on ECM derived from BCE cells in medium containing FGF-2. With time in culture, the cells demonstrate morphologic characteristics of, and express protein markers for, lens fiber cell differentiation. This in vitro model will be useful for investigations of radiation-induced cataractogenesis and other studies of lens toxicity.

Biological availability and nuclease resistance extend the in vitro activity of a phosphorothioate-3'hydroxypropylamine oligonucleotide

Augmented biological activity in vitro has been demonstrated in oligonucleotides (oligos) modified to provide nuclease resistance, to enhance cellular uptake or to increase target affinity. How chemical modification affects the duration of effect of an oligo with potent activity has not been investigated directly. We postulated that modification with internucleotide phosphorothioates and 3' alkylamine provided additional nuclease protection which could significantly extend the biological activity of a 26 mer, (T2). We showed this analog, sT2a, could maximally inhibit interferon gamma-induced HLA-DR mRNA synthesis and surface expression in both HeLa and retinal pigmented epithelial cells and could continue to be effective, in the absence of oligo, 15 days following initial oligo treatment; an effect not observed with its 3'amine counterpart, T2a. In vitro stability studies confirmed that sT2a conferred the greatest stability to nucleases and that cellular accumulation of 32P-sT2a in both cell types was also greater than other T2 oligos. Using confocal microscopy, we revealed that the intracellular distribution of sT2a favored greater nuclear accumulation and release of oligo from cytoplasmic vesicles; a pattern not observed with T2a. These results suggest that phosphorothioate-3'amine modification could increase the duration of effect of T2 oligo by altering nuclease resistance as well as intracellular accumulation and distribution; factors known to affect biological availability.

[D-Pen2,D-Pen5]enkephalin analogues with increased affinity and selectivity for delta opioid receptors

The conformationally restricted, cyclic disulfide-containing enkephalin analogue [D-Pen2,D-Pen5]enkephalin (DPDPE) was modified by halogenation (F, Cl, Br, I) of the phenylalanine-4 residue in the para position. The potency and selectivity of these analogues for the delta opioid receptor was greater than that of the parent peptide. The analogues possessed greater potency and affinity for the delta receptors than DPDPE in the mouse vas deferens assay and in radioreceptor assays (against [3H]DPDPE), respectively. [p-ClPhe4]DPDPE was the most selective in the radioligand binding assays (IC50(mu)/IC50(delta) = 574), being about 5-fold more delta opioid receptor selective than DPDPE in this assay, whereas [p-IPhe4]DPDPE was the most selective in the classical bioassay systems using the mouse vas deferens and guinea pig ileum assays (IC50(GPI)/IC50(MVD) = 17,374), making it nearly 9-fold more selective than DPDPE in direct comparisons using the same assay conditions.