Anti-VP1 and anti-VP2 antibodies detected by immunofluorescence assays in patients with acute human parvovirus B19 infection

Acute human parvovirus B19 infection is followed by an antibody response to the structural proteins of the viral capsid (VP1 and VP2). We used 80 sera collected from 58 erythema infectiosum and 6 transient aplastic crisis patients to test IgM and IgG antibodies against these two proteins in an immunofluorescence assay (IFA) using Sf9 cells infected with recombinant baculovirus expressing either VP1 or VP2 antigen. Although less sensitive than IgM capture enzyme immunoassay using native antigen (MACEIA), we could detect anti-VP1 or anti-VP2 IgM antibodies by IFA in 49 patients with acute infection (76.6%). Detection of IgG anti-VP1 and anti-VP2 by IFA, however, was as sensitive as IgG detection by indirect enzyme immunoassay. By applying IgG avidity IFA to sera of the 15 IgM IFA negative patients we were able to confirm acute infection in further 12 cases by IFA. Overall, acute infection was confirmed by IFA in 61 (95.3%) of the 64 patients.     

Drug-induced anemias

The facts known today about the occurrence and possible mechanisms of anaemias caused by medicaments are represented in a survey. In this connection toxic haemolytic anaemias, immunohaemolytic anaemias, toxic aplastic anaemias, megaloblastic anaemias, and some other, more rarely occurring types are referred to.     

Parvovirus B19 antibodies and correlates of infection in pregnant women attending an antenatal clinic in central Nigeria

Human parvovirus B19 infection is associated with spontaneous abortion, hydrops foetalis, intrauterine foetal death, erythema infectiosum (5th disease), aplastic crisis and acute symmetric polyarthropathy. However, data concerning Nigerian patients with B19 infection have not been published yet. The purpose of this study was to establish the prevalence of B19 IgG and IgM antibodies, including correlates of infection, among pregnant women attending an antenatal clinic in Nigeria. Subsequent to clearance from an ethical committee, blood samples were collected between August-November 2008 from 273 pregnant women between the ages of 15-40 years who have given their informed consent and completed self-administered questionnaires. Recombinant IgG and IgM enzyme linked immunosorbent assay kits (Demeditec Diagnostics, Germany) were used for the assays. Out of the 273 participants, 111 (40.7%) had either IgG or IgM antibodies. Out of these, 75 (27.5%) had IgG antibodies whereas 36 (13.2%) had IgM antibodies, and those aged 36-40 years had the highest prevalence of IgG antibodies. Significant determinants of infection (p < 0.05) included the receipt of a blood transfusion, occupation and the presence of a large number of children in the household. Our findings have important implications for transfusion and foeto-maternal health policy in Nigeria. Routine screening for B19 IgM antibodies and accompanying clinical management of positive cases should be made mandatory for all Nigerian blood donors and women of childbearing age.     

Human parvovirus (HPV/B19) infection with purpura

A 33-year-old man complained of purpura (petechial hemorrhage) in chelidons, poples, axillae, and bilateral chest in addition to other symptoms such as lumbago, arthralgia, muscular pain, and fever. On the next day of the onset, human parvovirus (HPV/B19) antigen and HPV/B19 DNA were detected in his serum, and twelve days later IgM antibody to HPV/B19 became detectable. This case supports the relationship between purpura and HPV/B19 infection.     

Evaluation of Anti-Toxoplasma IgG, IgM, and IgA in Mothers with Spontaneous Abortion in Zanjan, Northwest Iran

Toxoplasma gondii is one of the major agents of infectious abortions and due to its worldwide distribution can threat healthy pregnant women who had no previous exposure to this parasite. The present study was designed to investigate the contribution of T. gondii to spontaneous abortions in Zanjan, Northwest of Iran, using ELISA method. Blood Samples were collected from 264 mothers referred to the provincial hospitals of Zanjan due to spontaneous abortion. The sera were isolated and subjected to evaluate the anti-Toxoplasma IgG, IgM and IgA antibodies. The results showed IgG positive (IgG⁺) in 99 cases (37.5%). A total of 68 women (25.8%) showed seroconversion with IgM or IgA or both IgM and IgA. They included: IgM⁺ in 21 (8.0%), IgA⁺ in 23 (8.7%) and both IgM⁺ and IgA⁺ in 24 (9.1%) subjects. In 23 cases, positive titers of IgM and IgG were accompanied. In general, the analysis of anti-Toxoplasma antibody patterns, showed that about 17% of the spontaneous abortions were associated with serological patterns of acute infection. According to these findings, a considerable proportion of spontaneous abortions can be attributed to T. gondii in the study area.     

Listeria monocytogenes in spontaneous abortions in humans and its detection by multiplex PCR

AIM: To assess the extent of Listeria monocytogenes in causation of human spontaneous abortions by isolation methods and PCR analysis for the presence of virulence-associated genes. METHODS AND RESULTS: A total of 305 samples comprising blood, urine, placental bits, faecal and vaginal swabs were collected from 61 patients with spontaneous abortions. Listeria spp. were isolated from 10 samples collected from nine (14.8%) patients. Confirmation of these isolates was based on biochemical tests, haemolysis on blood agar, CAMP test, phosphatidylinositol-specific phospholipase C (PI-PLC) assay followed by in vivo pathogenicity tests and multiplex PCR to detect virulence-associated genes (prfA, plcA, hlyA, actA and iap). Three isolates were confirmed as L. monocytogenes. Of these, two isolates turned out to be pathogenic and found to posses all five genes. However, the remaining two haemolytic L. monocytogenes isolates lacking the plcA gene and activity in the PI-PLC assay were found to be nonpathogenic by in vivo tests. CONCLUSIONS: The occurrence of pathogenic L. monocytogenes in cases of spontaneous abortions was 3.3%. It seems that the plcA gene and its expression have an important role as essential virulence determinants in pathogenic Listeria spp. SIGNIFICANCE AND IMPACT OF THE STUDY: The recovery of pathogenic L. monocytogenes isolates from cases of spontaneous abortion indicates the significance of listeric infection in pregnant women.     

Erythema infectiosum and pregnancy-related complications.

Erythema infectiosum, an acute, communicable viral disease with a highly distinctive exanthem, follows the usual course of a self-limiting benign disease. In pregnant women, however, it may be associated with fetal death and nonimmune hydrops fetalis. Because of the association of human parvovirus (HPV) B19 infection with fetal damage we reviewed the current knowledge of the clinical aspects of erythema infectiosum, focusing on pregnancy and fetal outcome, to determine the magnitude of fetal risk and offer recommendations for management. Among 180 infected pregnant women 44 fetal deaths (24%) occurred, 1 to 12 weeks after the infection was noted. Pregnant women should be advised that (a) because of the high prevalence (up to 65%) of anti-HPV B19 IgG antibody among adults most of them are not at risk and (b) if maternal infection does occur therapeutic abortion is not indicated since intrauterine infection causes fetal death more often than abnormal development. Infection should be suspected in pregnant women who exhibit the symptoms of erythema infectiosum with or without arthropathy. They should be monitored for an elevated serum alpha-fetoprotein level (indicating fetal aplastic crisis) and undergo serial ultrasonography for the detection of hydrops fetalis. Although the incidence of congenital malformation is no higher than the expected rate in the general population (3% to 5%), the precise incidence of fetal adverse outcomes remains unknown and requires investigation in larger, prospective studies.     

特发性血小板减少性紫癜与巨细胞病毒、EB病毒感染相关性

目的：探讨小儿特发性血小板减少性紫癜（ITP）与巨细胞病毒、EB病毒感染的关系。方法：实验组：48例确诊断为ITP患儿,对照组：44例同期呼吸道感染患儿,应用酶联免疫吸附法（ELISA）对两组小儿外周血进行巨细胞病毒IgM抗体（HCMV-IgM）、EB病毒感染IgM抗体（EB-IgM）检测。结果：48例ITP患儿中HCMV-IgM抗体阳性者20例,阳性率为41.67%,明显高于对照组,两组之间差异有显著性（P〈0.01）;EBV-IgM抗体阳性者14例,阳性率为29.17%,明显高于正常对照组,两组之间差异有显著性（P〈0.05）。结论：1、巨细胞病毒感染是引起特发性血小板减少性紫癜的重要原因之一,且通过临床观察巨细胞病毒感染引起的ITP患儿病情重,病程长,治疗时间长,转为慢性ITP的可能性大;2、EB病毒感染可能是引起特发性血小板减少性紫癜的原因之一,并且EB病毒感染引起的特发性血小板减少性紫癜病情也偏重。     

Toxoplasma gondii: expression pattern and detection of infection using full-length recombinant P35 antigen

A complete P35 surface antigen of Toxoplasma gondii was sequenced (GenBank ). Immunoblot found that it reacted specially with T. gondii acute infected sera, and the recombinant P35 signal was specific for P35 antigen. The P35-GST protein was used as antigen to detect 125 sera samples by double-sandwich ELISA. P35-IgM positive rate in a chronic infected group, a persistent IgM positive chronic group, a recently seroconvered group and an acute infected group were 4% (1 out of 25), 16% (4 out of 25), 88% (22 out of 25), and 100% (25 out of 25), respectively. The sensitivity and specificity of the recombinant full-length P35 antigen were 100 and 96%, respectively. The detailed expression patterns of P35 antigen were studied in 36 IgM and IgG positive sequential samples from 10 recently seroconvered patients. Results showed that the P35-IgM positive rate decreased as the time after the first seroconversion increased. P35-IgM positive samples in the first, second, third, fourth, and fifth month after the first seroconversion test were 90, 78, 57, 50, and 33%, respectively. P35-IgG positive samples in the first, second, third, fourth, fifth, sixth, and seventh month after the first seroconversion test were 70, 100, 100, 100, 67, 100, and 100%, respectively. All samples were P35-IgM negative after the fifth month, and P35-IgG negative after the seventh month from seroconversion. P35-IgM existed the shortest time and was a more specific marker for T. gondii acute infection than P35-IgG, IgM, and IgG to whole tachyzoites antigens.     

特发性血小板减少性紫癜与巨细胞病毒、EB 病毒感染相关性

目的:探讨小儿特发性血小板减少性紫癜(ITP)与巨细胞病毒、EB病毒感染的关系。方法:实验组:48例确诊断为ITP患儿,对照组:44例同期呼吸道感染患儿,应用酶联免疫吸附法(ELISA)对两组小儿外周血进行巨细胞病毒IgM抗体(HCMV-IgM)、EB病毒感染IgM抗体(EB-IgM)检测。结果:48例ITP患儿中HCMV-IgM抗体阳性者20例,阳性率为41.67%,明显高于对照组,两组之间差异有显著性(P<0.01);EBV-IgM抗体阳性者14例,阳性率为29.17%,明显高于正常对照组,两组之间差异有显著性(P<0.05)。结论:1、巨细胞病毒感染是引起特发性血小板减少性紫癜的重要原因之一,且通过临床观察巨细胞病毒感染引起的ITP患儿病情重,病程长,治疗时间长,转为慢性ITP的可能性大;2、EB病毒感染可能是引起特发性血小板减少性紫癜的原因之一,并且EB病毒感染引起的特发性血小板减少性紫癜病情也偏重。     

Laboratory diagnostics of infections caused by cytomegalovirus and parvovirus B19 in patients with secondary immunodeficiency

To improve the quality of diagnostics and treatment of patients with immunodeficient states, two groups of patients were examined for the presence of cytomegalovirus (CMV) infection, among them 1,348--with clinical manifestations of CMV infection (group 1) and 335 hematological patients (group 2); in addition, 36 patients with secondary immunodeficiency and 31 patients with aplastic and hemolytic anemia, or with anemia of unclear origin were examined for the presence of parvovirusinfection (B19). The results of enzyme immunoassay, polymerase chain reaction and immunofluorescence tests active CMV infection, confirmed by determination of IgM, low avidity IgG, antigen and DNAemia, was registered in group 2 more often than in group 1. Examinations on the presence of parvovirus infection revealed that in anemia patients with the low level of IgG or its absence IgM was also detected more often than in group 1. In mixed infection caused by CMV and parvovirus B19 the disease took a more severe course than in monoinfection, which was probably due to the parallel action exerted by parvovirus on erythrocyte production in hematopoiesis and by CMV on the monocytic and macrophagal row of cell.     

Drug-induced Blood Dyscrasias in Sweden

Cases of drug-induced aplastic anaemia, haemolytic anaemia, thrombocytopenia, and agranulocytosis reported to the Swedish Adverse Drug Reaction Committee during the five-year period 1966-70 have been analysed and compared with cases of the same cytopenias from “all” causes. Oral diuretics were a dominant cause of drug-induced thrombocytopenia, methyldopa of haemolytic anaemia, and oxyphenbutazone of aplastic anaemia. Computer systems should help such studies, particularly in showing a changing pattern of complications and causes.     

Immunologic abortion and its treatment by immunotherapy

Recurrent spontaneous abortions in most cases, can be explained by classical abnormalities; but for some cases without etiology and consequently without appropriate therapy until a few years ago, there is hope a successful treatment, thanks to recent advances. Contrary to what was suspected in the past, during pregnancy, the mother is immunologically competent against the paternal antigens of the fetus; this competence is necessary for her to respond to the trophoblast paternal antigen stimulations and develop her immune tolerance. If, because of insufficient stimulation, the woman does not succeed in producing this tolerance, it is now possible to help her by vaccination with paternal lymphocytes, before she becomes pregnant. Our results confirm these data: Again, we observe a greater frequency of HLA antigen sharing in couples with recurrent spontaneous abortions (RSAs), especially at the DR locus, Women with three or more RSAs, produce fewer antibodies against their husbands HLA antigens than regular normal fertile women (none out of the 50 cases studied), Anti-paternal antibodies the specificity of which cannot be determined at the moment, are shown by means of the microlymphocytotoxicity test at 37 degrees C carried out on the paternal B lymphocytes. They appear with the cure of the abortive illness after treatment by paternal lymphocyte injections. In the control women who did not receive any immunotherapy, those who developed anti-paternal antibodies spontaneously had a new normal pregnancy; 57.2 of those who did not produce any anti-paternal antibodies aborted once more.     

Human Parvovirus B19 Induced Apoptotic Bodies Contain Altered Self-Antigens that are Phagocytosed by Antigen Presenting Cells

Human parvovirus B19 (B19V) from the erythrovirus genus is known to be a pathogenic virus in humans. Prevalence of B19V infection has been reported worldwide in all seasons, with a high incidence in the spring. B19V is responsible for erythema infectiosum (fifth disease) commonly seen in children. Its other clinical presentations include arthralgia, arthritis, transient aplastic crisis, chronic anemia, congenital anemia, and hydrops fetalis. In addition, B19V infection has been reported to trigger autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. However, the mechanisms of B19V participation in autoimmunity are not fully understood. B19V induced chronic disease and persistent infection suggests B19V can serve as a model for viral host interactions and the role of viruses in the pathogenesis of autoimmune diseases. Here we investigate the involvement of B19V in the breakdown of immune tolerance. Previously, we demonstrated that the non-structural protein 1 (NS 1) of B19V induces apoptosis in non-permissive cells lines and that this protein can cleave host DNA as well as form NS1-DNA adducts. Here we provide evidence that through programmed cell death, apoptotic bodies (ApoBods) are generated by B19V NS1 expression in a non-permissive cell line. Characterization of purified ApoBods identified potential self-antigens within them. In particular, signature self-antigens such as Smith, ApoH, DNA, histone H4 and phosphatidylserine associated with autoimmunity were present in these ApoBods. In addition, when purified ApoBods were introduced to differentiated macrophages, recognition, engulfment and uptake occurred. This suggests that B19V can produce a source of self-antigens for immune cell processing. The results support our hypothesis that B19V NS1-DNA adducts, and nucleosomal and lysosomal antigens present in ApoBods created in non-permissive cell lines, are a source of self-antigens.     

Genotyping of human parvovirus B19 in clinical samples from Brazil and Paraguay using heteroduplex mobility assay, single-stranded conformation polymorphism and nucleotide sequencing

Heteroduplex mobility assay, single-stranded conformation polymorphism and nucleotide sequencing were utilised to genotype human parvovirus B19 samples from Brazil and Paraguay. Ninety-seven serum samples were collected from individuals presenting with abortion or erythema infectiosum, arthropathies, severe anaemia and transient aplastic crisis; two additional skin samples were collected by biopsy. After the procedure, all clinical samples were classified as genotype 1.     

Favism in Polish families

Four cases of fawism are presented. The disease was seen in one male patient, one homozygote and in 3 carriers of G6PD deficit. Diagnostic procedures, course of the haemolytic crisis in these patients, and possibility of prophylaxis in the families with fawism are discussed.     

Serologic cross-reactivity of human IgM and IgG antibodies to five species of Ebola virus

Five species of Ebola virus (EBOV) have been identified, with nucleotide differences of 30-45% between species. Four of these species have been shown to cause Ebola hemorrhagic fever (EHF) in humans and a fifth species (Reston ebolavirus) is capable of causing a similar disease in non-human primates. While examining potential serologic cross-reactivity between EBOV species is important for diagnostic assays as well as putative vaccines, the nature of cross-reactive antibodies following EBOV infection has not been thoroughly characterized. In order to examine cross-reactivity of human serologic responses to EBOV, we developed antigen preparations for all five EBOV species, and compared serologic responses by IgM capture and IgG enzyme-linked immunosorbent assay (ELISA) in groups of convalescent diagnostic sera from outbreaks in Kikwit, Democratic Republic of Congo (n=24), Gulu, Uganda (n=20), Bundibugyo, Uganda (n=33), and the Philippines (n=18), which represent outbreaks due to four different EBOV species. For groups of samples from Kikwit, Gulu, and Bundibugyo, some limited IgM cross-reactivity was noted between heterologous sera-antigen pairs, however, IgM responses were largely stronger against autologous antigen. In some instances IgG responses were higher to autologous antigen than heterologous antigen, however, in contrast to IgM responses, we observed strong cross-reactive IgG antibody responses to heterologous antigens among all sets of samples. Finally, we examined autologous IgM and IgG antibody levels, relative to time following EHF onset, and observed early peaking and declining IgM antibody levels (by 80 days) and early development and persistence of IgG antibodies among all samples, implying a consistent pattern of antibody kinetics, regardless of EBOV species. Our findings demonstrate limited cross-reactivity of IgM antibodies to EBOV, however, the stronger tendency for cross-reactive IgG antibody responses can largely circumvent limitations in the utility of heterologous antigen for diagnostic assays and may assist in the development of antibody-mediated vaccines to EBOV.     

Cytogenetic analysis of 750 spontaneous abortions with the direct-preparation method of chorionic villi and its implications for studying genetic causes of pregnancy wastage

Altogether, 750 cases of spontaneous abortion between the fifth and 25th week of gestation were analyzed cytogenetically by the direct-preparation method using chorionic villi. The majority of cases (68%) were derived from early abortions before the 12th week of gestation. The frequency of abnormal karyotypes was 50.1%; trisomy was predominant (62.1%), followed by triploidy (12.4%), monosomy X (10.5%), tetraploidy (9.2%), and structural chromosome anomalies (4.7%). Among trisomies, chromosomes 16 (21.8%), 22 (17.9%), and 21 (10.0%) were prevalent. The frequency of chromosomally abnormal abortions increased with maternal age but only because of an increase of trisomy. Polyploidy and monosomy X, however, decreased. Mean maternal age was significantly increased for trisomies 16, 21, and 22 and was highest for trisomies 18 and 20. The results obtained are within the range of variability reported earlier from tissue culture-type studies. A consistent feature during our study is the excess of females in chromosomally normal abortions (male:female sex ratio 0.71). According to the methodology applied, maternal cell contamination and undetected 46,XX molar samples cannot have influenced the sex ratio. However, a bias introduced by social status or maternal age cannot be excluded. With the more rapid and convenient direct preparation of chorionic villi, reliable cytogenetic data on causes of spontaneous abortions can be obtained.     

Viremic blood donor found by a rapid screening method in a season of high human parvovirus B19 activity in Niterói, Rio de Janeiro, Brazil

Erythrovirus B19 infection is usually benign but may have serious consequences in patients with hemolytic anemia (transient aplastic crisis), immunodeficiency (in whom persistent infection can lead to chronic bone marrow failure with anemia), or who are in the first or second trimester of gestation (spontaneous abortion, hydrops fetalis, and fetal death). Being non-enveloped, B19 resists most inactivation methods and can be transmitted by transfusion. B19 is difficult to cultivate and native virus is usually obtained from viremic blood. As specific antibodies may be absent, and there is no reliable immunological method for antigen detection, hybridization or polymerase chain reaction are needed for detecting viremia. A rapid method, gel hemagglutination (Diamed ID-Parvovirus B19 Antigen Test), can disclose highly viremic donations, whose elimination lessens the viral burden in pooled blood products and may even render them non-infectious. In order to obtain native antigen and to determine the frequency of viremic donors, we applied this test to blood donors in a period of high viral activity in our community. Positive or indeterminate results were re-tested by dot-blot hybridization. We tested 472 donors in 1998 and 831 ones in 1999. One viremic donor was found in 1999. We suggest that in periods of high community viral activity the gel hemagglutination test may be useful in avoiding highly viremic blood being added to plasma pools or directly transfused to patients under risk.     

Characteristics of Memory B Cells Elicited by a Highly Efficacious HPV Vaccine in Subjects with No Pre-existing Immunity

Licensed human papillomavirus (HPV) vaccines provide near complete protection against the types of HPV that most commonly cause anogenital and oropharyngeal cancers (HPV 16 and 18) when administered to individuals naive to these types. These vaccines, like most other prophylactic vaccines, appear to protect by generating antibodies. However, almost nothing is known about the immunological memory that forms following HPV vaccination, which is required for long-term immunity. Here, we have identified and isolated HPV 16-specific memory B cells from female adolescents and young women who received the quadrivalent HPV vaccine in the absence of pre-existing immunity, using fluorescently conjugated HPV 16 pseudoviruses to label antigen receptors on the surface of memory B cells. Antibodies cloned and expressed from these singly sorted HPV 16-pseudovirus labeled memory B cells were predominantly IgG (>IgA>IgM), utilized diverse variable genes, and potently neutralized HPV 16 pseudoviruses in vitro despite possessing only average levels of somatic mutation. These findings suggest that the quadrivalent HPV vaccine provides an excellent model for studying the development of B cell memory; and, in the context of what is known about memory B cells elicited by influenza vaccination/infection, HIV-1 infection, or tetanus toxoid vaccination, indicates that extensive somatic hypermutation is not required to achieve potent vaccine-specific neutralizing antibody responses.