Takehiro Togashi

Epidemiology of influenza-associated encephalitis-encephalopathy in Hokkaido, the northernmost island of Japan

Abstract Background : It is well known that acute onset brain dysfunction, which usually is diagnosed as encephalitis or encephalopathy, occurs in association with influenza. However, this may have been underestimated as a rather infrequent event. Sixty‐four infants and children developed encephalitis‐encephalopathy during the five recent influenza seasons in Hokkaido, the northernmost island of Japan.

Interleukin-6 in cerebrospinal fluid of patients with central nervous system infections

Interleukin(IL)‐6 levels were measured in cerebrospinal fluid (CSF) and serum samples from pediatric patients with central nervous system (CNS) infections by means of an enzyme‐linked immunosorbent assay. Mean IL‐6 concentrations in CSF samples from patients with bacterial meningitis (49017 44 730 pg/ml) were significantly higher than those in patients with aseptic meningitis (10761572 pg/ml) or encephalitis (409835 pg/ml). In aseptic meningitis and encephalitis, IL‐6 levels in serum were within the lower ranges (< 100 pg/ml), in contrast with the highly elevated levels found in bacterial meningitis (14 33218 385 pg/ml). In 5 of the 15 patients with encephalitis, elevated levels of IL‐6 were observed in the initial CSF samples despite normal findings of routine CSF examinations. Also, sequential CSF samples revealed that there was an increase in the CSF cell count in two of the five patients. These results validated the potential of measuring IL‐6 in CSF samples for the purpose of providing additional information on routine laboratory test results. D Central nervous system infection, cerebrospinal fluid, children, enzyme‐linked immunosorbent assay, interleukin‐6.

Ocular Manifestations of Kawasaki's Disease (Mucocutaneous Lymph Node Syndrome)

In a prospective study of the ocular manifestations of Kawasakis disease (mucocutaneous lymph node syndrome) in 18 children (11 boys and seven girls, ranging in age from 5 months to 9 years), we found bilateral injection of the bulbar conjunctiva in 16, bilateral iridocyclitis in 14, superficial punctate keratitis in four, vitreous opacities in two, papilledema in two, and subconjunctival hemorrhage in one. Conjunctival injection and iridocyclitis were always bilateral, and fellow eyes always had the same degree of inflammation. There were significant correlations between ocular inflammation and erythrocyte sedimentation rate (P less than .0001) and C-reactive protein level (P less than .0009). No serious ocular complications occurred.

Close Association between Pulmonary Disease Manifestation in Mycoplasma pneumoniae Infection and Enhanced Local Production of Interleukin-18 in the Lung, Independent of Gamma Interferon

ABSTRACT To investigate pathophysiologies of Mycoplasma pneumoniae infection from an immunological point of view, we measured the levels of interleukin-18 (IL-18) (originally designated gamma interferon [IFN-γ]-inducing factor) in 19 serum samples from 10 patients with pneumonia without pleural effusion (ages 1 to 16 years), 3 serum and 13 pleural fluid samples from 11 patients with pleural effusions (ages 11 months to 15 years), and 18 serum and 27 cerebrospinal fluid samples from 24 patients with central nervous system complications (ages 1 to 15 years). IL-18 was measured by a commercially available enzyme-linked immunosorbent assay kit (MBL, Nagoya, Japan). In addition, the levels of tumor necrosis factor alpha, IFN-γ, IL-6, IL-12, and KL-6 (a mucin-like glycoprotein expressed on type 2 pneumocytes) were measured in selected samples. The results concerning pleural effusions showed that elevated levels of IL-18 in pleural fluid, but not in serum, were solely associated with a sustained fibrotic change of the lung on chest roentgenography which might represent a pathological feature of intraluminal organization. All the pleural fluid samples with elevated levels of IL-18 were positive by PCR for M. pneumoniae DNA. There was no association between IL-18 and IFN-γ levels in serum or in the pleural fluid. On the other hand, elevated levels of IL-18 in serum, but not in cerebrospinal fluid samples, were observed in the cases complicated by central nervous system involvement, including profound brain dysfunction with seizures. Our study demonstrated that M. pneumoniae can induce IL-18 and that the enhanced local production of IL-18 in the lung is closely associated with pulmonary disease manifestation.

Childhood bacterial meningitis in Japan.

Haemophilus influenzae type b (Hib) vaccines currently are not used in Japan, but interest in preventing H. influenzae disease by immunization has grown. We performed a retrospective survey for bacterial meningitis in 6 prefectures of Japan. Questionnaires requested the age, sex, clinical outcome and identity of the etiologic organism, if known, of all patients with meningitis younger than 16 years of age who were admitted during calendar year 1994. Of 876 hospitals within the 6 study prefectures, 363 (41.4%) returned a completed questionnaire. There were 1769 cases of meningitis reported, of which 160 (9%) were considered bacterial in origin. H. influenzae was the most common cause of bacterial meningitis, accounting for 68 cases (43%). Sixty-six cases (97%) of H. influenzae meningitis occurred in children 4 years of age or younger, and 27 (40%) occurred in children <1 year of age. Calculated incidence rates based on the population of children 4 years of age or less for each prefecture ranged from 3.4 to 9.9 cases per 100000 (mean, 4.7 cases/100000). H. influenzae is the most common cause of meningitis in Japan, and the estimated incidence rates from this study are very similar to those previously reported from Japan. More comprehensive, prospective surveillance studies will be needed to define better the incidence of Hib meningitis and to aid in making rational decisions regarding the use of Hib vaccination in Japan.

Nationwide population-based surveillance of invasive pneumococcal disease in Japanese children: Effects of the seven-valent pneumococcal conjugate vaccine.

BACKGROUND In Japan, the seven-valent pneumococcal conjugate vaccine (PCV7) was introduced in 2010. PCV13 has replaced PCV7 since November 2013. METHODS The effectiveness of PCV7 in protecting against invasive pneumococcal disease (IPD) in children aged <5 years was evaluated in a nationwide active population-based surveillance of IPD in 2008-2013 in 10 prefectures in Japan. RESULTS 1181 cases were identified; 711 pneumococcal strains were analyzed for serotyping and antimicrobial resistance. Compared with the baseline IPD incidence (25.0 per 100,000), a 98% decline in IPD caused by PCV7 serotypes was found after the introduction of PCV7. This was partially offset by an increased incidence of IPD caused by PCV13 minus PCV7 and non-PCV13 serotypes, resulting in a 57% decline in overall IPD incidence. Absolute increases in the incidence rates of IPD caused by PCV13 minus PCV7 and non-PCV13 serotypes were 2.1 and 2.8 per 100,000 during the study period, respectively. The proportion of meropenem-nonsusceptible strains, especially with serotypes 19A and 15A, increased significantly after PCV7 introduction. CONCLUSIONS Our data confirmed a 98% decline in IPD incidence caused by PCV7 serotypes in children aged <5 years and serotype replacement after PCV7 introduction. This shows the importance of continuing surveillance of serotypes responsible for IPD and their antimicrobial resistance in Japan.

Analysis of mycoplasmal pleural effusion by the polymerase chain reaction

Ten pediatric patients with mycoplasmal pleuritis were tested for the presence of Mycoplasma pneumoniae in pleural fluid by the polymerase chain reaction (PCR). Three of the four PCR positive cases left a persistent consolidation. The remaining one was an infant who required mechanical ventilation. PCR may be useful in predicting delayed resolution of roent- genographic abnormality.

Polymerase chain reaction for detection of Mycobacterium tuberculosis.

Rapid diagnosis of tuberculosis is essential, and therefore we use a polymerase chain reaction. In this report, we describe two cases of tuberculous lymphadenitis in childhood. Although histopathological findings were not specific for tuberculosis in both cases, distinct positive bands were amplified. For DNA diagnosis of tuberculosis, a lysis method of extracting chromosomal DNA from lipid‐rich cell walls of mycobacteria is of critical importance. We made use of a simple lysozyme‐proteinase K treatment for biopsied tissues. Although this extraction procedure was less efficient than those reported previously, it was considered sufficient for detecting mycobacterial DNA with the use of a highly sensitive polymerase chain reaction. We conclude that DNA amplification in combination with lysozyme lysis can be used routinely in clinical laboratories as a rapid and sensitive test for the diagnosis of tuberculosis.

Nested amplification protocol for the detection of Mycobacterium tuberculosis

Several methods for rapid diagnosis of tuberculosis have been devised through DNA amplification. However, the chemically strong cell wall of the species, the presumptively low numbers of organisms and their uneven distribution in clinical samples, and the lack of a “gold standard” for diagnosing tuberculosis, have hindered the routine clinical use of this method. In a pediatric patient group, these factors are more perplexing. To circumvent these problems, we made use of nested amplification and developed a standard protocol for extracting DNA from various forms of clinical samples which were suitable to our clinical laboratory. It is our impression that the overall sensitivity, including technical bias accompanying this method, is equal to, or at least greater than, that of culture. Most notably, the rapidity in obtaining results and the simplicity in handling, storage and transfer of samples are the principal advantages of this method.

Phase III Clinical Trials Comparing the Immunogenicity and Safety of the Vero Cell-Derived Japanese Encephalitis Vaccine Encevac with Those of Mouse Brain-Derived Vaccine by Using the Beijing-1 Strain

ABSTRACT The immunogenicity and safety of an inactivated cell culture Japanese encephalitis vaccine (CC-JEV) were compared with those of an inactivated mouse brain-derived Japanese encephalitis vaccine (MB-JEV) in phase III clinical multicenter trials conducted in children. The vaccines contain the same Japanese encephalitis virus strain, the Beijing-1 strain. Two independent clinical trials (trials 1 and 2) were conducted. Trial 1 was conducted in 468 healthy children. Each subject was injected with 17 μg per dose of either CC-JEV or MB-JEV, and the immunogenicity and safety of the vaccines were investigated. Trial 1 showed that CC-JEV was more immunogenic and reactive than MB-JEV at the same dose. Therefore, to adjust the immunogenicity of CC-JEV to that of MB-JEV, a vaccine that has had a good track record regarding its efficacy for a long time, trial 2 was conducted in 484 healthy children. To improve the stability, CC-JEV was converted from a liquid type to a freeze-dried type of vaccine. Each subject was injected subcutaneously with either 4 μg per dose of CC-JEV, 8 μg per dose of CC-JEV, or 17 μg per dose of MB-JEV twice, at an interval of 2 to 4 weeks, followed by an additional booster immunization 1 to 15 months after the primary immunization. Based on the results of trial 2, 4 μg per dose of the freeze-dried CC-JEV (under the label Encevac) was selected as a substitute for the MB-JEV. Encevac was approved and launched in 2011 and has since been in use as a 2nd-generation Japanese encephalitis vaccine in Japan. (These studies have been registered at the JapicCTI under registration no. JapicCTI-132063 and JapicCTI-080586 for trials 1 and 2, respectively.)