Development of a real-time fluorescent reverse transcription loop-mediated isothermal amplification assay with quenching primers for rapid detection of rubella virus.

Rubella virus infection during early pregnancy sometimes causes severe birth defects termed congenital rubella syndrome. Although there are safe and effective live-attenuated vaccines, rubella has only been certified as eliminated in the Americas within the six World Health Organization regions. Rubella remains an endemic disease in many regions, and outbreaks occur wherever population immunity is insufficient. There are two main methods for diagnosis of rubella: detection of anti-rubella IgM antibodies by enzyme immunoassay and detection of the viral genome by real-time RT-PCR. Both of these methods require substantial time and effort. In the present study, a rapid rubella detection assay using real-time fluorescent reverse transcription loop-mediated isothermal amplification with quenching primers was developed. The time required for the new assay was one-half that required for a real-time RT-PCR assay. The assay had 93.6% positive percent agreement and 100% negative percent agreement for clinical specimens compared with the real-time RT-PCR assay. The new assay is considered useful for diagnosis of rubella in areas where rubella is endemic.

Multiplex Bead Assay for the Serological Surveillance of Measles and Rubella.

There is increasing interest in evaluating antibody responses to multiple antigen targets in a single assay. Immunity to measles and rubella are often evaluated together because immunity is provided through combined vaccines and because routine immunization efforts and surveillance for measles and rubella pathogens are combined in many countries. The multiplex bead assay (MBA) also known as the multiplex immunoassay (MIA) described here combines the measurement of measles- and rubella-specific IgG antibodies in serum quantitatively according to international serum standards and has been successfully utilized in integrated serological surveillance.

A case of congenital rubella syndrome and epidemiology of related cases in China, 2014-2023.

Rubella is a major cause of congenital defects, and the presence of rubella infection in a pregnant woman may lead to fetal death or congenital defects known as congenital rubella syndrome(CRS). Since China has not yet established a national CRS surveillance system, the true incidence cannot be determined. To understand the disease burden and epidemiological characteristics of CRS cases in China, the article reports the first case of CRS in Quzhou, China, and conducts a retrospective analysis of related cases that have been reported in China over the past decade. Because the availability of rubella-containing vaccines (RCV) was not widespread in China before 2008, women of childbearing age born before 2008 are generally unvaccinated against RCV. Due to the lack of routine CRS monitoring and screening, CRS is underreported in China. Vaccination of nonimmune women of childbearing age with RCV and establishing a sensitive and timely case-based CRS surveillance system can accelerate the elimination of rubella and CRS.

Case report: Rubella virus-associated cutaneous granuloma in an adult with TAP1 deficiency.

Rubella virus-associated granulomas commonly occur in immunocompromised individuals, exhibiting a diverse range of clinical presentations. These manifestations can vary from predominantly superficial cutaneous plaques or nonulcerative nodules to more severe deep ulcerative lesions, often accompanied by extensive necrosis and significant tissue destruction. TAP1 deficiency, an exceedingly rare primary immune-deficiency disorder, presents with severe chronic sino-pulmonary infection and cutaneous granulomas. This report highlights the occurrence of rubella virus-associated cutaneous granulomas in patients with TAP1 deficiency. Notably, the pathogenic mutation responsible for TAP1 deficiency stems from a novel genetic alteration that has not been previously reported. This novel observation holds potential significance for the field of diagnosis and investigative efforts in the context of immunodeficiency disorders.

Age-specific prevalence of IgG against measles/rubella and the impact of routine and supplementary immunization activities: A multistage random cluster sampling study with mathematical modelling.

BACKGROUND: Vietnam continues to have measles and rubella outbreaks following supplementary immunization activities (SIA) and routine immunization despite both having high reported coverage. To evaluate immunization activities, age-specific immunity against measles and rubella, and the number of averted Congenital Rubella Syndrome (CRS) cases, must be estimated. METHODS: Dried blood spots were collected from 2091 randomly selected individuals aged 1-39 years. Measles and rubella virus-specific immunoglobulin G (IgG) were measured by enzyme immunoassay. Results were considered positive at ≥120 mIU/mL for measles and ≥10 IU/mL for rubella. The number of CRS cases averted by immunization since 2014 were estimated using mathematical modelling. RESULTS: Overall IgG seroprevalence was 99.7% (95%CI: 99.2-99.9) for measles and 83.6% (95%CI: 79.3-87.1) for rubella. Rubella IgG seroprevalence was higher among age groups targeted in the SIA than in non-targeted young adults (95.4% [95%CI: 92.9-97.0] vs 72.4% [95%CI: 63.1-80.1]; P < 0.001). The estimated number of CRS cases averted in 2019 by immunization activities since 2014 ranged from 126 (95%CI: 0-460) to 883 (95%CI: 0-2271) depending on the assumed postvaccination reduction in the force of infection. CONCLUSIONS: The results suggest the SIA was effective, while young adults born before 1998 who remain unprotected for rubella require further vaccination.

Frequency of an intrathecal IgM synthesis and MRZ reaction in children with MS.

BACKGROUND: Multiple sclerosis (MS) is a chronic inflammatory and demyelinating disease of the CNS. An intrathecal IgM synthesis is associated with a more rapid progression of MS and the intrathecal immune response to measles -, rubella -and varicella zoster virus (MRZR) which, if present, increases the likelihood of a diagnosis of MS in adults. OBJECTIVE: To evaluate the frequency of an intrathecal IgM synthesis and MRZR in children with MS. MethodsChildren with MS and a data set including clinical and treatment history, MRI at onset, in addition to a CSF analysis, and determination of antibody index (AI) of measles, rubella, and zoster antibodies, were eligible. The presence of an intrathecal IgM synthesis and/or a positive MRZ reaction were compared to biomarkers of a more progressive disease course. RESULTS: In 75 children with MS, OCBs were present in 93.3 %). 49,2 % experienced their first relapse within 6 months. 50.7 % had a total lesion load of more than 10 lesions in the first brain MRI. Spinal lesions were identified in 64 %. 23.5 % had a positive MRZR and 40.3 % an intrathecal IgM synthesis. No significant associations were detected between the presence of an intrathecal IgM synthesis and MRZR and parameters including the relapse rate in the first two years. CONCLUSION: An intrathecal IgM synthesis and a positive MRZR are found in a subset of MS children but are not associated with markers associated with a poor prognosis.

HLA Associations of Intrathecal IgG Production against Specific Viruses in Multiple Sclerosis.

OBJECTIVE: Specific human leucocyte antigen (HLA) alleles are not only associated with higher risk to develop multiple sclerosis (MS) and other autoimmune diseases, but also with the severity of various viral and bacterial infections. Here, we analyzed the most specific biomarker for MS, that is, the polyspecific intrathecal IgG antibody production against measles, rubella, and varicella zoster virus (MRZ reaction), for possible HLA associations in MS. METHODS: We assessed MRZ reaction from 184 Swiss patients with MS and clinically isolated syndrome (CIS) and 89 Swiss non-MS/non-CIS control patients, and performed HLA sequence-based typing, to check for associations of positive MRZ reaction with the most prevalent HLA alleles. We used a cohort of 176 Swedish MS/CIS patients to replicate significant findings. RESULTS: Whereas positive MRZ reaction showed a prevalence of 38.0% in MS/CIS patients, it was highly specific (97.7%) for MS/CIS. We identified HLA-DRB1*15:01 and other tightly linked alleles of the HLA-DR15 haplotype as the strongest HLA-encoded risk factors for a positive MRZ reaction in Swiss MS/CIS (odds ratio [OR], 3.90, 95% confidence interval [CI] 2.05-7.46, padjusted = 0.0004) and replicated these findings in Swedish MS/CIS patients (OR 2.18, 95%-CI 1.16-4.02, padjusted = 0.028). In addition, female MS/CIS patients had a significantly higher probability for a positive MRZ reaction than male patients in both cohorts combined (padjusted <0.005). INTERPRETATION: HLA-DRB1*15:01, the strongest genetic risk factor for MS, and female sex, 1 of the most prominent demographic risk factors for developing MS, predispose in MS/CIS patients for a positive MRZ reaction, the most specific CSF biomarker for MS. ANN NEUROL 2024;95:1112-1126.

A single-point mutation in the rubella virus E1 glycoprotein promotes rescue of recombinant vesicular stomatitis virus.

Rubella virus (RuV) is an enveloped plus-sense RNA virus and a member of the Rubivirus genus. RuV infection in pregnant women can lead to miscarriage or an array of severe birth defects known as congenital rubella syndrome. Novel rubiviruses were recently discovered in various mammals, highlighting the spillover potential of other rubiviruses to humans. Many features of the rubivirus infection cycle remain unexplored. To promote the study of rubivirus biology, here, we generated replication-competent recombinant VSV-RuV (rVSV-RuV) encoding the RuV transmembrane glycoproteins E2 and E1. Sequencing of rVSV-RuV showed that the RuV glycoproteins acquired a single-point mutation W448R in the E1 transmembrane domain. The E1 W448R mutation did not detectably alter the intracellular expression, processing, glycosylation, colocalization, or dimerization of the E2 and E1 glycoproteins. Nonetheless, the mutation enhanced the incorporation of RuV E2/E1 into VSV particles, which bud from the plasma membrane rather than the RuV budding site in the Golgi. Neutralization by E1 antibodies, calcium dependence, and cell tropism were comparable between WT-RuV and either rVSV-RuV or RuV containing the E1 W448R mutation. However, the E1 W448R mutation strongly shifted the threshold for the acid pH-triggered virus fusion reaction, from pH 6.2 for the WT RuV to pH 5.5 for the mutant. These results suggest that the increased resistance of the mutant RuV E1 to acidic pH promotes the ability of viral envelope proteins to generate infectious rVSV and provide insights into the regulation of RuV fusion during virus entry and exit.IMPORTANCERubella virus (RuV) infection in pregnant women can cause miscarriage or severe fetal birth defects. While a highly effective vaccine has been developed, RuV cases are still a significant problem in areas with inadequate vaccine coverage. In addition, related viruses have recently been discovered in mammals, such as bats and mice, leading to concerns about potential virus spillover to humans. To facilitate studies of RuV biology, here, we generated and characterized a replication-competent vesicular stomatitis virus encoding the RuV glycoproteins (rVSV-RuV). Sequence analysis of rVSV-RuV identified a single-point mutation in the transmembrane region of the E1 glycoprotein. While the overall properties of rVSV-RuV are similar to those of WT-RuV, the mutation caused a marked shift in the pH dependence of virus membrane fusion. Together, our studies of rVSV-RuV and the identified W448R mutation expand our understanding of rubivirus biology and provide new tools for its study.

Diagnostic accuracy of commercially available serological tests for the detection of measles and rubella viruses: a systematic review and meta-analysis.

Measles and rubella serological diagnoses are done by IgM detection. The World Health Organization Global Measles and Rubella Laboratory Network previously endorsed Siemens Enzygnost enzyme-linked immunosorbant assay kits, which have been discontinued. A recommended replacement has not been determined. We aimed to search for suitable replacements by conducting a systematic review and meta-analysis of IgM detection methods that are currently available for measles and rubella. A systematic literature search was performed in Medline, Embase, Global Health, Cochrane Central, and Scopus on March 22 and on 27 September 2023. Studies reporting measles and/or rubella IgM detection with terms around diagnostic accuracy were included. Risk of bias was assessed using QUADAS tools. Meta-DiSc and R were used for statistical analysis. Clinical samples totalling 5,579 from 28 index tests were included in the measles meta-analysis. Sensitivity and specificity of the individual measles studies ranged from 0.50 to 1.00 and 0.53 to 1.00, respectively. Pooled sensitivity and specificity of all measles IgM detection methods were 0.94 (CI: 0.90-0.97) and 0.94 (CI: 0.91-0.97), respectively. Clinical samples totalling 4,983 from 15 index tests were included in the rubella meta-analysis. Sensitivity and specificity of the individual rubella studies ranged from 0.78 to 1.00 and 0.52 to 1.00, respectively. Pooled sensitivity and specificity of all rubella IgM detection methods were 0.97 (CI: 0.93-0.98) and 0.96 (CI: 0.93-0.98), respectively. Although more studies would be ideal, our results may provide valuable information when selecting IgM detection methods for measles and/or rubella.

Crystal structure and biochemical activity of the macrodomain from rubella virus p150.

Rubella virus encodes a nonstructural polyprotein with RNA polymerase, methyltransferase, and papain-like cysteine protease activities, along with a putative macrodomain of unknown function. Macrodomains bind ADP-ribose adducts, a post-translational modification that plays a key role in host-virus conflicts. Some macrodomains can also remove the mono-ADP-ribose adduct or degrade poly-ADP-ribose chains. Here, we report high-resolution crystal structures of the macrodomain from rubella virus nonstructural protein p150, with and without ADP-ribose binding. The overall fold is most similar to macroD-type macrodomains from various nonviral species. The specific composition and structure of the residues that coordinate ADP-ribose in the rubella virus macrodomain are most similar to those of macrodomains from alphaviruses. Isothermal calorimetry shows that the rubella virus macrodomain binds ADP-ribose in solution. Enzyme assays show that the rubella virus macrodomain can hydrolyze both mono- and poly-ADP-ribose adducts. Site-directed mutagenesis identifies Asn39 and Cys49 required for mono-ADP-ribosylhydrolase (de-MARylation) activity.IMPORTANCERubella virus remains a global health threat. Rubella infections during pregnancy can cause serious congenital pathology, for which no antiviral treatments are available. Our work demonstrates that, like alpha- and coronaviruses, rubiviruses encode a mono-ADP-ribosylhydrolase with a structurally conserved macrodomain fold to counteract MARylation by poly (ADP-ribose) polymerases (PARPs) in the host innate immune response. Our structural data will guide future efforts to develop novel antiviral therapeutics against rubella or infections with related viruses.

Rubella virus chronic inflammatory disease and other unusual viral phenotypes in inborn errors of immunity.

Infectious susceptibility is a component of many inborn errors of immunity. Nevertheless, antibiotic use is often used as a surrogate in history taking for infectious susceptibility, thereby disadvantaging patients who present with viral infections as their phenotype. Further complicating clinical evaluations are unusual manifestations of viral infections which may be less familiar that the typical respiratory viral infections. This review covers several unusual viral phenotypes arising in patients with inborn errors of immunity and other settings of immune compromise. In some cases, chronic infections lead to oncogenesis or tumor-like growths and the conditions and mechanisms of viral-induced oncogenesis will be described. This review covers enterovirus, rubella, measles, papillomavirus, and parvovirus B19. It does not cover EBV and hemophagocytic lymphohistiocytosis nor lymphomagenesis related to EBV. EBV susceptibility has been recently reviewed. Our goal is to increase awareness of the unusual manifestations of viral infections in patients with IEI and to describe treatment modalities utilized in this setting. Coincidentally, each of the discussed viral infections can have a cutaneous component and figures will serve as a reminder of the physical features of these viruses. Given the high morbidity and mortality, early recognition can only improve outcomes.

Difficulty in Serologic Screening for Subclinical Rubella during Pregnancy.

In Japan, rubella antibodies are tested in all pregnant women to detect subclinical infections. This study aimed to assess the validity of measuring rubella antibodies for detecting subclinical rubella among pregnant women in Japan. This single-center retrospective study measured rubella hemagglutination inhibition (HI) titers and rubella-specific IgM antibody index (IgM) values. IgM values were measured by conducting enzyme immunoassay, and IgM-values >1.2 were considered positive. Of 14,965 included pregnant women, 186 (1.2%) were IgM-positive. Only one patient was clinically diagnosed with rubella (HI titer, 1:2,048; IgM value, 10) and developed fever and skin rash. She decided to terminate her pregnancy without undergoing repeated blood tests. Of the IgM-positive patients, 136 (73.1%) had rubella HI titers of < 1:256. The correlation coefficient between rubella HI and IgM titers was weakly positive (0.2527; P < 0.0001). This study showed that a single combination of rubella HI and rubella-specific IgM measurements alone could not detect subclinical rubella. Creating awareness among pregnant women by informing them that almost all rubella-specific IgM-positive individuals without symptoms are not acutely infected could decrease their anxiety and prevent unnecessary pregnancy termination.

Cutaneous granulomas associated with rubella virus: A clinical review.

Since the initial identification of vaccine-derived rubella virus (RuV) in the cutaneous granulomas of pediatric patients with inborn errors of immunity in 2014, more than 80 cases of RuV granulomas have been reported implicating both vaccine-derived and wild type RuV. Previously thought to arise exclusively in patients with significant immunocompromise, the identification of RuV granulomas in clinically immunocompetent patients adds nuance to our understanding of the interplay between host environment, immune dysregulation, and RuV granuloma formation. This review summarizes the literature on RuV granulomas including clinical and histopathologic features, proposed pathomechanisms supporting granuloma development, and potential therapeutic options. There is no standardized algorithm to guide the workup and diagnosis of suspected RuV granulomas. We highlight the importance of contributing RuV granuloma cases to ongoing Centers for Disease Control and Prevention surveillance efforts to monitor wild type and vaccine-derived RuV transmission. Studies advancing our understanding of RuV granulomas may provide insights into the role of viral infectious agents in granulomatous disease pathogenesis and guide the development of improved therapeutic options.

Seroepidemiology study of rubella virus antibodies among neonates and pregnant women at hospitals in Henan province, China.

Rubella virus infection can cause vertical transmission to the fetus during pregnancy. In China's Henan province, rubella surveillance needs to be well-established. In this research, a total of 1933 neonates and 2502 pregnant women were enrolled, and their sera for IgG and IgM antibodies against rubella were tested by chemiluminescence assay. Of 1933 neonates' sera tested, the seropositive of rubella IgG was 68.7%. The seroprevalence of rubella IgM in neonates was 0.4%. 30.9% of neonates had negative results for IgG and IgM antibodies. Two thousand five hundred and two pregnant women participated in the serosurvey, and 79.3% were rubella IgG positive. Rubella IgG seropositivity in pregnant women differed by age and number of births. 0.8% of the pregnant women had positive results for IgM against the rubella virus. The seronegative of rubella IgG and IgM antibodies in pregnant women was 19.8%. Due to the negative rubella-specific IgG antibody, many neonates remain at risk of rubella virus infection. Rubella virus continues to spread since some neonates and pregnant women with rubella-specific IgM antibody positive have been detected. Rubella vaccination may be introduced for childbearing-age women to increase immunity levels against rubella with periodic sero-surveillance.

The path to eradication of rubella.

Since 1969, rubella and its harmful effect on fetuses infected in utero can be prevented by rubella vaccine, usually given in combination with measles vaccine. The rubella vaccine is highly protective both in children and in adults including women intending to become pregnant. Owing to the use of combined measles and rubella vaccines, congenital rubella infection has been eliminated from the Western Hemisphere and nearly all of Europe. Such combined vaccination is now being applied throughout the world, posing the possibility of eventual rubella eradication. The existence of viruses of animals related to rubella does not appear to be a barrier to eradication of the human virus. However, persistent rubella virus in infants infected in utero and of immunosuppressed patients with granulomas may pose a problem for eradication. Nevertheless, this review posits that eradication of rubella is now feasible if routine vaccination of infants and surveillance for chronic infection are correctly applied.

Rubella virus-associated uveitis at a tertiary care hospital in Germany between 2013 and 2019.

Uveitis is a process of intraocular inflammation that may involve different sections of the uveal tract. Apart from systemic or localized immune-mediated diseases, infections are key players in the etiology of uveitis and entail different treatment strategies. Rubella virus (RuV) is a recognized causative agent for the development of Fuchs uveitis, representing a major cause of virus-associated intraocular inflammation. A cohort of 159 patients diagnosed with different forms of uveitis between 2013 and 2019 was subjected to diagnostic antibody testing of the aqueous or vitreous humor. The diagnostic panel included RuV, cytomegalovirus, herpes simplex virus, varicella-zoster virus, and toxoplasmosis. Within this cohort, 38 RuV-associated uveitis (RAU) patients were identified based on a pathologic Goldman-Witmer coefficient indicative of an underlying RuV infection. With a mean age of 45.9 years, the RAU patients were younger than the non-RAU patients (56.3, p < 0.001). The evaluation of clinical parameters revealed a predominance of anterior uveitis and late sequalae such as cataract and glaucoma among the RAU patients. In 15 of the patients a history of prior RuV infections could be confirmed. The study underlines the importance of long-term surveillance of RuV associated diseases that originate from infections before the introduction of RuV vaccination programs.

Rubella virus genotype 2B endemicity and related utility of serum-based molecular characterization in Uganda.

There are 13 globally recognized rubella virus genotypes of which only 2 (1E and 2B) have been detected recently. The largest percentage of all reported rubella virus sequences come from China and Japan with Africa reporting limited data. In a bid to address the lack of rubella genotype data in Uganda and the World Health Organization Africa region, we sought to characterize rubella viruses retrospectively using sera collected from suspected measles patients that turned out rubella IgM positive.Seven sequences belonging to genotype 2B sub-lineage 2B-L2c were obtained. These sequences clustered with other genotype 2B sequences previously reported from Uganda. None of the other genotypes (1E and 1G) reported from Uganda in the earlier years were detected. In addition, none of the sequences were obtained after the introduction of the measles-rubella containing vaccine. The above highlight the need for continuous rubella virological surveillance to confirm interruption of endemic rubella genotype circulation.

Rubella virus-associated necrotizing neutrophilic granuloma in a patient with common variable immunodeficiency.

Patients with inborn errors of immunity (IEI) may develop granulomas in multiple organ systems including the skin. Vaccine strain rubella virus (RuV), part of the live attenuated measles, mumps, and rubella (MMR) vaccine, has been identified within these granulomas. RuV is typically found in macrophages; however, recently neutrophils have been identified as a novel cell type infected. Here, we present a case of RuV-associated cutaneous granuloma with RuV localized to neutrophils. A 46-year-old female with common variable immunodeficiency presented with verrucous papules and crusted plaques from the right knee to the distal shin of 20 years duration, associated with prior physical trauma. Biopsy specimen showed palisaded granulomas surrounding central necrosis with scattered aggregates of neutrophils. Vaccine-derived RuV was detected by molecular sequencing in lesional skin. Fluorescent immunohistochemistry with CD206, myeloperoxidase (MPO), and RV capsid (RVC) antibodies demonstrated that RuV localized to neutrophils but not macrophages. The clinical presentation, cutaneous findings, and likely presence of RVC-positive granulocytes in bone marrow provide potential support to the evolving hypothesis of persistent RuV within neutrophils contributing to chronic granulomatous inflammation in a milieu of immune dysregulation.