Genetic and antigenic characterization of measles viruses that circulated in Korea during the 2000-2001 epidemic

Macrophages and Dendritic Cells Are the Predominant Cells Infected in Measles in Humans

Characterization of human measles cases is essential in order to better assess the data generated in model systems of morbillivirus infection. To this end, we collected formalin-fixed tissue samples from 23 natural measles cases from different areas in the world and different phases of disease ranging from prodromal and acute measles to a persistent infection in an immunocompromised subject. We show that the vast majority of measles virus (MV)-infected cells in epithelia were intraepithelial immune cells that were, in most cases, positive for the CD11c myeloid cell marker. Small numbers of measles virus-infected cytokeratin-positive epithelial cells were also detected in bronchial and appendix epithelia. Dissolution and disruption of uninfected and MV-infected alveolar and bronchial epithelia were prominent features of the measles cases, especially in the established and late phases of the disease. In some instances, this was associated with the formation of MV-infected multinucleated giant cells which expressed CD11c and/or macrophage cell marker 68, a pathological feature also prominently observed in closely associated mucosa-associated lymphoid tissue. Collectively, these data show that resident and inflammatory infiltrating immune cells alter the architecture of respiratory tract epithelia and highlight the necessity for additional research into the function(s) and expression of nectin-4 in human tissues.IMPORTANCE We have brought together a unique collection of 23 human cases of measles infection and studied the types of cells that are infected. This work has not been done with modern technologies such as double labeling with antibodies and confocal microscopy in human cases primarily due to the fact that it is difficult to obtain the material because, fortunately, measles is fatal in only a very small fraction of infected patients. During the past decades, the receptors for measles virus have been elucidated and monkey models have been developed. We found that, in most cases, independently of whether the tissues were obtained early or later in the infection, the primary cell types that were infected were those of the immune system such as lymphocytes, macrophages, and dendritic cells. A very small number of epithelial cells were also found to be infected.

Vaccination of hematopoietic stem cell transplantation recipients: perspective in Korea

Antibody titers to vaccine-preventable diseases such as tetanus, polio, measles, mumps, and rubella decline within 1-10 years after allogeneic or autologous hematopoietic stem cell transplantation (SCT) if the recipient is not vaccinated. Vaccine-preventable diseases such as pneumococcal diseases, Haemophilus influenzae type b infections, influenza, measles, and varicella can pose an increased risk for SCT recipients. Therefore, after SCT, the recipients should be routinely revaccinated. Vaccination recommendations have previously been developed and published by the European Group of Blood and Marrow Transplantation and the Centers for Disease Control, by the Infectious Diseases Society of America, and by the American Society for Blood and Marrow Transplantation in 2009. Different epidemiologies and strategies have existed in Korea. In 2012, the Korean Society of Infectious Diseases published "Vaccination for Adult" describing the guidelines for vaccination, one of the chapters assigned for vaccination of SCT recipients. The present article reviews the current available vaccination strategies for SCT recipients, their family members, and healthcare workers, with the focus on recent Korean perspectives.

Molecular epidemiology of measles virus in Iran 2009-2010: first detection of measles genotype H1

Measles virus (MV) genotyping is an important component of measles surveillance in the context of monitoring immunization program effectiveness and documenting MV elimination. The molecular epidemiology and genetic variability of circulating MV strains in Iran during the 2009-2010 were studied in consecutive MV isolates from throat swab and urine. Sequence information obtained from 41 cases based on the 456 nucleotides of the most variable region of the C-terminal part of the N-protein revealed that these sequences belonged to two different genotypes. This is the first description of the genetic characterization of sporadic MV genotype H1 cases in northern Iran. Cases were probably linked to MV importation from distant parts of Asia. The genotype H1 has not been detected in the Eastern Mediterranean Region. In addition, both sequence analysis and epidemiologic data indicated that the more recently detected genotype D4 viruses in Iran were related very closely to viruses that were detected in Pakistan, suggesting that these viruses may have been imported from Pakistan. J. Med. Virol. 83:2200-2207, 2011. © 2011 Wiley Periodicals, Inc.

Effects of early measles on later rhinitis and bronchial hyperresponsiveness

BACKGROUND

The hygiene hypothesis suggests that infectious diseases in early life reduce the risk of allergic diseases.

OBJECTIVE

To investigate the association between measles infection during early childhood and the prevalence of allergic diseases, lung function, bronchial hyperresponsiveness (BHR), and sensitization in later childhood.

METHODS

A survey was conducted 5 years after a nationwide measles outbreak in Korea. From September 1 through November 30, 2006, we obtained information on history of measles and allergic diseases but not of measles vaccination through a questionnaire completed by 1004 schoolchildren aged 6 to 7 years. Furthermore, we measured measles antibody titers and performed skin prick tests, pulmonary function tests, and methacholine challenge tests. Children were divided into groups based on their history of measles infection and antibody titers.

RESULTS

Prevalence of measles infection was 8.2%. Children with both a positive measles history and a positive antimeasles antibody had significantly higher antimeasles antibody levels than those without a measles history. The prevalence of current rhinitis (adjusted odds ratio [aOR], 1.86; 95% confidence interval [CI], 1.02-3.40), rhinitis ever (aOR, 2.17; 95% CI, 1.19-3.94), and current BHR (aOR, 1.98; 95% CI, 1.04-3.78) was significantly higher in the group with a positive measles history compared with the group with a negative measles antibody. No differences were found among groups in the prevalence of asthma, lung function, provocation concentration that caused a decrease in forced expiratory volume of 1 second of 20%, or sensitization.

CONCLUSION

Early measles infection was associated with increased prevalence of rhinitis and BHR at the age of 7 years but has no effect on the development of asthma and allergy at the age of 7 years. This study indicates that common childhood infections such as measles in early age do not protect against later development of allergic diseases.

Molecular evolution of measles viruses circulated in Taiwan 1992-2008

Genetic analyses of viral samples from 74 laboratory confirmed measles cases occurring in Taiwan during 1992-2008 identified six viral genotypes D3, D5, D9, G2, H1 and H2. The most frequently detected genotype, H1, was associated with outbreaks in 1994 and 2002, and was the likely indigenous genotype in 1992. In response to the outbreaks, two catch-up campaigns were launched and a routine second dose of measles, mumps, and rubella vaccine at entry to elementary school was introduced. The vaccination campaigns successfully reduced the number of measles cases in Taiwan, and many of the more recent cases can be traced to importations, primarily from other Asian countries. A number of measles genotypes which were associated with outbreaks in other Asian countries were detected among the more recent cases. The more recent genotype H1 viruses had sequences that were identical to those currently circulating in China or associated with international importation of virus.

Measles viruses of genotype H1 evade recognition by vaccine-induced neutralizing antibodies targeting the linear haemagglutinin noose epitope

The linear haemagglutinin noose epitope (HNE; aa 379–410) is a protective B-cell epitope and considered to be highly conserved in both the vaccine and the wild-type measles virus (MeV) haemagglutinin (H) proteins. Vaccine virus-derived monoclonal antibodies (mAbs) BH6 and BH216, which target the HNE, neutralized MeVs of genotypes B3, C2, D4, D5, D6, D7 and D8, and the vaccine strain Edmonston Zagreb. In the case of genotype H1, only strain Berlin.DEU/44.01 was neutralized by these mAbs, whereas strains Shenyang.CHN/22.99 and Sofia.BGR/19.05 were not. The H gene sequences of these two strains showed an exchange of proline 397 (P397) to leucine (L397). Mutated H proteins, with P397 exchanged to L and vice versa, were compared with original H proteins by indirect fluorescence assay. H proteins exhibiting P397 but not those with L397 were recognized by BH6 and BH216. This indicates that L397 leads to the loss of the neutralizing HNE. In contrast, human sera obtained from vaccinees (n=10) did not discriminate between genotype H1 variants P397 and L397. This concurs with the epidemiological observation that the live-attenuated vaccine protects against both H1 variants. Furthermore, we demonstrated that MeVs of genotype H1 also lack the neutralizing epitopes defined by the vaccine virus-induced mAbs BH15, BH125 and BH47. The loss of several neutralizing epitopes, as shown for H1 viruses currently circulating endemically in Asia, implies that epitope monitoring should be considered to be included in measles surveillance.

Molecular epidemiology of measles virus

Genetic characterization of wild-type measles viruses provides a means to study the transmission pathways of the virus and is an essential component of laboratory-based surveillance. Laboratory-based surveillance for measles and rubella, including genetic characterization of wild-type viruses, is performed throughout the world by the WHO Measles and Rubella Laboratory Network, which serves 166 countries in all WHO regions. In particular, the genetic data can help confirm the sources of virus or suggest a source for unknown-source cases as well as to establish links, or lack thereof, between various cases and outbreaks. Virologic surveillance has helped to document the interruption of transmission of endemic measles in some regions. Thus, molecular characterization of measles viruses has provided a valuable tool for measuring the effectiveness of measles control programs, and virologic surveillance needs to be expanded in all areas of the world and conducted during all phases of measles control.

Genetic characterization of measles viruses in China, 2004

Genetic characterization of wild-type measles virus was studied using nucleotide sequencing of the C-terminal region of the N protein gene and phylogenetic analysis on 59 isolates from 16 provinces of China in 2004. The results showed that all of the isolates belonged to genotype H1. 51 isolates were belonged to cluster 1 and 8 isolates were cluster 2 and Viruses from both clusters were distributed throughout China without distinct geographic pattern. The nucleotide sequence and predicted amino acid homologies of the 59 H1 strains were 96.5%-100% and 95.7%-100%, respectively. The report showed that the transmission pattern of genotype H1 viruses in China in 2004 was consistent with ongoing endemic transmission of multiple lineages of a single, endemic genotype. Multiple transmission pathways leaded to multiple lineages within endemic genotype.

Genotyping of recent measles virus strains from Russia and Vietnam by nucleotide-specific multiplex PCR

The nucleoprotein genes of 49 measles virus (MV) strains circulating in Russia between 2000 and 2006 and in Vietnam in 2003 were analyzed by genotype-specific PCR and the results were compared with their sequences. The sequences revealed the presence of genotypes H1 and H2 in the center (Nha Trang) and the north (Hanoi) of Vietnam, respectively. The relative diversity of the H2 strains suggested an endemic circulation of these viruses in the capital. In contrast genotype H1 strains from Nha Trang were homogenous genetically, which may indicate a recent importation. The strains obtained from 12 different regions of the Russian Federation were assigned to the genotypes H1, D4, and D6. Most strains (81.4%) were correctly genotyped by a multiplex PCR method which was sensitive to genotype-specific mutations [Kremer et al. (2004): J Clin Microbiol 42: 3017-3022]. Ambiguous or negative results for some clade H and genotype D6 strains were due to point mutations in the type-specific primer binding sites. After exchanging a single nucleotide in both the clade H- and the genotype D6-specific primers, all strains were assigned correctly to their genotype. A simplified procedure for use in Vietnam was developed to distinguish directly between genotypes H1 and H2 and any non-H genotype. These results demonstrate that our multiplex PCR method can be adapted easily to new sequence variants or specific epidemiological situations, and thus be very useful for rapid genotyping of large number of samples even in laboratories which do not have sequencing facilities.

Bronchoalveolar cellularity and interleukin-8 levels in measles bronchiolitis obliterans

BACKGROUND

Measles virus infection may progress to a chronic obstructive process including bronchiolitis obliterans (BO). This study investigates pulmonary cellular profiles and interleukin (IL)-8 levels in patients with BO following the measles.

METHODS

BAL fluid was obtained from 12 children with BO who had a history of measles pneumonia during an outbreak in 2000 and 2001. BAL cell counts and differentials were compared to control patients as well as BAL IL-8 levels, which were measured by enzyme-linked immunosorbent assay. Immunohistochemical staining of BAL cells and three open-lung biopsy specimens were also analyzed for T-cell surface markers CD3, CD4, and CD8.

RESULTS

BAL cellular profiles were characterized by a significantly increased percentage of neutrophils in the measles BO group (median, 16.0%) compared to the control group (2.3%) [p < 0.01]. BAL IL-8 levels were also markedly increased in the measles BO group (mean +/- SD, 418.6 +/- 286.0 pg/mL) compared to the control group (92.8 +/- 126.7 pg/mL) [p < 0.01]. BAL IL-8 levels correlated significantly with neutrophil percentages in both the measles BO group (r = 0.86, p = 0.000) and the control group (r = 0.79, p = 0.007). The lymphocyte subsets were characterized by a significantly increased number of CD8+ cells, resulting in a decreased CD4/CD8 ratio in the BAL and the biopsy specimens.

CONCLUSION

These results suggest that pulmonary neutrophils and IL-8, along with CD8+ T lymphocytes may play an important role in the pathogenesis of BO after measles virus infection.

Molecular epidemiology of measles viruses in China, 1995-2003

This report describes the genetic characterization of 297 wild-type measles viruses that were isolated in 24 provinces of China between 1995 and 2003. Phylogenetic analysis of the N gene sequences showed that all of the isolates belonged to genotype H1 except 3 isolates, which were genotype A. The nucleotide sequence and predicted amino acid homologies of the 294-genotype H1 strains were 94.7%-100% and 93.3%-100%, respectively. The genotype H1 isolates were divided into 2 clusters, which differed by approximately 2.9% at the nucleotide level. Viruses from both clusters were distributed throughout China with no apparent geographic restriction and multiple co-circulating lineages were present in many provinces. Even though other measles genotypes have been detected in countries that border China, this report shows that genotype H1 is widely distributed throughout the country and that China has a single, endemic genotype. This important baseline data will help to monitor the progress of measles control in China.

Laboratory investigations are indispensable to monitor the progress of measles elimination--results of the German Measles Sentinel 1999-2003

BACKGROUND

The elimination of measles is a goal set by the World Health Organisation to be reached by 2010 in the European region.

OBJECTIVES

To enhance the measles surveillance in Germany, a country-wide laboratory supported a sentinel was established.

STUDY DESIGN

A network of >1200 representatively distributed practitioners reported detailed data on all clinically diagnosed cases and provided specimens for laboratory diagnosis.

RESULTS

A total of 3225 suspected cases were reported between October 1999 and December 2003. The incidence in Western Germany decreased from >15 cases per 100,000 population to one case in 2003, while in Eastern Germany <1 case per 100,000 population was observed during these years. Laboratory investigations were undertaken in 40% of cases in 2000/2001. This rate increased to 79% in 2003. Simultaneously, the rate of confirmed cases dropped from 60% in the former years to 23% in 2003. Measles virus (MV) detection by serology and by PCR revealed concordant results in 92%. Most suspected cases (85%) were unvaccinated with 66% being laboratory confirmed. Only 10% of suspected cases occurred in vaccinated individuals and very few (22%) could be confirmed. Analyses of confirmed measles in vaccinated patients (n = 49) revealed 24.5% primary vaccine failures, 24.5% reinfections after successful vaccination and 31% MV infection before or shortly after vaccination. The genetic characterisation of 389 MV isolates identified eight genotypes: B3, C2, D4, D5, D6, D7, G2 and H1. Only the C2, D6 and D7 MV genotypes circulated endemically in Western Germany. The newly emerged MV D7 almost completely replaced the pre-existing C2 and D6 MVs in 2001. The few measles cases detected in Eastern Germany were mostly caused by imported MVs.

CONCLUSION

The data demonstrate that laboratory investigations including molecular methods are an indispensable tool for surveillance in all countries advanced in measles elimination.

Infectious complications and outcomes after allogeneic hematopoietic stem cell transplantation in Korea

We reviewed 242 allogeneic hematopoietic stem cell transplantation (HSCT) recipients retrospectively over a 2-year period (January 1998-December 1999) in order to analyze the characteristics and assess the outcomes of infectious complications in patients after HSCT in Korea. Bacteria were the major pathogens before engraftment, and viral and fungal infections predominated during the post-engraftment period. Varicella zoster virus was the most common viral pathogen after engraftment. Cytomegalovirus disease occurred mainly in the late-recovery phase. The frequency of mold infection was higher than that of yeast. There was a relatively high incidence of tuberculosis (3.0%) and Pneumocystis carinii pneumonia (6.5%). One case of death by measles confirmed by autopsy was also noted. Overall, cumulative mortality was 43% (104/242), and 59.6% of these deaths (62/104) were infection-related. Allogeneic HSCT recipients from unrelated donors were prone to infectious complication and higher mortality than those from matched sibling (17/39 (43.6%) vs 45/203 (22.2%), respectively; P<0.01; odd ratio 2.5; 95% confidence interval 1.2-5.1). As infection was the main post-HSCT complication in our data, more attention should be given to the management of infections in HSCT recipients.