COVID-19 vaccine effectiveness against severe COVID-19 requiring oxygen therapy, invasive mechanical ventilation, and death in Japan: A multicenter case-control study (MOTIVATE study)

INTRODUCTION

Since the SARS-CoV-2 Omicron variant became dominant, assessing COVID-19 vaccine effectiveness (VE) against severe disease using hospitalization as an outcome became more challenging due to incidental infections via admission screening and variable admission criteria, resulting in a wide range of estimates. To address this, the World Health Organization (WHO) guidance recommends the use of outcomes that are more specific to severe pneumonia such as oxygen use and mechanical ventilation.

METHODS

A case-control study was conducted in 24 hospitals in Japan for the Delta-dominant period (August-November 2021; "Delta") and early Omicron (BA.1/BA.2)-dominant period (January-June 2022; "Omicron"). Detailed chart review/interviews were conducted in January-May 2023. VE was measured using various outcomes including disease requiring oxygen therapy, disease requiring invasive mechanical ventilation (IMV), death, outcome restricting to "true" severe COVID-19 (where oxygen requirement is due to COVID-19 rather than another condition(s)), and progression from oxygen use to IMV or death among COVID-19 patients.

RESULTS

The analysis included 2125 individuals with respiratory failure (1608 cases [75.7%]; 99.2% of vaccinees received mRNA vaccines). During Delta, 2 doses provided high protection for up to 6 months (oxygen requirement: 95.2% [95% CI:88.7-98.0%] [restricted to "true" severe COVID-19: 95.5% {89.3-98.1%}]; IMV: 99.6% [97.3-99.9%]; fatal: 98.6% [92.3-99.7%]). During Omicron, 3 doses provided high protection for up to 6 months (oxygen requirement: 85.5% [68.8-93.3%] ["true" severe COVID-19: 88.1% {73.6-94.7%}]; IMV: 97.9% [85.9-99.7%]; fatal: 99.6% [95.2-99.97]). There was a trend towards higher VE for more severe and specific outcomes.

CONCLUSION

Multiple outcomes pointed towards high protection of 2 doses during Delta and 3 doses during Omicron. These results demonstrate the importance of using severe and specific outcomes to accurately measure VE against severe COVID-19, as recommended in WHO guidance in settings of intense transmission as seen during Omicron.

Immune escape and waning immunity of COVID-19 monovalent mRNA vaccines against symptomatic infection with BA.1/BA.2 and BA.5 in Japan

BACKGROUND

Repeated emergence of variants with immune escape capacity and waning immunity from vaccination are major concerns for COVID-19. We examined whether the surge in Omicron subvariant BA.5 cases was due to immune escape or waning immunity through vaccine effectiveness (VE) evaluation.

METHODS

A test-negative case-control study was conducted in 16 clinics/hospitals during the BA.1/BA.2-dominant and BA.5-dominant periods. VE against symptomatic infection was estimated after adjusting for age, sex, comorbidity, occupation, testing frequency, prior infection, close contact history, clinic/hospital, week, and preventive measures. Absolute VE (aVE) was calculated for 2/3/4 doses, compared to the unvaccinated. Relative VE (rVE) was calculated, comparing 3 vs 2 and 4 vs 3 doses.

RESULTS

13,025 individuals were tested during the BA.1/BA.2-dominant and BA.5-dominant periods with similar baseline characteristics. For BA.1/BA.2, aVE was 52 % (95 %CI:34-66) 14 days-3 months post-dose 2, 42 % (29-52) > 6 months post-dose 2, 71 % (64-77) 14 days-3 months post-dose 3, and 68 % (52-79) 3-6 months post-dose 3. rVE was 49 % (38-57) 14 days-3 months post-dose 3 and 45 % (18-63) 3-6 months post-dose 3. For BA.5, aVE was 56 % (27-73) 3-6 months post-dose 2, 32 % (12-47) > 6 months post-dose 2, 70 % (61-78) 14 days-3 months post-dose 3, 59 % (48-68) 3-6 months post-dose 3, 50 % (29-64) > 6 months post-dose 3, and 74 % (61-83) ≥ 14 days post-dose 4. rVE was 56 % (45-65) 14 days-3 months post-dose 3, 39 % (27-48) 3-6 months post-dose 3, 25 % (-2-45) > 6 months post-dose 3, and 30 % (-6-54) ≥ 14 days post-dose 4.

CONCLUSIONS

Booster doses initially provided high protection against BA.5 at a level similar to that against BA.1/BA.2. However, the protection seemed shorter-lasting against BA.5, which likely contributed to the surge. Furthermore, rVE post-dose 4 was low even among recent vaccinees. These results support the introduction of variant-containing vaccines and emphasize the need for vaccines with longer duration of protection.

Left-Right Reversal Recurrently Evolved Regardless of Diaphanous-Related Formin Gene Duplication or Loss in Snails

Bilateria exhibit whole-body handedness in internal structure. This left-right polarity is evolutionarily conserved with virtually no reversed extant lineage, except in molluscan Gastropoda. Phylogenetically independent snail groups contain both clockwise-coiled (dextral) and counterclockwise-coiled (sinistral) taxa that are reversed from each other in bilateral handedness as well as in coiling direction. Within freshwater Hygrophila, Lymnaea with derived dextrality have diaphanous related formin (diaph) gene duplicates, while basal sinistral groups possess one diaph gene. In terrestrial Stylommatophora, dextral Bradybaena also have diaph duplicates. Defective maternal expression of one of those duplicates gives rise to sinistral hatchlings in Lymnaea and handedness-mixed broods in Bradybaena, through polarity change in spiral cleavage of embryos. These findings led to the hypothesis that diaph duplication was crucial for the evolution of dextrality by reversal. The present study discovered that diaph duplication independently occurred four times and its duplicate became lost twice in gastropods. The dextrality of Bradybaena represents the ancestral handedness conserved across gastropods, unlike the derived dextrality of Lymnaea. Sinistral lineages recurrently evolved by reversal regardless of whether diaph had been duplicated. Amongst the seven formin gene subfamilies, diaph has most thoroughly been conserved across eukaryotes of the 14 metazoan phyla and choanoflagellate. Severe embryonic mortalities resulting from insufficient expression of the duplicate in both of Bradybaena and Lymnaea also support that diaph duplicates bare general roles for cytoskeletal dynamics other than controlling spiralian handedness. Our study rules out the possibility that diaph duplication or loss played a primary role for reversal evolution.

Propensity-Score Matched Analysis of the Effectiveness of Baricitinib in Patients With Coronavirus Disease 2019 (COVID-19) Using Nationwide Real-World Data: An Observational Matched Cohort Study From the Japan COVID-19 Task Force

Background

To determine the effectiveness of baricitinib in patients with coronavirus disease 2019 (COVID-19), investigate whether baricitinib prevents the need for invasive mechanical ventilation and identify patient subgroups that would benefit from baricitinib.

Methods

This observational matched-cohort study was conducted by the Japan COVID-19 Task Force, a nationwide multicenter consortium. Patients with COVID-19 aged ≥18 years were identified from 70 hospitals in Japan. Among patients with confirmed COVID-19 from February 2020 to September 2021, those receiving baricitinib were propensity-score matched with controls.

Results

Among 3309 patients, 144 propensity score-matched pairs were identified. Thirteen (9.0%) patients in the baricitinib group and 27 (18.8%) in the control group required invasive mechanical ventilation during the disease course (odds ratio, 0.43). Although the baricitinib group had more severe disease, there were no significant differences in the intensive care unit admission rates (odds ratio, 1.16) and mortality rates (odds ratio, 0.74) between groups. In subgroup analyses, baricitinib was associated with a significant reduction in the need for invasive mechanical ventilation in patients requiring oxygen support (odds ratio, 0.28), with rapid shadow spread on chest radiography (odds ratio, 0.11), or treated with remdesivir (odds ratio, 0.27), systemic corticosteroids (odds ratio, 0.31), or anticoagulants (odds ratio, 0.17).

Conclusions

Baricitinib is effective at preventing the need for invasive mechanical ventilation in patients with COVID-19.

In Vitro Synergistic Effects of Omadacycline with Other Antimicrobial Agents against Mycobacterium abscessus

The clinical importance of Mycobacterium abscessus species (MABS) infections has been increasing. However, the standard treatment regimens recommended in the current guidelines often result in unfavorable outcomes. Therefore, we investigated the in vitro activity of omadacycline (OMC), a novel tetracycline, against MABS to explore its potential as a novel therapeutic option. The drug susceptibilities of 40 Mycobacterium abscessus subsp. abscessus (Mab) clinical strains obtained from the sputum of 40 patients from January 2005 to May 2014 were investigated. The MIC results for OMC, amikacin (AMK), clarithromycin (CLR), clofazimine (CLO), imipenem (IPM), rifabutin (RFB), and tedizolid (TZD) alone and their combined effects (with OMC) were examined using the checkerboard method. Additionally, we studied the differences in the effectiveness of the antibiotic combinations based on the colony morphotype of Mab. The MIC50 and MIC90 of OMC alone were 2 and 4 μg/mL, respectively. The combinations of OMC with AMK, CLR, CLO, IPM, RFB, and TZD showed synergy against 17.5%, 75.8%, 25.0%, 21.1%, 76.9%, and 34.4% of the strains, respectively. Additionally, OMC combined with CLO (47.1% versus 9.5%, P = 0.023) or TZD (60.0% versus 12.5%, P = 0.009) showed significantly higher synergy against strains with rough morphotypes than those with smooth morphotypes. In conclusion, the checkerboard analyses revealed that the synergistic effects of OMC were observed most frequently with RFB, followed by CLR, TZD, CLO, IPM, and AMK. Furthermore, OMC tended to be more effective against rough-morphotype Mab strains.

Effectiveness of BA.1- and BA.4/BA. 5-Containing Bivalent COVID-19 mRNA Vaccines Against Symptomatic SARS-CoV-2 Infection During the BA.5-Dominant Period in Japan

In this multicenter, prospective, test-negative, case-control study in Japan, the effectiveness of both BA.1-containing and BA.4/BA.5-containing bivalent coronavirus disease 2019 mRNA vaccines against symptomatic infection during the BA.5-dominant period was high compared with no vaccination (65% and 76%) and moderate compared with monovalent vaccines administered over half a year earlier (46% combined).

Plasma MMP-9 Levels as the Future Risk of Conversion to Dementia in ApoE4-Positive MCI Patients: Investigation Based on the Alzheimer's Disease Neuroimaging Initiative Database

BACKGROUND

Matrix metalloproteinase 9 (MMP-9) has been reported to be correlated with declines in hippocampal volume and cognitive function in ApoE4-positive MCI patients.

OBJECTIVES

The present study was aimed to investigate the effects of plasma matrix MMP-9 on the conversion risk between mild cognitive impairment (MCI) patients with and without ApoE4.

DESIGN AND SETTING

Retrospective observational study using the data extracted from the Alzheimer's Disease Neuroimaging Initiative database.

PARTICIPANTS

We included 211 ApoE4-positive MCI subjects (ApoE4+ MCI) and 184 ApoE4-negative MCI subjects (ApoE4- MCI).

MEASUREMENTS

We obtained demographic and data including plasma MMP-9 levels at baseline and longitudinal changes in Clinical Dementia Rating (CDR) up to 15 years. We compared conversion rates between ApoE4+ MCI and ApoE4- MCI by the Log-rank test and calculated the hazard ratio (HR) for covariates including age, sex, educational attainment, drinking and smoking histories, medications, and plasma MMP-9 levels using a multiple Cox regression analysis of ApoE4+ MCI and ApoE4- MCI.

RESULTS

No significant differences were observed in baseline plasma MMP-9 levels between ApoE4+ MCI and ApoE4- MCI. High plasma MMP-9 levels increased the conversion risk significantly more than low plasma MMP-9 levels (HR, 2.46 [95% CI, 1.31-4.48]) and middle plasma MMP-9 levels (HR, 1.67 [95% CI, 1.04-2.65]) in ApoE4+ MCI, but not in ApoE4- MCI.

CONCLUSION

Plasma MMP-9 would be the risk of the future conversion to dementia in ApoE4+ MCI.

Genome-wide association study in patients with pulmonary Mycobacterium avium complex disease

RATIONALE

Nontuberculous mycobacteria (NTM) are environmental mycobacteria that can cause a chronic progressive lung disease. Although epidemiological data indicate potential genetic predisposition, its nature remains unclear.

OBJECTIVES

We aimed to identify host susceptibility loci for Mycobacterium avium complex (MAC), the most common NTM pathogen.

METHODS

This genome-wide association study (GWAS) was conducted in Japanese patients with pulmonary MAC and healthy controls, followed by genotyping of candidate single-nucleotide polymorphisms (SNPs) in another Japanese cohort. For verification by Korean and European ancestry, we performed SNP genotyping.

RESULTS

The GWAS discovery set included 475 pulmonary MAC cases and 417 controls. Both GWAS and replication analysis of 591 pulmonary MAC cases and 718 controls revealed the strongest association with chromosome 16p21, particularly with rs109592 (p=1.64×10^-13, OR 0.54), which is in an intronic region of the calcineurin-like EF-hand protein 2 (CHP2). Expression quantitative trait loci analysis demonstrated an association with lung CHP2 expression. CHP2 was expressed in the lung tissue in pulmonary MAC disease. This SNP was associated with the nodular bronchiectasis subtype. Additionally, this SNP was significantly associated with the disease in patients of Korean (p=2.18×10^-12, OR 0.54) and European (p=5.12×10^-03, OR 0.63) ancestry.

CONCLUSIONS

We identified rs109592 in the CHP2 locus as a susceptibility marker for pulmonary MAC disease.

Efficacy estimation of a combination of triple antimicrobial agents against clinical isolates of Mycobacterium abscessus subsp. abscessus in vitro

Background

Mycobacterium abscessus subsp. abscessus (M. abscessus) is a rapidly growing mycobacterium that is resistant to most antibiotics. The number of patients with pulmonary disease caused by M. abscessus is increasing in several regions, and therapy involves long-term antibiotic combination treatments, although no standard treatment regimen has been established.

Objectives

To examine candidate regimens for maintenance of antimicrobial treatment against M. abscessus by measuring MIC using the three-drug chequerboard method.

Methods

We evaluated the drug susceptibility of 70 clinical isolates of M. abscessus using the three-drug chequerboard method. We tested the antimycobacterial agents bedaquiline, clofazimine, amikacin, and sitafloxacin (which showed a relatively low MIC range when used as single agents) alone and in combinations.

Results

The three-drug combinations of bedaquiline/clofazimine/amikacin, and bedaquiline/clofazimine/sitafloxacin were studied. Among isolates for which the fractional inhibitory concentration index (FICI) could be calculated, 29/70 isolates (41%) and 11/70 isolates (16%) showed a synergistic response (FICI ≤0.75) with combined use of bedaquiline/clofazimine/amikacin, or with bedaquiline/clofazimine/sitafloxacin, respectively.

Conclusions

The combination of bedaquiline with clofazimine plus either amikacin or sitafloxacin may be useful as maintenance regimens when treating pulmonary disease caused by M. abscessus.

Genus-level revision of the Alycaeidae (Gastropoda, Cyclophoroidea), with an annotated species catalogue

412 species-group names (including 11 replacement names), and 14 genus-group names of the Alycaeidae have been introduced to date. Type materials of 85% (336) of the known species and subspecies were examined, a further 5% (19) of the taxa were studied using available non-type material, and for another 6% (22) the original descriptions were sufficiently detailed to evaluate their taxonomic status. Only 3% of the taxa (12) could not be examined. Special attention was paid to the sculpture of the embryonic whorls and the sutural tube-microtunnel system in order to provide a novel classification for this group.

In this study 363 taxa (320 species or 43 subspecies) are accepted within the family Alycaeidae. Of these, 22 have been described by the lead author and his coauthors in previous publications. In addition, there are 18 species that were formerly classified in Cycloryx and now belong to Pincerna due to its synonymy with Cycloryx. Among the remaining 323 species, 209 (65%) are transferred here to another genus, whilst 114 (35%) have remained in their original genus.

Seven genera are accepted. While some questions (e.g., the distinction between Pincerna and Alycaeus) remained unanswered, this revision made three main achievements: (1) The Dicharax species were identified based on the absence of spiral striation on the entire shell; (2) the Metalycaeus species were identified based on the spiral striation of the protoconch; (3) and Stomacosmethis was separated from Alycaeus based on the extremely short sutural tube.

Five nominal species are being synonymised with other species, and eight species are now treated as subspecies. The following replacement names are proposed: Dioryxurnulaniosiensis Páll-Gergely, nom. nov. for Alycaeusurnulavar.daflaensis Godwin-Austen, 1914; Dioryxurnularotundus Páll-Gergely, nom. nov. for Alycaeusurnulavar.globosus Godwin-Austen, 1914; Pincernacrenilabrisjuttingae Páll-Gergely, nom. nov. for Alycaeuscrenilabrislaevis van Benthem Jutting, 1959; Pincernacrenilabriskorintjiensis Páll-Gergely, nom. nov. for Alycaeuscrenilabrislatecostatus van Benthem Jutting, 1959; Dicharaxconicusjatingaensis Páll-Gergely, nom. nov. for Alycaeusconicusvar.nanus Godwin-Austen, 1914; Metalycaeusgodwinausteni Páll-Gergely, nom. nov. for Alycaeusneglectus Godwin-Austen, 1914; and finally Metalycaeussuhajdai Páll-Gergely, nom. nov. for Alycaeusvarius Godwin-Austen, 1914.

SARS-CoV-2 and Legionella co-infection in a person returning from a Nile cruise

We report a case of severe acute respiratory syndrome coronavirus 2 and Legionella co-infection manifesting as pneumonia with gastrointestinal symptoms. The case highlights the importance of differential diagnosis during the COVID-19 pandemic, so we do not miss the opportunity to diagnose other treatable causes of disease with similar symptoms.

Retrospective evaluation of natural course in mild cases of Mycobacterium avium complex pulmonary disease

Background

There is no proven management for mild cases of Mycobacterium avium complex (MAC) pulmonary disease, who do not immediately receive treatment and are managed with observation alone, because its long term-natural course, factors predictive of deterioration, and the effect of treating the disease remain unclear. Thus, we sought to investigate the natural course of mild cases of MAC pulmonary disease.

Methods

We conducted a multicenter retrospective study. Sixty-five patients with mild MAC pulmonary disease in whom treatment was withheld for at least 6 months after diagnosis were retrospectively recruited after a review of 747 medical records. Longitudinal changes in clinical features were evaluated by using a mixed effects model.

Results

Mean follow-up was 6.9 ± 5.7 years. During the follow-up period, 15 patients (23%) required treatment and 50 (77%) were managed with observation alone. At diagnosis, 65 patients had nodular bronchiectatic disease without fibrocavitary lesions. Among clinical features, mean body mass index (BMI), forced expiratory volume in 1 second as percent of forced vital capacity (%FEV₁), nodular lung lesions, and bronchiectasis worsened significantly in the observation group during follow-up. In the treatment group, BMI, and %FEV₁ were stable, but bronchiectasis significantly worsened. At diagnosis, the polyclonal MAC infection rate in the treatment group was higher than that in the observation group. Other microbiological factors, such as insertion sequences, did not differ significantly between the groups.

Conclusions

Mild MAC pulmonary disease progresses slowly but substantially without treatment. Treatment prevents the deterioration of the disease but not the progression of bronchiectasis. Polyclonal MAC infection is a predictor of disease progression.

Heterochirality results from reduction of maternal diaph expression in a terrestrial pulmonate snail

BACKGROUND

Spiral cleavage is a feature of non-ecdysozoan protostomes, in which left-right reversal frequently evolved in gastropod molluscs. In pulmonate gastropods, maternal molecules are responsible for chirality patterning, on which the polarities of visceral and coiling asymmetries depend. In the pond snail, Lymnaea stagnalis (the clade Hygrophila), a frame-shift mutation of one of tandem-duplicated, diaphanous-related formin genes (diaph) resulted in incomplete reversal from dextral to sinistral cleavage. Is this mechanism of chirality regulation common to, or shared with other pulmonates? To answer this question, we examined genes involved in chirality patterning in the land snail, Bradybaena similaris which belongs to the clade Stylommatophora.

RESULTS

Both dextral and sinistral siblings develop from progeny of a racemic mutant of B. similaris. Differences in maternal mRNAs between the two strains were searched by transcriptome analyses. We found fifty maternal transcripts that exhibited less expression in early embryos of the mutant strain. The most conspicuous was a homolog of diaph. The diaph gene was duplicated in the stylommatophoran ancestor (diaph-a and diaph-b), as in the case of the ancestor of Lymnaea (Lsdiaph1 and Lsdiaph2). The quantity of maternal diaph-b mRNA was drastically reduced in early embryos of the racemic mutant compared to wild-type, while diaph-a expression was at nearly the same level in both strains. Unlike the case of Lsdiaph2, which is frame-shifted to produce truncated peptides in the mutant of L. stagnalis, however, Bsdiaph-b mRNA in the mutant strain is not frame-shifted and most probably produces normal Diaph-b protein. These results suggest the presence of regulatory mechanisms of gene expression for chirality patterning in pulmonate gastropods, although genomic analyses are required for confirmation.

CONCLUSIONS

Heterochirality resulting from the loss of polarity control in spiral cleavage does not require mutation of the diaph gene in B. similaris. The determination of left-right polarity instead depends on the expression of this diaph gene, which is duplicated in stylommatophoran Bradybaena, as well as in hygrophilan Lymnaea. Our results provide an avenue to identifying a regulatory mechanism that controls the direction of spiral cleavage in gastropods.

Enantiomorphs and taxonomy of three conchological species in flat-shelled snails Trichocathaica (Pulmonata, Camaenidae)

Biomodal (flat/globular or slender/tall) shell/body shapes are associated with dichotomous (simultaneous reciprocal or non-reciprocal) modes of copulation behaviour in the fully-shelled stylommatophoran snails. In flat-shelled groups that copulate simultaneously reciprocally, no study has found an example of enantiomorphism that persists within a population. However, the original description of a flat camaenid snail, Trichocathaicaamphidroma, noted that it is dextral- or sinistral-coiled. By examination of shell surface morphology, we found that shell specimens classified as those of this species include shells of three different morphological species. Namely, T.amphidroma, Trichocathaicavestita (Pilsbry, 1934), comb. n., and Trichocathaicamacrosquamata Páll-Gergely, sp. n. In each of the three species, both sinistral and dextral shells have been collected from presumably one area. Ethanol-fixed soft bodies of single dextral and sinistral individuals of T.vestita, which were available for the first time for interchiral comparison of genital morphology in the present genus, differed from each other in the pattern of penial microsculpture. They might represent enantiomorphs that have recently diverged in allopatry instead of enantiomorphism within a population or species. However, their shell and genital differences were not discrete enough to divide them taxonomically into two morphologically distinct species. Our results demonstrate the importance of evaluating individual variation relative to differences between incipient species in penial morphology, especially between conchologically indistinguishable enantiomorphs in the flat groups. We revise the taxonomy of the genus Trichocathaica including the above-mentioned new species, and Trichocathaicaputeolata Páll-Gergely, sp. n.

Clinico-microbiological analysis of 121 patients with pulmonary Mycobacteroides abscessus complex disease in Japan - An NTM-JRC study with RIT

RATIONALE

No comprehensive analysis has previously been performed to evaluate the clinical aspects of and microbiological evidence associated with Mycobacteroides abscessus complex (MABC) infection in a region, such as Japan, with a low MABC incidence.

OBJECTIVES

This study aimed to clarify the clinicopathological characteristics of MABC, which included clinical relatedness to erm(41) sequevar, phenotype (as colony morphology and minimum inhibitory concentration), and genotype.

METHODS

A total of 121 MABC patients (68 with M. abscessus subsp. abscessus and 53 with M. abscessus subsp. massiliense) were recruited into this retrospective clinical-biological study from tertiary hospitals in Japan between 2004 and 2014.

RESULTS

Approximately 30% of MABC patients had a history of previous nontuberculous mycobacterium (NTM) disease. Furthermore, 24.8% of the patients had another concomitant NTM infection after they were diagnosed with MABC. Fewer than 10% of the patients in the M. abscessus group had T28C in erm(41). While we observed a higher conversion rate for M. massiliense than for M. abscessus (72.4% and 34.8%, respectively, p = 0.002), recurrence remained relatively common for M. massiliense (31.0%). In the M. abscessus patients, the MIC of clarithromycin (CLR) was significantly lower on day 3 in patients with a better treatment response than in refractory patients (The median MIC; 0.75 μg/ml v.s 2.0 μg/ml, p = 0.03). There was no significant relation between clinical manifestations and variable number of tandem repeat genotypes.

CONCLUSIONS

Because the history and simultaneous isolation of other NTM in MABC infection are relatively common, these information should be carefully translated into clinical actions. The evaluation of early CLR resistance in M. abscessus and the erm(41) functions should be important to improve the treatment strategy.

Association between six-minute walk test parameters and the health-related quality of life in patients with pulmonary Mycobacterium avium complex disease

Background

Pulmonary Mycobacterium avium complex (pMAC) disease is a chronic, slowly progressive disease. The aim of the present study was to determine the association of six-minute walk test (6MWT) parameters with pulmonary function and the health-related quality of life (HRQL) in patients with pMAC disease.

Methods

This cross-sectional study included adult patients with pMAC and was conducted at Keio University Hospital. We investigated the relationship of 6MWT parameters with clinical parameters, including pulmonary function, and HRQL, which was assessed using the 36-Item Short Form Health Survey (SF-36) and St. George’s Respiratory Questionnaire (SGRQ).

Results

In total, 103 consecutive patients with pMAC participated in 6MWT (median age, 64 years; 80 women) and completed SF-36 and SGRQ. The six-minute walk distance (6MWD) showed significant negative and positive correlations with all SGRQ domain scores [ρ = (− 0.54)–(− 0.32)] and the physical component summary (PCS) score (ρ = 0.39) in SF-36, respectively; the opposite was observed for the final Borg scale (FBS) score (all SGRQ scores, ρ = 0.34–0.58; PCS score, ρ = − 0.50). The distance-saturation product showed significant negative and positive correlations with all SGRQ scores [ρ = (− 0.29)–(− 0.55)] and the PCS score (ρ = 0.40), respectively. Multivariate analysis revealed that 6MWD and the FBS score were significant predictors of HRQL.

Conclusions

Our findings suggest that 6MWD and the FBS score are useful parameters for evaluating HRQL in patients with pMAC. Further studies should investigate the impact of 6WMT parameters on disease progression, treatment responses, and prognosis.

Electronic supplementary material

The online version of this article (10.1186/s12890-018-0686-5) contains supplementary material, which is available to authorized users.

Clarithromycin expands CD11b+Gr-1+ cells via the STAT3/Bv8 axis to ameliorate lethal endotoxic shock and post-influenza bacterial pneumonia

Macrolides are used to treat various inflammatory diseases owing to their immunomodulatory properties; however, little is known about their precise mechanism of action. In this study, we investigated the functional significance of the expansion of myeloid-derived suppressor cell (MDSC)-like CD11b⁺Gr-1⁺ cells in response to the macrolide antibiotic clarithromycin (CAM) in mouse models of shock and post-influenza pneumococcal pneumonia as well as in humans. Intraperitoneal administration of CAM markedly expanded splenic and lung CD11b⁺Gr-1⁺ cell populations in naïve mice. Notably, CAM pretreatment enhanced survival in a mouse model of lipopolysaccharide (LPS)-induced shock. In addition, adoptive transfer of CAM-treated CD11b⁺Gr-1⁺ cells protected mice against LPS-induced lethality via increased IL-10 expression. CAM also improved survival in post-influenza, CAM-resistant pneumococcal pneumonia, with improved lung pathology as well as decreased interferon (IFN)-γ and increased IL-10 levels. Adoptive transfer of CAM-treated CD11b⁺Gr-1⁺ cells protected mice from post-influenza pneumococcal pneumonia. Further analysis revealed that the CAM-induced CD11b⁺Gr-1⁺ cell expansion was dependent on STAT3-mediated Bv8 production and may be facilitated by the presence of gut commensal microbiota. Lastly, an analysis of peripheral blood obtained from healthy volunteers following oral CAM administration showed a trend toward the expansion of human MDSC-like cells (Lineage⁻HLA-DR⁻CD11b⁺CD33⁺) with increased arginase 1 mRNA expression. Thus, CAM promoted the expansion of a unique population of immunosuppressive CD11b⁺Gr-1⁺ cells essential for the immunomodulatory properties of macrolides.

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of anti-inflammatory myeloid progenitors that expand in response to acute and chronic inflammation as well as in various diseases, such as autoimmune diseases and cancer. The macrolide antibiotic clarithromycin has immunomodulatory effects in various inflammatory diseases, distinct from its antimicrobial effects, but the mechanism underlying these effects is unknown. The present study demonstrates that clarithromycin treatment induces a marked expansion of CD11b⁺Gr-1⁺ MDSC-like cells in the spleen and lungs, sufficient to protect mice from LPS-induced lethality and clarithromycin-resistant bacterial pneumonia via increased IL-10 and decreased IFN-γ levels. Clarithromycin-induced CD11b⁺Gr-1⁺ cell expansion was dependent on STAT3-mediated Bv8 production. Moreover, expansion of the immunosuppressive MDSC-like cell population was observed following clarithromycin treatment in humans. Collectively, these results suggest that the immunomodulatory effects of clarithromycin can be attributed to the induction of CD11b⁺Gr-1⁺ MDSC-like cells via the STAT3/Bv8 axis.

Anti-inflammatory roles of mesenchymal stromal cells during acute Streptococcus pneumoniae pulmonary infection in mice

BACKGROUND

Pneumonia is the fourth leading cause of death worldwide, and Streptococcus pneumoniae is the most commonly associated pathogen. Increasing evidence suggests that mesenchymal stromal cells (MSCs) have anti-inflammatory roles during innate immune responses such as sepsis. However, little is known about the effect of MSCs on pneumococcal pneumonia.

METHODS

Bone marrow-derived macrophages (BMDMs) were stimulated with various ligands in the presence or absence of MSC-conditioned medium. For in vivo studies, mice intranasally-inoculated with S. pneumoniae were intravenously treated with MSCs or vehicle, and various parameters were assessed.

RESULTS

After stimulation with toll-like receptor (TLR) 2, TLR9 or TLR4 ligands, or live S. pneumoniae, TNF-α and interleukin (IL)-6 levels were significantly decreased, whereas IL-10 was significantly increased in BMDMs cultured in MSC-conditioned medium. In mice, MSC treatment decreased the number of neutrophils in bronchoalveolar lavage fluid (BALF) after pneumococcal infection, and this was associated with a decrease in myeloperoxidase activity in the lungs. Levels of proinflammatory cytokines, including TNF-α, IL-6, GM-CSF and IFN-γ, were significantly lower in MSC-treated mice, and the bacterial load in the lung after pneumococcal infection was significantly reduced. In addition, histopathologic analysis confirmed a decrease in the number of cells recruited to the lungs; however, lung edema, protein leakage into the BALF and levels of the antibacterial protein lipocalin 2 in the BALF were comparable between the groups.

CONCLUSIONS

These results indicate that MSCs could represent a potential therapeutic application for the treatment of pneumonia caused by S. pneumoniae.

Clinical characteristics of pulmonary Mycobacterium lentiflavum disease in adult patients

BACKGROUND

Mycobacterium lentiflavum is a slow-growing non-tuberculous Mycobacterium that is often associated with an immunocompromised state and cervical lymphadenitis in young children. However, little is known about the clinical importance of pulmonary infection with M. lentiflavum in adults.

METHODS

The medical records of all adults who met the diagnostic criteria of pulmonary M. lentiflavum disease at Keio University Hospital and Fukujuji Hospital from 2001 to 2015 were reviewed. In addition, the PubMed database was searched to identify further reported cases in non-HIV adults.

RESULTS

Five cases of pulmonary M. lentiflavum disease were identified in the medical records search and 11 additional cases were identified in the literature review. Eleven of the total 16 cases were female, and 15 of 16 cases showed a nodular/bronchiectatic pattern on chest computed tomography imaging. No cases showed an aggressive clinical course of pulmonary M. lentiflavum disease, although one patient died of an exacerbation of underlying vasculitis and bacterial pneumonia.

CONCLUSIONS

The clinical characteristics of pulmonary M. lentiflavum disease in adult patients were identified. This disease mainly affects females, displays a nodular/bronchiectatic pattern on chest computed tomography imaging, and does not demonstrate an aggressive clinical course. Further larger studies are needed to reveal detailed clinical features.