Low household income increases the risk of tuberculosis recurrence: a retrospective nationwide cohort study in South Korea

OBJECTIVES

We assessed the impact of household income on tuberculosis (TB) recurrence and the long-term impact of TB on household income.

STUDY DESIGN

This was a retrospective nationwide cohort study of patients with drug-susceptible TB (DS-TB) and TB recurrence.

METHODS

Using the South Korean national TB cohort database, we identified a sub-set cohort of patients with newly diagnosed drug-susceptible TB between 2013 and 2016 and tracked their TB recurrence and longitudinal income data from 2007 to 2018. Income levels were evaluated as 'Medical aid' and quintile categories. To assess risk factors associated with TB recurrence, we used a sub-distribution hazard model, adjusting for the competing risks of death.

RESULTS

Of 66,690 patients successfully treated with DS-TB, 2095 (3.1 %) experienced recurrence during a median follow-up of 39 months. The incidence of TB recurrence was 982.1/100,000 person-years, with 50.3 % of the recurrences occurring within 1 year of treatment completion. The risk of TB recurrence increased with decreasing income levels, with the highest risk observed in the lowest income group. The effect of income on TB recurrence was prominent in males but not in females. Overall, patients with TB recurrence experienced a linear decline in income levels, compared with those without recurrence.

CONCLUSIONS

Household income during the initial TB episode was an important risk factor for TB recurrence, particularly in males.

Secretory MPP3 reinforce myeloid differentiation trajectory and amplify myeloid cell production

Hematopoietic stem cells (HSC) and downstream lineage-biased multipotent progenitors (MPP) tailor blood production and control myelopoiesis on demand. Recent lineage tracing analyses revealed MPPs to be major functional contributors to steady-state hematopoiesis. However, we still lack a precise resolution of myeloid differentiation trajectories and cellular heterogeneity in the MPP compartment. Here, we found that myeloid-biased MPP3 are functionally and molecularly heterogeneous, with a distinct subset of myeloid-primed secretory cells with high endoplasmic reticulum (ER) volume and FcγR expression. We show that FcγR+/ERhigh MPP3 are a transitional population serving as a reservoir for rapid production of granulocyte/macrophage progenitors (GMP), which directly amplify myelopoiesis through inflammation-triggered secretion of cytokines in the local bone marrow (BM) microenvironment. Our results identify a novel regulatory function for a secretory MPP3 subset that controls myeloid differentiation through lineage-priming and cytokine production and acts as a self-reinforcing amplification compartment in inflammatory stress and disease conditions.

Aged hematopoietic stem cells are refractory to bloodborne systemic rejuvenation interventions

While young blood can restore many aged tissues, its effects on the aged blood system itself and old hematopoietic stem cells (HSCs) have not been determined. Here, we used transplantation, parabiosis, plasma transfer, exercise, calorie restriction, and aging mutant mice to understand the effects of age-regulated systemic factors on HSCs and their bone marrow (BM) niche. We found that neither exposure to young blood, nor long-term residence in young niches after parabiont separation, nor direct heterochronic transplantation had any observable rejuvenating effects on old HSCs. Likewise, exercise and calorie restriction did not improve old HSC function, nor old BM niches. Conversely, young HSCs were not affected by systemic pro-aging conditions, and HSC function was not impacted by mutations influencing organismal aging in established long-lived or progeroid genetic models. Therefore, the blood system that carries factors with either rejuvenating or pro-aging properties for many other tissues is itself refractory to those factors.

Normal Hematopoiesis Is a Balancing Act of Self-Renewal and Regeneration

The hematopoietic system is highly organized to maintain its functional integrity and to meet lifelong organismal demands. Hematopoietic stem cells (HSCs) must balance self-renewal with differentiation and the regeneration of the blood system. It is a complex balancing act between these competing HSC functions. Although highly quiescent at steady state, HSCs become activated in response to inflammatory cytokines and regenerative challenges. This activation phase leads to many intrinsic stresses such as replicative, metabolic, and oxidative stress, which can cause functional decline, impaired self-renewal, and exhaustion of HSCs. To cope with these insults, HSCs use both built-in and emergency-triggered stress-response mechanisms to maintain homeostasis and to defend against disease development. In this review, we discuss how the hematopoietic system operates in steady state and stress conditions, what strategies are used to maintain functional integrity, and how deregulation in the balance between self-renewal and regeneration can drive malignant transformation.

Deregulated Notch and Wnt signaling activates early-stage myeloid regeneration pathways in leukemia

Targeting commonly altered mechanisms in leukemia can provide additional treatment options. Here, we show that an inducible pathway of myeloid regeneration involving the remodeling of the multipotent progenitor (MPP) compartment downstream of hematopoietic stem cells (HSCs) is commonly hijacked in myeloid malignancies. We establish that differential regulation of Notch and Wnt signaling transiently triggers myeloid regeneration from HSCs in response to stress, and that constitutive low Notch and high Wnt activity in leukemic stem cells (LSCs) maintains this pathway activated in malignancies. We also identify compensatory crosstalk mechanisms between Notch and Wnt signaling that prevent damaging HSC function, MPP production, and blood output in conditions of high Notch and low Wnt activity. Finally, we demonstrate that restoring Notch and Wnt deregulated activity in LSCs attenuates disease progression. Our results uncover a mechanism that controls myeloid regeneration and early lineage decisions in HSCs and could be targeted in LSCs to normalize leukemic myeloid cell production.

Long-term mortality of patients with tuberculosis in Korea

BACKGROUND: Long-term mortality following tuberculosis (TB) diagnosis in Korea remains unclear.METHODS: The present study used data from the National Health Insurance Service database, an extensive health-related database including most Korean residents. TB patients were identified using International Classification of Diseases, Tenth Revision coding (A15-19, U88.0-88.1) and the type of anti-TB drug(s) between 2003 and 2016. Long-term mortality and causes of death in TB patients were analysed.RESULTS: A total of 357 211 individuals had TB over the period from 2003 to 2016 and 103 682 died. The mean age of the cohort was 54.7 ± 20.7 years, and 59.8% were male. The survival probability of TB patients at 1, 5, and 10 years after diagnosis was 87.8%, 75.3%, and 63.3%, respectively. High mortality and TB-related death rates were especially prominent in the early stages after TB diagnosis. The overall standardized mortality ratio of TB patients to the general Korean population was 3.23 (95% confidence interval 3.21-3.25).CONCLUSION: Mortality in TB patients was especially high in the early stages of disease after TB diagnosis, and mostly due to TB. This figure was approximately three-times higher than the mortality rate in the general population.

Treatment of latent tuberculous infection among health care workers at a tertiary hospital in Korea

OBJECTIVE

To evaluate the acceptance of, adherence to, and outcomes of latent tuberculous infection (LTBI) treatment among health care workers (HCWs).

DESIGN

This was a retrospective study in a tertiary hospital in Korea. From May to August 2017, 2190 HCWs simultaneously underwent a tuberculin skin test (TST) and interferon-gamma release assay (IGRA). LTBI was diagnosed if the TST induration was 10 mm or IGRA results were positive.

RESULTS

Of 2190 HCWs tested, 1006 (45.9%) were diagnosed with LTBI. Of these, 655 (65.1%) HCWs visited out-patient clinics, 234 (35.7%) of whom were advised treatment by physicians. Among these, 120 (51.3%) accepted the physicians' recommendations. In general, HCWs who were older, male and smoked were less likely to visit out-patient clinics. Sixty (50%) HCWs received 3 months of isoniazid plus rifampicin (3HR) and 57 (47.5%) HCWs received 4 months of rifampicin (4R). The proportion of HCWs with 2 side effects (3HR 20% vs. 4R 7.0%, P = 0.041) and drug stoppage rate (3HR 20% vs. 4R 5.3%, P = 0.017) were higher in the 3HR group than in the 4R group. Of the 120 HCWs, 78 (65%) completed LTBI treatment.

CONCLUSION

Overall, the acceptance and completion rate for LTBI treatment was not adequate. For effective LTBI management in HCWs, further programmatic strategies are needed.

Myeloid progenitor cluster formation drives emergency and leukaemic myelopoiesis

Although many aspects of blood production are well understood, the spatial organization of myeloid differentiation in the bone marrow remains unknown. Here we use imaging to track granulocyte/macrophage progenitor (GMP) behaviour in mice during emergency and leukaemic myelopoiesis. In the steady state, we find individual GMPs scattered throughout the bone marrow. During regeneration, we observe expanding GMP patches forming defined GMP clusters, which, in turn, locally differentiate into granulocytes. The timed release of important bone marrow niche signals (SCF, IL-1β, G-CSF, TGFβ and CXCL4) and activation of an inducible Irf8 and β-catenin progenitor self-renewal network control the transient formation of regenerating GMP clusters. In leukaemia, we show that GMP clusters are constantly produced owing to persistent activation of the self-renewal network and a lack of termination cytokines that normally restore haematopoietic stem-cell quiescence. Our results uncover a previously unrecognized dynamic behaviour of GMPs in situ, which tunes emergency myelopoiesis and is hijacked in leukaemia.

Exosome complex orchestrates developmental signaling to balance proliferation and differentiation during erythropoiesis

Since the highly conserved exosome complex mediates the degradation and processing of multiple classes of RNAs, it almost certainly controls diverse biological processes. How this post-transcriptional RNA-regulatory machine impacts cell fate decisions and differentiation is poorly understood. Previously, we demonstrated that exosome complex subunits confer an erythroid maturation barricade, and the erythroid transcription factor GATA-1 dismantles the barricade by transcriptionally repressing the cognate genes. While dissecting requirements for the maturation barricade in Mus musculus, we discovered that the exosome complex is a vital determinant of a developmental signaling transition that dictates proliferation/amplification versus differentiation. Exosome complex integrity in erythroid precursor cells ensures Kit receptor tyrosine kinase expression and stem cell factor/Kit signaling, while preventing responsiveness to erythropoietin-instigated signals that promote differentiation. Functioning as a gatekeeper of this developmental signaling transition, the exosome complex controls the massive production of erythroid cells that ensures organismal survival in homeostatic and stress contexts.

DOI:http://dx.doi.org/10.7554/eLife.17877.001

Red blood cells supply an animal’s tissues with the oxygen they need to survive. These cells circulate for a certain amount of time before they die. To replenish the red blood cells that are lost, first a protein called stem cell factor (SCF) instructs stem cells and precursor cells to proliferate, and a second protein, known as erythropoietin, then signals to these cells to differentiate into mature red blood cells. It is important to maintain this balance between these two processes because too much proliferation can lead to cancer while too much differentiation will exhaust the supply of stem cells.

Previous work has shown that a collection of proteins called the exosome complex can block steps leading towards mature red blood cells. The exosome complex controls several processes within cells by modifying or degrading a variety of messenger RNAs, the molecules that serve as intermediates between DNA and protein. However, it was not clear how the exosome complex sets up the differentiation block and whether it is somehow connected to the signaling from SCF and erythropoietin.

McIver et al. set out to address this issue by isolating precursor cells with the potential to become red blood cells from mouse fetal livers and experimentally reducing the levels of the exosome complex. The experiments showed that these cells were no longer able to respond when treated with SCF in culture, whereas the control cells responded as normal. Further experiments showed that cells with less of the exosome complex also made less of a protein named Kit. Normally, SCF interacts with Kit to instruct cells to multiply. Lastly, although the experimental cells could no longer respond to these proliferation signals, they could react to erythropoietin, which promotes differentiation. Thus, normal levels of the exosome complex keep the delicate balance between proliferation and differentiation, which is crucial to the development of red blood cells.

In future, it will be important to study the exosome complex in living mice and in human cells, and to see whether it also controls other signaling pathways. Furthermore, it is worth exploring whether this new knowledge can help efforts to produce red blood cells on an industrial scale, which could then be used to treat patients with conditions such as anemia.

DOI:http://dx.doi.org/10.7554/eLife.17877.002

Tuberculosis is frequently diagnosed within 12 months of diabetes mellitus

BACKGROUND

Evidence regarding the effects of tuberculosis (TB) screening among patients with diabetes mellitus (DM) in intermediate TB burden countries is insufficient, and the most appropriate time point for TB screening is unclear.

OBJECTIVE

To investigate trends in TB incidence among newly diagnosed DM patients.

DESIGN

A retrospective cohort study of the claims database of the Health Insurance Review and Assessment Service in Korea was performed. Participants were newly diagnosed with type 2 DM in 2009. The study outcome was TB incidence between 2009 and 2011 among participants according to duration of type 2 DM.

RESULTS

A cohort of 331,601 patients with newly diagnosed type 2 DM in 2009 was identified. During the 3-year follow-up period, 1533 patients were diagnosed with TB. The estimated incidence of TB among newly diagnosed type 2 DM patients was 18/10,000 patient-years (py) (95%CI 17.5-19.4). TB incidence was 33/10,000 py (95%CI 30.0-35.6) in the first 6 months, and 19/10,000 py (95%CI 16.5-20.6) in the following 6-month period.

CONCLUSIONS

The risk of developing TB was increased among DM patients, particularly during the first 12 months after DM diagnosis.

Functionally Distinct Subsets of Lineage-Biased Multipotent Progenitors Control Blood Production in Normal and Regenerative Conditions

Despite great advances in understanding the mechanisms underlying blood production, lineage specification at the level of multipotent progenitors (MPPs) remains poorly understood. Here, we show that MPP2 and MPP3 are distinct myeloid-biased MPP subsets that work together with lymphoid-primed MPP4 cells to control blood production. We find that all MPPs are produced in parallel by hematopoietic stem cells (HSCs), but with different kinetics and at variable levels depending on hematopoietic demands. We also show that the normally rare myeloid-biased MPPs are transiently overproduced by HSCs in regenerating conditions, hence supporting myeloid amplification to rebuild the hematopoietic system. This shift is accompanied by a reduction in self-renewal activity in regenerating HSCs and reprogramming of MPP4 fate toward the myeloid lineage. Our results support a dynamic model of blood development in which HSCs convey lineage specification through independent production of distinct lineage-biased MPP subsets that, in turn, support lineage expansion and differentiation.

Hematopoietic Signaling Mechanism Revealed from a Stem/Progenitor Cell Cistrome

Thousands of cis-elements in genomes are predicted to have vital functions. Although conservation, activity in surrogate assays, polymorphisms, and disease mutations provide functional clues, deletion from endogenous loci constitutes the gold-standard test. A GATA-2-binding, Gata2 intronic cis-element (+9.5) required for hematopoietic stem cell genesis in mice is mutated in a human immunodeficiency syndrome. Because +9.5 is the only cis-element known to mediate stem cell genesis, we devised a strategy to identify functionally comparable enhancers ("+9.5-like") genome-wide. Gene editing revealed +9.5-like activity to mediate GATA-2 occupancy, chromatin opening, and transcriptional activation. A +9.5-like element resided in Samd14, which encodes a protein of unknown function. Samd14 increased hematopoietic progenitor levels/activity and promoted signaling by a pathway vital for hematopoietic stem/progenitor cell regulation (stem cell factor/c-Kit), and c-Kit rescued Samd14 loss-of-function phenotypes. Thus, the hematopoietic stem/progenitor cell cistrome revealed a mediator of a signaling pathway that has broad importance for stem/progenitor cell biology.

The effects of statin use on the development of tuberculosis among patients with diabetes mellitus

OBJECTIVE

To evaluate whether statin use affects the development of tuberculosis (TB) among patients with diabetes mellitus (DM).

METHODS

This is a retrospective cohort study of patients with newly diagnosed type 2 DM based on the South Korean nationwide claims database. The participants were type 2 DM patients aged 20-99 years who were newly treated with anti-diabetic drugs between 1 January 2007 and 31 December 2010. Patients who had statin prescriptions before a diagnosis of diabetes or were diagnosed with TB before diabetes were excluded.

RESULTS

Of 840,899 newly diagnosed type 2 DM patients, 281,842 (33.5%) patients were statin users and 559,057 (66.5%) were non-users. During the study period, 4075 [corrected] individuals were diagnosed with TB; the estimated incidence of TB in our cohort was 251/100,000 patient-years (95%CI 243-258). In comparison to non-TB patients, statin users were less frequent among TB patients (19.2% vs. 33.6%). After adjustment for potential baseline confounders, statin use was not associated with the development of TB in DM patients (aHR 0.98; 95%CI 0.89-1.07).

CONCLUSIONS

TB development among newly diagnosed type 2 DM was considerable, and statin use among these diabetics was not associated with a protective effect on TB incidence.

The exosome complex establishes a barricade to erythroid maturation

Complex genetic networks control hematopoietic stem cell differentiation into progenitors that give rise to billions of erythrocytes daily. Previously, we described a role for the master regulator of erythropoiesis, GATA-1, in inducing genes encoding components of the autophagy machinery. In this context, the Forkhead transcription factor, Foxo3, amplified GATA-1-mediated transcriptional activation. To determine the scope of the GATA-1/Foxo3 cooperativity, and to develop functional insights, we analyzed the GATA-1/Foxo3-dependent transcriptome in erythroid cells. GATA-1/Foxo3 repressed expression of Exosc8, a pivotal component of the exosome complex, which mediates RNA surveillance and epigenetic regulation. Strikingly, downregulating Exosc8, or additional exosome complex components, in primary erythroid precursor cells induced erythroid cell maturation. Our results demonstrate a new mode of controlling erythropoiesis in which multiple components of the exosome complex are endogenous suppressors of the erythroid developmental program.

Association between vitamin D deficiency and tuberculosis in a Korean population

BACKGROUND

Several in vitro studies have been conducted regarding the immunomodulatory and mycobactericidal roles of vitamin D in tuberculous infection. However, discrepancies exist among epidemiological studies. We compared vitamin D deficiency between patients with tuberculosis (TB) and healthy control subjects and identified risk factors for vitamin D deficiency.

METHOD

This was an age- and sex-matched case-control analysis of 94 TB cohort and 282 Korean national survey participants.

RESULTS

The median baseline 25-hydroxyvitamin D (25[OH]D) level in the TB group (9.86 ng/ml, IQR 7.19-14.15) was lower than in controls (16.03 ng/ml, IQR 12.38-20.30, P < 0.001). The prevalence of severe vitamin D deficiency was higher in patients with TB (51.1%) than in controls (8.2%, P = 0.001). The median 25(OH)D level increased from 11.40 ng/ml (IQR 7.85-15.73) to 13.18 ng/ml (IQR 10.60-19.71) after treatment completion (P = 0.037). On multivariate analysis, presence of TB and history of TB were independently associated with severe vitamin D deficiency.

CONCLUSION

Patients with TB had a higher prevalence of vitamin D deficiency than control subjects in a Korean population. The median 25(OH)D level increased after TB treatment. Further studies are needed to establish a causal relationship.

Validation of a scoring tool to predict drug-resistant pathogens in hospitalised pneumonia patients

BACKGROUND

Health care-associated pneumonia (HCAP) affects a heterogeneous group of patients in frequent contact with health care systems. However, HCAP criteria poorly predict infection with drug-resistant (DR) pathogens.

OBJECTIVE

To validate our previously reported risk-scoring model (predictive of DR pathogen infection) in patients admitted to hospital with pneumonia.

DESIGN

We evaluated 580 patients admitted with culture-positive bacterial pneumonia. We identified risk factors, evaluated the risk-scoring model's capacity to predict infection by DR pathogens and compared the model's diagnostic accuracy with that of current HCAP criteria.

RESULTS

DR pathogens were observed in 227/580 patients (39.1%). Of 269 HCAP patients, 153 (56.9%) were infected with DR pathogens. Overtreatment was more common in HCAP than in community-acquired pneumonia (58.7% vs. 41.2%, P < 0.001). Recent hospitalisation, admission from a long-term care facility, recent antibiotic treatment and tube feeding were independently associated with DR pathogens. For pathogen prediction, the risk-scoring model showed better diagnostic accuracy than HCAP criteria (area under receiver operating-characteristic curve = 0.723 vs. 0.673, P < 0.001).

CONCLUSION

According to current HCAP criteria, half of the HCAP patients were treated unnecessarily with broad-spectrum antibiotics. Risk scoring by stratifying risk factors could improve the identification of patients likely to be infected with DR pathogens.

The responses of multiple cytokines following incubation of whole blood from TB patients, latently infected individuals and controls with the TB antigens ESAT-6, CFP-10 and TB7.7

The development of clinically relevant biomarkers is important for diagnosing latent tuberculosis infection (LTBI) and active tuberculosis (TB) and predicting their prognoses. This study examined whether the responses of multiple cytokines can be used as a biomarker to distinguish the TB infection status and mycobacterial load. We analysed the responses of multiple cytokines (IFN-γ, IL-2, IL-10, IL-13, IL-17 and TNF-α) in the supernatant from the QuantiFERON-TB Gold In-Tube assay following stimulation of whole blood from the TB group (n = 32), LTBI group (n = 19) and healthy controls (n = 30) with TB antigens (ESAT-6, CFP-10 and TB7.7). The median responses of IFN-γ, IL-2, IL-10 and IL-13 were higher in the LTBI and active TB groups than in the non-TB control group (IFN-γ, P < 0.001; IL-2, P < 0.001; IL-10, P = 0.012; IL-13, P < 0.001). The median IL-2/IFN-γ ratio of the LTBI group was higher than that of the active TB group (P = 0.014) and differed significantly between patients with LTBI, patients with smear-negative TB and patients with smear-positive TB (P = 0.027). This difference was especially evident between the patients with LTBI and patients with smear-positive TB (P = 0.047). In conclusion, IFN-γ, IL-2, IL-10 and IL-13 can serve as biomarkers for distinguishing TB infection. In addition, the IL-2/IFN-γ ratio appears to be a biomarker for diagnosing LTBI and may be useful as a prognostic factor and for evaluating treatment responses.

Conversion rates of an interferon-γ release assay and the tuberculin skin test in the serial monitoring of healthcare workers

PURPOSE

Regular monitoring of latent tuberculosis (TB) infection in healthcare workers (HCWs) is recommended, but the view about the effective method and performance of serial monitoring is controversial. The aim of this study was to determine differences in conversion rates according to TB exposure risk using the tuberculin skin test (TST) and the QuantiFERON-TB Gold In-Tube (QFT-GIT), and to evaluate the reproducibility and within-subject variability of the QFT-GIT in South Korea.

METHODS

Fifty-three HCWs were grouped according to their risk for TB exposure: group 1, high risk (n = 21); group 2, low risk (n = 32). Baseline and follow-up TSTs and QFT-GITs were performed from June 2009 to July 2011. Enzyme-linked immunosorbent assays (ELISAs) were repeated for the second QFT-GIT and a third QFT-GIT was performed after 8 weeks when discordant results of the second TST and QFT-GIT or a conversion or reversion were observed.

RESULTS

No difference in the QFT-GIT conversion rate was evident between the two groups (15.4 vs. 6.5 %, p = 0.57), and no TST conversion was observed. The rate of QFT-GIT positivity was higher in the high-risk group (first QFT-GIT: 38.1 vs. 3.1 %, p = 0.002; second QFT-GIT: 33.3 vs. 9.4 %, p = 0.039). The re-test reproducibility of QFT-GIT results was high (100 %), and the within-subject results of repetitive QFT-GITs were variable.

CONCLUSIONS

Stricter prevention strategies remain necessary in HCWs at high risk of TB exposure, and serial interferon-γ release assays (IGRAs) should be interpreted with caution in HCWs.

Guidelines for the use and interpretation of assays for monitoring autophagy

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.

Chronic obstructive pulmonary disease and metabolic syndrome: a nationwide survey in Korea

SETTING

Systemic inflammation has been suggested to be involved in the pathogenesis of chronic obstructive pulmonary disease (COPD) and metabolic syndrome. However, the association between these two conditions is not fully understood.

OBJECTIVE

To evaluate the relationship between COPD and metabolic syndrome.

DESIGN

Among subjects aged ≥40 years from the 2001 Korean National Health and Nutrition Examination Survey, 1215 subjects with two or more acceptable spirometry measurements and complete anthropometric/laboratory examinations were analysed.

RESULTS

A total of 133 subjects (11%, 100 men and 33 women) were newly diagnosed with COPD (forced expiratory volume in 1 second/forced vital capacity ≤ 70%). The prevalence of metabolic syndrome, based on the National Cholesterol Education Program Adult Treatment Panel III, was significantly higher in COPD subjects compared with non-COPD subjects in both sexes (33.0% vs. 22.2% in men and 48.5% vs. 29.6% in women). In men, the risk of COPD was higher in subjects with metabolic syndrome than in those without (OR 2.03, 95%CI 1.08-3.80), after adjusting for potential confounders. There was a borderline significant association between COPD and abdominal obesity among the individual component of metabolic syndrome (OR 1.95, 95%CI 0.93-4.11).

CONCLUSION

In the Republic of Korea, metabolic syndrome was associated with COPD in men.

Chronic obstructive lung disease-related health care utilisation in Korean adults with obstructive lung disease

OBJECTIVES

The numbers of nationwide epidemiological surveys about chronic obstructive pulmonary disease (COPD) prevalence and prospective cohort studies for health care utilisation are limited. We investigated COPD-related health care utilisation in adults with obstructive lung disease in the second Korean National Health and Nutritional Survey (KNHANES II) in 2001 using Korean national medical insurance claim data.

METHODS

Among people aged >40 years, obstructive lung disease (OLD) is defined according to Global Initiative for Chronic Obstructive Lung Disease criteria. Data from a total of 1942 subjects were linked with Korean national medical insurance claims data, and we investigated their COPD-related out-patient visits from 2002 to 2005.

RESULTS

Among the 1942 subjects, 256 (13.2%) had airflow obstruction. COPD-related out-patient visits were reported for 8.2% of patients without airway obstruction, 18.1% of those with mild airway obstruction, and 33.9% of those with moderate to very severe airway obstruction. Multivariate analysis revealed that previous COPD diagnosis by a physician (OR 2.54; P = 0.02) and lower socio-economic status (OR 0.45; P = 0.02) were independent predictors of COPD-related out-patient visits in subjects with OLD.

CONCLUSIONS

Of the subjects with airway obstruction, those with poor financial status utilised COPD-related health care services less frequently, and those previously diagnosed as having COPD by a physician utilised the services more frequently.

Prognostic factors for idiopathic pulmonary fibrosis: clinical, physiologic, pathologic, and molecular aspects

BACKGROUND

Previous studies identified clinical and physiologic factors of idiopathic pulmonary fibrosis (IPF) that are related to an increased risk of mortality. But there are few studies about histologic and molecular approach.

OBJECTIVE

We investigated whether the C-reactive protein (CRP), fibroblastic foci, phosphorylated Smad2/3 (p-Smad2/3), tumor growth factor-beta (TGF-beta), TGF-beta receptor II (TbetaRII), and the polymorphism of the TGF-beta1 codon 10 are associated with the progression of IPF patients.

DESIGN

Eighty-six IPF patients who underwent surgical lung biopsies were examined. For each patient, clinical and physiologic parameters were investigated, and we performed immunohistochemical staining for p-Smad2/3 and TbetaRII, and genotyping of the TGF-beta1 codon 10 polymorphism.

RESULTS

Age at diagnosis, gender, symptom duration, and smoking status did not show a significant association. However, the amount of smoking (p = 0.002), severe reduction in the percentages of predicted forced vital capacity (p = 0.013) and diffusion lung capacity of carbon monoxide (p = 0.023), CRP (p = 0.009) at diagnosis, and fibroblastic foci (p = 0.026) were associated with a poor prognosis. Cellularity, fibrosis, expression level of p-Smad2/3 and TbetaRII, and genotype of the TGF-beta1 codon 10 polymorphism did not have a statistically significant association with the prognosis.

CONCLUSION

This study confirmed the amount of smoking, abrupt decrease in follow-up pulmonary function parameters, fibroblastic foci, and increased levels of CRP concentration at diagnosis were significantly associated with poor survival. Larger studies are required to confirm all prognostic factors including CRP.

Discovering hematopoietic mechanisms through genome-wide analysis of GATA factor chromatin occupancy

GATA factors interact with simple DNA motifs (WGATAR) to regulate critical processes, including hematopoiesis, but very few WGATAR motifs are occupied in genomes. Given the rudimentary knowledge of mechanisms underlying this restriction and how GATA factors establish genetic networks, we used ChIP-seq to define GATA-1 and GATA-2 occupancy genome-wide in erythroid cells. Coupled with genetic complementation analysis and transcriptional profiling, these studies revealed a rich collection of targets containing a characteristic binding motif of greater complexity than WGATAR. GATA factors occupied loci encoding multiple components of the Scl/TAL1 complex, a master regulator of hematopoiesis and leukemogenic target. Mechanistic analyses provided evidence for crossregulatory and autoregulatory interactions among components of this complex, including GATA-2 induction of the hematopoietic corepressor ETO-2 and an ETO-2-negative autoregulatory loop. These results establish fundamental principles underlying GATA factor mechanisms in chromatin and illustrate a complex network of considerable importance for the control of hematopoiesis.

Nested PCR in lung tissue for diagnosis of pulmonary tuberculosis

Diagnosis of pulmonary tuberculosis (TB) is difficult in cases with an unusual presentation and often requires a lung biopsy. The goal of this study was to determine the clinical usefulness of nested PCR on lung tissue for the diagnosis of pulmonary TB. Clinical and laboratory data were reviewed from patients who underwent diagnostic lung biopsies, followed by nested TB PCR on formalin-fixed paraffin-embedded lung tissue specimens. The diagnostic yield and clinical impact of nested PCR were investigated. Of the 223 patients studied, 142 were diagnosed with TB. Microbiologically confirmed TB was identified in 71 patients. Compared to culture results, the sensitivity, specificity, positive predictive value and negative predictive value of nested PCR were 85%, 99%, 98% and 88%, respectively. Nested PCR was more sensitive than acid-fast bacilli smear of respiratory specimens and histopathological findings. The PCR results provided an early diagnosis and initiation of treatment for TB. However, negative PCR results did not lead to discontinuation of unnecessary TB treatment in patients on medication. In conclusion, nested PCR on lung tissue specimens is a useful diagnostic test for pulmonary TB in patients with an unusual presentation.

Transduction of artificial transcriptional regulatory proteins into human cells

Protein transduction (PT) is a method for delivering proteins into mammalian cells. PT is accomplished by linking a small peptide tag—called a PT domain (PTD)—to a protein of interest, which generates a functional fusion protein that can penetrate efficiently into mammalian cells. In order to study the functions of a transcription factor (TF) of interest, expression plasmids that encode the TF often are transfected into mammalian cells. However, the efficiency of DNA transfection is highly variable among different cell types and is usually very low in primary cells, stem cells and tumor cells. Zinc-finger transcription factors (ZF-TFs) can be tailor-made to target almost any gene in the human genome. However, the extremely low efficiency of DNA transfection into cancer cells, both in vivo and in vitro, limits the utility of ZF-TFs. Here, we report on an artificial ZF-TF that has been fused to a well-characterized PTD from the human immunodeficiency virus-1 (HIV-1) transcriptional activator protein, Tat. This ZF-TF targeted the endogenous promoter of the human VEGF-A gene. The PTD-attached ZF-TF was delivered efficiently into human cells in vitro. In addition, the VEGF-A-specific transcriptional repressor retarded the growth rate of tumor cells in a mouse xenograft experiment.

Aetiologies and predictors of pulmonary cavities in South Korea

OBJECTIVE

To identify the aetiologies of pulmonary cavities and the clinical predictors of cavities of mycobacterial origin.

SETTING

A tertiary referral hospital in South Korea, where the prevalence of tuberculosis (TB) is intermediate.

DESIGN

A retrospective review of clinical records and radiographic examinations of patients presenting pulmonary cavities on simple chest radiograph between January and December 2005.

RESULTS

Of 131 patients enrolled with pulmonary cavities, 66 (50.4%) had cavities of mycobacterial origin. Age <50 years (P = 0.04) and largest cavity located in the upper lobes (P = 0.04) increased the likelihood that the cavities were of mycobacterial origin. Conversely, history of malignancy (P = 0.02), lesions confined to one lobe (P = 0.02) and multiple enlarged mediastinal lymph nodes (P = 0.03) suggested a non-mycobacterial cause.

CONCLUSION

Mycobacterial infection accounted for half of the cavitary lesions identified in this study. In older patients with a history of malignancy, non-nodular infiltration, lesions confined to one lobe and with multiple lymphadenopathy, diseases not caused by mycobacteria should be considered.