Shunzo Chiba

PROTECTIVE EFFECT OF NATURALLY ACQUIRED HOMOTYPIC AND HETEROTYPIC ROTAVIRUS ANTIBODIES

To assess serotype specificity of immune resistance to rotavirus gastroenteritis, the relation between pre-existing neutralising antibodies to homotypic and heterotypic rotaviruses and protection against infection or clinical illness was investigated. The subjects were 44 orphans exposed once or twice to consecutive outbreaks of gastroenteritis due to type 3 rotavirus in an orphanage in Sapporo. Sera were collected throughout these outbreaks and the serum levels of neutralising antibodies against four different serotypes of group A human rotavirus were measured before and after the outbreaks. Protection against rotavirus gastroenteritis seemed to be serotype specific and to be related to levels of antibody against homotypic virus. A neutralising antibody level of 1/128 or greater seemed to be protective. The protective effect was of short duration, which was probably the explanation for recurrent attacks of gastroenteritis due to a rotavirus of the same serotype. Seroconversions or concomitant antibody responses to type 1 or 4 rotavirus in most children with type 3 rotavirus infection suggested that immunity to heterotypic virus can be induced by a rotavirus vaccine.

Human parvovirus B19 infection associated with acute hepatitis

BACKGROUND Human parvovirus (HPV) B19 infection produces a range of clinical manifestations including erythema infectiosum in children. Here we describe seven children who had acute hepatitis with HPV B19 infection. METHODS Hepatic dysfunction was noted in three children referred to our hospital during the course of erythema infectiosum caused by HPV B19 infection diagnosed by ELISA and PCR. The role of HPV B19 in the pathogenesis of hepatic involvement was investigated retrospectively by PCR assay of stored serum samples from 773 patients admitted to our hospital. FINDINGS 15 patients admitted to our hospital from January, 1991, to June, 1992, were HPV B19 DNA positive, of whom four had acute hepatitis of unknown origin. These four patients were aged between 7 months and 5 years. Of the seven patients, infection with hepatitis A, B, or C viruses or Epstein-Barr virus was ruled out in six by virological examinations. INTERPRETATION Epidemiological evidence suggests that HPV B19 can be the cause of acute hepatitis.

Identification of human and bovine rotavirus serotypes by polymerase chain reaction.

The use of the polymerase chain reaction (PCR) for identifying serotypes of human and bovine rotaviruses was examined. In the identification of 115 human rotavirus samples in stools, results with PCR showed excellent agreement with results of serotyping by an enzyme-linked immunosorbent assay (ELISA) using serotype-specific monoclonal antibodies. Furthermore, the PCR showed a much higher sensitivity (93%) than the ELISA test (82.6%). The PCR method could also be applied for identifying the serotype of bovine rotaviruses.

Gelatin-specific humoral and cellular immune responses in children with immediate- and nonimmediate-type reactions to live measles, mumps, rubella, and varicella vaccines ☆ ☆☆ ★

BACKGROUND This study was designed to investigate the development of both cellular and humoral immune responses to gelatin in patients with vaccine-related immediate and nonimmediate reactions. Our purpose was to define the nature of the responses in the different clinical states. METHODS Six patients with immediate reactions and 21 patients with nonimmediate reactions after inoculation of various live vaccines were studied. Measurement of gelatin-specific IgE was performed in all subjects. Gelatin-specific T-cell responses detected by an in vitro lymphocyte proliferation assay and by an assay for IL-2 responsiveness were investigated to compare the immune response in patients with the two types of reaction. RESULTS All six patients with immediate reactions had IgE responses to gelatin, whereas none of the 21 patients with nonimmediate reactions had any anti-gelatin IgE. All of the six patients with immediate reactions and 17 of the 21 patients with nonimmediate reactions exhibited positive T-lymphocyte responses specific to gelatin. CONCLUSIONS Immediate and nonimmediate reactions are caused by different types of allergy to gelatin, and cell-mediated immunity to gelatin may play an important role in the pathogenesis of nonimmediate reactions.

Clinical severity of Norwalk virus and Sapporo virus gastroenteritis in children in Hokkaido, Japan

Objective. To clarify the clinical significance and etiologic impact of Norwalk virus (NV) and Sapporo virus (SV) in viral gastroenteritis in Japanese children. Study design. Two outbreaks each of NV gastroenteritis and SV gastroenteritis occurring in an infant home in Sapporo, Japan, as well as 95 hospitalized children with acute gastroenteritis were retrospectively evaluated using a 0- to 20-point clinical severity scoring system. Result. The mean severity scores for NV and SV gastroenteritis outbreaks were 7.9 and 5.2, respectively, as compared with 8.4 for rotavirus A gastroenteritis that occurred in the same infant home. Among 95 hospitalized children with acute gastroenteritis, rotavirus A was detected in 47% followed by NV in 18%. SV was not found. Conclusion. Our data indicate that NV can cause severe gastroenteritis and is an important etiologic agent in hospitalized cases, whereas SV causes mild gastroenteritis in Japanese children.

Incidence of human parvovirus B19 DNA detection in blood donors.

Summary. 1000 serum samples from blood donors were tested for human parvovirus B19 (B19) DNA by a nested PCR assay: six samples were positive for B19 DNA. The frequency was 1/167 (0‐6%), considerably higher than previous surveys (0‐004‐0‐03%). Five of the six samples were also positive for anti‐B19 IgM, indicating an acute phase of infection. It is recommended to screen for B19 DNA in blood products to prevent transfusion mediated viral infection for those susceptible such as immunocompromised patients and pregnant women.

Members of the Family Caliciviridae (Norwalk Virus and Sapporo Virus) Are the Most Prevalent Cause of Gastroenteritis Outbreaks among Infants in Japan

Norwalk virus (NV) and Sapporo virus (SV) were approved as type species of the genus Norwalk-like viruses and the genus Sapporo-like viruses, respectively, within the family Caliciviridae. To clarify the importance of NV and SV as causes of gastroenteritis outbreaks in infants, stool samples obtained from 36 outbreaks of nonbacterial gastroenteritis that occurred during 1976-1995 in an infant home in Sapporo, Japan, were examined for diarrhea viruses using electron microscopy, enzyme immunoassays, reverse transcriptase-polymerase chain reaction (PCR), and sequencing of the PCR products. NV and SV were associated with 15 (42%) of the 36 outbreaks and were more prevalent than rotavirus (RV) A, which was associated with 10 (28%) of the 36 outbreaks. Our data indicate that NV and SV were the most common cause of outbreaks of viral gastroenteritis in infants and were indeed more prevalent than RV-A in Sapporo, Japan, during 1976-1995.

Respiratory syncytial virus infection of human respiratory epithelial cells enhances inducible nitric oxide synthase gene expression.

The induction kinetics of the mRNA of interferon regulatory factor 1 (IRF‐1), inducible nitric oxide synthase (iNOS), and proinflammatory cytokines in respiratory syncytial virus (RSV)‐infected human type 2 alveolar epithelial cells (A549 cells) were analyzed semiquantitatively by RT‐PCR. RSV enhanced IRF‐1 and iNOS mRNA expression as early as 4 h after RSV infection and this enhancement lasted several hours. No IFN‐γ gene expression was observed during the whole course of the infection. Expression of IFN‐β, IL‐1β, and TNF‐α genes was observed slightly at 4 h and became marked 7 h after infection. Addition of neutralizing antibodies to these cytokines to the culture had no effect on the induction of iNOS mRNA. The iNOS transcriptional activity in RSV‐infected cells was significantly enhanced by an exogenous cytokine mixture (IL‐1β, TNF‐α, and IFN‐γ). An apparent nitric oxide (NO) production was identified only when cytokines were added together with RSV infection. A significant increase of iNOS gene expression was observed in nasopharyngeal exudate cells obtained from infants during the acute phase of RSV bronchiolitis. These observations suggest that RSV infection of human respiratory epithelial cells induces the iNOS gene both in vitro and in vivo; this induction may occur rather promptly and involves transcriptional activator IRF‐1 induced by the RSV infection itself. The iNOS gene, which is initially induced by RSV infection, may be further enhanced in a paracrine fashion by proinflammatory cytokines released by infection‐activated inflammatory cells. J. Leukoc. Biol. 66: 99–104; 1999.

OUTBREAK OF INFANTILE GASTROENTERITIS DUE TO TYPE 40 ADENOVIRUS

Genetic and antigenic characterisation was performed on a strain of adenovirus (EAd) isolated from an outbreak of gastroenteritis which occurred in an orphanage in the City of Sapporo, in the room housing the eldest children, who ranged in age from 14 to 22 months. 7 of the 11 children housed in that room had diarrhoea between July 11 and July 22, 1982. All 7 shed adenoviruses detectable by electron microscopy in their stools. Immune electron microscopy showed that all patients as well as the healthy contacts sharing the room underwent seroconversion to EAd. There was no homology, or very slight homology, between DNA of EAd and those of adenoviruses belonging to subgroups A to E. Antigenically EAd was closely related to type 40 adenovirus, so far the sole member of the newly identified subgroup F. This outbreak of gastroenteritis is the first in which the causative agent has been identified as being a member of subgroup F adenoviruses.

Survey on the distribution of the gene 4 alleles of human rotaviruses by polymerase chain reaction

The presence of six gene 4 alleles (or VP4 genotypes) in human rotaviruses has been recognized. Using 16 representative cultivable human rotavirus strains, we confirmed the specificity of VP4 genotyping by polymerase chain reaction (PCR) using the nested oligonucleotides specific to each of the four representative gene 4 alleles. Using the PCR, we surveyed the gene 4 alleles of 199 human rotaviruses in stools collected in Japan and Thailand. Strains with the gene 4 allele, corresponding to P1A serotype, were shown to be the most prevalent, but two strains with P2 gene 4 allele and one strain with P3 gene 4 allele were detected in Thailand and in Japan, respectively.