Correction: Unique characteristics of new complete blood count parameters, the Immature Platelet Fraction and the Immature Platelet Fraction Count, in dengue patients.

[This corrects the article DOI: 10.1371/journal.pone.0258936.].

Evaluation of cytokine profiles related to Mycobacterium tuberculosis latent antigens using a whole-blood assay in the Philippines.

Introduction: There is no useful method to discriminate between latent tuberculosis infection (LTBI) and active pulmonary tuberculosis (PTB). This study aimed to investigate the potential of cytokine profiles to discriminate between LTBI and active PTB using whole-blood stimulation with Mycobacterium tuberculosis (MTB) antigens, including latency-associated antigens. Materials and methods: Patients with active PTB, household contacts of active PTB patients and community exposure subjects were recruited in Manila, the Philippines. Peripheral blood was collected from the participants and used for whole-blood stimulation (WBS) with either the early secretory antigenic target and the 10-kDa culture filtrate protein (ESAT-6/CFP-10), Rv3879c or latency-associated MTB antigens, including mycobacterial DNA-binding protein 1 (MDP-1), α-crystallin (Acr) and heparin-binding hemagglutinin (HBHA). Multiple cytokine concentrations were analyzed using the Bio-Plex™ multiplex cytokine assay. Results: A total of 78 participants consisting of 15 active PTB patients, 48 household contacts and 15 community exposure subjects were eligible. The MDP-1-specific IFN-γ level in the active PTB group was significantly lower than that in the household contact group (p < 0.001) and the community exposure group (p < 0.001). The Acr-specific TNF-α and IL-10 levels in the active PTB group were significantly higher than those in the household contact (TNF-α; p = 0.001, IL-10; p = 0.001) and community exposure (TNF-α; p < 0.001, IL-10; p = 0.01) groups. However, there was no significant difference in the ESAT-6/CFP-10-specific IFN-γ levels among the groups. Conclusion: The patterns of cytokine profiles induced by latency-associated MTB antigens using WBS have the potential to discriminate between LTBI and active PTB. In particular, combinations of IFN-γ and MDP-1, TNF-α and Acr, and IL-10 and Acr are promising. This study provides the first demonstration of the utility of MDP-1-specific cytokine responses in WBS.

Corrigendum: Antigen-specific cytokine profiles for pulmonary Mycobacterium avium complex disease stage diagnosis.

[This corrects the article DOI: 10.3389/fimmu.2023.1222428.].

Antigen-specific cytokine profiles for pulmonary Mycobacterium avium complex disease stage diagnosis.

Introduction: Controlling pulmonary Mycobacterium avium complex (MAC) disease is difficult because there is no way to know the clinical stage accurately. There have been few attempts to use cell-mediated immunity for diagnosing the stage. The objective of this study was to characterize cytokine profiles of CD4+T and CD19+B cells that recognize various Mycobacterium avium-associated antigens in different clinical stages of MAC. Methods: A total of 47 MAC patients at different stages based on clinical information (14 before-treatment, 16 on-treatment, and 17 after-treatment) and 17 healthy controls were recruited. Peripheral blood mononuclear cells were cultured with specific antigens (MAV0968, 1160, 1276, and 4925), and the cytokine profiles (IFN-γ, TNF-α, IL-2, IL-10, IL-13, and IL-17) of CD4+/CD3+ and CD19+ cells were analyzed by flow cytometry. Results: The response of Th1 cytokines such as IFN-γ and TNF-α against various antigens was significantly higher in both the on-treatment and after-treatment groups than in the before-treatment group and control (P < 0.01-0.0001 and P < 0.05-0.0001). An analysis of polyfunctional T cells suggested that the presence of IL-2 is closely related to the stage after the start of treatment (P = 0.0309-P < 0.0001) and is involved in memory function. Non-Th1 cytokines, such as IL-10 and IL-17, showed significantly higher responses in the before-treatment group (P < 0.0001 and P < 0.01-0.0001). These responses were not observed with purified protein derivative (PPD). CD19+B cells showed a response similar to that of CD4+T cells. Conclusion: There is a characteristic cytokine profile at each clinical stage of MAC.

Clinical Characteristics of Corynebacterium ulcerans Infection, Japan.

Corynebacterium ulcerans is a closely related bacterium to the diphtheria bacterium C. diphtheriae, and some C. ulcerans strains produce toxins that are similar to diphtheria toxin. C. ulcerans is widely distributed in the environment and is considered one of the most harmful pathogens to livestock and wildlife. Infection with C. ulcerans can cause respiratory or nonrespiratory symptoms in patients. Recently, the microorganism has been increasingly recognized as an emerging zoonotic agent of diphtheria-like illness in Japan. To clarify the overall clinical characteristics, treatment-related factors, and outcomes of C. ulcerans infection, we analyzed 34 cases of C. ulcerans that occurred in Japan during 2001-2020. During 2010-2020, the incidence rate of C. ulcerans infection increased markedly, and the overall mortality rate was 5.9%. It is recommended that adults be vaccinated with diphtheria toxoid vaccine to prevent the spread of this infection.

Exacerbation of autoimmune hemolytic anemia associated with pure red cell aplasia after COVID-19: A case report.

Autoimmune hemolytic anemia (AIHA) and pure red cell aplasia (PRCA) are rare complications of coronavirus disease 2019 (COVID-19). Herein, we report the case of a 28-year-old Japanese man who showed severe AIHA exacerbation associated with PRCA after COVID-19. AIHA was diagnosed and maintained for 5 years. Approximately 4 weeks after COVID-19, the patient developed severe anemia (hemoglobin level, 3.4 g/dL). Laboratory test results confirmed hemolytic exacerbation of IgG-mediated warm-type AIHA. Despite the hemolysis phase, the bone marrow revealed extreme hypoplasia of erythroblasts with a decreased reticulocyte count, similar to that observed in patients with PRCA. During oral prednisolone treatment, the patient recovered from anemia and showed increased reticulocyte count and reduced hypoplasia of marrow erythroblasts. Exacerbation of AIHA and PRCA was triggered by COVID-19 because other causes were ruled out. Although this case report highlights that COVID-19 could lead to hematological complications such as AIHA and PRCA, the exact mechanisms remain unclear.

A prospective observational study of community-acquired bacterial bloodstream infections in Metro Manila, the Philippines.

Community-acquired bacterial bloodstream infections are caused by diverse pathogens with changing antimicrobial-resistance patterns. In low-middle income countries in Southeast Asia, where dengue fever is endemic and a leading cause of fever, limited information is available about bacterial bloodstream infections due to challenges of implementing a blood culture service. This study describes bacterial bloodstream pathogens and antimicrobial-resistance patterns in Metro Manila, the Philippines. We aimed to identify the proportion of patients with a positive blood culture, the bacteria isolated and their antimicrobial resistance patterns, and the clinical characteristics of these patients, in this dengue endemic area. We conducted a prospective observational study in a single hospital enrolling febrile patients clinically suspected of having a community-acquired bacterial bloodstream infection between 1st July 2015 and 30th June 2019. Each patient had a blood culture and additional diagnostic tests according to their clinical presentation. We enrolled 1315 patients and a significant positive blood culture was found in 77 (5.9%) including Staphylococcus aureus (n = 20), Salmonella enterica Typhi (n = 18), Escherichia coli (n = 16), Streptococcus pneumoniae (n = 3) and Burkholderia pseudomallei (n = 2). Thirty-four patients had meningococcal disease diagnosed by culture (n = 8) or blood PCR (n = 26). Additional confirmed diagnoses included leptospirosis (n = 177), dengue virus infection (n = 159) and respiratory diphtheria (n = 50). There were 79 (6.0%, 95%CI 4.8%-7.4%) patients who died within 28 days of enrollment. Patients with a positive blood culture were significantly more likely to die than patients with negative culture (15.2% vs 4.4%, P<0.01). Among S. aureus isolates, 11/20 (55%) were methicillin-resistant (MRSA) and ST30: USA1100 was dominant sequence type (88.9%). Antimicrobial-susceptibility was well preserved in S. enterica Typhi. Among hospitalized patients with clinically suspected community-acquired bacterial bloodstream infection in Metro Manila, the Philippines, 5.9% had a blood culture confirmed infection of whom 15.6% died. S. aureus, including a significant number of MRSA (USA1100 clones), S. enterica Typhi, E.coli and Neisseria meningitidis were frequently identified pathogens.

Respiratory virus detection in the upper respiratory tract of asymptomatic, community-dwelling older people.

BACKGROUND: The prevalence of virus positivity in the upper respiratory tract of asymptomatic community-dwelling older people remains elusive. Our objective was to investigate the prevalence of respiratory virus PCR positivity in asymptomatic community-dwelling older people using saliva samples and nasopharyngeal and oropharyngeal swabs. METHODS: We analyzed 504 community-dwelling adults aged ≥ 65 years who were ambulatory and enrolled in a cross-sectional study conducted from February to December 2018 in Nagasaki city, Japan. Fourteen respiratory viruses were identified in saliva, nasopharyngeal and oropharyngeal samples using multiplex PCR assays. RESULTS: The prevalences of PCR positivity for rhinovirus, influenza A, enterovirus and any respiratory virus were 12.9% (95% CI: 10.1-16.1%), 7.1% (95% CI: 5.1-9.8%), 6.9% (95% CI: 4.9-9.5%) and 25.2% (95% CI: 21.5-29.2%), respectively. Rhinovirus was detected in 21.5% of subjects, influenza A in 38.9% of subjects, enterovirus in 51.4% of subjects and any virus in 32.3% of subjects using only saliva sampling. CONCLUSIONS: The prevalences of several respiratory viruses were higher than the percentages reported previously in pharyngeal samples from younger adults. Saliva sampling is a potentially useful method for respiratory virus detection in asymptomatic populations.

Epidemiological Factors Associated with COVID-19 Clusters in Medical and Social Welfare Facilities.

The characteristics of coronavirus disease 2019 (COVID-19) clusters in medical and social welfare facilities and the factors associated with cluster size are still not yet fully understood. We reviewed COVID-19 cases in Japan identified from January 15 to April 30, 2020 and analyzed the factors associated with cluster size in medical and social welfare facilities. In this study, COVID-19 clusters were identified in 56 medical and 34 social welfare facilities. The number of cases in those facilities peaked after the peak of the general population. The duration of occurrence of new cases in clusters was positively correlated with the number of cases in both types of facilities (rho = 0.44, P < 0.001; and rho = 0.69, P < 0.001, respectively). However, the number of days between the first case in a prefecture and the onset of clusters was negatively correlated with the number of cases only in clusters in social welfare facilities (rho = - 0.4, P = 0.004). Our results suggest that COVID-19 cases in those facilities were prevalent in the latter phase of the disease's community transmission, although the underlying mechanisms for such a trend could differ between medical and social welfare facilities.

Unique characteristics of new complete blood count parameters, the Immature Platelet Fraction and the Immature Platelet Fraction Count, in dengue patients.

The advanced platelet parameters Immature Platelet Fraction and Immature Platelet Fraction Count have been implemented in clinical practice as measures of thrombopoietic activity, mainly in hematologic disorders that cause thrombocytopenia. The purpose of this observational study was to examine thrombopoiesis as reflected by these 2 new CBC parameters in patients infected with dengue. The study was conducted in infectious disease referral hospital in Metro Manila, the Philippines. We enrolled hospitalized patients at admission who were diagnosed with acute dengue or community acquired bacterial infection (CABI). Immature Platelet Fraction (IPF) and Immature Platelet Fraction Count were evaluated at admission and during hospitalization. A total of 606 patients were enrolled from May 1, 2017 to June 1, 2018. The participants consisted of 152 patients with dengue infection, 180 confirmed CABI, and 274 suspected CABI patients. At admission, the percent IPF (IPF%) of the patients with dengue was significantly higher than that of the confirmed CABI patients (median 3.7% versus 1.9%; p <0.001). In a time course evaluation, there was no significant difference of IPF% between the patients with dengue infection and the confirmed CABI patients in the febrile phase (median 1.9% versus 2.4%; p = 0.488), however, the IPF% of the patients with dengue infection increased to be significantly higher than that of the confirmed CABI patients in the critical phase (median 5.2% versus 2.2%; p <0.001). Our study elucidated the unique characteristics and time-course trends of IPF percent and number (IPF#) in the patients with dengue infection. IPF% and IPF# are potentially valuable parameters in dengue and further investigation is required for the optimal use in clinical practice.

Roles of Children and Adolescents in COVID-19 Transmission in the Community: A Retrospective Analysis of Nationwide Data in Japan.

Background: Roles of children and adolescents in spreading coronavirus disease 2019 (COVID-19) in the community is not fully understood. Methods: We analyzed the data of 7,758 children and adolescents with COVID-19 and characteristics of secondary transmission generated by these cases using case information published by local governments. Ratio of pediatric and adolescent cases generating secondary transmission was calculated for various social settings. Results: The incidence of COVID-19 was 24.8 cases per 105 population aged between 0 and 9 years, and 59.2 among those aged between 10 and 19 years, which was lower than that among individuals of all age groups (79.6 per 105 population) between January 15 and October 31, 2020. The proportion of cases generating secondary cases was 8.3% among infants and young children in nursery schools and kindergartens, 16% among children and adolescents attending primary schools, 34% among those attending junior high schools, 43% among those attending high schools, 31% among those attending professional training colleges, and 24% in those attending universities. Households were the most common setting for secondary transmission. Conclusion: The risk of generating secondary cases might be limited among pediatric and adolescent cases with COVID-19, especially in settings outside households. Effectiveness of traditional mitigation measures (e.g., school closures) to suppress COVID-19 transmissions should be carefully evaluated.

Epidemiology of Coronavirus Disease Outbreak among Crewmembers on Cruise Ship, Nagasaki City, Japan, April 2020.

In April 2020, a coronavirus disease (COVID-19) outbreak occurred on the cruise ship Costa Atlantica in Nagasaki, Japan. Our outbreak investigation included 623 multinational crewmembers onboard on April 20. Median age was 31 years; 84% were men. Each crewmember was isolated or quarantined in a single room inside the ship, and monitoring of health status was supported by a remote health monitoring system. Crewmembers with more severe illness were hospitalized. The investigation found that the outbreak started in late March and peaked in late April, resulting in 149 laboratory-confirmed and 107 probable cases of infection with severe acute respiratory syndrome coronavirus 2. Six case-patients were hospitalized for COVID-19 pneumonia, including 1 in severe condition and 2 who required oxygen administration, but no deaths occurred. Although the virus can spread rapidly on a cruise ship, we describe how prompt isolation and quarantine combined with a sensitive syndromic surveillance system can control a COVID-19 outbreak.

Familial Clusters of Coronavirus Disease in 10 Prefectures, Japan, February-May 2020.

The overall coronavirus disease secondary attack rate (SAR) in family members was 19.0% in 10 prefectures of Japan during February 22-May 31, 2020. The SAR was lower for primary cases diagnosed early, within 2 days after symptom onset. The SAR of asymptomatic primary cases was 11.8%.

Clusters of Coronavirus Disease in Communities, Japan, January-April 2020.

We analyzed 3,184 cases of coronavirus disease in Japan and identified 61 case-clusters in healthcare and other care facilities, restaurants and bars, workplaces, and music events. We also identified 22 probable primary case-patients for the clusters; most were 20-39 years of age and presymptomatic or asymptomatic at virus transmission.

The low carriage prevalence of pneumococcus among community-dwelling older people: A cross-sectional study in Japan.

BACKGROUND: The carriage prevalence of pneumococcus among community-dwelling older adults is not fully understood, especially in superaged societies. Our purpose was to elucidate the carriage prevalence of pneumococcus in the upper respiratory tract among Japanese community-dwelling adults aged ≥65 years. METHODS: We conducted a cross-sectional study of generally healthy community-dwelling adults aged ≥65 years in Nagasaki city, Japan. Demographic and clinical data and nasopharyngeal, oropharyngeal and saliva samples were collected from February 21st, 2018, to December 17th, 2018. The specimens were tested by culture and molecular methods. RESULTS: Among a total of 504 enrolled participants, none were positive for pneumococcus by culture, and 22 were positive by PCR. The overall carriage prevalence was 4.4% (95% CI: 2.8-6.5%). The prevalence was highest in saliva samples, followed by oropharyngeal and nasopharyngeal samples. No demographic characteristics were associated with carriage prevalence, including age (4.7% among participants aged 65-74 years and 4.1% among those 75 years and older). Among the pneumococcal-positive participants, 18.2% were PCV13-covered serotypes. CONCLUSIONS: Our data suggest a low carriage prevalence of S. pneumoniae among community-dwelling older people in Japan.

CD4+ T Responses Other Than Th1 Type Are Preferentially Induced by Latency-Associated Antigens in the State of Latent Mycobacterium tuberculosis Infection.

Mycobacterium tuberculosis (M. tuberculosis) produces a diverse range of antigenic proteins in its dormant phase. The cytokine profiles of CD4+ T cell responses, especially subsets other than Th1 type (non-Th1 type), against these latency-associated M. tuberculosis antigens such as α-crystallin (Acr), heparin-binding hemagglutinin (HBHA), and mycobacterial DNA-binding protein 1 (MDP-1) remain elusive in relation to the clinical stage of M. tuberculosis infection. In the present study, peripheral blood mononuclear cells (PBMCs) collected from different stages of M. tuberculosis-infected cases and control PBMCs were stimulated with these antigens and ESAT-6/CFP-10. Cytokine profiles of CD4+ T cells were evaluated by intracellular cytokine staining using multicolor flow cytometry. Our results demonstrate that Th1 cytokine responses were predominant after TB onset independent of the type of antigen stimulation. On the contrary, non-Th1 cytokine responses were preferentially induced by latency-associated M. tuberculosis antigens, specifically IL-10 response against Acr in latent M. tuberculosis infection. From these results, we surmise a shift in the CD4+ T cell response from mixed non-Th1 to Th1 dominant type during TB progression.

Severe Pneumonia Caused by Toxigenic Corynebacterium ulcerans Infection, Japan.

Corynebacterium ulcerans infection was recently recognized as a zoonosis. We present 2 cases of severe pneumonia complicated by diffuse pseudomembrane formation on the bronchus caused by C. ulcerans-producing diphtheria toxin. Our purpose is to alert medical professionals to the virulence of Corynebacterium species other than C. diphtheriae.

Nontuberculous mycobacteria in diffuse panbronchiolitis.

BACKGROUND AND OBJECTIVE: Nontuberculous mycobacterial (NTM) lung disease secondary to cystic fibrosis (CF) has been reported, but there is limited data about NTM prevalence in non-CF bronchiectasis. We retrospectively investigated the prevalence of NTM associated with diffuse panbronchiolitis (DPB), a disorder also characterized by reduced mucociliary clearance with bronchiectasis. METHODS: We reviewed mycobacterial cultures, patient characteristics and computed tomography findings of 33 patients with DPB between January 2000 and December 2012. Prevalence was based on at least one positive NTM culture. RESULTS: Mean patient age was 51.5 years. During a mean 162.8-month follow-up, the prevalence of NTM in sputum was 21.2% (seven patients). Of the seven positive patients, six had Mycobacterium avium complex, one had M. kansasii and M. chelonae co-cultured with M. avium complex. Three patients were positive twice, and two had positive smears. The mean time from DPB diagnosis to the first positive result was 194.6 months. NTM-positive patients tended to have lower forced expiratory volume in 1 s (% predicted) than NTM-negative patients (50.0% vs 77.3%, P = 0.03), but there were no radiological or clinical differences between the two groups. CONCLUSIONS: Our observations suggest that NTM is found more often in DPB. Defects of mucociliary clearance may predispose individuals to NTM infection.