Comparative analysis of the efficacy of vaccines using structural protein subunits of the severe fever with thrombocytopenia syndrome virus

The severe fever with thrombocytopenia syndrome virus (SFTSV) represents a significant emerging health threat as a tick-borne pathogen that causes SFTS, with mortality rates ranging between 10 and 30%. Despite the considerable risk presented by SFTSV, an effective vaccine has yet to be developed. Our study assessed the efficacy of recombinant protein vaccines, focusing on the purified nucleocapsid protein (NP) and surface glycoproteins (Gn and Gc), against SFTSV in both singular and combined formulations. Individual vaccinations with NP or Gn subunits yielded partial protection in type I interferon receptor-knockout (IFNAR-KO) mice, with survival rates of 66.7 and 16.7%, respectively, whereas Gc vaccination did not confer significant protection, resulting in 100% mortality similar to that of the unvaccinated control group. Notably, NP vaccination substantially enhanced antigen-specific T cell responses, and Gc vaccination exhibited strong neutralizing activity against SFTSV. Among the combined recombinant protein formulations (Gn + NP, Gc + NP, and Gn + Gc + NP) tested, the Gc + NP combination provided the highest survival rate (85.7%) following challenge with a lethal dose of SFTSV, highlighting its potential as a vaccine candidate. Longitudinal studies showed that antibody levels in both wild type C57BL/6 and IFNAR-KO mice peaked between 2 and 3 months post-vaccination and declined over time. A notable decrease in NP-specific CD8+ T cell responses was observed 6 months post-vaccination in C57BL/6 mice, while NP-specific CD4+ T cell responses persisted up to 12 months. By 12 months post-vaccination, all IFNAR-KO mice vaccinated with single subunit antigens succumbed to the virus, suggesting that effective protection against SFTS may rely on antibody responses to subunit antigens and/or CD8+ T cell activity. These findings underscore the necessity of an optimized SFTS vaccine that combines protective antigens with an adjuvant system to ensure durable humoral and cellular immunity.

Rise in broadly cross-reactive adaptive immunity against human β-coronaviruses in MERS-recovered patients during the COVID-19 pandemic

To develop a universal coronavirus (CoV) vaccine, long-term immunity against multiple CoVs, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, Middle East respiratory syndrome (MERS)-CoV, and future CoV strains, is crucial. Following the 2015 Korean MERS outbreak, we conducted a long-term follow-up study and found that although neutralizing antibodies and memory T cells against MERS-CoV declined over 5 years, some recovered patients exhibited increased antibody levels during the COVID-19 pandemic. This likely resulted from cross-reactive immunity induced by SARS-CoV-2 vaccines or infections. A significant correlation in antibody responses across various CoVs indicates shared immunogenic epitopes. Two epitopes-the spike protein's stem helix and intracellular domain-were highly immunogenic after MERS-CoV infection and after SARS-CoV-2 vaccination or infection. In addition, memory T cell responses, especially polyfunctional CD4+ T cells, were enhanced during the pandemic, correlating significantly with MERS-CoV spike-specific antibodies and neutralizing activity. Therefore, incorporating these cross-reactive and immunogenic epitopes into pan-CoV vaccine formulations may facilitate effective vaccine development.

mRNA vaccine encoding Gn provides protection against severe fever with thrombocytopenia syndrome virus in mice

We developed a promising mRNA vaccine against severe fever with thrombocytopenia syndrome (SFTS), an infectious disease caused by the SFTS virus that is primarily transmitted through tick bites. Administration of lipid nanoparticle-encapsulated mRNA-Gn successfully induced neutralizing antibodies and T-cell responses in mice. The vaccinated mice were protected against a lethal SFTS virus challenge, suggesting that this mRNA vaccine may be an effective and successful SFTS vaccine candidate.

Genome-informed investigation of the molecular evolution and genetic reassortment of severe fever with thrombocytopenia syndrome virus

BACKGROUND

Severe fever with thrombocytopenia syndrome virus (SFTSV) is a viral pathogen causing significant clinical signs from mild fever with thrombocytopenia to severe hemorrhages. World Health Organization has paid special attention to the dramatic increase in human SFTS cases in China, Japan, and South Korea since the 2010s. The present study investigated the molecular evolution and genetic reassortment of SFTSVs using complete genomic sequences.

METHODS/PRINCIPAL FINDING

We collected the complete genome sequences of SFTSVs globally isolated until 2019 (L segment, n = 307; M segment, n = 326; and S segment, n = 564) and evaluated the evolutionary profiles of SFTSVs based on phylogenetic and molecular selection pressure analyses. By employing a time-scaled Bayesian inference method, we found the geographical heterogeneity of dominant SFTSV genotypes in China, Japan, and South Korea around several centuries before and locally spread by tick-born spillover with infrequent long-distance transmission. Purifying selection predominated the molecular evolution of SFTSVs with limited gene reassortment and fixed substitution, but almost all three gene segments appeared to harbor at least one amino acid residue under positive selection. Specifically, the nonstructural protein and glycoprotein (Gn/Gc) genes were preferential selective targets, and the Gn region retained the highest number of positively selected residues.

CONCLUSION/SIGNIFICANCE

Here, the large-scale genomic analyses of SFTSVs improved prior knowledge of how this virus emerged and evolved in China, Japan, and South Korea. Our results highlight the importance of SFTSV surveillance in both human and non-human reservoirs at the molecular level to fight against fatal human infection with the virus.

A natural variation in the RNA polymerase of severe fever with thrombocytopenia syndrome virus enhances viral replication and in vivo virulence

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne disease with high mortality in Eastern Asia. The disease is caused by the SFTS virus (SFTSV), also known as Dabie bandavirus, which has a segmented RNA genome consisting of L, M, and S segments. Previous studies have suggested differential viral virulence depending on the genotypes of SFTSV; however, the critical viral factor involved in the differential viral virulence is unknown. Here, we found a significant difference in viral replication in vitro and virulence in vivo between two Korean isolates belonging to the F and B genotypes, respectively. By generating viral reassortants using the two viral strains, we demonstrated that the L segment, which encodes viral RNA-dependent RNA polymerase (RdRp), is responsible for the enhanced viral replication and virulence. Comparison of amino acid sequences and viral replication rates revealed a point variation, E251K, on the surface of RdRp to be the most significant determinant for the enhanced viral replication rate and in vivo virulence. The effect of the variation was further confirmed using recombinant SFTSV generated by reverse genetic engineering. Therefore, our results indicate that natural variations affecting the viral replicase activity could significantly contribute to the viral virulence of SFTSV.

Heterologous vaccination utilizing viral vector and protein platforms confers complete protection against SFTSV

Severe fever with thrombocytopenia syndrome virus was first discovered in 2009 as the causative agent of severe fever with thrombocytopenia syndrome. Despite its potential threat to public health, no prophylactic vaccine is yet available. This study developed a heterologous prime-boost strategy comprising priming with recombinant replication-deficient human adenovirus type 5 (rAd5) expressing the surface glycoprotein, Gn, and boosting with Gn protein. This vaccination regimen induced balanced Th1/Th2 immune responses and resulted in potent humoral and T cell-mediated responses in mice. It elicited high neutralizing antibody titers in both mice and non-human primates. Transcriptome analysis revealed that rAd5 and Gn proteins induced adaptive and innate immune pathways, respectively. This study provides immunological and mechanistic insight into this heterologous regimen and paves the way for future strategies against emerging infectious diseases.

Enhancing immune protection against MERS-CoV: the synergistic effect of proteolytic cleavage sites and the fusion peptide and RBD domain targeting VLP immunization

Introduction

The Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is a zoonotic infectious virus that has caused significant outbreaks in the Middle East and beyond. Due to a highly mortality rate, easy transmission, and rapid spread of the MERS-CoV, it remains as a significant public health treat. There is currently no licensed vaccine available to protect against MERS-CoV.

Methods

In this study, we investigated whether the proteolytic cleavage sites and fusion peptide domain of the MERS-CoV spike (S) protein could be a vaccine target to elicit the MERS-CoV S protein-specific antibody responses and confer immune protection against MERS-CoV infection. Our results demonstrate that immunization of the proteolytic cleavage sites and the fusion peptide domain using virus-like particle (VLP) induced the MERS-CoV S protein-specific IgG antibodies with capacity to neutralize pseudotyped MERS-CoV infection in vitro. Moreover, proteolytic cleavage sites and the fusion peptide VLP immunization showed a synergistic effect on the immune protection against MERS-CoV infection elicited by immunization with VLP expressing the receptor binding domain (RBD) of the S protein. Additionally, immune evasion of MERS-CoV RBD variants from anti-RBD sera was significantly controlled by anti-proteolytic cleavage sites and the fusion peptide sera.

Conclusion and discussion

Our study demonstrates the potential of VLP immunization targeting the proteolytic cleavage sites and the fusion peptide and RBD domains of the MERS-CoV S protein for the development of effective treatments and vaccines against MERS-CoV and related variants.

Elevated IFNA1 and suppressed IL12p40 associated with persistent hyperinflammation in COVID-19 pneumonia

Introduction

Despite of massive endeavors to characterize inflammation in COVID-19 patients, the core network of inflammatory mediators responsible for severe pneumonia stillremain remains elusive.

Methods

Here, we performed quantitative and kinetic analysis of 191 inflammatory factors in 955 plasma samples from 80 normal controls (sample n = 80) and 347 confirmed COVID-19 pneumonia patients (sample n = 875), including 8 deceased patients.

Results

Differential expression analysis showed that 76% of plasmaproteins (145 factors) were upregulated in severe COVID-19 patients comparedwith moderate patients, confirming overt inflammatory responses in severe COVID-19 pneumonia patients. Global correlation analysis of the plasma factorsrevealed two core inflammatory modules, core I and II, comprising mainly myeloid cell and lymphoid cell compartments, respectively, with enhanced impact in a severity-dependent manner. We observed elevated IFNA1 and suppressed IL12p40, presenting a robust inverse correlation in severe patients, which was strongly associated with persistent hyperinflammation in 8.3% of moderate pneumonia patients and 59.4% of severe patients.

Discussion

Aberrant persistence of pulmonary and systemic inflammation might be associated with long COVID-19 sequelae. Our comprehensive analysis of inflammatory mediators in plasmarevealed the complexity of pneumonic inflammation in COVID-19 patients anddefined critical modules responsible for severe pneumonic progression.

Genetic and clinical characteristics of transthyretin cardiac amyloidosis in Koreans

Background/Introduction

Transthyretin amyloidosis with mutations (aTTRv amyloidosis) have over 100 recognized pathogenic mutations of the TTR gene and its clinical manifestations are very heterogenous. Through the global THAOS (Transthyretin Amyloidosis Outcomes Survey) patient registry, different and several types of mutants and clinical differences have been identified. Awareness of aTTRv amyloidosis is now becoming somewhat significant amongst physicians all over the world. This is a detailed look at such efforts in Korea.

Purpose

We aimed to seek the geologic significance of aTTRv amyloidosis in South Korea.

Methods

This was an analysis of 638 Korean amyloidosis patients in a single center over a period of 16 years from 1995 to October 2021. 95 individuals were found with aTTR mutations.

Results

aTTRv amyloidosis constituted 14.8% (n=95) of amyloidosis patients, and the most commonly involved organ being the heart (61.7%, n=58). Unlike the rest of the world, the mixed phenotype was most common (51.0%, n=48) in Korea and the most universal mutation in Koreans were Asp38Ala, which only constitutes about 1.0% in the THAOS registry. Val30Met mutation, which comprises 76% of the mutation in the THAOS registry, was mostly associated the neurologic phenotypes. However, the same mutations in Korea mixed phenotypes with cardiac (38.4%) and neurologic (37%) symptoms.

Conclusion

aTTRv amyloidosis in Korea is different from other patients worldwide. The mixed phenotype was most common, emphasizing the need for heart failure management in the Korean population. Genotype wise, Koreans held a less common mutation of Asp38Ala. The most common mutation of Val30Met was more likely to be associated cardiac symptoms, which concurs with other studies that suggesting that geological features are more important than mutations itself.

Funding Acknowledgement

Type of funding sources: None.

Pulmonary arterial angioplasty in peripheral pulmonary arterial stenosis in RNF213 vasculopathy: effective but high-risk treatment with reperfusion injury

Background

p.Arg4810Lys variant of the ring finger protein 213 (RNF213) vasculopathy is a nonsyndromatic vasculopathy involving multisystemic organs including pulmonary arteries. Peripheral pulmonary arterial stenosis (PPAS) with diffuse stenosis and beaded appearance is a unique feature of this disease and no treatment option has been tried before.

Methods

We performed BPA for PPAS in RNF213 patients (n=7). Severity of pulmonary hypertension was assessed by echocardiography and right heart catheterization at the baseline. Several clinical and hemodynamic parameters were followed up after each BPA sessions.

Results

All of the patients had dyspnea on exertion. Right ventricular dysfunction was observed in six patients and NT-proBNP was elevated (949.2±1148.1 pg/mL). Baseline echocardiography showed severe pulmonary hypertension (70.1±19.2 mmHg). Pulmonary arterial ballooning was performed to all patients, but stenting (n=6) and cutting balloon (n=1) was necessary due to elastic recoil. Improvement of clinical and hemodynamic parameters was achieved in six patients after 5.3 sessions of BPA in average. Reperfusion edema was seen in four patients, eventually leading to death in one patient.

Conclusions

Pulmonary arterial angioplasty, when coupled with stenting, is an effective treatment for PPAS with RNF213 vasculopathy. Although reperfusion injury was common and fatal in a few cases, it is the only modality to improve the patient's symptom and hemodynamics till now. Careful selection of the target population should be preceded to perform the intervention.

Funding Acknowledgement

Type of funding sources: None.

Inducing Ectopic T Cell Clusters Using Stromal Vascular Fraction Spheroid-Based Immunotherapy to Enhance Anti-Tumor Immunity

Tertiary lymphoid structures (TLSs) provide specialized niches for immune cells, resulting in improved prognoses for patients undergoing cancer immunotherapy. Shaping TLS-like niches may improve anti-cancer immunity and overcome the current limitations of immune cell-based immunotherapy. Here, it is shown that stromal vascular fraction (SVF) from adipose tissues can enhance dendritic cell (DC)-mediated T cell immunity by inducing ectopic T lymphocyte clusters. SVF cells expanded ex vivo have phenotypes and functions similar to those of fibroblastic reticular cells in a secondary lymphoid organ, and their properties can be modulated using three-dimensional spheroid culture and coculture with DCs spiked with antigen-loaded iron oxide-zinc oxide core-shell nanoparticles. Thereby, the combination of SVF spheroids and mature DCs significantly augments T cell recruitment and retention at the injection site. This strategy elicits enhanced antigen-specific immune response and anti-tumoral immunity in mice, illustrating the potential for a novel immunotherapeutic design using SVF as a structural scaffold for TLS.

Enhanced eosinophil-mediated inflammation associated with antibody and complement-dependent pneumonic insults in critical COVID-19

Despite the worldwide effect of the coronavirus disease 2019 (COVID-19) pandemic, the underlying mechanisms of fatal viral pneumonia remain elusive. Here, we show that critical COVID-19 is associated with enhanced eosinophil-mediated inflammation when compared to non-critical cases. In addition, we confirm increased T helper (Th)2-biased adaptive immune responses, accompanying overt complement activation, in the critical group. Moreover, enhanced antibody responses and complement activation are associated with disease pathogenesis as evidenced by formation of immune complexes and membrane attack complexes in airways and vasculature of lung biopsies from six fatal cases, as well as by enhanced hallmark gene set signatures of Fcγ receptor (FcγR) signaling and complement activation in myeloid cells of respiratory specimens from critical COVID-19 patients. These results suggest that SARS-CoV-2 infection may drive specific innate immune responses, including eosinophil-mediated inflammation, and subsequent pulmonary pathogenesis via enhanced Th2-biased immune responses, which might be crucial drivers of critical disease in COVID-19 patients.

The Orientia tsutsugamushi ScaB Autotransporter Protein Is Required for Adhesion and Invasion of Mammalian Cells

Autotransporter proteins are widely present in Gram-negative bacteria. They play a pivotal role in processes related to bacterial pathogenesis, including adhesion, invasion, colonization, biofilm formation, and cellular toxicity. Bioinformatics analysis revealed that Orientia tsutsugamushi, the causative agent of scrub typhus, encodes six different autotransporter genes (scaA-scaF). Although four of these genes (scaA, scaC, scaD, and scaE) are present in diverse strains, scaB and scaF have been detected in only a limited number of strains. Previous studies have demonstrated that ScaA and ScaC are involved in the adherence of host cells. However, the putative function of other O. tsutsugamushi Sca proteins has not been studied yet. In this study, we show that scaB is transcribed and expressed on the surface of O. tsutsugamushi Boryong strain. Using a heterologous Escherichia coli expression system, we demonstrated that ScaB-expressing E. coli can successfully mediate adherence to and invasion into non-phagocytic cells, including epithelial and endothelial cells. In addition, pretreatment with a recombinant ScaB polypeptide inhibits the entry of O. tsutsugamushi into cultured mammalian cells. Finally, we also identified the scaB gene in the Kuroki and TA686 strains and observed high levels of sequence variation in the passenger domains. Here, we propose that the ScaB protein of O. tsutsugamushi can mediate both adhesion to and invasion into host cells in the absence of other O. tsutsugamushi genes and may play important roles in bacterial pathogenesis.

Molecular and Serological Investigation of Severe Fever with Thrombocytopenia Syndrome Virus in Cats

Background: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne zoonosis in China, the Republic of Korea (ROK), and Japan. The presence of the SFTS virus (SFTSV) in companion, livestock, and wild animals has been reported. Recently, human SFTS-like clinical symptoms in cats and cheetahs have been reported in Japan. Therefore, the prevalence of the SFTSV gene or antibody in cats is important for public health as well as veterinary medicine. Materials and Methods: Sera were collected from 201 feral and house cats in the ROK in 2017. Samples were analyzed for the presence of the SFTSV gene after RT-nested PCR amplification and for anti-SFTSV antibodies after enzyme linked immunosorbent assay. Results: Eight (4.0%) and nine (4.5%) of 201 cat sera were found to be positive for the SFTSV gene and anti-SFTSV nucleocapsid protein antibodies, respectively. Specifically, 5.9% feral and 2.0% house cats were positive for the SFTSV gene, and 6.9% feral and 2.0% house cats were positive for anti-SFTSV antibodies. All sequences of the SFTSV S segment obtained were included in Japanese/Korean SFTSV clades, as opposed to the Chinese clade. Conclusions: This study constitutes the first serological study of SFTSV in house and feral cats in the ROK. Evidence of SFTSV in companion animals indicates that SFTSV can circulate in homes and that more intensive precautions and education measures are needed for companion animal guardians and veterinarians.

Severe Fever with Thrombocytopenia Syndrome Virus Infection or Mixed Infection with Scrub Typhus in South Korea in 2000-2003

Severe fever with thrombocytopenia syndrome is a tick-borne viral disease, with a high mortality rate that was first reported in China in 2009. Scrub typhus is an acute febrile illness caused by Orientia tsutsugamushi, a bacterium transmitted to humans through chigger mite bites. Severe fever with thrombocytopenia syndrome and scrub typhus are endemic to South Korea. To investigate evidence of severe fever with thrombocytopenia syndrome virus (SFTSV) infection or mixed infection with scrub typhus in South Korea, we examined 2,329 sera samples collected from patients presenting from November 1, 2000, to November 1, 2003, for the diagnosis of rickettisal diseases at Seoul National University, Seoul, South Korea. We found retrospective evidence of SFTSV infection or mixed infection with scrub typhus in South Korea in 2000-2003. Severe fever with thrombocytopenia syndrome virus infections in South Korea occurred before previously reported cases and were more concurrent with those in China. It is important to consider SFTSV infection in patients with scrub typhus.

Once-daily dosing of amikacin for treatment of Mycobacterium abscessus lung disease

SETTING

Tertiary referral centre, Samsung Medical Center, South Korea.

OBJECTIVE

To evaluate the pharmacokinetic parameters and toxicities of once-daily amikacin (AMK) dosing for lung disease due to Mycobacterium abscessus.

DESIGN

A retrospective review of 48 patients with M. abscessus lung disease who received once-daily AMK for 4 weeks between January 2012 and June 2015.

RESULTS

With a starting dose of 15 mg/kg/day and adjustment of AMK dose according to the peak serum level (Cmax), the Cmax target of 55-65 μg/ml was achieved in 31.3% (15/48) of patients in the first week, 68.8% (33/48) in week 2, 91.7% (44/48) in week 3 and 95.8% (46/48) in week 4. Transient nephrotoxicity developed in 6.3% (3/48) of patients and ototoxicity in 25.0% (6/24), which was determined by audiogram as hearing loss, asymptomatic in five patients and tinnitus in one. Multivariate analysis revealed that the highest drug concentration 12 h after administration was significantly associated with the development of toxicities (adjusted odds ratio 1.862, P = 0.047).

CONCLUSION

Our results suggest that once-daily AMK for 4 weeks with a target Cmax of 55-65 μg/ml can be used in patients with M. abscessus lung disease, with careful monitoring of toxicity.

First Report of the Korean Lung Transplantation Registry

BACKGROUND

The Korean Organ Transplantation Registry (KOTRY) began to register lung transplants in 2015. This is an initial report on the status of patients receiving lung transplants over the past 2 years.

METHODS

We analyzed a total of 69 patients who received lung transplants in 2015 and 2016 and who registered with the KOTRY.

RESULTS

The 69 patients were treated in 5 institutions. The average (SD) donor age was 39.2 (12.6) years; there were 40 male patients. The average (SD) recipient age was 55.7 (10.0) years, and the number of male recipients was 46. A total of 66 patients underwent bilateral lung transplantation, 3 underwent single-lung transplantation, and 1 underwent simultaneous heart-lung transplantation. The most frequent indication for lung transplantation was idiopathic pulmonary fibrosis (35 patients), followed by connective tissue disease-related interstitial lung disease (9) and acute respiratory failure (8). Prior to transplantation, 23 patients required ventilator care, and 12 required extracorporeal membrane oxygenation while on the waiting list. Episodes of acute rejection during follow-up were reported in 4, 2, 1, and 1 patients at 3, 6, 9, and 12 months, respectively. Infections requiring hospitalization were reported in 27, 10, 4, and 3 patients at 3, 6, 9, and 12 months, respectively.

CONCLUSION

The establishment of KOTRY renders it possible to collect nationwide data on lung transplantation, improving research on the topic and clarifying clinical feasibility.

The 100 most-cited articles on non-tuberculous mycobacterial infection from 1995 to 2015

SETTING

Citation analyses aid in assessing quality, trends and future directions of research fields.

OBJECTIVE

To identify the most influential articles on infections caused by non-tuberculous mycobacteria (NTM) in the last 20 years.

DESIGN

We performed a cited reference search of the Web of Science database from 1995 to 2015. The 100 most cited articles on NTM infections were analysed.

RESULTS

The top 100 articles were cited 114-1471 times, and were published from 1995 to 2013. Sixty-five were laboratory-based, basic science articles, with the major topics being pathophysiology (n = 20) and molecular methods for NTM identification (n = 15). Among the 35 non-laboratory studies, major topics were clinical management (n = 15) and epidemiology (n = 14). The top article was a clinical treatise on the management of NTM disease, published in 2007. Although there was a correlation between article rank and journal impact factor (P = 0.043, ρ = -0.202), the five articles from the journals with highest impact factors did not rank among the top 10 articles.

CONCLUSION

A large proportion of influential articles on NTM infection are basic scientific studies, and the most influential articles are not always published in high-impact journals.

Liquid culture enhances diagnosis of patients with milder forms of non-tuberculous mycobacterial lung disease

OBJECTIVE

To evaluate the proportion and clinical characteristics of patients with non-tuberculous mycobacteria (NTM) lung disease diagnosed based on positive culture results in liquid medium only.

METHODS

We reviewed the medical records of 978 patients diagnosed with NTM lung disease. All clinical samples were cultured in both solid and liquid media.

RESULTS

Of the 978 patients, 111 (11.3%) were culture-positive in liquid medium only (liquid culture group), and 867 (88.7%) (solid culture group) on solid medium, regardless of the culture results in liquid medium. At the time of diagnosis, the liquid culture group was less likely than the solid culture group to have haemoptysis (11.7% vs. 20.0%, P = 0.04), positive sputum smear for acid-fast bacilli (14.4% vs. 50.2%, P < 0.001) or the fibrocavitary form of NTM lung disease (3.6% vs. 14.6%, P = 0.001). During the median follow-up period of 28.9 months (interquartile range 19.1-41.6), the proportion of patients requiring antibiotic treatment was lower in the liquid culture group than in the solid culture group (44.1% vs. 61.6%, P < 0.001).

CONCLUSIONS

Liquid media culture is helpful in the diagnosis of patients with less severe forms of NTM lung disease.

Implication of vitamin D-associated factors in patients with non-tuberculous mycobacterial lung disease

BACKGROUND

Little information is available regarding vitamin D-associated factors in patients with non-tuberculous mycobacteria (NTM) lung disease.

OBJECTIVE

To determine the association between vitamin D-related factors and susceptibility to NTM lung disease.

DESIGN

The relative gene expression levels of cathelicidin (CAMP), defensin (DEFB4), vitamin D receptor (VDR) and 1-hydroxylase (CYP27B1), as well as the serum levels of 25-hydroxyvitamin D (25[OH]D), cathelicidin (LL-37), defensin (hBD-2) and vitamin D-binding protein (DBP) from 82 patients with NTM lung disease and 28 control subjects were analysed.

RESULTS

Gene expression of CAMP and DEFB4 was significantly higher, and gene expression of VDR and CYP27B1 was significantly lower, in NTM patients than controls. Serum LL-37 and hBD-2 levels were not significantly different between NTM patients and controls; however, the serum DBP level was higher in NTM patients than controls. The serum vitamin D status of patients did not correlate with serum LL-37, hBD-2, or DBP concentration or gene expression of CAMP, DEFB4, VDR or CYP27B1.

CONCLUSION

A higher level of gene expression for antimicrobial peptide is more likely to be associated with NTM lung disease than serum vitamin D status.

Changes in serum immunomolecules during antibiotic therapy for Mycobacterium avium complex lung disease

Little information is available regarding changes in immune status for patients with Mycobacterium avium complex (MAC) lung disease during antibiotic therapy. Serum immunomolecules from 42 patients with MAC lung disease were assayed comparatively using an array-based system according to (i) patients with MAC lung disease at the time of diagnosis versus healthy controls and (ii) alterations after 12 months of antibiotic therapy in the MAC lung disease group. In addition, cytokine analyses were performed to determine whether cytokine responses were associated specifically with the disease phenotype, treatment outcome and aetiological agent. Notably, the serum concentrations of type 1 cytokine-associated molecules, such as CD40L, interferon (IFN)-γ, interleukin (IL)-8 and IL-23, were decreased significantly in patients at the time of diagnosis, suggesting that these molecules may serve as indicators of host susceptibility to MAC disease. Although the overall serum level of T helper type 1 (Th1)-related molecules, such as CD40L and IFN-γ, was restored after treatment, Th17-related cytokines, such as IL-17 and IL-23, were down-regulated significantly at 12 months post-treatment compared to pretreatment. Furthermore, these cytokine patterns differed among patient subgroups. Decreased serum concentrations of IL-17 and/or IL-23 were associated with failure of sputum conversion, the fibrocavitary disease phenotype and M. intracellulare lung disease. Thus, the reciprocal balance between Th1 and Th17 immunity during antibiotic therapy for MAC lung disease is critical for dictating the treatment response. In conclusion, a low level of Th1-related immunomolecules may perpetuate MAC lung disease, and the serum concentrations of Th17-related cytokines can reflect the treatment outcome, disease phenotype and aetiological agent.

Genotyping of Mycobacterium intracellulare isolates and clinical characteristics of lung disease

BACKGROUND

Variable number of tandem repeats (VNTR) loci were recently identified in Japanese isolates of Mycobacterium intracellulare. We hypothesised that some mycobacterial genotypes are more virulent than others, resulting in particular genotypes being associated with disease phenotype and progression.

OBJECTIVE

To evaluate the VNTR loci of M. intracellulare in clinical isolates from Korean patients, and investigate the association between mycobacterial genotype and disease phenotype and progression.

DESIGN

In total, 70 M. intracellulare clinical isolates were genotyped using 16 M. intracellulare VNTR loci.

RESULTS

VNTR typing showed strong discriminatory power and genetic diversity for molecular epidemiological studies of M. intracellulare. In a phylogenetic tree, the M. intracellulare clinical isolates were divided into two clusters (A and B). Cluster A was observed more frequently (77%) than Cluster B; however, there was no association between the clinical characteristics, disease progression, drug susceptibility and clusters based on VNTR genotyping.

CONCLUSIONS

VNTR typing could be used for epidemiological studies of M. intracellulare lung disease; however, no association was found between the specific VNTR genotypes of M. intracellulare and the clinical characteristics of Korean patients.

Toxocariasis as a cause of new pulmonary infiltrates

SETTING

Patients with new pulmonary infiltrates on chest computed tomography (CT) scans at a tertiary centre in South Korea.

OBJECTIVE

To demonstrate associations among radiological changes, blood eosinophilia (E) and Toxocara (T) seropositivity.

DESIGN

We retrospectively reviewed blood eosinophilia, Toxocara seropositivity, history of raw meat intake and radiological features, and divided study patients into four groups according to blood eosinophilia and Toxocara seropositivity.

RESULTS

Among 150 patients, 62 were E- and T-positive (E+T+), 45 were E-negative and T-positive (E-T+), 7 were E-positive and T-negative (E+T-), and 36 were E- and T-negative (E-T-). History of raw meat intake was found in 95 (63%) patients. The type and number of lesions on CT did not show any significant differences among the four groups. Among 119 patients who were not diagnosed with a specific disease, transient or migrating lesions were seen in 93% of E+T+, 93% of E-T+, 80% of E+T- and 52% of E-T- patients (P < 0.0001). Furthermore, the frequencies of migrating or new lesions and improvement were significantly higher in the Toxocara-positive group (88/95, 93%) than in the Toxocara-negative group (14/24, 58%; P = 0.002).

CONCLUSION

Transient and migratory pulmonary infiltrates on chest CT scans were associated with blood eosinophilia and Toxocara seropositivity. Clinicians should consider asymptomatic toxocariasis as a cause of unexplained new pulmonary infiltrates in countries with dietary habits of raw meat intake.

Clinical significance of mycobacterial genotyping in Mycobacterium avium lung disease in Korea

SETTING

A recent study in Japan found that mycobacterial genotyping was associated with disease progression and susceptibility to certain drugs in Mycobacterium avium lung disease. However, it is not known whether this association is true in other populations.

OBJECTIVE

To investigate the association between mycobacterial genotype, clinical characteristics and the progression of M. avium lung disease in Korean patients.

DESIGN

A total of 102 M. avium clinical isolates were genotyped using M. avium tandem repeats-variable number of tandem repeats (MATR-VNTR).

RESULTS

MATR-VNTR typing demonstrated a high discriminatory power and genetic diversity for molecular epidemiological studies of M. avium. In the phylogenetic tree, the M. avium clinical isolates were divided into three major clusters: A, B and C. Cluster A was observed most frequently (64/102, 63%), whereas cluster C was found in a minor proportion of the isolates (8/102, 8%). However, there was no association between the clinical characteristics, disease progression and drug susceptibility and the phylogenetic tree based on VNTR genotyping.

CONCLUSIONS

MATR-VNTR genotyping may be useful for epidemiological studies of M. avium lung disease; however, no association was found between the specific VNTR genotypes of M. avium and the clinical characteristics of Korean patients.

Paradoxical response in HIV-negative patients with pleural tuberculosis: a retrospective multicentre study

OBJECTIVE

To evaluate the incidence, clinical characteristics and predicting factors for the development of paradoxical response in human immunodeficiency virus negative patients with isolated pleural tuberculosis (TB).

DESIGN

A multicentre, retrospective cohort study including 458 patients who were diagnosed and treated with isolated pleural TB between March 2005 and February 2010.

RESULTS

Paradoxical response developed in 72 patients (16%) with isolated pleural TB. The mean time to development of paradoxical response was 8.8 ± 6.4 weeks after initiation of anti-tuberculosis treatment. The main presentation of paradoxical response was aggravation of pre-existing pleural effusion in 58 patients (81%). However, the majority of the patients who developed paradoxical response had no associated symptoms (n = 49, 68%). In multiple logistic regression analysis, development of paradoxical response was independently associated with the proportion of eosinophils (adjusted OR 1.293, 95%CI 1.077-1.553) and protein concentrations (adjusted OR 0.590, 95%CI 0.397-0.878) in the pleural fluid at the time of diagnosis.

CONCLUSION

Paradoxical response developed in 16% of the patients approximately 2 months after initiation of anti-tuberculosis treatment, presenting with aggravation of pre-existing pleural effusion. Development of paradoxical response was associated with the proportion of eosinophils and protein concentrations in the pleural fluid at the time of diagnosis.

Initial lactate level and mortality in septic shock patients with hepatic dysfunction

An elevated serum lactate level is associated with morbidity and mortality in patients with severe sepsis and septic shock. In patients with hepatic dysfunction, however an elevated serum lactate level may be due to either impaired lactate clearance or excessive production. Thus, we evaluated whether the initial serum lactate level was also associated with mortality in septic shock patients with hepatic dysfunction. A retrospective observational study enrolled 307 patients with septic shock admitted to the intensive care unit (ICU) between May 2007 and July 2009. Hepatic dysfunction was defined as a serum total bilirubin > 34.2 micromol/l (2 mg/dl). Selected patients were divided into high (> or = 4 mmol/l) and low (< 4 mmol/l) lactate groups, according to the initial serum lactate level. Of 307 patients with septic shock, 118 (38%) patients with hepatic dysfunction were eligible for this study. The median lactate levels were 5.9 (interquartile range 4.7 to 9.0) and 2.6 (interquartile range 1.7 to 3.2) mmol/l for the high and low lactate groups respectively (P < 0.001). The initial serum lactate level was strongly associated with in hospital mortality in a univariate analysis (P < 0.001). After adjusting for potential confounding factors, the initial serum lactate level remained significantly associated with in-hospital mortality (odds ratio 1.281, 95% confidence interval 1.097 to 1.496, P = 0.002). In conclusion, the serum lactate level could be useful in predicting the outcome of patients with septic shock regardless of hepatic dysfunction.

Clinical characteristics and outcomes of H1N1-associated pneumonia among adults in South Korea

BACKGROUND

Pneumonia has been reported to be the most life-threatening complication of influenza virus infection.

OBJECTIVE

to describe clinical characteristics and determine risk factors for death among patients with H1N1-associated pneumonia.

DESIGN

A retrospective cohort study included all adult patients diagnosed and treated with H1N1-associated pneumonia in 14 participating institutions between 1 May 2009 and 28 February 2010 in South Korea. Clinical outcomes were summarised and predictors for death evaluated through univariate and multivariate analysis.

RESULTS

A total of 269 adult patients with H1N1-associated pneumonia were diagnosed and treated. Hospital visits or admissions peaked in November 2009, coinciding with the peak in the 2009 H1N1 epidemic in South Korea. The patients' median age was 48 years; 143 were male. Most (n = 266, 98.9%) were admitted for treatment: 97 (36.1%) required intensive care and 28 (10.4%) needed mechanical ventilation. Despite the use of antiviral and antibacterial agents, 19 patients (7.1%) died. Risk factors predictive of death included presence of malignancy (aOR 12.0, 95%CI 2.8-51.5), and pneumonia severity index (PSI) score (aOR 1.03, 95%CI 1.01-1.04).

CONCLUSION

Deaths among adult patients with H1N1-associated pneumonia were not rare. Clinicians should be aware of the possibility of a poor prognosis among H1N1-associated pneumonia patients with underlying malignancy or high PSI score.

High isolation rate of adenovirus serotype 7 from South Korean military recruits with mild acute respiratory disease

Adenovirus is a major cause of acute respiratory disease (ARD) in military recruits. When South Korean military recruits with ARD were surveyed, adenovirus was identified in 122 (61.0%) of the 200 recruits studied. Moreover, all cases of ARD involving adenovirus were caused by serotype 7.

Recovery rate of NTM from AFB smear-positive sputum specimens at a medical centre in South Korea

OBJECTIVE

To investigate the recovery rate of non-tuberculous mycobacteria (NTM) from acid-fast bacilli (AFB) smear-positive sputum specimens at a tertiary care medical centre in South Korea with a high pulmonary tuberculosis (PTB) burden.

DESIGN

Retrospective analysis of data from AFB smear- and culture-positive sputum specimens collected between January 1998 and December 2001.

RESULTS

Over 4 years, 1328 sputum specimens collected from 616 patients were AFB smear- and culture-positive. NTM were recovered from 9.1% (121/1328) of the smear-positive sputum specimens, and from 8.1% (50/616) of patients with smear-positive sputum. NTM were isolated at least twice in 94% (47/50) of the patients from whom NTM was recovered. The most common organism found was Mycobacterium avium complex, followed by M. abscessus.

CONCLUSION

These results suggest that a substantial proportion of patients at a tertiary care medical centre in South Korea with AFB smear-positive sputum specimens may have NTM lung disease rather than PTB.

An efficient real time focusing delay calculation in ultrasonic imaging systems

An efficient real time focusing delay calculation algorithm is proposed for variable sampling clock generation (SCG) with high accuracy needed in digital focusing in ultrasonic imaging systems. The proposed algorithm is an extension of the midpoint drawing algorithm that is well known in the computer graphics area. It can be implemented with simple hardware amenable to VLSI realization, without using a large amount of look-up memory to store the sampling clock information otherwise required.