Acute Rubella Infection Research Articles

Bilateral Isolated Acute Optic Neuritis in a Child After Acute Rubella Infection

Bilateral Isolated Acute Optic Neuritis in a Child After Acute Rubella Infection

SEROPREVALENCE AND INCIDENCE OF RUBELLA IN AND AROUND DELHI (1988-2002)

National Institute of Communicable Diseases (NICD) has been engaged in rubella testing for serodiagnosis of the infection and screening for immunity status. The compiled and evaluated data of the work done on rubella testing for the past fifteen years has been presented here to show the trend and changing scenario of the disease in Delhi. Blood samples were from 7424 patients referred to NICD, Delhi for serodiagnosis of congenital Rubella syndrome (CRS) in malformed babies, in utero rubella infection in women and immunity status of pregnant women and women with bad obstetric history. They were tested for rubella IgG and/or rubella IgM antibodies using commercially available reagents and kits. The data from the 15 years of testing was then compiled and evaluated. From the available data it was seen that immunity status against rubella in childbearing age group of women increased steadily from 49% in 1988 to 87% in 2002. Reported cases of CRS at NICD are also on the decline over the time period. There is periodic indication of high incidence of rubella in the year 1988; 1991and 1998 as the reported cases of acute rubella infection in childbearing age group is high during these years.

Seroprevalence and incidence of rubella in and around Delhi (1988-2002)

National Institute of Communicable Diseases (NICD) has been engaged in rubella testing for serodiagnosis of the infection and screening for immunity status. The compiled and evaluated data of the work done on rubella testing for the past fifteen years has been presented here to show the trend and changing scenario of the disease in Delhi. Blood samples were from 7424 patients referred to NICD, Delhi for serodiagnosis of congenital Rubella syndrome (CRS) in malformed babies, in utero rubella infection in women and immunity status of pregnant women and women with bad obstetric history. They were tested for rubella IgG and/or rubella IgM antibodies using commercially available reagents and kits. The data from the 15 years of testing was then compiled and evaluated. From the available data it was seen that immunity status against rubella in childbearing age group of women increased steadily from 49% in 1988 to 87% in 2002. Reported cases of CRS at NICD are also on the decline over the time period. There is periodic indication of high incidence of rubella in the year 1988; 1991 and 1998 as the reported cases of acute rubella infection in childbearing age group is high during these years.

Diagnostic anténatal des infections rubéoliques

Diagnosis of congenital rubella infection which is realized in authorized laboratory, must be established in pregnant women with proven acute rubella infection. This diagnosis should also be considered in any infant presenting evidence of intrauterine growth retardation, or with others consistent signs of congenital infection. Presence of rubella-specific IgM antibody in fetal blood or presence of viral genomic RNA in amniotic fluid confirms the diagnosis so that accurate counselling can be offered to pregnant woman about the risks and damage to the fetus.

Elevated serum levels of interleukin-10 in children with acute rubella infection.

Interleukin-10 (IL-10) is known to be an anti-inflammatory cytokine which inhibits cell growth and cytokine production of both Th1 and Th2 cells. Using a human IL-10 ELISA kit we investigated whether serum IL-10 levels increased during the acute and convalescent stages in 45 children with rubella infections. Serum levels of IL-10 were markedly elevated in rubella patients during the acute stage, compared with those at the convalescent stage and those in healthy age-matched children (mean +/- SEM): 18.5 +/- 3.4 vs. 6.0 +/- 0.6 vs. 7.9 +/- 1.3 pg/ml. IL-10 levels determined 5 d after the onset of the disease had returned to the normal range. In patients with rubella, there were significant negative correlations between serum IL-10 levels and both rubella virus-specific IgM and IgG antibodies. These findings suggest that IL-10 may play a role in the pathogenesis of acute rubella infections.

Distinct Serum Cytokine Levels in Drug– and Measles–Induced Exanthema

Background: Macular or maculopapular skin reactions are frequent events in drug allergy as well as in viral infections. Clinically, the differentiation may be difficult in the absence of a clear relationship to drug intake or failure to detect virus–specific antibodies of the IgM class. Studies on drug–specific T cell lines and T cell clones isolated from drug–allergic patients have suggested that these cells may represent a significant source of IL–5. On the other hand, viral infections are frequently associated with elevated IFN–γ levels. Objective: Determination of serum–cytokine levels to differentiate between drug– and virally induced skin eruptions. Patients: 18 patients suffering from acute drug allergy and 19 patients with acute measles, rubella or parvovirus infection. Measurements: Cytokine–ELISA (IL–5, IL–4 and IFN–γ) of sera collected during acute drug allergy or during acute measles, rubella or parvovirus infection. Results: In 12/18 patients with drug allergy, IL–5 and/or IL–4 were elevated. A significant correlation (r_Spearman = 0.84) between IL–5 serum levels and eosinophil counts in the blood was found. No correlation was detected between IL–4 and blood eosinophilia or between IL–4 and IL–5 levels. After remission, IL–5 and IL–4 decreased to undetectable levels. IFN–γ on the other hand was not measurable in patients with drug allergy while elevated IFN–γ serum levels were detected in 17/19 patients with measles, rubella or parvovirus infection; 2 patients with acute virus infection had elevated IL–5, and/or IL–4 and IFN–γ levels. Conclusion: These data underline the distinct pathogenesis of these morphologically similar exanthemas and suggest that the combined analysis of eosinophilia in the blood, IL–4 and IFN–γ might help in differentiating skin eruptions.

Maturation of rubella IgG avidity over time after acute rubella infection

Background: As the incidence of rubella has diminished, the proportion of unspecific rubella IgM reactivity among all samples with rubella IgM reactivity has increased. It is important to distinguish IgM reactivity caused by primary infection from that caused by reinfection or persistence, especially in pregnant women, as termination of pregnancy should be considered when primary rubella is diagnosed during the first trimester. Objectives: To elucidate the changes over time of the avidity of rubella IgG antibodies after acute rubella infection. Study design: Serial samples, 84, were collected from 15 patients up to 4–5 months after acute rubella infection. Rubella specific IgG avidity was tested by the eluting principle adding 35 mM diethylamine to the washing buffer of a commercially available rubella IgG ELISA. As controls, 137 samples from women with remote rubella and 94 samples from patients with a rubelliform rash, were tested. Results: The avidity index increased steadily in all patients during the observation time. A low avidity index (<40%) was seen up to 6 weeks after onset of rash. A high avidity index (>60%) was not observed until 13 weeks after infection and only in four of the 15 patients during the observation time. Conclusions: An increase of rubella IgG antibody avidity was seen during the whole observation time but was most pronounced during the first 3 months after onset of rash. Measurement of rubella IgG avidity is a good supplemental test for cases with rubella IgM reactivity to confirm or exclude a recent rubella infection.

Expression and characterization of a soluble rubella virus E1 envelope protein

Individual specific antigenic rubella virus (RV) structural proteins are required for accurate serological diagnosis of acute and congenital rubella infections as well as rubella immune status. The RV envelope glycoprotein E1 is the major target antigen and plays an important role in viral-specific immune responses. The native virion is difficult to produce in large quantities and the protein subunits are also difficult to isolate without loss of antigenicity. The production of a soluble RV E1 (designated E1 delta Tm) using the baculovirus-insect cell expression system is described. In contrast to wild-type RV E1, the genetically engineered E1 delta Tm protein lacks a transmembrane anchor. It behaved as a secretory protein and was secreted abundantly from insect cells. Pulse-chase studies were used to examine the synthesis, glycosylation, and secretion of E1 delta Tm by the insect cells. The secreted E1 delta Tm protein was purified from serum-free medium by one-step immunochromatography. The purified E1 delta Tm protein retained full antigenicity and may be a convenient source of E1 protein for use in diagnostic assay and rubella vaccine development.

Serologically proven acute rubella infection in patients with clinical diagnosis of dengue

Patients with a clinical diagnosis of dengue but negative by serological testing were studied for rubella infection. Paired sera were obtained from 69 patients during an outbreak in Yucatán, México. The presence of specific anti-viral IgM in the acute sera was considered as diagnostic for rubella infection. The immunoglobulin was determined by measuring the difference in the inhibition of hemagglutination between the non-reduced and the reduced fractionated sera. Immunoglobulins were separated by sucrose density centrifugation. Acute rubella infection was found in 7 (10.1%) of the patients. These results demonstrate active rubella infection in patients clinically diagnosed as dengue.

Abnormal antibody response against the rubella virus haemagglutinin

Reported here is a case of rubella with an abnormally delayed and weak antibody response to the viral haemagglutinin (HA). Initially, neutralizing antibodies and IgM class antibodies were detected with no activity in the haemagglutination inhibition (HAI) test. A serum taken seven weeks later showed seroconversion by HAI, single radial haemolysis and IgG immunoassays. Specific polypeptide and epitope binding assays confirmed the absence of antibody reactivity against the HA epitopes of the E1 glycoprotein in the first serum. This reactivity was detected with the second serum but was markedly weaker than that normally seen after acute rubella infection. Thus, the production of HAI and neutralizing antibodies do not always correlate and this could lead to difficulties in the early diagnosis of rubella.

Prenatal diagnosis of intrauterine rubella.

The results of prenatal diagnosis of fetal rubella infection by specific IgM antibody detection in fetal infection by specific IgM antibody detection in fetal blood obtained in the 21st to 23rd weeks of pregnancy of women with different types of rubella problems during pregnancy (categorised in four groups) showed that in 28 of 31 cases the diagnosis apparently assisted in the correct management of the pregnancy. However, in two cases with negative IgM findings in the fetal blood, children with rubella embryopathy were born, and in one case with positive IgM antibody findings, the child was infected but healthy. From this experience we recommend that in all cases of symptomatic rubella infection in the first 12 weeks, termination of pregnancy should be considered without prenatal diagnosis. Prenatal diagnosis, if considered at all, should be limited to "symptomless" acute rubella infection and reinfection in the first 12 weeks and to symptomatic rubella infection in the 12th to 17th weeks of pregnancy.

The development of an M antibody capture ELISA for rubella IgM

An M antibody capture enzyme-linked immunosorbent assay for rubella IgM was developed. The enzyme label was prepared from a monoclonal antibody raised against rubella haemagglutinin (Tedder et al., 1982). Paired sera from acute rubella infections and vaccines as well as sera from blood donors, antenatal patients and patients whose sera contained rheumatoid factor and patients with acute nonrubella infections were tested by this method.

Direct enzyme immunoassay for detection of specific igg antibody to rubella virus by use of labelled antigen

A new solid phase enzyme immunoassay(ElA) for detection of rubella-specific immunoglobulin G (IgG) antibody was developed. The test uses polystyrene microtiter strips coated with rabbit anti-human IgG immunoglobulins as the solid phase and an enzyme-labelled semipurified rubella antigen as indicator. The direct EIA was compared with hemagglutination inhibition (HI), single radial heinolysis(SRH),radioimmu-noassay (RIA) and time-resolved fluoroimmunoassay (TR-FIA) using 52 serum specimens from patients with remote rubella infection. The overall agreement of direct EIA with HI was 96.1%, with SRH and RIA 98.1% and with TR-FIA 100%. The linear regression coefficient varied from 0.77 to 0.91, the best being obtained with direct EIA and SRH. The direct EIA was also suitable for diagnosis of acute infections, as a significant increase in antibody levels was detected in all paired serum specimens tested from patients with acute rubella infection. The sensitivity and specificity were comparable to those of the other assays employed. An advantage of the present assay is that the same method and same labelled antigen can be used to test for different classes of antibody using simply a solid phase coated with capture antibodies of different chain specificity.

Clinical validation of an antibody-capture anti-rubella IgM-ELISA

An antibody-capture IgM-ELISA using monoclonal antibodies for conjugate was subjected to clinical validation with respect to sensitivity and specificity. In 103 serum specimens, known to contain anti-rubella IgM by a sucrose density gradient method, IgM was found by the ELISA in 99 sera. In a second study, 16 out of 17 acute rubella infections were detected by the IgM-ELISA. In 17 out of 17 vaccinees, a specific IgM response could be demonstrated. Specificity of the antibody-capture ELISA was found to be high; no interference was seen in 60 rheumatoid-factor positive sera, in 100 highly positive IgG sera or 10 sera with anti-CMV IgM, Only one out of 100 sera with heterophile antibodies showed a positive response. In acute rubella infections, IgM was shown to be detectable from 1 to 4 days after onset of illness up to about 12 wk, with peak values at about 1 wk after onset.

Time-resolved fluoroimmunoassay: a new test for rubella antibodies.

A new solid-phase immunoassay, time-resolved fluoroimmunoassay (TR-FIA), for rubella antibody was developed. The test used polystyrene beads coated with rubella antigen as the solid phase and a chelate of the rare earth metal europium as fluorescent label. A fast light pulse from a xenon flash lamp was used to excite the label, and after a 400-mus delay time the emission fluorescence was measured for 500-mus at 1-ms intervals during a total counting time of 1 s. Background fluorescence of short duration caused by fluorescent serum components and scattering could be eliminated by including the delay time. The TR-FIA was compared with hemagglutination inhibition, single radial hemolysis, and two types of radioimmunoassay (RIA) (a commercial RIA [GammaCoat] and a noncommercial RIA [T-RIA]) by using 60 serum specimens from patients with remote rubella infection. Overall agreement of TR-FIA with hemagglutination inhibition and GammaCoat was 96.7%, with single radial hemolysis 98.3%, and with T-RIA 100%. Linear regression coefficients varied from 0.83 to 0.94, the best being obtained with single radial hemolysis and T-RIA. TR-FIA was also found to be suitable for the diagnosis of acute infections, as significant increases of antibody level were detected in all 30 paired serum specimens tested from patients with an acute rubella infection. Sensitivity and specificity comparable to those of RIA and enzyme immunoassay were obtained with TR-FIA. Furthermore, the advantage that TR-FIA has over RIA is that it incorporates a nonisotopic and stable label; its advantage over EIA is that it is easier to standardize because no additional reaction with substrate is required.

Comparison of different methods for assessment of rubella infection and immunity

Three different enzyme-linked immunosorbent assays (ELISA), a fluorescence immunoassay (FIAX), and a hemolysis-in-gel test (HIG) were examined for sensitive detection of specifie antibodies in sera of persons with acute and previous rubella infection. In comparison to hemagglutination inhibition (HI), all tests were able to detect previously formed rubella antibodies. In sera of patients with acute rubella infection, only the FIAX system showed always positive results. Nevertheless, it remains unclear, if these findings are due to a higher sensitivity of the FIAX system or are possibly non-specific results. In some cases, however, this test system failed to detect significant titre rises seen in HI, because it showed high antibody titres already in the first serum sample.

Assessing Risks of Rubella Infection During Pregnancy

Three algorithms have been prepared that should permit a rational and consistent assessment of the likelihood of acute rubella infection in the pregnant woman whose previous rubella immune status is unknown, and the attendant risks, if any, to her unborn child.

IgA antibody response in acute rubella determined by solid-phase radioimmunoassay

A solid-phase radioimmunoassay (RIA) for detecting rubella virus IgA serum antibodies was developed. Purified rubella virus grown in roller cultures of Vero cells was adsorbed onto polystyrene beads. The coated beads were then incubated with dilutions of serum, and rubella IgA antibodies which attached to the virus antigen on the solid-phase were subsequently detected with 125I-labelled anti-human-alpha antibodies. The specificity of the iodinated anti-human immunoglobulins was confirmed by RIA analysis of fractions obtained by chromatography of an early convalescent serum on an agarose column. A complete separation of IgM, IgA, and IgG was observed. A total of 144 serial serum specimens from 31 adult patients with an acute rubella infection were tested for rubella IgA antibodies, and the results were compared with the RIA IgG and IgM titres reported earlier from the same specimens. The RIA IgA response was detected in each of the 31 patients and the IgA antibodies appeared almost simultaneously with the IgG and IgM antibodies. The maximum titres, which were lower than the IgG and IgM titres, were reached in about 1 week after the onset of rash. In 6 patients out of 31 the IgA antibody response was transient and persisted approximately two months, while in the remaining 25 patients the IgA antibodies persisted throughout the study period of more than 5 months. The results obtained indicate that the presence of rubella IgA antibodies in serum is not an indication for a recent rubella infection.

Comparison of passive haemagglutination and haemagglutination-inhibition techniques for detection of antibodies to rubella virus.

Because of the technical problems and length of time involved in the satisfactory performance of the haemagglutination-inhibition test for detection of rubella-specific antibodies, a commercially available passive haemagglutination (PHA) kit utilising rubella antigen-sensitised human erythrocytes was tested for its suitability for use in diagnostic laboratories. The immune response to acute rubella infections as measured by PHA was considerably delayed compared to the response measured by haemagglutination-inhitition. Titres of rubella-specific antibody only became comparable six months after the infection. The commercially available PHA kits is a useful addition to diagnostic laboratories for the determination of immune status and, in conjunction with the haemagglutination-inhibition test, can be an indicator of recent rubella infection.

IgM-class rheumatoid factor interference in the solid-phase radioimmunoassay of rubella-specific IgM antibodies.

The interference of IgM-class rheumatoid factor (RF) in the solid-phase radioimmunoassay (RIA) of rubella virus IgM antibodies was studied. Acute rubella infections did not significantly activate RF. False-positive rubella antibody results were obtained, however, when patients with raised RF levels were tested. If a low rubella IgG antibody titre was present, a high level of RF was required to cause a false-positive IgM result; conversely, in sera with high IgG titres, only a low level of RF was required for interference. Although the false-positive IgM titres obtained were generally low, thet did show a positive correlation to both RF levels and rubella IgG titres. False-positive results were successfully avoided by removing the RF by absorption with heat-aggregated human gamma globulin. The absorption procedure did not affect true rubella IgM antibody titres.