Detection of serum antibodies against Chlamydia pneumoniae by ELISA

Abstract Chlamydia pneumoniae causes pneumonia and other respiratory infections in children, adolescents and adults. We tried to evaluate the diagnostic value of detection of serum antibodies by ELISA for C. pneumoniae infections in Japanese children. Serum IgG, IgA and IgM antibodies to C. pneumoniae were determined by the microimmunofluorescence (MIF) test. Serum IgG and IgA antibodies were also determined by ELISA test kits. Results obtained by ELISA were compared with those obtained by MIF test. IgG antibody to C. pneumoniae was detected in 135 (39.5%) by ELISA and in 125 (36.5%) by MIF out of 342 sera from Japanese infants and children without respiratory infections (aged from 2 months old to 15 years old). IgA antibody to C. pneumoniae was detected in 129 (37.7%) by ELISA and in 117 (34.2%) by MIF out of 342 sera tested. Of 342 specimens 113 were IgG-positive by ELISA and MIF (sensitivity: 90.4%, specificity: 89.9%, r = 0.853). Of 342 sera 28 had IgG antibody titers of 1:256 and none had titers 1:512 or higher by MIF. Of 28 infants and children a total of nine were less than 4 years of age. On the other hand, of 342 specimens 99 were IgA-positive by ELISA and MIF (sensitivity: 84.6%, specificity: 86.7%, r = 0.769). Of 342 sera 16 had IgA antibody titers of 1:256 or higher by MIF. Of 16 infants and children, ten were less than 4 years of age. ELISA had excellent sensitivity and specificity relative to MIF test for detection of IgC and IgA antibodies to C. pneumoniae . It was suggested that C. pneumoniae infection in Japanese infants and children under 4 years of age was not infrequent.     

Comparative information value of humoral immunity characteristics in some bacterial and viral infections

Serological examination of 144 patients with different bacterial and viral infections was carried out. Antibodies to Brucella were detected in blood serum in 42 patients (85.7%) with the average titer of 1:996 and in saliva in 41 patients (83.7%) with the average titer of 1:567 by passive hemagglutination test with brucella erythrocyte diagnosticum. Out of 26 dysentery patients, antibodies in blood serum were detected in the diagnostic titer in 17 patients (65.4%) with the average titer of 1:282 and in saliva in 21 patients (80.8%) in the titer of 1:100 and higher. Anti-HAV and anti-HBc IgM were detected in specimens of saliva from patients with serologically confirmed viral hepatitis A and B in 100% of cases. The presence of HBsAg in saliva from hepatitis B patients was established in 95.4% of cases. In blood serum and in specimens of saliva anti-HCV IgM were detected in 100% and 85.7% of cases respectively. Out of 25 women with aggravated obstetric history, IgG antibodies to CMV were detected in blood serum in 23 women (88.5%) and in saliva in 22 women (84.6%). The results of these investigations revealed that the detection rate of antibodies in blood serum and saliva in cases of infections, both bacterial (brucellosis, shigellosis) and viral (hepatitis A, B, C and CMV infection), was not essentially different. The simplicity of obtaining material for analysis make it possible to recommend the use of saliva for diagnosing bacterial and viral infections, especially in mass epidemiological surveys.     

Detection of antibodies to herpes simplex virus type 2 with a mammalian cell line expressing glycoprotein gG-2

The gene (US4) coding for herpes simplex virus type 2 (HSV-2) glycoprotein G (gG-2) was cloned and constitutively expressed in Chinese hamster ovary (CHO) cells. The expression vector containing the dihydrofolate reductase (dhfr) gene, and the HSV-2 US4 gene under the control of the Simian virus 40 early promoter (SV40 EP), was transfected into dhfr-deficient CHO cells. The transfected cells were selected and amplified using methotrexate (MTX). To demonstrate that the gG-2 produced in these transformed cells had antigenic determinants in common with the native glycoprotein, CHO cells expressing gG-2 were used in an immunofluorescent assay (IFA) for the detection of HSV-2 type-specific antibodies in human serum samples. Seven of eight serum samples from adults with prior episodes of culture proven HSV-2 infections were found to be positive by the IFA method whereas none of seven serum samples from young children with culture documented HSV-1 infections were positive by IFA. Thus the recombinant CHO : gG-2 cells have diagnostic utility in an HSV-2 specific serologic assay.     

Human antibodies to group A streptococcal carbohydrate. Ontogeny, subclass restriction, and clonal diversity

To investigate immuno-incompetence to polysaccharide Ag in young children, antibodies to the polysaccharide and protein Ag of Streptococcus pyogenes were studied. S. pyogenes was chosen because it commonly causes natural infections and has well-characterized polysaccharide and protein Ag. In children over the age of 2 yr it was found that the maturation of antibody responses to the polysaccharide Ag of S. pyogenes (A-CHO) appeared to occur in parallel with, or even earlier, than the responses to streptococcal protein Ag. When antibodies to group A carbohydrate (A-CHO) were studied in detail, qualitative differences between the antibodies of children and adults were demonstrated. Although anti-A-CHO antibodies of adults were strikingly restricted to the IgG2 subclass, those of children were found in both the IgG1 and IgG2 subclasses. In addition, the clonal diversity of IgG antibodies to A-CHO increased with age, and additional clonotypes were detectable in convalescent sera of some subjects of all ages after infection. Two cases with major additional clonotypes after group A streptococcal infection were studied in detail. In these two cases the additional clonotypes belonged to a different IgG subclass than the previously dominant clonotypes, and the expression of the additional major clonotypes occurred in both IgG1 and IgG2 subclasses.     

Rotavirus and adenovirus in Rondônia

Acute gastroenteritis is one of the most common diseases in humans worldwide. Viral gastroenteritis is a global problem in infants and young children. In this study the incidence of diarrhea was assessed in 877 hospitalized children under five years old, over a period of 24 months and distributed in 470 cases of diarrhea and 407 age-matched group with other pathologies, as control group. Two antigen detection techniques based on enzyme immunoassay (EIA) and latex particles were used for detection of rotavirus and adenovirus. Rotavirus A was a major cause of gastroenteritis with 23.6% of cases, being 90% of these cases in young children. Adenovirus infections was detected by EIA with frequency of 6.4%. Rotavirus and adenovirus were detected in 10.1 and 1.7% of stools from control group, respectively. Interestingly, the frequency of the youngest children in the control group excreting Rotavirus A was comparable to that detected in stools from diarrheic children. We cannot rule out the existence of other enteric viruses because the etiology of 171 cases of diarrhea was not determined and active search for astrovirus and calicivirus was not done. This is the first study that shows the presence of enteric viruses in the infantile population from Western Brazilian Amazonia and it was important to help physicians in the treatment of viral gastroenteritis.     

闽南地区5 869例儿童社区获得性肺炎患者 病原学特点分析

目的通过对闽南地区社区获得性肺炎(CAP)患儿病原特点进行分析,为CAP早期预警、预防和早期经验治疗提供指导和依据。方法收集我院2015年1月至2017年5月5 869例CAP患儿静脉血、呼吸道分泌物及痰标本分别进行肺炎支原体(MP)、呼吸道病毒检测以及细菌培养和鉴定。结果 5 869例CAP患儿中明确病原体感染4 931例,其中单纯细菌感染3 054例,单纯病毒感染966例,单纯MP感染620例,混合感染291例,未检出病原体938例。细菌性病原主要以肺炎链球菌、流感嗜血杆菌和卡他莫拉菌为主,在各季节检出率不同且男性多于女性,主要在低龄儿童中检出。病毒感染者主要分布于低龄儿童,夏季检出率最高,病原以呼吸道合胞病毒(RSV)为主,占68.22%。该类患者在性别上比较差异无统计学意义。MP感染者中女性多于男性,主要分布于大龄儿童,冬季检出率最高。结论本地区CAP患儿病原检出率由高到低分别为细菌、病毒和MP。细菌和MP检出率在患儿中具有性别差异,各种病原在不同年龄段儿童及季节中检出率不同。     

Laboratory diagnosis of Epstein-Barr virus infection

Laboratory confirmation of EBV infection requires proper methods and schema of investigation adequate to aim of diagnostic procedure. In paper the results of routine diagnostic tests of EBV infection performed in Department of Virology NIH in 2005-2006 years was included and also, evaluation of usefulness of different laboratory methods was done. Based on results of ELISA tests 10,7% routine investigated subjects was classified as primary EBV infection, 20,1% was seronegative, 7,4% was classified as reactivation of latent infection and serological markers in 45,6% subjects pointed past EBV infection. Positive result of PCR method was obtain in 11,2% samples subjected of routine laboratory investigation. Comparison of specific and non-specific serological methods results (ELISA versus tests of heterophile antibodies) showed the high percentage of false negative results in children tested by non-specific tests. PCR results in serum samples from patients with primary infection (confirmed by serological tests) were positive in 15% cases only. Based on analyzed results it could be stated that reliable confirmation of infectious mononucleosis, as primary EBV infection, is detection of specific IgM antibodies and in case of heterophile antibodies tests the possibility of false negative results, mainly in children, must be taken into account. The most proper samples for PCR method are whole blood, sections of tissue or cells from swabs.     

Diagnostic virology in a community hospital

Seven and one-half years of experience in a small diagnostic virology laboratory of a large inner-city hospital are reported. Seven hundred fifty-one viruses were isolated from over 8,000 specimens, using two types of tissue culture cells, human and monkey kidney. The most common isolates were Herpes simplex viruses (HSV) and Enteroviruses. Similar results have been reported by larger laboratories. Sensitivity for HSV in monkey kidney cells was only 75 percent that in human cells. An enzyme-linked immunosorbent assay (ELISA) for cytomegalovirus (CMV) was found to be a suitable substitute for the traditional complement fixation test (CF). IgM antibodies were not found in all HSV infections, but these antibodies did appear before CF antibodies in some cases. Monoclonal antibodies to HSV were effective in typing isolates, but for detection of viral antigen in brain smears of HSV encephalitis patients, polyclonal antibody gave better results.     

The prevalence of helicobacteriosis in regions of Siberia based on serological study data

687 adults in 5 regions of Siberia and 79 children and young persons in Novosibirsk were examined. IgG antibodies to H. pylori in their blood sera were determined with the use the enzyme immunoassay. The detection rate of antibodies among the adult population varied within 70-87%, depending on the region, being somewhat lower among the population north of latitude 60 degrees (75%) in comparison with the population residing south of this latitude (86%, p < 0.001). In Novosibirsk the number of seropositive persons was found to be unrelated to sex, age and clinical manifestations of digestive tract diseases. A high detection rate of antibodies to H. pylori was registered in persons aged 25-34 years with a minor increase in older age groups. In children the detection rate increased with age: 29% in children of 5-10 years old and 56% in children 11-14 years old. By the age of 15 more than a half of the children had antibodies.     

Seroepidemiological study of coronavirus infection in children and adults in St. Petersburg

As the result of prolonged (17 years) observations of patients with acute respiratory infections hospitalized in basic departments of clinics of the Research Institute of Influenza, coronavirus infection was found to be the cause of respiratory diseases, on the average, in 12% of cases (in some years in 6.8% to 28.6% of cases). The analysis of extensive morbidity rates among different age groups of the population showed that children were affected by coronavirus infection 5-7 times more often than adults. Three year cycles of this infection were established. The periods of coronaviruses activation were accompanied by their detection in patient material by electron-microscopy, a sharp increase of immune response of patients as well as in the number of nosocomial infections and the proportion of the monoinfection of the coronavirus nature. Coronaviruses played the leading role among other viruses in the etiology of hospital respiratory infections. Mucosal antibodies to coronaviruses in the secretions of the nasal cavity proved to be more important than serum antibodies not only in protection from infection, but also in the pattern of clinical manifestations of the disease.     

Schistosoma mansoni Infections in Young Children: When Are Schistosome Antigens in Urine,Eggs in Stool and Antibodies to Eggs First Detectable?

Background

In Uganda, control of intestinal schistosomiasis with preventive chemotherapy is typically focused towards treatment of school-aged children; the needs of younger children are presently being investigated as in lakeshore communities very young children can be infected. In the context of future epidemiological monitoring, we sought to compare the detection thresholds of available diagnostic tools for Schistosoma mansoni and estimate a likely age of first infection for these children.

Methods and Findings

A total of 242 infants and preschool children (134 boys and 108 girls, mean age 2.9 years, minimum 5 months and maximum 5 years) were examined from Bugoigo, a well-known disease endemic village on Lake Albert. Schistosome antigens in urine, eggs in stool and host antibodies to eggs were inspected to reveal a general prevalence of 47.5% (CI₉₅ 41.1–54.0%), as ascertained by a positive criterion from at least one diagnostic method. Although children as young as 6 months old could be found infected, the average age of infected children was between 3¼–3¾ years, when diagnostic techniques became broadly congruent.

Conclusion

Whilst different assays have particular (dis)advantages, direct detection of eggs in stool was least sensitive having a temporal lag behind antigen and antibody methods. Setting precisely a general age of first infection is problematic but if present Ugandan policies continue, a large proportion of infected children could wait up to 3–4 years before receiving first medication. To better tailor treatment needs for this younger ageclass, we suggest that the circulating cathodic antigen urine dipstick method to be used as an epidemiological indicator.     

Rotavirus diarrhea in young infants]

Clinical and serological studies were made in 62 children with various purulent infections, who were placed in the same hospital unit. The precipitation test with the antigen of monkey virus SA-11 showed that diarrhea in 32 of these children was etiologically linked with rotaviruses. The diagnostic titers of virus antibodies were detected in children having diarrhea 5.5 times as frequently as in the control group. The characteristic feature in the clinical picture of this diarrhea was the absence of the severe form.     

Etiology of Maculopapular Rash in Measles and Rubella Suspected Patients from Belarus

As a result of successful implementation of the measles/rubella elimination program, the etiology of more and more double negative cases remains elusive. The present study determined the role of different viruses as causative agents in measles or rubella suspected cases in Belarus. A total of 856 sera sent to the WHO National Laboratory between 2009 and 2011 were tested for specific IgM antibodies to measles virus (MV), rubella virus (RV) and human parvovirus B19 (B19V). The negatives were further investigated for antibodies to enterovirus (EV) and adenovirus (AdV). Children of up to 3 years were tested for IgM antibodies to human herpesvirus 6 (HHV6). A viral etiology was identified in 451 (52.7%) cases, with 6.1% of the samples being positive for MV; 2.6% for RV; 26.2% for B19V; 9.7% for EV; 4.6% for AdV; and 3.6% for HHV6. Almost all measles and rubella cases occurred during limited outbreaks in 2011 and nearly all patients were at least 15 years old. B19V, EV and AdV infections were prevalent both in children and adults and were found throughout the 3 years. B19V occurred mainly in 3–10 years old children and 20–29 years old adults. EV infection was most common in children up to 6 years of age and AdV was confirmed mainly in 3–6 years old children. HHV6 infection was mostly detected in 6–11 months old infants. Laboratory investigation of measles/rubella suspected cases also for B19V, EV, AdV and HHV6 allows diagnosing more than half of all cases, thus strengthening rash/fever disease surveillance in Belarus.     

Performance of a rapid immuno-chromatographic test (Schistosoma ICT IgG-IgM) for detecting Schistosoma-specific antibodies in sera of endemic and non-endemic populations

BackgroundSchistosomiasis, an acute and chronic parasitic disease caused by human pathogenic Schistosoma species, is a neglected tropical disease affecting more than 220 million people worldwide.For diagnosis of schistosomiasis, stool and urine microscopy for egg detection is still the recommended method, however sensitivity of these methods is limited. Therefore, other methods like molecular detection of DNA in stool, detection of circulating cathodic antigen in urine or circulating anodic antigen in urine and serum, as well as serological tests have gained more attention. This study examines the sensitivity and specificity of a rapid diagnostic test based on immunochromatography (Schistosoma ICT IgG-IgM, LD Bio, Lyon, France) for simultaneous detection of specific IgG and IgM antibodies in serum, against Schistosoma spp. in endemic and non-endemic populations.Methodology/Principal findingsFrozen banked serum samples from patients with confirmed schistosomiasis, patients with other helminth infections, patients with seropositive rheumatoid arthritis and healthy blood donors were used to assess the sensitivity and the specificity of the Schistosoma ICT IgG-IgM rapid diagnostic test.The test showed a sensitivity of 100% in patients with parasitologically confirmed schistosomiasis, irrespective of the species (S. mansoni, S. haematobium, S. japonicum, S. mekongi). In healthy blood donors and patients with rheumatoid factor positive rheumatoid arthritis from Europe, specificity was 100%. However, in serum samples of patients with other tissue invasive helminth infections, the test showed some cross-reactivity, resulting in a specificity of 85%.Conclusion/SignificanceWith its high sensitivity, the Schistosoma ICT IgG-IgM rapid diagnostic test is a suitable screening test for detection of Schistosoma specific antibodies, including S. mekongi. However, in populations with a high prevalence of co-infection with other tissue invasive helminths, positive results should be confirmed with other diagnostic assays due to the test’s imperfect specificity.     

Outbreaks of pseudotuberculosis and intestinal yersiniosis among Soviet specialists and members of their families in the Mongolian People's Republic

In summer and winter of 1986 two outbreaks of alimentary enteric diseases occurred among Soviet specialists and members of their families in Ulan Bator. These diseases were identified as Yersinia infections registered in Mongolia for the first time. In July 114 children in a kindergarten fell ill after being fed with salad prepared from vegetables and spring onions supplied from a nearby state farm. 20 Y. pseudotuberculosis cultures, serovar 1, were isolated, and in 25 persons antibodies to the isolated microorganisms were detected; altogether 32% of cases were confirmed by laboratory methods. During the December outbreak 187 persons were affected, among them 90% of children, through the consumption of imported oranges and tangerines, simultaneous infection with Y. enterocolitica, serovars 05.27 and 09, and hepatitis A virus being observed. The fact of associated infection was registered after the simultaneous detection of the markers of viral hepatitis A and Yersinia infection in 61 patients. In the kindergarten the disease produced a typical clinical picture of Far Eastern scarlatiniform fever, and in winter the abdominal forms of the disease prevailed. In cases of combined Yersinia and viral infection a specific variant of acute hepatitis developed; as regards this variant, the authors present heretofore unknown information on its epidemiology, clinical features and outcome.     

The choice of rational methods for determining antibodies to Yersinia enterocolitica. The agglutination reaction

Six tests suitable for the detection of antibodies to Y. enterocolitica, serovars 03 and 09, were studied. The results of the study of hyperimmune sera revealed that the agglutination test and the indirect hemagglutination test were the most promising methods and deserved efforts for their further development. Bacterial diagnostic agents were prepared from live, heat-killed and formalin-killed Yersinia cultures and tested. The titration of homologous and heterologous sera revealed no essential differences in the preparations; in the serological examination of healthy persons (102), patients with Yersinia enteral infection (150) and with other acute enteral infections (92), the results obtained with the use of the above-mentioned preparations carried the highest information content. OH diagnostic agents proved to have the highest specificity; of these, the diagnosticum obtained by treatment 0.3-0.4% formalin vas found to be the most stable and technologically effective preparation. The minimal diagnostic titer of the agglutination test for the presence of Yersinia enteral infection was established (1:60 = 1:320). This titer was determined in 73% of the patients with bacteriologically confirmed Yersinia enteral infection and only in 1% of healthy persons and patients with other acute enteral infections.     

A Prospective Study of the Prevalence of Tuberculosis and Bacteraemia in Bangladeshi Children with Severe Malnutrition and Pneumonia Including an Evaluation of Xpert MTB/RIF Assay

Background

Severe malnutrition is a risk factor for pneumonia due to a wide range of pathogens but aetiological data are limited and the role of Mycobacterium tuberculosis is uncertain.

Methods

We prospectively investigated severely malnourished young children (<5 years) with radiological pneumonia admitted over a 15-month period. Investigations included blood culture, sputa for microscopy and mycobacterial culture. Xpert MTB/RIF assay was introduced during the study. Study children were followed for 12 weeks following their discharge from the hospital.

Results

405 eligible children were enrolled, with a median age of 10 months. Bacterial pathogens were isolated from blood culture in 18 (4.4%) children, of which 72% were Gram negatives. Tuberculosis was confirmed microbiologically in 7% (27/396) of children that provided sputum - 10 by culture, 21 by Xpert MTB/RIF assay, and 4 by both tests. The diagnostic yield from induced sputum was 6% compared to 3.5% from gastric aspirate. Sixty (16%) additional children had tuberculosis diagnosed clinically that was not microbiologically confirmed. Most confirmed tuberculosis cases did not have a positive contact history or positive tuberculin test. The sensitivity and specificity of Xpert MTB/RIF assay compared to culture was 67% (95% CI: 24–94) and 92% (95% CI: 87–95) respectively. Overall case-fatality rate was 17% and half of the deaths occurred in home following discharge from the hospital.

Conclusion and Significance

TB was common in severely malnourished Bangladeshi children with pneumonia. X-pert MTB/RIF assay provided higher case detection rate compared to sputum microscopy and culture. The high mortality among the study children underscores the need for further research aimed at improved case detection and management for better outcomes.     

Occurrence of Acute Upper Respiratory Diseases among Children as a Result of Infection by Herpes Simplex Virus

One hundred and twenty-one children showing symptoms of acute upper respiratory disease were bled during a period of nine months, from winter to summer, for detection of complement-requiring neutralizing (CRN) antibody against herpes simplex virus. Six of the cases, all from children under the age of 13 years, were unequivocally related to herpetic infection as evidenced by the presence of anti-herpes CRN antibody. During the same period, 144 other children who were normal healthy or suffering from unrelated non-febrile diseases were tested as controls; anti-herpes CRN antibody was not detected in any of them. Further, the age distribution of individuals with antibodies was compared between patients in the acute upper respiratory disease group and the control group. This analysis showed that approximately 5 to 7% of the acute upper respiratory diseases in the young children in this study would be attributed to herpetic infection.     

Etiology of acute pneumonias in an organized collective

In this work the immune structure of an organized group with respect to acute respiratory infections and the etiological structure of cases of acute pneumonia was studied. The sera taken from 602 persons were tested for the presence of antibodies to 14 infective agents of the viral, bacterial and mycoplasmal nature. The data indicate that all these agents circulate in the group under study with the prevalence of influenza A (H3N2), influenza B and group III parainfluenza viruses. Among etiological agents of acute pneumonia, the combination of Staphylococcus with Mycoplasma pneumoniae and adenovirus was noted. The Legionella etiology of some group cases of acute pneumonia among young persons was established on the basis of the increased titers of L. pneumophila antibodies in the indirect hemagglutination, indirect immunofluorescence and enzyme immunoassay. The source of this infection was highly dispersed water aerosol, containing the infective agent, in shower baths. This was bacteriologically confirmed by the isolation of three Legionella strains. The study showed that no transfer of Legionella infection in the group through contacts was possible.