Investigation on the Maternal-Infantile Infection with Human Parvovirus B19

With the investigations on pregnant women and newbornsinfected withToxoplasma, rubella virus, cytomegalovirus,herpes simplex virus (TORCH), it was found that humanparvovirus B19 (B19 virus), which belongs to the familyParvoviridae and the genus Erythrovir…     

Little role of anti-gB antibodies in neutralizing activity of patient's sera with human cytomegalovirus (HCMV) infection

Human cytomegalovirus (HCMV) gB is known to play important roles in cell surface attachment, virion penetration, spread of infection from cell to cell, and provocation of neutralizing antibody. This study was performed to determine the role of anti-HCMV gB antibody in overall neutralizing response in patients with HCMV infection and healthy control with past infection. HCMV gB was stably expressed in 293 cells. With the stable cell line expressing gB as a specific immunosorbent, anti-gB antibody was removed from the current and past HCMV-infected sera and the remaining neutralizing activity was measured by plaque assay. It was shown that 19-50% of the total virus-neutralizing activity of sera with past HCMV infections was derived from anti-gB antibody, but anti-gB antibody had little effect on the total serum virus-neutralizing activity in patients currently infected with HCMV. This result suggests that neutralizing antibody to HCMV gB may reflect disease status.     

Relationship between antigenic type of virus and antibody response in female patients with herpes genitalis

The antigenic types of virus recovered from genital sites in cases of adult female genital herpes and antibody response in these patients were investigated. Twelve strains were isolated from 23 clinical specimens, and half the number of the isolates was classified as type 1 virus and the remaining half as type 2 virus. The results of serological typing corresponded well to biological differentiation by plaque-forming ability on chick embryo cultures. The patients with type 1 virus infection had only the complement requiring neutralizing antibody, thus indicating a fresh infection. On the other hand, the noncomplement requiring neutralizing antibody was found in the patients with type 2 virus infection, indicating a later phase of infection.     

SARS corona virus peptides recognized by antibodies in the sera of convalescent cases

We synthesized on cellulose membranes 4942 ten-amino-acid peptides which included all of the sequences predicted for the severe acute respiratory syndrome (SARS) corona virus. We probed these membranes with four pairs of acute and convalescent sera from recovered SARS cases. We correlated positively reacting peptides with the in vitro SARS-CoV neutralizing activity of the samples. We found that convalescent sera with high neutralizing activity recognized exclusively only a limited number of peptides on the membranes. This suggests that antibodies against the epitopes represented by these peptides could be responsible for much of the SARS-CoV neutralizing activity. The findings have implications for monitoring humoral responses to SARS-CoV as well as for developing a successful SARS vaccine.     

Establishment of titration system for human herpesvirus 6 and evaluation of neutralizing antibody response to the virus.

The susceptibilities of seven T-cell lines to human herpesvirus 6 (HHV-6) infection were examined. MT-4 cells were the most susceptible of these lines to infection with this virus. Therefore, chemically adhered MT-4 cell monolayers were used for infectious HHV-6 assay by indirect immunofluorescent-antibody (IFA) staining. When cell monolayers were fixed 30 to 45 h postinfection, the foci stained with IFA were easy to count and a linear relationship was observed between the number of foci and the virus concentration. MT-4 cell monolayers were also used for a focus reduction neutralizing-antibody test. In this test, sera from patients in the convalescent stage of exanthem subitum all showed significant neutralizing activity (1:80 to 1:320), whereas sera from patients in the acute stage of disease showed no detectable neutralizing activity. The titers of neutralizing antibody correlated well with the levels of anti-HHV-6 antibodies detected by IFA.     

Production of a Shiga-like cytotoxin by Campylobacter

Cell lysates and culture supernatants of 36 Campylobacter isolates from patients with enteritis were tested for cytotoxic activity on HeLa cells. Cytotoxic activity was considered Shiga-like if neutralized by monoclonal antibody to the B subunit of Shiga-like toxin I of Escherichia coli and rabbit anti-Shiga toxin. Fifteen of the Campylobacter isolates produced no detectable cytotoxin, 10 produced a non-neutralizable cytotoxin, and 11 produced low levels of a cell-associated SLT. However, under low stringency conditions no hybridization was observed between a DNA fragment containing cloned SLT-I genes and restriction enzyme-digested total DNA from a Campylobacter strain that produced low levels of a Shiga-like toxin I. The Shiga-like toxin neutralizing titers in sera from 15 patients with C. jejuni infections, 5 patients infected with S. sonnei, and 20 healthy persons were then determined. No rise in neutralizing titer between acute and convalescent sera of patients with C. jejuni infection or S. sonnei infection was observed, although 27% of C. jejuni-infected patients, 40% of S. sonnei-infected patients, and 30% of the healthy controls had neutralizing activity in their sera. These data indicate that low levels of Shiga-like toxin are produced by some Campylobacter isolates but that SLT is genetically distinct from the SLT-I toxin produced at high levels by certain E. coli. The findings also suggest that exposure to SLTs is common in the adult population but not as a consequence of infection with C. jejuni or S. sonnei.     

Identification of different states of hepatitis B virus infection with a quantitative PCR assay

The level of hepatitis B virus (HBV) DNA in serum reflects the replicative activity of HBV. To compare serum HBV DNA levels in different states of hepatitis B, 47 sera of patients with HBeAg-positive chronic hepatitis B, 4 sera of patients with HBeAg-negative chronic hepatitis B, 40 samples of patients after HBeAg seroconversion during alpha interferon treatment, 57 sera of inactive HBsAg carriers, and 42 sera of patients who had recovered from chronic hepatitis B more than 12 months prior to blood collection were checked for the presence of HBV DNA with the Amplicor HBV Monitor Test. In patients with HBeAg-positive chronic hepatitis B, the median of serum HBV DNA levels (8.3 x 10(8) copies/ml) was significantly higher than that for patients after HBeAg seroconversion (6.2 x 10(3) copies/ml) and than that for inactive HBsAg carriers (5.6 x 10(3) copies/ml). None of the patients who had recovered from hepatitis B had detectable HBV DNA in serum. Quantitative PCR proved to be a valuable tool for identification of different states of HBV infection. This technique was found to be a good method for determination of serum HBV DNA levels both for patients with HBeAg seroconversion and for inactive carriers who showed low viremia not detectable by conventional hybridization assays.     

Differences in Acute and Convalescent-Phase Antibodies of Cats Infected with Feline Picornaviruses

Complement fixation inhibiting and complement-fixing antibodies were demonstrated in sera from cats during the acute and convalescent stages, respectively, of feline picornavirus infections. Complement-fixing antibody activity was present in 19S and 7S globulins, whereas complement fixation inhibiting antibody activity was confined to the 7S globulins. Sera with complement-fixing antibody and sera with complement fixation inhibiting antibody were also shown to have neutralizing and precipitating antibodies. In a study of antibody responses to homotypic and heterotypic strains of feline picornavirus, less serological cross-reactions were observed between strains of feline picornavirus in sera from cats in the acute phase of feline picornavirus infection than in the convalescent phase. The temporal relationship of complement fixation inhibiting and complement-fixing antibody responses of cats after acute viral respiratory infections is contrasted with previously observed antibody response in cats to feline leukemia virus.     

Recovery of Salmonella group B from blood and Salmonella group C2 from feces and serological evidence of dual infection in one patient.

A patient with a dual Salmonella infection is described. Salmonella group B was recovered from three blood culture sets but was not detected in seven stool cultures. Salmonella group C2 was isolated from three of seven stool cultures but was not recovered from blood cultures. Specific, non-cross-reactive antibodies to Salmonella groups B and C2 were detected in the sera of the patient by passive hemagglutination assays.     

Detection of parvovirus B19 in the lower respiratory tract

BackgroundHuman parvovirus B19 infection generally displays a self-limiting course followed by viral clearance; although, in some cases, persistent infection may occur. Few cases of severe pulmonary disease following primary infection in both immunocompetent and immunocompromised patients were reported.ObjectivesTo investigate the prevalence and clinical impact of parvovirus B19 in the lower respiratory tract.Study designThe prevalence of parvovirus B19-DNA was evaluated by Real-Time PCR in 264 bronchoalveolar lavages (BAL) from 189 adult patients over a full-year period and related to demographic characteristics, underlying pathologies, immune status, admission to intensive care unit, mortality within 28 days, and discharge diagnosis.ResultsParvovirus B19-DNA was detected in 7/189 (3.7%) patients, without significant association to demographic characteristics, immune status, transplant versus non-transplant status, admission to intensive care unit, presence of haematological conditions. In two lung transplant recipients surveillance specimens were positive to B19. Four of the remaining five patients presented respiratory insufficiency. A significant association to mortality was found, as 3/7 (42.9%) positive patients died within 28 days. No patient presented serological evidence of recent or acute infection and viremia.ConclusionsParvovirus B19 may be detected at low frequency in BAL specimens from patients with different pathological backgrounds. This finding could be due to chronic infection with virus persistence in the lower respiratory tract, also in the absence of symptoms unequivocally attributable to B19. The high rate of mortality warrants the need for further studies to evaluate the opportunity to consider parvovirus B19 in the diagnostic work-up of lower respiratory tract infections.     

Persistent parvovirus B19 infections with different clinical outcomes in renal transplant recipients: diagnostic relevance of polymerase chain reaction (PCR) and of quantification of B19 DNA in sera

Objective: To study parvovirus B19 infection in immunocompromised subjects such as renal transplantation recipients.
Methods: Two cases of B19 infection in renal transplant recipients have been included in the study. The outcome of the infection has been studied by both serologic and virologic methods. A monitoring of the DNAemia was done by a nested PCR in endpoint titration assays.
Results: In one patient with severe anemia an acute B19 infection was diagnosed by PCR 26 days after the transplant; a high level of DNAemia persisted until an intravenous immunoglobulin treatment. Then a sharp decrease of the DNAemia was shown, without full clearance of B19 virus. In a lymphocyte suspension from the organ donor, B19 DNA was detected. In the other patient, who recovered spontaneously from anemia, a persistent B19 infection was demonstrated at day 106 after transplantation and was still demonstrable after 470 days.
Conclusions: A high level of B19 DNAemia was associated with symptomatic infection, with severe anemia, whereas low-level DNAemia was long-lasting in asymptomatic subjects with impaired immunologic responses. The endpoint titration assay by nested PCR was very useful for the monitoring of B19 infection, particularly following the therapeutic intravenous immunoglobulin administration.     

Human parvovirus B19 infection during pregnancy--value of modern molecular and serological diagnostics.

BACKGROUND: Over 95% of fetal complications (fetal hydrops and death) occur within 12 weeks following acute parvovirus B19 (B19) infection in pregnancy. Therefore, weekly fetal ultrasound monitoring is generally recommended for this time period. However, in the majority of women, typical symptoms of acute infection (rash or arthropathy) are absent, and during epidemics, B19 infection may be diagnosed incidentally by antibody screening of women at risk. OBJECTIVE: To assess the diagnostic value of currently available molecular and serological methods for reliable diagnosis of primary B19 infection in pregnancy. STUDY DESIGN: Large panels of well-characterized acute-phase or convalescent sera were used to investigate the ability of a VP2 IgM EIA, a Light-Cycler-based B19-DNA PCR, a VP1-IgG avidity EIA and two VP2-IgG epitope-type specificity [ETS] EIAs to pinpoint the time of primary B19 infection in pregnancy. RESULTS: The duration of low-level IgM positivity varied greatly (range 4-26 weeks). Samples collected within the first 2 weeks of infection showed high-level viremia (mean 1.75 x 10(8) geq/ml). During follow-up, low-level DNAemia (mean 9.7 x 10(4)geq/ml) persisted for at least 18 weeks in 91% (20/22) of patients. Considering the first 12 weeks after onset of disease the window of greatest risk for fetal complications, the "acute" phase was extended to cover this full period. In this case, performing the avidity and ETS-EIA sequentially, the positive predictive value was 100% in patients showing concordant avidity and ETS-EIA results. CONCLUSIONS: In the presence of low IgM titres and/or low-level DNAemia the use of supplementary serological assays such as VP1-IgG avidity EIA and VP2-ETS-EIA is advisable for restriction or avoidance of unnecessary fetal ultrasound examinations or invasive diagnostics; and in general for strengthening the reliability of B19 serodiagnosis of pregnant women.     

Convalescent Plasma Therapy in the management of COVID-19 patients-The newer dimensions

BackgroundCOVID 19 infection caused by novel coronavirus with no specific established treatment. Convalescent Plasma Therapy has been authorized as an off-label therapeutic procedure. We assessed the outcome of convalescent plasma (CP) units versus standard treatment on the complete recovery, improvement and 28 days’ mortality of COVID 19 patients.Materials and methodsThe present was multi-centric case controlled observational prospective study. The study was conducted for a period of four and half months from July 15 2020 to 30 November 2020 after taking approval from the Expert Committee, Health & Family Welfare Department, Government of Odisha. Plasma therapy was applied on two groups of 1189 serious COVID patients (959 number of pre- critical and 230 number of critical patients) not responding to oxygen therapy. It was compared with non- transfused control group of 1243 patients (996 number of pre-critical and 247 number of critical patients).ResultsDischarge was better in (55.5%) transfused than (43%)in non-transfused pre-critical patients and the mortality was lower (44.3%) in transfused, (48.9%) than non-transfused critical patients respectively. Complete recovery was highest in those who were transfused with CP with neutralizing titer more than 1:160 (52.5%), 18–30 years’ age group (64%), females (53%), ‘O’ Rh D positive blood group (51.5%). There was no adverse reaction due to CP transfusion.ConclusionsCP is effective in improving the recovery rate with earlier discharge and decrease in the 28 days’ mortality than in the control non-transfused group. CP with neutralizing antibody titer more than 1:160 has the best outcome with complete recovery and decrease in the mortality. It is more effective in treating pre-critical patients when transfused early, in female patients, in younger age group and in blood group ‘O’ Rh D positive.     

Identification of Different States of Hepatitis B Virus Infection with a Quantitative PCR Assay

The level of hepatitis B virus (HBV) DNA in serum reflects the replicative activity of HBV. To compare serum HBV DNA levels in different states of hepatitis B, 47 sera of patients with HBeAg-positive chronic hepatitis B, 4 sera of patients with HBeAg-negative chronic hepatitis B, 40 samples of patients after HBeAg seroconversion during alpha interferon treatment, 57 sera of inactive HBsAg carriers, and 42 sera of patients who had recovered from chronic hepatitis B more than 12 months prior to blood collection were checked for the presence of HBV DNA with the Amplicor HBV Monitor Test. In patients with HBeAg-positive chronic hepatitis B, the median of serum HBV DNA levels (8.3 × 10⁸ copies/ml) was significantly higher than that for patients after HBeAg seroconversion (6.2 × 10³ copies/ml) and than that for inactive HBsAg carriers (5.6 × 10³ copies/ml). None of the patients who had recovered from hepatitis B had detectable HBV DNA in serum. Quantitative PCR proved to be a valuable tool for identification of different states of HBV infection. This technique was found to be a good method for determination of serum HBV DNA levels both for patients with HBeAg seroconversion and for inactive carriers who showed low viremia not detectable by conventional hybridization assays.     

Comparative evaluation of two commercial enzyme immunoassays for serodiagnosis of human parvovirus B19 infection

The present study describes the performance of two commercial enzyme immunoassays (EIAs) employing recombinant capsid proteins derived from baculovirus or from yeast for diagnosis of human parvovirus B19 (B19) infection. At first, 450 sera from routine daily practice submitted consecutively for B19 antibody testing during a 2-week period in March 2006 were tested. Eighty percent of the routine sera were from pregnant women. There was a high degree of accordance between the two assay systems in detection of B19 IgG antibodies (98.9%) and B19 IgM antibodies (98.7%). Specific antibody concentrations of serum specimens with discordant test results (n=11) were within or close to the equivocal range of the respective assay. Subsequently, specificity and sensitivity of the IgM EIAs were assessed in detail by testing 160 sera collected from patients with a defined disease state. Specificity ranged between 94.2 and 98.5% in patients (n=70) with other acute infections or autoimmune diseases. In sera from pregnant women (n=30) and children (n=30) with acute B19 infection, both assays were 100% sensitive. Whereas sensitivity varied from 63.0 to 70.0% in pregnant women (n=30) investigated 8-12 weeks after onset of disease. According to our evaluation the diagnostic performance of the two assay systems appears to be substantially equivalent. Fetal hydrops is sometimes a late complication of gestational B19 infection and maternal B19 IgM antibodies may already have declined to undetectable levels at the time of clinical diagnosis. A negative B19 IgM test during pregnancy should therefore be interpreted with caution.     

Spontaneous Resolution of Hemophagocytic Syndrome Associated with Acute Parvovirus B19 Infection and Concomitant Epstein-Barr Virus Reactivation in an Otherwise Healthy Adult

Reported here is the case of a patient who spontaneously recovered from hemophagocytic syndrome associated with acute B19 infection and concomitant Epstein-Barr virus reactivation. The previously healthy 37-year-old-man was hospitalized after 10 days of high fever, arthralgia and arthritis and was determined to have hemophagocytic syndrome. Immunoglobulin (Ig) M antibodies to Epstein-Barr virus (EBV) capsid antigen, early antigen and parvovirus B19 (B19) were found. B19 DNA and low-level EBV DNA were detected in bone marrow, serum and peripheral blood mononuclear cells. The patient recovered spontaneously without any treatment. Two months later anti-B19 IgG antibodies were detected, while at 9-month follow-up, anti-B19 IgM antibodies were no longer detectable and B19 DNA had disappeared from serum. To the best of our knowledge, this is the first report of spontaneous resolution of hemophagocytic syndrome associated with acute B19 infection and concomitant EBV reactivation in an otherwise healthy adult. Electronic Publication     

Differentiation between acute primary and recurrent human cytomegalovirus infection in pregnancy,using a microneutralization assay

Acute primary human cytomegalovirus (HCMV) infection in pregnancy, the major cause of congenital symptomatic infection, is often difficult to differentiate from recurrent infection, which presents a considerably smaller risk to the fetus. Therefore, the diagnosis of primary infection in pregnancy is very important, especially if seroconversion is not documented and follow-up sera with declining IgM-titers are not available. To investigate the value of the neutralizing antibody response against HCMV in differentiating acute primary from recurrent and past infection, well-characterized sera from pregnant women were examined. Employing a microneutralization assay, it was found that neutralizing antibodies first appeared approximately 15 weeks after acute infection. However, serum samples of pregnant women with recurrent or past infection consistently displayed neutralizing activity. In conclusion, the neutralization assay can be used as a reliable method for discriminating acute primary from previous or recurrent infection in a single serum sample. J. Med. Virol. 56:351–358, 1998 . © 1998 Wiley-Liss, Inc.     

Lymphocyte recognition of human parvovirus B19 non-structural (NS1) protein: associations with occurrence of acute and chronic arthropathy?

Immune recognition of recombinant parvovirus B19 non-structural (rNS1) protein was studied by immunoblot and lymphoproliferative assays in blood from the following B19 seropositive groups: B19 infected (n = 14), B19 exposed but non-infected (n = 16), other illness with rash (n = 3), chronic arthropathy of unknown aetiology (n = 4) and healthy controls (n = 7). Sera from 11 B19 seronegative subjects were also studied. Sera collected at initial diagnosis or at the time of accidental B19 exposure in pregnancy were tested for NS1 antibody and evidence of B19 DNA by nested PCR. Follow-up specimens were obtained 3-12 months later for serological, PCR and proliferation studies. B19 DNA was detected sporadically in early specimens and in one follow-up specimen from a subject who developed chronic arthropathy after B19 infection. There was no correlation with development of arthropathy. NS1-specific IgG was detected in early sera from B19-infected and exposed subjects but to a lesser degree in follow-up specimens, and in only one healthy control serum. No correlation with the presence of NS1-specific antibodies was found with development of acute or chronic arthropathy. Although lymphocyte proliferation in response to stimulation with rNS1 in vitro occurred at a higher frequency in patients who developed acute and chronic joint manifestations after B19 infection, suggesting an association with this outcome, NS1-reactive lymphocytes were also found in three B19 seronegative patients, two of whom had recently been exposed to B19 but had no illness. Hence, immune recognition of NS1 may be more indicative of recent infection with, or exposure to, parvovirus B19 than associated with development of arthropathy as previously reported.     

Presence of neutralizing antibodies to heterologous human immunodeficiency virus type 1 isolates in sera of infected individuals is not predictive of rate of disease progression.

These studies were undertaken to examine whether the presence of human immunodeficiency virus type 1 (HIV-1)-neutralizing antibodies in sera of infected individuals would alter the rate of disease progression. HIV-1-infected individuals (n = 87) were initially examined for neutralizing activity in vitro against both laboratory and tissue culture-adapted clinical heterologous HIV-1 isolates. The neutralizing activities of sera were determined by a 90% or greater reduction in HIV-1 p24 levels in vitro. In a cross-sectional analysis of all infected individuals, we observed that sera from asymptomatic individuals neutralized a significantly greater number of heterologous HIV-1 isolates than sera from symptomatic patients. Patients who could be followed up longitudinally (n = 24) were then studied to determine the impact of neutralizing antibodies on the rate of disease progression. We observed no significant difference between the numbers of HIV-1 isolates neutralized in vitro by sera from patients who remained clinically stable and by those from patients who progressed rapidly. Our data indicated that the presence or absence of neutralizing antibodies to heterologous HIV-1 isolates was not associated with the rate of disease progression.